diff --git a/src/hb-blob.cc b/src/hb-blob.cc
index 41e99da..e390d75 100644
--- a/src/hb-blob.cc
+++ b/src/hb-blob.cc
@@ -72,8 +72,8 @@
 {
   if (blob->destroy) {
     blob->destroy (blob->user_data);
-    blob->user_data = NULL;
-    blob->destroy = NULL;
+    blob->user_data = nullptr;
+    blob->destroy = nullptr;
   }
 }
 
@@ -194,12 +194,12 @@
 
     true, /* immutable */
 
-    NULL, /* data */
+    nullptr, /* data */
     0, /* length */
     HB_MEMORY_MODE_READONLY, /* mode */
 
-    NULL, /* user_data */
-    NULL  /* destroy */
+    nullptr, /* user_data */
+    nullptr  /* destroy */
   };
 
   return const_cast<hb_blob_t *> (&_hb_blob_nil);
@@ -379,7 +379,7 @@
     if (length)
       *length = 0;
 
-    return NULL;
+    return nullptr;
   }
 
   if (length)
diff --git a/src/hb-buffer-serialize.cc b/src/hb-buffer-serialize.cc
index 517d746..ea62e9f 100644
--- a/src/hb-buffer-serialize.cc
+++ b/src/hb-buffer-serialize.cc
@@ -30,7 +30,7 @@
 static const char *serialize_formats[] = {
   "text",
   "json",
-  NULL
+  nullptr
 };
 
 /**
@@ -90,7 +90,7 @@
     case HB_BUFFER_SERIALIZE_FORMAT_TEXT:	return serialize_formats[0];
     case HB_BUFFER_SERIALIZE_FORMAT_JSON:	return serialize_formats[1];
     default:
-    case HB_BUFFER_SERIALIZE_FORMAT_INVALID:	return NULL;
+    case HB_BUFFER_SERIALIZE_FORMAT_INVALID:	return nullptr;
   }
 }
 
@@ -104,9 +104,9 @@
 				  hb_font_t *font,
 				  hb_buffer_serialize_flags_t flags)
 {
-  hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, NULL);
+  hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
   hb_glyph_position_t *pos = (flags & HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS) ?
-			     NULL : hb_buffer_get_glyph_positions (buffer, NULL);
+			     nullptr : hb_buffer_get_glyph_positions (buffer, nullptr);
 
   *buf_consumed = 0;
   for (unsigned int i = start; i < end; i++)
@@ -194,9 +194,9 @@
 				  hb_font_t *font,
 				  hb_buffer_serialize_flags_t flags)
 {
-  hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, NULL);
+  hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
   hb_glyph_position_t *pos = (flags & HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS) ?
-			     NULL : hb_buffer_get_glyph_positions (buffer, NULL);
+			     nullptr : hb_buffer_get_glyph_positions (buffer, nullptr);
 
   *buf_consumed = 0;
   for (unsigned int i = start; i < end; i++)
@@ -422,8 +422,8 @@
 hb_buffer_deserialize_glyphs (hb_buffer_t *buffer,
 			      const char *buf,
 			      int buf_len, /* -1 means nul-terminated */
-			      const char **end_ptr, /* May be NULL */
-			      hb_font_t *font, /* May be NULL */
+			      const char **end_ptr, /* May be nullptr */
+			      hb_font_t *font, /* May be nullptr */
 			      hb_buffer_serialize_format_t format)
 {
   const char *end;
diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 25b798b..73b3e4b 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -120,8 +120,8 @@
   }
 
   unsigned int new_allocated = allocated;
-  hb_glyph_position_t *new_pos = NULL;
-  hb_glyph_info_t *new_info = NULL;
+  hb_glyph_position_t *new_pos = nullptr;
+  hb_glyph_info_t *new_info = nullptr;
   bool separate_out = out_info != info;
 
   if (unlikely (_hb_unsigned_int_mul_overflows (size, sizeof (info[0]))))
@@ -1993,9 +1993,9 @@
     buffer->message_data = user_data;
     buffer->message_destroy = destroy;
   } else {
-    buffer->message_func = NULL;
-    buffer->message_data = NULL;
-    buffer->message_destroy = NULL;
+    buffer->message_func = nullptr;
+    buffer->message_data = nullptr;
+    buffer->message_destroy = nullptr;
   }
 }
 
diff --git a/src/hb-common.cc b/src/hb-common.cc
index 8e8e556..2f9b3b8 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -274,13 +274,13 @@
   /* Not found; allocate one. */
   hb_language_item_t *lang = (hb_language_item_t *) calloc (1, sizeof (hb_language_item_t));
   if (unlikely (!lang))
-    return NULL;
+    return nullptr;
   lang->next = first_lang;
   *lang = key;
   if (unlikely (!lang->lang))
   {
     free (lang);
-    return NULL;
+    return nullptr;
   }
 
   if (!hb_atomic_ptr_cmpexch (&langs, first_lang, lang)) {
@@ -318,7 +318,7 @@
   if (!str || !len || !*str)
     return HB_LANGUAGE_INVALID;
 
-  hb_language_item_t *item = NULL;
+  hb_language_item_t *item = nullptr;
   if (len >= 0)
   {
     /* NUL-terminate it. */
@@ -349,7 +349,7 @@
 const char *
 hb_language_to_string (hb_language_t language)
 {
-  /* This is actually NULL-safe! */
+  /* This is actually nullptr-safe! */
   return language->s;
 }
 
@@ -369,7 +369,7 @@
 
   hb_language_t language = (hb_language_t) hb_atomic_ptr_get (&default_language);
   if (unlikely (language == HB_LANGUAGE_INVALID)) {
-    language = hb_language_from_string (setlocale (LC_CTYPE, NULL), -1);
+    language = hb_language_from_string (setlocale (LC_CTYPE, nullptr), -1);
     (void) hb_atomic_ptr_cmpexch (&default_language, HB_LANGUAGE_INVALID, language);
   }
 
@@ -562,9 +562,9 @@
 void *
 hb_user_data_array_t::get (hb_user_data_key_t *key)
 {
-  hb_user_data_item_t item = {NULL, NULL, NULL};
+  hb_user_data_item_t item = {nullptr, nullptr, nullptr};
 
-  return items.find (key, &item, lock) ? item.data : NULL;
+  return items.find (key, &item, lock) ? item.data : nullptr;
 }
 
 
@@ -722,9 +722,9 @@
 
   if (unlikely (!C))
   {
-    C = newlocale (LC_ALL_MASK, "C", NULL);
+    C = newlocale (LC_ALL_MASK, "C", nullptr);
 
-    if (!hb_atomic_ptr_cmpexch (&C_locale, NULL, C))
+    if (!hb_atomic_ptr_cmpexch (&C_locale, nullptr, C))
     {
       freelocale (C_locale);
       goto retry;
diff --git a/src/hb-coretext.cc b/src/hb-coretext.cc
index 5697939..ca54833 100644
--- a/src/hb-coretext.cc
+++ b/src/hb-coretext.cc
@@ -65,12 +65,12 @@
   CGFontRef cg_font = reinterpret_cast<CGFontRef> (user_data);
   CFDataRef cf_data = CGFontCopyTableForTag (cg_font, tag);
   if (unlikely (!cf_data))
-    return NULL;
+    return nullptr;
 
   const char *data = reinterpret_cast<const char*> (CFDataGetBytePtr (cf_data));
   const size_t length = CFDataGetLength (cf_data);
   if (!data || !length)
-    return NULL;
+    return nullptr;
 
   return hb_blob_create (data, length, HB_MEMORY_MODE_READONLY,
 			 reinterpret_cast<void *> (const_cast<__CFData *> (cf_data)),
@@ -125,7 +125,7 @@
 release_data (void *info, const void *data, size_t size)
 {
   assert (hb_blob_get_length ((hb_blob_t *) info) == size &&
-          hb_blob_get_data ((hb_blob_t *) info, NULL) == data);
+          hb_blob_get_data ((hb_blob_t *) info, nullptr) == data);
 
   hb_blob_destroy ((hb_blob_t *) info);
 }
@@ -133,7 +133,7 @@
 static CGFontRef
 create_cg_font (hb_face_t *face)
 {
-  CGFontRef cg_font = NULL;
+  CGFontRef cg_font = nullptr;
   if (face->destroy == _hb_cg_font_release)
   {
     cg_font = CGFontRetain ((CGFontRef) face->user_data);
@@ -161,7 +161,7 @@
 static CTFontRef
 create_ct_font (CGFontRef cg_font, CGFloat font_size)
 {
-  CTFontRef ct_font = NULL;
+  CTFontRef ct_font = nullptr;
 
   /* CoreText does not enable trak table usage / tracking when creating a CTFont
    * using CTFontCreateWithGraphicsFont. The only way of enabling tracking seems
@@ -174,23 +174,23 @@
     if (CFStringHasSuffix (cg_postscript_name, CFSTR ("-Bold")))
       font_type = kCTFontUIFontEmphasizedSystem;
 
-    ct_font = CTFontCreateUIFontForLanguage (font_type, font_size, NULL);
+    ct_font = CTFontCreateUIFontForLanguage (font_type, font_size, nullptr);
     CFStringRef ct_result_name = CTFontCopyPostScriptName(ct_font);
     if (CFStringCompare (ct_result_name, cg_postscript_name, 0) != kCFCompareEqualTo)
     {
       CFRelease(ct_font);
-      ct_font = NULL;
+      ct_font = nullptr;
     }
     CFRelease (ct_result_name);
   }
   CFRelease (cg_postscript_name);
 
   if (!ct_font)
-    ct_font = CTFontCreateWithGraphicsFont (cg_font, font_size, NULL, NULL);
+    ct_font = CTFontCreateWithGraphicsFont (cg_font, font_size, nullptr, nullptr);
 
   if (unlikely (!ct_font)) {
     DEBUG_MSG (CORETEXT, cg_font, "Font CTFontCreateWithGraphicsFont() failed");
-    return NULL;
+    return nullptr;
   }
 
   /* crbug.com/576941 and crbug.com/625902 and the investigation in the latter
@@ -200,7 +200,7 @@
    * reconfiguring the cascade list causes CoreText crashes. For details, see
    * crbug.com/549610 */
   // 0x00070000 stands for "kCTVersionNumber10_10", see CoreText.h
-  if (&CTGetCoreTextVersion != NULL && CTGetCoreTextVersion() < 0x00070000) {
+  if (&CTGetCoreTextVersion != nullptr && CTGetCoreTextVersion() < 0x00070000) {
     CFStringRef fontName = CTFontCopyPostScriptName (ct_font);
     bool isEmojiFont = CFStringCompare (fontName, CFSTR("AppleColorEmoji"), 0) == kCFCompareEqualTo;
     CFRelease (fontName);
@@ -214,7 +214,7 @@
    * font fallback which we don't need anyway. */
   {
     CTFontDescriptorRef last_resort_font_desc = get_last_resort_font_desc ();
-    CTFontRef new_ct_font = CTFontCreateCopyWithAttributes (ct_font, 0.0, NULL, last_resort_font_desc);
+    CTFontRef new_ct_font = CTFontCreateCopyWithAttributes (ct_font, 0.0, nullptr, last_resort_font_desc);
     CFRelease (last_resort_font_desc);
     if (new_ct_font)
     {
@@ -257,7 +257,7 @@
   if (unlikely (!cg_font))
   {
     DEBUG_MSG (CORETEXT, face, "CGFont creation failed..");
-    return NULL;
+    return nullptr;
   }
 
   return (hb_coretext_shaper_face_data_t *) cg_font;
@@ -275,7 +275,7 @@
 CGFontRef
 hb_coretext_face_get_cg_font (hb_face_t *face)
 {
-  if (unlikely (!hb_coretext_shaper_face_data_ensure (face))) return NULL;
+  if (unlikely (!hb_coretext_shaper_face_data_ensure (face))) return nullptr;
   return (CGFontRef) HB_SHAPER_DATA_GET (face);
 }
 
@@ -288,7 +288,7 @@
 _hb_coretext_shaper_font_data_create (hb_font_t *font)
 {
   hb_face_t *face = font->face;
-  if (unlikely (!hb_coretext_shaper_face_data_ensure (face))) return NULL;
+  if (unlikely (!hb_coretext_shaper_face_data_ensure (face))) return nullptr;
   CGFontRef cg_font = (CGFontRef) HB_SHAPER_DATA_GET (face);
 
   CTFontRef ct_font = create_ct_font (cg_font, coretext_font_size (font->ptem));
@@ -296,7 +296,7 @@
   if (unlikely (!ct_font))
   {
     DEBUG_MSG (CORETEXT, font, "CGFont creation failed..");
-    return NULL;
+    return nullptr;
   }
 
   return (hb_coretext_shaper_font_data_t *) ct_font;
@@ -333,7 +333,7 @@
 CTFontRef
 hb_coretext_font_get_ct_font (hb_font_t *font)
 {
-  if (unlikely (!hb_coretext_shaper_font_data_ensure (font))) return NULL;
+  if (unlikely (!hb_coretext_shaper_font_data_ensure (font))) return nullptr;
   return (CTFontRef)HB_SHAPER_DATA_GET (font);
 }
 
@@ -704,12 +704,12 @@
 	  CTFontDescriptorRef font_desc = CTFontDescriptorCreateWithAttributes (attributes);
 	  CFRelease (attributes);
 
-	  range->font = CTFontCreateCopyWithAttributes (ct_font, 0.0, NULL, font_desc);
+	  range->font = CTFontCreateCopyWithAttributes (ct_font, 0.0, nullptr, font_desc);
 	  CFRelease (font_desc);
 	}
 	else
 	{
-	  range->font = NULL;
+	  range->font = nullptr;
 	}
 
 	range->index_first = last_index;
@@ -779,14 +779,14 @@
 
 #define FAIL(...) \
   HB_STMT_START { \
-    DEBUG_MSG (CORETEXT, NULL, __VA_ARGS__); \
+    DEBUG_MSG (CORETEXT, nullptr, __VA_ARGS__); \
     ret = false; \
     goto fail; \
   } HB_STMT_END;
 
   bool ret = true;
-  CFStringRef string_ref = NULL;
-  CTLineRef line = NULL;
+  CFStringRef string_ref = nullptr;
+  CTLineRef line = nullptr;
 
   if (0)
   {
@@ -798,8 +798,8 @@
     assert (line);
     CFRelease (string_ref);
     CFRelease (line);
-    string_ref = NULL;
-    line = NULL;
+    string_ref = nullptr;
+    line = nullptr;
 
     /* Get previous start-of-scratch-area, that we use later for readjusting
      * our existing scratch arrays. */
@@ -820,7 +820,7 @@
     scratch_size -= old_scratch_used;
   }
   {
-    string_ref = CFStringCreateWithCharactersNoCopy (NULL,
+    string_ref = CFStringCreateWithCharactersNoCopy (nullptr,
 						     pchars, chars_len,
 						     kCFAllocatorNull);
     if (unlikely (!string_ref))
@@ -937,7 +937,7 @@
 
     CFArrayRef glyph_runs = CTLineGetGlyphRuns (line);
     unsigned int num_runs = CFArrayGetCount (glyph_runs);
-    DEBUG_MSG (CORETEXT, NULL, "Num runs: %d", num_runs);
+    DEBUG_MSG (CORETEXT, nullptr, "Num runs: %d", num_runs);
 
     buffer->len = 0;
     uint32_t status_and = ~0, status_or = 0;
@@ -963,7 +963,7 @@
       status_or  |= run_status;
       status_and &= run_status;
       DEBUG_MSG (CORETEXT, run, "CTRunStatus: %x", run_status);
-      double run_advance = CTRunGetTypographicBounds (run, range_all, NULL, NULL, NULL);
+      double run_advance = CTRunGetTypographicBounds (run, range_all, nullptr, nullptr, nullptr);
       if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
 	  run_advance = -run_advance;
       DEBUG_MSG (CORETEXT, run, "Run advance: %g", run_advance);
@@ -1089,7 +1089,7 @@
 
       /* Testing used to indicate that CTRunGetGlyphsPtr, etc (almost?) always
        * succeed, and so copying data to our own buffer will be rare.  Reports
-       * have it that this changed in OS X 10.10 Yosemite, and NULL is returned
+       * have it that this changed in OS X 10.10 Yosemite, and nullptr is returned
        * frequently.  At any rate, we can test that codepath by setting USE_PTR
        * to false. */
 
@@ -1105,13 +1105,13 @@
 
       { /* Setup glyphs */
         SCRATCH_SAVE();
-	const CGGlyph* glyphs = USE_PTR ? CTRunGetGlyphsPtr (run) : NULL;
+	const CGGlyph* glyphs = USE_PTR ? CTRunGetGlyphsPtr (run) : nullptr;
 	if (!glyphs) {
 	  ALLOCATE_ARRAY (CGGlyph, glyph_buf, num_glyphs, goto resize_and_retry);
 	  CTRunGetGlyphs (run, range_all, glyph_buf);
 	  glyphs = glyph_buf;
 	}
-	const CFIndex* string_indices = USE_PTR ? CTRunGetStringIndicesPtr (run) : NULL;
+	const CFIndex* string_indices = USE_PTR ? CTRunGetStringIndicesPtr (run) : nullptr;
 	if (!string_indices) {
 	  ALLOCATE_ARRAY (CFIndex, index_buf, num_glyphs, goto resize_and_retry);
 	  CTRunGetStringIndices (run, range_all, index_buf);
@@ -1133,7 +1133,7 @@
 	 * advance (in the advance direction only), and for last glyph we set
 	 * whatever is needed to make the whole run's advance add up. */
         SCRATCH_SAVE();
-	const CGPoint* positions = USE_PTR ? CTRunGetPositionsPtr (run) : NULL;
+	const CGPoint* positions = USE_PTR ? CTRunGetPositionsPtr (run) : nullptr;
 	if (!positions) {
 	  ALLOCATE_ARRAY (CGPoint, position_buf, num_glyphs, goto resize_and_retry);
 	  CTRunGetPositions (run, range_all, position_buf);
@@ -1300,12 +1300,12 @@
     if (hb_blob_get_length (blob))
     {
       hb_blob_destroy (blob);
-      return hb_coretext_shaper_face_data_ensure (face) ? (hb_coretext_aat_shaper_face_data_t *) HB_SHAPER_DATA_SUCCEEDED : NULL;
+      return hb_coretext_shaper_face_data_ensure (face) ? (hb_coretext_aat_shaper_face_data_t *) HB_SHAPER_DATA_SUCCEEDED : nullptr;
     }
     hb_blob_destroy (blob);
   }
 
-  return NULL;
+  return nullptr;
 }
 
 void
@@ -1323,7 +1323,7 @@
 hb_coretext_aat_shaper_font_data_t *
 _hb_coretext_aat_shaper_font_data_create (hb_font_t *font)
 {
-  return hb_coretext_shaper_font_data_ensure (font) ? (hb_coretext_aat_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED : NULL;
+  return hb_coretext_shaper_font_data_ensure (font) ? (hb_coretext_aat_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED : nullptr;
 }
 
 void
diff --git a/src/hb-directwrite.cc b/src/hb-directwrite.cc
index 14df822..a6693ef 100644
--- a/src/hb-directwrite.cc
+++ b/src/hb-directwrite.cc
@@ -140,7 +140,7 @@
   hb_directwrite_shaper_face_data_t *data =
     (hb_directwrite_shaper_face_data_t *) malloc (sizeof (hb_directwrite_shaper_face_data_t));
   if (unlikely (!data))
-    return NULL;
+    return nullptr;
 
   // TODO: factory and fontFileLoader should be cached separately
   IDWriteFactory* dwriteFactory;
@@ -153,7 +153,7 @@
   HRESULT hr;
   hb_blob_t *blob = hb_face_reference_blob (face);
   IDWriteFontFileStream *fontFileStream = new DWriteFontFileStream (
-    (uint8_t*) hb_blob_get_data (blob, NULL), hb_blob_get_length (blob));
+    (uint8_t*) hb_blob_get_data (blob, nullptr), hb_blob_get_length (blob));
 
   IDWriteFontFileLoader *fontFileLoader = new DWriteFontFileLoader (fontFileStream);
   dwriteFactory->RegisterFontFileLoader (fontFileLoader);
@@ -165,7 +165,7 @@
 
 #define FAIL(...) \
   HB_STMT_START { \
-    DEBUG_MSG (DIRECTWRITE, NULL, __VA_ARGS__); \
+    DEBUG_MSG (DIRECTWRITE, nullptr, __VA_ARGS__); \
     return false; \
   } HB_STMT_END;
 
@@ -233,12 +233,12 @@
 hb_directwrite_shaper_font_data_t *
 _hb_directwrite_shaper_font_data_create (hb_font_t *font)
 {
-  if (unlikely (!hb_directwrite_shaper_face_data_ensure (font->face))) return NULL;
+  if (unlikely (!hb_directwrite_shaper_face_data_ensure (font->face))) return nullptr;
 
   hb_directwrite_shaper_font_data_t *data =
     (hb_directwrite_shaper_font_data_t *) malloc (sizeof (hb_directwrite_shaper_font_data_t));
   if (unlikely (!data))
-    return NULL;
+    return nullptr;
 
   return data;
 }
@@ -313,7 +313,7 @@
     , mTextLength(textLength)
     , mLocaleName(localeName)
     , mReadingDirection(readingDirection)
-    , mCurrentRun(NULL) { };
+    , mCurrentRun(nullptr) { };
 
   ~TextAnalysis() {
     // delete runs, except mRunHead which is part of the TextAnalysis object
@@ -337,7 +337,7 @@
     mRunHead.mTextLength = mTextLength;
     mRunHead.mBidiLevel =
       (mReadingDirection == DWRITE_READING_DIRECTION_RIGHT_TO_LEFT);
-    mRunHead.nextRun = NULL;
+    mRunHead.nextRun = nullptr;
     mCurrentRun = &mRunHead;
 
     // Call each of the analyzers in sequence, recording their results.
@@ -356,7 +356,7 @@
   {
     if (textPosition >= mTextLength) {
       // No text at this position, valid query though.
-      *textString = NULL;
+      *textString = nullptr;
       *textLength = 0;
     }
     else {
@@ -373,7 +373,7 @@
     if (textPosition == 0 || textPosition > mTextLength) {
       // Either there is no text before here (== 0), or this
       // is an invalid position. The query is considered valid thouh.
-      *textString = NULL;
+      *textString = nullptr;
       *textLength = 0;
     }
     else {
@@ -399,7 +399,7 @@
     OUT IDWriteNumberSubstitution** numberSubstitution)
   {
     // We do not support number substitution.
-    *numberSubstitution = NULL;
+    *numberSubstitution = nullptr;
     *textLength = mTextLength - textPosition;
 
     return S_OK;
@@ -617,14 +617,14 @@
   */
   uint32_t textLength = buffer->len;
 
-  TextAnalysis analysis(textString, textLength, NULL, readingDirection);
+  TextAnalysis analysis(textString, textLength, nullptr, readingDirection);
   TextAnalysis::Run *runHead;
   HRESULT hr;
   hr = analysis.GenerateResults(analyzer, &runHead);
 
 #define FAIL(...) \
   HB_STMT_START { \
-    DEBUG_MSG (DIRECTWRITE, NULL, __VA_ARGS__); \
+    DEBUG_MSG (DIRECTWRITE, nullptr, __VA_ARGS__); \
     return false; \
   } HB_STMT_END;
 
@@ -639,7 +639,7 @@
   bool isRightToLeft = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);
 
   const wchar_t localeName[20] = {0};
-  if (buffer->props.language != NULL)
+  if (buffer->props.language != nullptr)
   {
     mbstowcs ((wchar_t*) localeName,
       hb_language_to_string (buffer->props.language), 20);
@@ -672,7 +672,7 @@
     malloc (maxGlyphCount * sizeof (DWRITE_SHAPING_GLYPH_PROPERTIES));
 
   hr = analyzer->GetGlyphs (textString, textLength, fontFace, false,
-    isRightToLeft, &runHead->mScript, localeName, NULL, &dwFeatures,
+    isRightToLeft, &runHead->mScript, localeName, nullptr, &dwFeatures,
     featureRangeLengths, 1, maxGlyphCount, clusterMap, textProperties, glyphIndices,
     glyphProperties, &glyphCount);
 
diff --git a/src/hb-face.cc b/src/hb-face.cc
index e96c8ac..26fddbe 100644
--- a/src/hb-face.cc
+++ b/src/hb-face.cc
@@ -43,9 +43,9 @@
 
   true, /* immutable */
 
-  NULL, /* reference_table_func */
-  NULL, /* user_data */
-  NULL, /* destroy */
+  nullptr, /* reference_table_func */
+  nullptr, /* user_data */
+  nullptr, /* destroy */
 
   0,    /* index */
   1000, /* upem */
@@ -57,7 +57,7 @@
 #undef HB_SHAPER_IMPLEMENT
   },
 
-  NULL, /* shape_plans */
+  nullptr, /* shape_plans */
 };
 
 
@@ -109,7 +109,7 @@
 
   closure = (hb_face_for_data_closure_t *) calloc (1, sizeof (hb_face_for_data_closure_t));
   if (unlikely (!closure))
-    return NULL;
+    return nullptr;
 
   closure->blob = blob;
   closure->index = index;
diff --git a/src/hb-font.cc b/src/hb-font.cc
index 5673e66..c03917e 100644
--- a/src/hb-font.cc
+++ b/src/hb-font.cc
@@ -347,12 +347,12 @@
   true, /* immutable */
 
   {
-#define HB_FONT_FUNC_IMPLEMENT(name) NULL,
+#define HB_FONT_FUNC_IMPLEMENT(name) nullptr,
     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_FONT_FUNC_IMPLEMENT
   },
   {
-#define HB_FONT_FUNC_IMPLEMENT(name) NULL,
+#define HB_FONT_FUNC_IMPLEMENT(name) nullptr,
     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_FONT_FUNC_IMPLEMENT
   },
@@ -370,12 +370,12 @@
   true, /* immutable */
 
   {
-#define HB_FONT_FUNC_IMPLEMENT(name) NULL,
+#define HB_FONT_FUNC_IMPLEMENT(name) nullptr,
     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_FONT_FUNC_IMPLEMENT
   },
   {
-#define HB_FONT_FUNC_IMPLEMENT(name) NULL,
+#define HB_FONT_FUNC_IMPLEMENT(name) nullptr,
     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_FONT_FUNC_IMPLEMENT
   },
@@ -563,8 +563,8 @@
     ffuncs->destroy.name = destroy;                                      \
   } else {                                                               \
     ffuncs->get.f.name = hb_font_get_##name##_parent;                    \
-    ffuncs->user_data.name = NULL;                                       \
-    ffuncs->destroy.name = NULL;                                         \
+    ffuncs->user_data.name = nullptr;                                       \
+    ffuncs->destroy.name = nullptr;                                         \
   }                                                                      \
 }
 
@@ -1161,7 +1161,7 @@
 
   font->num_coords = parent->num_coords;
   if (!font->num_coords)
-    font->coords = NULL;
+    font->coords = nullptr;
   else
   {
     unsigned int size = parent->num_coords * sizeof (parent->coords[0]);
@@ -1192,7 +1192,7 @@
 
     true, /* immutable */
 
-    NULL, /* parent */
+    nullptr, /* parent */
     const_cast<hb_face_t *> (&_hb_face_nil),
 
     1000, /* x_scale */
@@ -1203,11 +1203,11 @@
     0, /* ptem */
 
     0, /* num_coords */
-    NULL, /* coords */
+    nullptr, /* coords */
 
     const_cast<hb_font_funcs_t *> (&_hb_font_funcs_nil), /* klass */
-    NULL, /* user_data */
-    NULL, /* destroy */
+    nullptr, /* user_data */
+    nullptr, /* destroy */
 
     {
 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_INVALID,
@@ -1639,13 +1639,13 @@
 
   if (!variations_length)
   {
-    hb_font_set_var_coords_normalized (font, NULL, 0);
+    hb_font_set_var_coords_normalized (font, nullptr, 0);
     return;
   }
 
   unsigned int coords_length = hb_ot_var_get_axis_count (font->face);
 
-  int *normalized = coords_length ? (int *) calloc (coords_length, sizeof (int)) : NULL;
+  int *normalized = coords_length ? (int *) calloc (coords_length, sizeof (int)) : nullptr;
   if (unlikely (coords_length && !normalized))
     return;
 
@@ -1668,7 +1668,7 @@
   if (font->immutable)
     return;
 
-  int *normalized = coords_length ? (int *) calloc (coords_length, sizeof (int)) : NULL;
+  int *normalized = coords_length ? (int *) calloc (coords_length, sizeof (int)) : nullptr;
   if (unlikely (coords_length && !normalized))
     return;
 
@@ -1689,7 +1689,7 @@
   if (font->immutable)
     return;
 
-  int *copy = coords_length ? (int *) calloc (coords_length, sizeof (coords[0])) : NULL;
+  int *copy = coords_length ? (int *) calloc (coords_length, sizeof (coords[0])) : nullptr;
   if (unlikely (coords_length && !copy))
     return;
 
@@ -1749,7 +1749,7 @@
   trampoline_t *trampoline = (trampoline_t *) calloc (1, sizeof (trampoline_t));
 
   if (unlikely (!trampoline))
-    return NULL;
+    return nullptr;
 
   trampoline->closure.user_data = user_data;
   trampoline->closure.destroy = destroy;
diff --git a/src/hb-ft.cc b/src/hb-ft.cc
index 83af994..6036f30 100644
--- a/src/hb-ft.cc
+++ b/src/hb-ft.cc
@@ -83,7 +83,7 @@
   hb_ft_font_t *ft_font = (hb_ft_font_t *) calloc (1, sizeof (hb_ft_font_t));
 
   if (unlikely (!ft_font))
-    return NULL;
+    return nullptr;
 
   ft_font->ft_face = ft_face;
   ft_font->symbol = symbol;
@@ -158,7 +158,7 @@
 hb_ft_font_get_face (hb_font_t *font)
 {
   if (font->destroy != _hb_ft_font_destroy)
-    return NULL;
+    return nullptr;
 
   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;
 
@@ -424,7 +424,7 @@
   return true;
 }
 
-static hb_font_funcs_t *static_ft_funcs = NULL;
+static hb_font_funcs_t *static_ft_funcs = nullptr;
 
 #ifdef HB_USE_ATEXIT
 static
@@ -444,24 +444,24 @@
   {
     funcs = hb_font_funcs_create ();
 
-    hb_font_funcs_set_font_h_extents_func (funcs, hb_ft_get_font_h_extents, NULL, NULL);
-    //hb_font_funcs_set_font_v_extents_func (funcs, hb_ft_get_font_v_extents, NULL, NULL);
-    hb_font_funcs_set_nominal_glyph_func (funcs, hb_ft_get_nominal_glyph, NULL, NULL);
-    hb_font_funcs_set_variation_glyph_func (funcs, hb_ft_get_variation_glyph, NULL, NULL);
-    hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ft_get_glyph_h_advance, NULL, NULL);
-    hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ft_get_glyph_v_advance, NULL, NULL);
-    //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ft_get_glyph_h_origin, NULL, NULL);
-    hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ft_get_glyph_v_origin, NULL, NULL);
-    hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ft_get_glyph_h_kerning, NULL, NULL);
-    //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ft_get_glyph_v_kerning, NULL, NULL);
-    hb_font_funcs_set_glyph_extents_func (funcs, hb_ft_get_glyph_extents, NULL, NULL);
-    hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ft_get_glyph_contour_point, NULL, NULL);
-    hb_font_funcs_set_glyph_name_func (funcs, hb_ft_get_glyph_name, NULL, NULL);
-    hb_font_funcs_set_glyph_from_name_func (funcs, hb_ft_get_glyph_from_name, NULL, NULL);
+    hb_font_funcs_set_font_h_extents_func (funcs, hb_ft_get_font_h_extents, nullptr, nullptr);
+    //hb_font_funcs_set_font_v_extents_func (funcs, hb_ft_get_font_v_extents, nullptr, nullptr);
+    hb_font_funcs_set_nominal_glyph_func (funcs, hb_ft_get_nominal_glyph, nullptr, nullptr);
+    hb_font_funcs_set_variation_glyph_func (funcs, hb_ft_get_variation_glyph, nullptr, nullptr);
+    hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ft_get_glyph_h_advance, nullptr, nullptr);
+    hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ft_get_glyph_v_advance, nullptr, nullptr);
+    //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ft_get_glyph_h_origin, nullptr, nullptr);
+    hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ft_get_glyph_v_origin, nullptr, nullptr);
+    hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ft_get_glyph_h_kerning, nullptr, nullptr);
+    //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ft_get_glyph_v_kerning, nullptr, nullptr);
+    hb_font_funcs_set_glyph_extents_func (funcs, hb_ft_get_glyph_extents, nullptr, nullptr);
+    hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ft_get_glyph_contour_point, nullptr, nullptr);
+    hb_font_funcs_set_glyph_name_func (funcs, hb_ft_get_glyph_name, nullptr, nullptr);
+    hb_font_funcs_set_glyph_from_name_func (funcs, hb_ft_get_glyph_from_name, nullptr, nullptr);
 
     hb_font_funcs_make_immutable (funcs);
 
-    if (!hb_atomic_ptr_cmpexch (&static_ft_funcs, NULL, funcs)) {
+    if (!hb_atomic_ptr_cmpexch (&static_ft_funcs, nullptr, funcs)) {
       hb_font_funcs_destroy (funcs);
       goto retry;
     }
@@ -490,17 +490,17 @@
 
   /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */
 
-  error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);
+  error = FT_Load_Sfnt_Table (ft_face, tag, 0, nullptr, &length);
   if (error)
-    return NULL;
+    return nullptr;
 
   buffer = (FT_Byte *) malloc (length);
   if (!buffer)
-    return NULL;
+    return nullptr;
 
   error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
   if (error)
-    return NULL;
+    return nullptr;
 
   return hb_blob_create ((const char *) buffer, length,
 			 HB_MEMORY_MODE_WRITABLE,
@@ -581,7 +581,7 @@
     if (ft_face->generic.finalizer)
       ft_face->generic.finalizer (ft_face);
 
-    ft_face->generic.data = hb_ft_face_create (ft_face, NULL);
+    ft_face->generic.data = hb_ft_face_create (ft_face, nullptr);
     ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;
   }
 
@@ -633,7 +633,7 @@
 #endif
 
 #ifdef HAVE_FT_GET_VAR_BLEND_COORDINATES
-  FT_MM_Var *mm_var = NULL;
+  FT_MM_Var *mm_var = nullptr;
   if (!FT_Get_MM_Var (ft_face, &mm_var))
   {
     FT_Fixed *ft_coords = (FT_Fixed *) calloc (mm_var->num_axis, sizeof (FT_Fixed));
@@ -694,9 +694,9 @@
   {
     /* Not found; allocate one. */
     if (FT_Init_FreeType (&library))
-      return NULL;
+      return nullptr;
 
-    if (!hb_atomic_ptr_cmpexch (&ft_library, NULL, library)) {
+    if (!hb_atomic_ptr_cmpexch (&ft_library, nullptr, library)) {
       FT_Done_FreeType (library);
       goto retry;
     }
@@ -724,7 +724,7 @@
   if (unlikely (!blob_length))
     DEBUG_MSG (FT, font, "Font face has empty blob");
 
-  FT_Face ft_face = NULL;
+  FT_Face ft_face = nullptr;
   FT_Error err = FT_New_Memory_Face (get_ft_library (),
 				     (const FT_Byte *) blob_data,
 				     blob_length,
@@ -751,7 +751,7 @@
   {
     FT_Matrix matrix = { font->x_scale < 0 ? -1 : +1, 0,
 			  0, font->y_scale < 0 ? -1 : +1};
-    FT_Set_Transform (ft_face, &matrix, NULL);
+    FT_Set_Transform (ft_face, &matrix, nullptr);
   }
 
   unsigned int num_coords;
diff --git a/src/hb-glib.cc b/src/hb-glib.cc
index 8b49955..5b0a1eb 100644
--- a/src/hb-glib.cc
+++ b/src/hb-glib.cc
@@ -370,7 +370,7 @@
   static const hb_unicode_funcs_t _hb_glib_unicode_funcs = {
     HB_OBJECT_HEADER_STATIC,
 
-    NULL, /* parent */
+    nullptr, /* parent */
     true, /* immutable */
     {
 #define HB_UNICODE_FUNC_IMPLEMENT(name) hb_glib_unicode_##name,
diff --git a/src/hb-gobject-structs.cc b/src/hb-gobject-structs.cc
index fef0024..a96c358 100644
--- a/src/hb-gobject-structs.cc
+++ b/src/hb-gobject-structs.cc
@@ -58,7 +58,7 @@
 	static hb_##name##_t *_hb_##name##_reference (const hb_##name##_t *l) \
 	{ \
 	  hb_##name##_t *c = (hb_##name##_t *) calloc (1, sizeof (hb_##name##_t)); \
-	  if (unlikely (!c)) return NULL; \
+	  if (unlikely (!c)) return nullptr; \
 	  *c = *l; \
 	  return c; \
 	} \
diff --git a/src/hb-graphite2.cc b/src/hb-graphite2.cc
index bc247c6..6f0598d 100644
--- a/src/hb-graphite2.cc
+++ b/src/hb-graphite2.cc
@@ -59,7 +59,7 @@
   hb_graphite2_shaper_face_data_t *face_data = (hb_graphite2_shaper_face_data_t *) data;
   hb_graphite2_tablelist_t *tlist = face_data->tlist;
 
-  hb_blob_t *blob = NULL;
+  hb_blob_t *blob = nullptr;
 
   for (hb_graphite2_tablelist_t *p = tlist; p; p = p->next)
     if (p->tag == tag) {
@@ -74,7 +74,7 @@
     hb_graphite2_tablelist_t *p = (hb_graphite2_tablelist_t *) calloc (1, sizeof (hb_graphite2_tablelist_t));
     if (unlikely (!p)) {
       hb_blob_destroy (blob);
-      return NULL;
+      return nullptr;
     }
     p->blob = blob;
     p->tag = tag;
@@ -100,20 +100,20 @@
   if (!hb_blob_get_length (silf_blob))
   {
     hb_blob_destroy (silf_blob);
-    return NULL;
+    return nullptr;
   }
   hb_blob_destroy (silf_blob);
 
   hb_graphite2_shaper_face_data_t *data = (hb_graphite2_shaper_face_data_t *) calloc (1, sizeof (hb_graphite2_shaper_face_data_t));
   if (unlikely (!data))
-    return NULL;
+    return nullptr;
 
   data->face = face;
   data->grface = gr_make_face (data, &hb_graphite2_get_table, gr_face_preloadAll);
 
   if (unlikely (!data->grface)) {
     free (data);
-    return NULL;
+    return nullptr;
   }
 
   return data;
@@ -143,7 +143,7 @@
 gr_face *
 hb_graphite2_face_get_gr_face (hb_face_t *face)
 {
-  if (unlikely (!hb_graphite2_shaper_face_data_ensure (face))) return NULL;
+  if (unlikely (!hb_graphite2_shaper_face_data_ensure (face))) return nullptr;
   return HB_SHAPER_DATA_GET (face)->grface;
 }
 
@@ -171,7 +171,7 @@
 gr_font *
 hb_graphite2_font_get_gr_font (hb_font_t *font)
 {
-  return NULL;
+  return nullptr;
 }
 
 
@@ -221,7 +221,7 @@
   gr_face *grface = HB_SHAPER_DATA_GET (face)->grface;
 
   const char *lang = hb_language_to_string (hb_buffer_get_language (buffer));
-  const char *lang_end = lang ? strchr (lang, '-') : NULL;
+  const char *lang_end = lang ? strchr (lang, '-') : nullptr;
   int lang_len = lang_end ? lang_end - lang : -1;
   gr_feature_val *feats = gr_face_featureval_for_lang (grface, lang ? hb_tag_from_string (lang, lang_len) : 0);
 
@@ -232,7 +232,7 @@
       gr_fref_set_feature_value (fref, features[i].value, feats);
   }
 
-  gr_segment *seg = NULL;
+  gr_segment *seg = nullptr;
   const gr_slot *is;
   unsigned int ci = 0, ic = 0;
   float curradvx = 0., curradvy = 0.;
@@ -250,7 +250,7 @@
   hb_tag_t script_tag[2];
   hb_ot_tags_from_script (hb_buffer_get_script (buffer), &script_tag[0], &script_tag[1]);
 
-  seg = gr_make_seg (NULL, grface,
+  seg = gr_make_seg (nullptr, grface,
 		     script_tag[1] == HB_TAG_NONE ? script_tag[0] : script_tag[1],
 		     feats,
 		     gr_utf32, chars, buffer->len,
@@ -368,7 +368,7 @@
   /* Positioning. */
   unsigned int currclus = (unsigned int) -1;
   const hb_glyph_info_t *info = buffer->info;
-  hb_glyph_position_t *pPos = hb_buffer_get_glyph_positions (buffer, NULL);
+  hb_glyph_position_t *pPos = hb_buffer_get_glyph_positions (buffer, nullptr);
   if (!HB_DIRECTION_IS_BACKWARD(buffer->props.direction))
   {
     curradvx = 0;
@@ -383,7 +383,7 @@
       } else
         pPos->x_advance = 0.;
 
-      pPos->y_advance = gr_slot_advance_Y (is, grface, NULL) * yscale;
+      pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;
       curradvy += pPos->y_advance;
     }
   }
@@ -400,7 +400,7 @@
       } else
         pPos->x_advance = 0.;
 
-      pPos->y_advance = gr_slot_advance_Y (is, grface, NULL) * yscale;
+      pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;
       curradvy -= pPos->y_advance;
       pPos->x_offset = (gr_slot_origin_X (is) - info->var1.i32) * xscale - curradvx + pPos->x_advance;
       pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;
diff --git a/src/hb-icu.cc b/src/hb-icu.cc
index ee54721..ce179e3 100644
--- a/src/hb-icu.cc
+++ b/src/hb-icu.cc
@@ -351,7 +351,7 @@
   static const hb_unicode_funcs_t _hb_icu_unicode_funcs = {
     HB_OBJECT_HEADER_STATIC,
 
-    NULL, /* parent */
+    nullptr, /* parent */
     true, /* immutable */
     {
 #define HB_UNICODE_FUNC_IMPLEMENT(name) hb_icu_unicode_##name,
@@ -364,7 +364,7 @@
   if (!hb_atomic_ptr_get (&normalizer)) {
     UErrorCode icu_err = U_ZERO_ERROR;
     /* We ignore failure in getNFCInstace(). */
-    (void) hb_atomic_ptr_cmpexch (&normalizer, NULL, unorm2_getNFCInstance (&icu_err));
+    (void) hb_atomic_ptr_cmpexch (&normalizer, nullptr, unorm2_getNFCInstance (&icu_err));
   }
 #endif
   return const_cast<hb_unicode_funcs_t *> (&_hb_icu_unicode_funcs);
diff --git a/src/hb-mutex-private.hh b/src/hb-mutex-private.hh
index ed27035..49ed10e 100644
--- a/src/hb-mutex-private.hh
+++ b/src/hb-mutex-private.hh
@@ -68,7 +68,7 @@
 #include <pthread.h>
 typedef pthread_mutex_t hb_mutex_impl_t;
 #define HB_MUTEX_IMPL_INIT	PTHREAD_MUTEX_INITIALIZER
-#define hb_mutex_impl_init(M)	pthread_mutex_init (M, NULL)
+#define hb_mutex_impl_init(M)	pthread_mutex_init (M, nullptr)
 #define hb_mutex_impl_lock(M)	pthread_mutex_lock (M)
 #define hb_mutex_impl_unlock(M)	pthread_mutex_unlock (M)
 #define hb_mutex_impl_finish(M)	pthread_mutex_destroy (M)
diff --git a/src/hb-object-private.hh b/src/hb-object-private.hh
index 6b73ff9..d678ae3 100644
--- a/src/hb-object-private.hh
+++ b/src/hb-object-private.hh
@@ -193,7 +193,7 @@
 					     hb_user_data_key_t *key)
 {
   if (unlikely (!obj || hb_object_is_inert (obj)))
-    return NULL;
+    return nullptr;
   assert (hb_object_is_valid (obj));
   return obj->header.user_data.get (key);
 }
diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index 9cd482a..bed5eea 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -192,9 +192,9 @@
 {
   inline hb_sanitize_context_t (void) :
 	debug_depth (0),
-	start (NULL), end (NULL),
+	start (nullptr), end (nullptr),
 	writable (false), edit_count (0),
-	blob (NULL) {}
+	blob (nullptr) {}
 
   inline const char *get_name (void) { return "SANITIZE"; }
   template <typename T, typename F>
@@ -214,7 +214,7 @@
 
   inline void start_processing (void)
   {
-    this->start = hb_blob_get_data (this->blob, NULL);
+    this->start = hb_blob_get_data (this->blob, nullptr);
     this->end = this->start + hb_blob_get_length (this->blob);
     assert (this->start <= this->end); /* Must not overflow. */
     this->edit_count = 0;
@@ -233,8 +233,8 @@
 		     this->start, this->end, this->edit_count);
 
     hb_blob_destroy (this->blob);
-    this->blob = NULL;
-    this->start = this->end = NULL;
+    this->blob = nullptr;
+    this->start = this->end = nullptr;
   }
 
   inline bool check_range (const void *base, unsigned int len) const
@@ -349,7 +349,7 @@
     } else {
       unsigned int edit_count = c->edit_count;
       if (edit_count && !c->writable) {
-        c->start = hb_blob_get_data_writable (blob, NULL);
+        c->start = hb_blob_get_data_writable (blob, nullptr);
 	c->end = c->start + hb_blob_get_length (blob);
 
 	if (c->start) {
@@ -374,7 +374,7 @@
 
   static const Type* lock_instance (hb_blob_t *blob) {
     hb_blob_make_immutable (blob);
-    const char *base = hb_blob_get_data (blob, NULL);
+    const char *base = hb_blob_get_data (blob, nullptr);
     return unlikely (!base) ? &Null(Type) : CastP<Type> (base);
   }
 };
@@ -445,7 +445,7 @@
   {
     if (unlikely (this->ran_out_of_room || this->end - this->head < ptrdiff_t (size))) {
       this->ran_out_of_room = true;
-      return NULL;
+      return nullptr;
     }
     memset (this->head, 0, size);
     char *ret = this->head;
@@ -471,7 +471,7 @@
   {
     unsigned int size = obj.get_size ();
     Type *ret = this->allocate_size<Type> (size);
-    if (unlikely (!ret)) return NULL;
+    if (unlikely (!ret)) return nullptr;
     memcpy (ret, obj, size);
     return ret;
   }
@@ -481,7 +481,7 @@
   {
     unsigned int size = obj.min_size;
     assert (this->start <= (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
-    if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;
+    if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return nullptr;
     return reinterpret_cast<Type *> (&obj);
   }
 
@@ -490,7 +490,7 @@
   {
     unsigned int size = obj.get_size ();
     assert (this->start < (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
-    if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;
+    if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return nullptr;
     return reinterpret_cast<Type *> (&obj);
   }
 
@@ -1073,7 +1073,7 @@
   inline void init (hb_face_t *face_)
   {
     face = face_;
-    instance = NULL;
+    instance = nullptr;
   }
 
   inline void fini (void)
@@ -1096,7 +1096,7 @@
         p = const_cast<T *> (&OT::Null(T));
       else
 	p->init (face);
-      if (unlikely (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), NULL, p)))
+      if (unlikely (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), nullptr, p)))
       {
 	if (p != &OT::Null(T))
 	  p->fini ();
@@ -1123,8 +1123,8 @@
   inline void init (hb_face_t *face_)
   {
     face = face_;
-    instance = NULL;
-    blob = NULL;
+    instance = nullptr;
+    blob = nullptr;
   }
 
   inline void fini (void)
@@ -1140,7 +1140,7 @@
     {
       hb_blob_t *blob_ = OT::Sanitizer<T>::sanitize (face->reference_table (T::tableTag));
       p = const_cast<T *>(OT::Sanitizer<T>::lock_instance (blob_));
-      if (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), NULL, p))
+      if (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), nullptr, p))
       {
 	hb_blob_destroy (blob_);
 	goto retry;
diff --git a/src/hb-ot-cbdt-table.hh b/src/hb-ot-cbdt-table.hh
index 0a7fbf5..3c6855b 100644
--- a/src/hb-ot-cbdt-table.hh
+++ b/src/hb-ot-cbdt-table.hh
@@ -245,7 +245,7 @@
         return &indexSubtablesZ[i];
       }
     }
-    return NULL;
+    return nullptr;
   }
 
   protected:
@@ -344,7 +344,7 @@
       }
     }
 
-    return NULL;
+    return nullptr;
   }
 
   protected:
diff --git a/src/hb-ot-cmap-table.hh b/src/hb-ot-cmap-table.hh
index 3a53a1c..93f38c5 100644
--- a/src/hb-ot-cmap-table.hh
+++ b/src/hb-ot-cmap-table.hh
@@ -508,7 +508,7 @@
      * unsorted subtable list. */
     int result = encodingRecord./*bsearch*/lsearch (key);
     if (result == -1 || !encodingRecord[result].subtable)
-      return NULL;
+      return nullptr;
 
     return &(this+encodingRecord[result].subtable);
   }
diff --git a/src/hb-ot-font.cc b/src/hb-ot-font.cc
index a56f4c0..06d1b80 100644
--- a/src/hb-ot-font.cc
+++ b/src/hb-ot-font.cc
@@ -235,8 +235,8 @@
     cbdt_len = hb_blob_get_length (cbdt_blob);
 
     if (hb_blob_get_length (cblc_blob) == 0) {
-      cblc = NULL;
-      cbdt = NULL;
+      cblc = nullptr;
+      cbdt = nullptr;
       return;  /* Not a bitmap font. */
     }
     cblc = OT::Sanitizer<OT::CBLC>::lock_instance (cblc_blob);
@@ -349,8 +349,8 @@
   {
     this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
     const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
-    const OT::CmapSubtable *subtable = NULL;
-    const OT::CmapSubtableFormat14 *subtable_uvs = NULL;
+    const OT::CmapSubtable *subtable = nullptr;
+    const OT::CmapSubtableFormat14 *subtable_uvs = nullptr;
 
     bool symbol = false;
     /* 32-bit subtables. */
@@ -445,7 +445,7 @@
   hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
 
   if (unlikely (!ot_font))
-    return NULL;
+    return nullptr;
 
   ot_font->cmap.init (face);
   ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, HB_OT_TAG_HVAR, HB_OT_TAG_os2);
@@ -563,7 +563,7 @@
   return ot_font->v_metrics.has_font_extents;
 }
 
-static hb_font_funcs_t *static_ot_funcs = NULL;
+static hb_font_funcs_t *static_ot_funcs = nullptr;
 
 #ifdef HB_USE_ATEXIT
 static
@@ -583,24 +583,24 @@
   {
     funcs = hb_font_funcs_create ();
 
-    hb_font_funcs_set_font_h_extents_func (funcs, hb_ot_get_font_h_extents, NULL, NULL);
-    hb_font_funcs_set_font_v_extents_func (funcs, hb_ot_get_font_v_extents, NULL, NULL);
-    hb_font_funcs_set_nominal_glyph_func (funcs, hb_ot_get_nominal_glyph, NULL, NULL);
-    hb_font_funcs_set_variation_glyph_func (funcs, hb_ot_get_variation_glyph, NULL, NULL);
-    hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ot_get_glyph_h_advance, NULL, NULL);
-    hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ot_get_glyph_v_advance, NULL, NULL);
-    //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ot_get_glyph_h_origin, NULL, NULL);
-    //hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ot_get_glyph_v_origin, NULL, NULL);
-    //hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ot_get_glyph_h_kerning, NULL, NULL); TODO
-    //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ot_get_glyph_v_kerning, NULL, NULL);
-    hb_font_funcs_set_glyph_extents_func (funcs, hb_ot_get_glyph_extents, NULL, NULL);
-    //hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ot_get_glyph_contour_point, NULL, NULL); TODO
-    //hb_font_funcs_set_glyph_name_func (funcs, hb_ot_get_glyph_name, NULL, NULL); TODO
-    //hb_font_funcs_set_glyph_from_name_func (funcs, hb_ot_get_glyph_from_name, NULL, NULL); TODO
+    hb_font_funcs_set_font_h_extents_func (funcs, hb_ot_get_font_h_extents, nullptr, nullptr);
+    hb_font_funcs_set_font_v_extents_func (funcs, hb_ot_get_font_v_extents, nullptr, nullptr);
+    hb_font_funcs_set_nominal_glyph_func (funcs, hb_ot_get_nominal_glyph, nullptr, nullptr);
+    hb_font_funcs_set_variation_glyph_func (funcs, hb_ot_get_variation_glyph, nullptr, nullptr);
+    hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ot_get_glyph_h_advance, nullptr, nullptr);
+    hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ot_get_glyph_v_advance, nullptr, nullptr);
+    //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ot_get_glyph_h_origin, nullptr, nullptr);
+    //hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ot_get_glyph_v_origin, nullptr, nullptr);
+    //hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ot_get_glyph_h_kerning, nullptr, nullptr); TODO
+    //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ot_get_glyph_v_kerning, nullptr, nullptr);
+    hb_font_funcs_set_glyph_extents_func (funcs, hb_ot_get_glyph_extents, nullptr, nullptr);
+    //hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ot_get_glyph_contour_point, nullptr, nullptr); TODO
+    //hb_font_funcs_set_glyph_name_func (funcs, hb_ot_get_glyph_name, nullptr, nullptr); TODO
+    //hb_font_funcs_set_glyph_from_name_func (funcs, hb_ot_get_glyph_from_name, nullptr, nullptr); TODO
 
     hb_font_funcs_make_immutable (funcs);
 
-    if (!hb_atomic_ptr_cmpexch (&static_ot_funcs, NULL, funcs)) {
+    if (!hb_atomic_ptr_cmpexch (&static_ot_funcs, nullptr, funcs)) {
       hb_font_funcs_destroy (funcs);
       goto retry;
     }
diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index f22d990..ed18bd8 100644
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -214,7 +214,7 @@
   }
 
   inline bool sanitize (hb_sanitize_context_t *c,
-			const Record<LangSys>::sanitize_closure_t * = NULL) const
+			const Record<LangSys>::sanitize_closure_t * = nullptr) const
   {
     TRACE_SANITIZE (this);
     return_trace (c->check_struct (this) && featureIndex.sanitize (c));
@@ -254,7 +254,7 @@
   inline const LangSys& get_default_lang_sys (void) const { return this+defaultLangSys; }
 
   inline bool sanitize (hb_sanitize_context_t *c,
-			const Record<Script>::sanitize_closure_t * = NULL) const
+			const Record<Script>::sanitize_closure_t * = nullptr) const
   {
     TRACE_SANITIZE (this);
     return_trace (defaultLangSys.sanitize (c, this) && langSys.sanitize (c, this));
@@ -435,17 +435,17 @@
 					 * specifies a string (or strings,
 					 * for multiple languages) for a
 					 * user-interface label for this
-					 * feature. (May be NULL.) */
+					 * feature. (May be nullptr.) */
   USHORT	featUITooltipTextNameID;/* The ‘name’ table name ID that
 					 * specifies a string (or strings,
 					 * for multiple languages) that an
 					 * application can use for tooltip
 					 * text for this feature. (May be
-					 * NULL.) */
+					 * nullptr.) */
   USHORT	sampleTextNameID;	/* The ‘name’ table name ID that
 					 * specifies sample text that
 					 * illustrates the effect of this
-					 * feature. (May be NULL.) */
+					 * feature. (May be nullptr.) */
   USHORT	numNamedParameters;	/* Number of named parameters. (May
 					 * be zero.) */
   USHORT	firstParamUILabelNameID;/* The first ‘name’ table name ID
@@ -507,7 +507,7 @@
   { return this+featureParams; }
 
   inline bool sanitize (hb_sanitize_context_t *c,
-			const Record<Feature>::sanitize_closure_t *closure = NULL) const
+			const Record<Feature>::sanitize_closure_t *closure = nullptr) const
   {
     TRACE_SANITIZE (this);
     if (unlikely (!(c->check_struct (this) && lookupIndex.sanitize (c))))
@@ -1458,7 +1458,7 @@
       if (record.featureIndex == feature_index)
 	return &(this+record.feature);
     }
-    return NULL;
+    return nullptr;
   }
 
   inline bool sanitize (hb_sanitize_context_t *c) const
diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index 85be7e7..4ae45b9 100644
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -658,7 +658,7 @@
     if (likely (!match_input (c, count,
 			      &component[1],
 			      match_glyph,
-			      NULL,
+			      nullptr,
 			      &match_length,
 			      match_positions,
 			      &is_mark_ligature,
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index cedf96e..4abd4b7 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -77,7 +77,7 @@
 		        unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :
 			  face (face_),
 			  glyphs (glyphs_),
-			  recurse_func (NULL),
+			  recurse_func (nullptr),
 			  nesting_level_left (nesting_level_left_),
 			  debug_depth (0) {}
 
@@ -146,7 +146,7 @@
     if (unlikely (nesting_level_left == 0 || !recurse_func))
       return default_return_value ();
 
-    /* Note that GPOS sets recurse_func to NULL already, so it doesn't get
+    /* Note that GPOS sets recurse_func to nullptr already, so it doesn't get
      * past the previous check.  For GSUB, we only want to collect the output
      * glyphs in the recursion.  If output is not requested, we can go home now.
      *
@@ -192,17 +192,17 @@
   unsigned int debug_depth;
 
   hb_collect_glyphs_context_t (hb_face_t *face_,
-			       hb_set_t  *glyphs_before, /* OUT. May be NULL */
-			       hb_set_t  *glyphs_input,  /* OUT. May be NULL */
-			       hb_set_t  *glyphs_after,  /* OUT. May be NULL */
-			       hb_set_t  *glyphs_output, /* OUT. May be NULL */
+			       hb_set_t  *glyphs_before, /* OUT. May be nullptr */
+			       hb_set_t  *glyphs_input,  /* OUT. May be nullptr */
+			       hb_set_t  *glyphs_after,  /* OUT. May be nullptr */
+			       hb_set_t  *glyphs_output, /* OUT. May be nullptr */
 			       unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :
 			      face (face_),
 			      before (glyphs_before ? glyphs_before : hb_set_get_empty ()),
 			      input  (glyphs_input  ? glyphs_input  : hb_set_get_empty ()),
 			      after  (glyphs_after  ? glyphs_after  : hb_set_get_empty ()),
 			      output (glyphs_output ? glyphs_output : hb_set_get_empty ()),
-			      recurse_func (NULL),
+			      recurse_func (nullptr),
 			      recursed_lookups (),
 			      nesting_level_left (nesting_level_left_),
 			      debug_depth (0)
@@ -273,8 +273,8 @@
 #define arg1(arg) (arg) /* Remove the macro to see why it's needed! */
 	     syllable arg1(0),
 #undef arg1
-	     match_func (NULL),
-	     match_data (NULL) {};
+	     match_func (nullptr),
+	     match_data (nullptr) {};
 
     typedef bool (*match_func_t) (hb_codepoint_t glyph_id, const USHORT &value, const void *data);
 
@@ -342,8 +342,8 @@
     inline void init (hb_apply_context_t *c_, bool context_match = false)
     {
       c = c_;
-      match_glyph_data = NULL;
-      matcher.set_match_func (NULL, NULL);
+      match_glyph_data = nullptr;
+      matcher.set_match_func (nullptr, nullptr);
       matcher.set_lookup_props (c->lookup_props);
       /* Ignore ZWNJ if we are matching GSUB context, or matching GPOS. */
       matcher.set_ignore_zwnj (c->table_index == 1 || (context_match && c->auto_zwnj));
@@ -491,7 +491,7 @@
 		      hb_buffer_t *buffer_) :
 			iter_input (), iter_context (),
 			font (font_), face (font->face), buffer (buffer_),
-			recurse_func (NULL),
+			recurse_func (nullptr),
 			gdef (*hb_ot_layout_from_face (face)->gdef),
 			var_store (gdef.get_var_store ()),
 			direction (buffer_->props.direction),
@@ -719,10 +719,10 @@
 				const void *match_data,
 				unsigned int *end_offset,
 				unsigned int match_positions[HB_MAX_CONTEXT_LENGTH],
-				bool *p_is_mark_ligature = NULL,
-				unsigned int *p_total_component_count = NULL)
+				bool *p_is_mark_ligature = nullptr,
+				unsigned int *p_total_component_count = nullptr)
 {
-  TRACE_APPLY (NULL);
+  TRACE_APPLY (nullptr);
 
   if (unlikely (count > HB_MAX_CONTEXT_LENGTH)) return_trace (false);
 
@@ -846,7 +846,7 @@
 				 bool is_mark_ligature,
 				 unsigned int total_component_count)
 {
-  TRACE_APPLY (NULL);
+  TRACE_APPLY (nullptr);
 
   hb_buffer_t *buffer = c->buffer;
 
@@ -943,7 +943,7 @@
 				    const void *match_data,
 				    unsigned int *match_start)
 {
-  TRACE_APPLY (NULL);
+  TRACE_APPLY (nullptr);
 
   hb_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_context;
   skippy_iter.reset (c->buffer->backtrack_len (), count);
@@ -966,7 +966,7 @@
 				    unsigned int offset,
 				    unsigned int *end_index)
 {
-  TRACE_APPLY (NULL);
+  TRACE_APPLY (nullptr);
 
   hb_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_context;
   skippy_iter.reset (c->buffer->idx + offset - 1, count);
@@ -1016,7 +1016,7 @@
 				 const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
 				 unsigned int match_length)
 {
-  TRACE_APPLY (NULL);
+  TRACE_APPLY (nullptr);
 
   hb_buffer_t *buffer = c->buffer;
   int end;
@@ -1334,7 +1334,7 @@
 
     struct ContextClosureLookupContext lookup_context = {
       {intersects_glyph},
-      NULL
+      nullptr
     };
 
     unsigned int count = ruleSet.len;
@@ -1352,7 +1352,7 @@
 
     struct ContextCollectGlyphsLookupContext lookup_context = {
       {collect_glyph},
-      NULL
+      nullptr
     };
 
     unsigned int count = ruleSet.len;
@@ -1367,7 +1367,7 @@
     const RuleSet &rule_set = this+ruleSet[(this+coverage).get_coverage (c->glyphs[0])];
     struct ContextApplyLookupContext lookup_context = {
       {match_glyph},
-      NULL
+      nullptr
     };
     return_trace (rule_set.would_apply (c, lookup_context));
   }
@@ -1387,7 +1387,7 @@
     const RuleSet &rule_set = this+ruleSet[index];
     struct ContextApplyLookupContext lookup_context = {
       {match_glyph},
-      NULL
+      nullptr
     };
     return_trace (rule_set.apply (c, lookup_context));
   }
@@ -1892,7 +1892,7 @@
 
     struct ChainContextClosureLookupContext lookup_context = {
       {intersects_glyph},
-      {NULL, NULL, NULL}
+      {nullptr, nullptr, nullptr}
     };
 
     unsigned int count = ruleSet.len;
@@ -1910,7 +1910,7 @@
 
     struct ChainContextCollectGlyphsLookupContext lookup_context = {
       {collect_glyph},
-      {NULL, NULL, NULL}
+      {nullptr, nullptr, nullptr}
     };
 
     unsigned int count = ruleSet.len;
@@ -1925,7 +1925,7 @@
     const ChainRuleSet &rule_set = this+ruleSet[(this+coverage).get_coverage (c->glyphs[0])];
     struct ChainContextApplyLookupContext lookup_context = {
       {match_glyph},
-      {NULL, NULL, NULL}
+      {nullptr, nullptr, nullptr}
     };
     return_trace (rule_set.would_apply (c, lookup_context));
   }
@@ -1944,7 +1944,7 @@
     const ChainRuleSet &rule_set = this+ruleSet[index];
     struct ChainContextApplyLookupContext lookup_context = {
       {match_glyph},
-      {NULL, NULL, NULL}
+      {nullptr, nullptr, nullptr}
     };
     return_trace (rule_set.apply (c, lookup_context));
   }
diff --git a/src/hb-ot-layout-jstf-table.hh b/src/hb-ot-layout-jstf-table.hh
index c306849..adbaad6 100644
--- a/src/hb-ot-layout-jstf-table.hh
+++ b/src/hb-ot-layout-jstf-table.hh
@@ -124,7 +124,7 @@
 struct JstfLangSys : OffsetListOf<JstfPriority>
 {
   inline bool sanitize (hb_sanitize_context_t *c,
-			const Record<JstfLangSys>::sanitize_closure_t * = NULL) const
+			const Record<JstfLangSys>::sanitize_closure_t * = nullptr) const
   {
     TRACE_SANITIZE (this);
     return_trace (OffsetListOf<JstfPriority>::sanitize (c));
@@ -165,7 +165,7 @@
   inline const JstfLangSys& get_default_lang_sys (void) const { return this+defaultLangSys; }
 
   inline bool sanitize (hb_sanitize_context_t *c,
-			const Record<JstfScript>::sanitize_closure_t * = NULL) const
+			const Record<JstfScript>::sanitize_closure_t * = nullptr) const
   {
     TRACE_SANITIZE (this);
     return_trace (extenderGlyphs.sanitize (c, this) &&
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index ecf45f1..71e7826 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -44,7 +44,7 @@
 {
   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
   if (unlikely (!layout))
-    return NULL;
+    return nullptr;
 
   layout->gdef_blob = OT::Sanitizer<OT::GDEF>::sanitize (face->reference_table (HB_OT_TAG_GDEF));
   layout->gdef = OT::Sanitizer<OT::GDEF>::lock_instance (layout->gdef_blob);
@@ -176,7 +176,7 @@
 		(layout->gpos_lookup_count && !layout->gpos_accels)))
   {
     _hb_ot_layout_destroy (layout);
-    return NULL;
+    return nullptr;
   }
 
   for (unsigned int i = 0; i < layout->gsub_lookup_count; i++)
@@ -474,7 +474,7 @@
 						     script_index,
 						     language_index,
 						     feature_index,
-						     NULL);
+						     nullptr);
 }
 
 /**
@@ -652,7 +652,7 @@
 						    script_index,
 						    language_index,
 						    &required_feature_index,
-						    NULL))
+						    nullptr))
       _hb_ot_layout_collect_lookups_lookups (face,
 					     table_tag,
 					     required_feature_index,
@@ -721,7 +721,7 @@
     unsigned int count = hb_ot_layout_script_get_language_tags (face,
 								table_tag,
 								script_index,
-								0, NULL, NULL);
+								0, nullptr, nullptr);
     for (unsigned int language_index = 0; language_index < count; language_index++)
       _hb_ot_layout_collect_lookups_features (face,
 					      table_tag,
@@ -768,7 +768,7 @@
     /* All scripts */
     unsigned int count = hb_ot_layout_table_get_script_tags (face,
 							     table_tag,
-							     0, NULL, NULL);
+							     0, nullptr, nullptr);
     for (unsigned int script_index = 0; script_index < count; script_index++)
       _hb_ot_layout_collect_lookups_languages (face,
 					       table_tag,
@@ -805,10 +805,10 @@
 hb_ot_layout_lookup_collect_glyphs (hb_face_t    *face,
 				    hb_tag_t      table_tag,
 				    unsigned int  lookup_index,
-				    hb_set_t     *glyphs_before, /* OUT. May be NULL */
-				    hb_set_t     *glyphs_input,  /* OUT. May be NULL */
-				    hb_set_t     *glyphs_after,  /* OUT. May be NULL */
-				    hb_set_t     *glyphs_output  /* OUT. May be NULL */)
+				    hb_set_t     *glyphs_before, /* OUT. May be nullptr */
+				    hb_set_t     *glyphs_input,  /* OUT. May be nullptr */
+				    hb_set_t     *glyphs_after,  /* OUT. May be nullptr */
+				    hb_set_t     *glyphs_output  /* OUT. May be nullptr */)
 {
   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return;
 
@@ -967,11 +967,11 @@
  **/
 hb_bool_t
 hb_ot_layout_get_size_params (hb_face_t    *face,
-			      unsigned int *design_size,       /* OUT.  May be NULL */
-			      unsigned int *subfamily_id,      /* OUT.  May be NULL */
-			      unsigned int *subfamily_name_id, /* OUT.  May be NULL */
-			      unsigned int *range_start,       /* OUT.  May be NULL */
-			      unsigned int *range_end          /* OUT.  May be NULL */)
+			      unsigned int *design_size,       /* OUT.  May be nullptr */
+			      unsigned int *subfamily_id,      /* OUT.  May be nullptr */
+			      unsigned int *subfamily_name_id, /* OUT.  May be nullptr */
+			      unsigned int *range_start,       /* OUT.  May be nullptr */
+			      unsigned int *range_end          /* OUT.  May be nullptr */)
 {
   const OT::GPOS &gpos = _get_gpos (face);
   const hb_tag_t tag = HB_TAG ('s','i','z','e');
diff --git a/src/hb-ot-map-private.hh b/src/hb-ot-map-private.hh
index 6f774dd..22690de 100644
--- a/src/hb-ot-map-private.hh
+++ b/src/hb-ot-map-private.hh
@@ -79,7 +79,7 @@
 
   inline hb_mask_t get_global_mask (void) const { return global_mask; }
 
-  inline hb_mask_t get_mask (hb_tag_t feature_tag, unsigned int *shift = NULL) const {
+  inline hb_mask_t get_mask (hb_tag_t feature_tag, unsigned int *shift = nullptr) const {
     const feature_map_t *map = features.bsearch (&feature_tag);
     if (shift) *shift = map ? map->shift : 0;
     return map ? map->mask : 0;
@@ -108,14 +108,14 @@
   inline void get_stage_lookups (unsigned int table_index, unsigned int stage,
 				 const struct lookup_map_t **plookups, unsigned int *lookup_count) const {
     if (unlikely (stage == (unsigned int) -1)) {
-      *plookups = NULL;
+      *plookups = nullptr;
       *lookup_count = 0;
       return;
     }
     assert (stage <= stages[table_index].len);
     unsigned int start = stage ? stages[table_index][stage - 1].last_lookup : 0;
     unsigned int end   = stage < stages[table_index].len ? stages[table_index][stage].last_lookup : lookups[table_index].len;
-    *plookups = end == start ? NULL : &lookups[table_index][start];
+    *plookups = end == start ? nullptr : &lookups[table_index][start];
     *lookup_count = end - start;
   }
 
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 0922d75..ea9bde9 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -269,8 +269,8 @@
   feature_infos.shrink (0); /* Done with these */
 
 
-  add_gsub_pause (NULL);
-  add_gpos_pause (NULL);
+  add_gsub_pause (nullptr);
+  add_gpos_pause (nullptr);
 
   for (unsigned int table_index = 0; table_index < 2; table_index++)
   {
diff --git a/src/hb-ot-math-table.hh b/src/hb-ot-math-table.hh
index 3607dbe..b3c8571 100644
--- a/src/hb-ot-math-table.hh
+++ b/src/hb-ot-math-table.hh
@@ -50,7 +50,7 @@
   protected:
   SHORT			value;		/* The X or Y value in design units */
   OffsetTo<Device>	deviceTable;	/* Offset to the device table - from the
-					 * beginning of parent table. May be NULL.
+					 * beginning of parent table. May be nullptr.
 					 * Suggested format for device table is 1. */
 
   public:
@@ -319,7 +319,7 @@
 
   protected:
   /* Offset to MathKern table for each corner -
-   * from the beginning of MathKernInfo table. May be NULL. */
+   * from the beginning of MathKernInfo table. May be nullptr. */
   OffsetTo<MathKern> mathKern[4];
 
   public:
@@ -402,7 +402,7 @@
    * from the beginning of MathGlyphInfo table. When the left or right glyph of
    * a box is an extended shape variant, the (ink) box (and not the default
    * position defined by values in MathConstants table) should be used for
-   * vertical positioning purposes. May be NULL.. */
+   * vertical positioning purposes. May be nullptr.. */
   OffsetTo<Coverage> extendedShapeCoverage;
 
    /* Offset to MathKernInfo table -
@@ -571,7 +571,7 @@
 
   protected:
   /* Offset to MathGlyphAssembly table for this shape - from the beginning of
-     MathGlyphConstruction table. May be NULL. */
+     MathGlyphConstruction table. May be nullptr. */
   OffsetTo<MathGlyphAssembly>	  glyphAssembly;
 
   /* MathGlyphVariantRecords for alternative variants of the glyphs. */
diff --git a/src/hb-ot-shape-complex-arabic-fallback.hh b/src/hb-ot-shape-complex-arabic-fallback.hh
index 92f6cdf..b7638b7 100644
--- a/src/hb-ot-shape-complex-arabic-fallback.hh
+++ b/src/hb-ot-shape-complex-arabic-fallback.hh
@@ -73,7 +73,7 @@
   }
 
   if (!num_glyphs)
-    return NULL;
+    return nullptr;
 
   /* Bubble-sort or something equally good!
    * May not be good-enough for presidential candidate interviews, but good-enough for us... */
@@ -94,7 +94,7 @@
   c.end_serialize ();
   /* TODO sanitize the results? */
 
-  return ret ? c.copy<OT::SubstLookup> () : NULL;
+  return ret ? c.copy<OT::SubstLookup> () : nullptr;
 }
 
 static OT::SubstLookup *
@@ -153,7 +153,7 @@
   }
 
   if (!num_ligatures)
-    return NULL;
+    return nullptr;
 
   OT::Supplier<OT::GlyphID>   first_glyphs_supplier                      (first_glyphs, num_first_glyphs);
   OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier    (ligature_per_first_glyph_count_list, num_first_glyphs);
@@ -177,7 +177,7 @@
   c.end_serialize ();
   /* TODO sanitize the results? */
 
-  return ret ? c.copy<OT::SubstLookup> () : NULL;
+  return ret ? c.copy<OT::SubstLookup> () : nullptr;
 }
 
 static OT::SubstLookup *
diff --git a/src/hb-ot-shape-complex-arabic.cc b/src/hb-ot-shape-complex-arabic.cc
index f741961..be02e3f 100644
--- a/src/hb-ot-shape-complex-arabic.cc
+++ b/src/hb-ot-shape-complex-arabic.cc
@@ -212,13 +212,13 @@
   map->add_global_bool_feature (HB_TAG('c','c','m','p'));
   map->add_global_bool_feature (HB_TAG('l','o','c','l'));
 
-  map->add_gsub_pause (NULL);
+  map->add_gsub_pause (nullptr);
 
   for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++)
   {
     bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]);
     map->add_feature (arabic_features[i], 1, has_fallback ? F_HAS_FALLBACK : F_NONE);
-    map->add_gsub_pause (NULL);
+    map->add_gsub_pause (nullptr);
   }
 
   map->add_feature (HB_TAG('r','l','i','g'), 1, F_GLOBAL|F_HAS_FALLBACK);
@@ -228,7 +228,7 @@
   /* No pause after rclt.  See 98460779bae19e4d64d29461ff154b3527bf8420. */
   map->add_global_bool_feature (HB_TAG('r','c','l','t'));
   map->add_global_bool_feature (HB_TAG('c','a','l','t'));
-  map->add_gsub_pause (NULL);
+  map->add_gsub_pause (nullptr);
 
   /* The spec includes 'cswh'.  Earlier versions of Windows
    * used to enable this by default, but testing suggests
@@ -265,7 +265,7 @@
 {
   arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t));
   if (unlikely (!arabic_plan))
-    return NULL;
+    return nullptr;
 
   arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC;
   arabic_plan->has_stch = !!plan->map.get_1_mask (HB_TAG ('s','t','c','h'));
@@ -412,7 +412,7 @@
   {
     /* This sucks.  We need a font to build the fallback plan... */
     fallback_plan = arabic_fallback_plan_create (plan, font);
-    if (unlikely (!hb_atomic_ptr_cmpexch (&(const_cast<arabic_shape_plan_t *> (arabic_plan))->fallback_plan, NULL, fallback_plan))) {
+    if (unlikely (!hb_atomic_ptr_cmpexch (&(const_cast<arabic_shape_plan_t *> (arabic_plan))->fallback_plan, nullptr, fallback_plan))) {
       arabic_fallback_plan_destroy (fallback_plan);
       goto retry;
     }
@@ -532,11 +532,11 @@
       }
       i++; // Don't touch i again.
 
-      DEBUG_MSG (ARABIC, NULL, "%s stretch at (%d,%d,%d)",
+      DEBUG_MSG (ARABIC, nullptr, "%s stretch at (%d,%d,%d)",
 		 step == MEASURE ? "measuring" : "cutting", context, start, end);
-      DEBUG_MSG (ARABIC, NULL, "rest of word:    count=%d width %d", start - context, w_total);
-      DEBUG_MSG (ARABIC, NULL, "fixed tiles:     count=%d width=%d", n_fixed, w_fixed);
-      DEBUG_MSG (ARABIC, NULL, "repeating tiles: count=%d width=%d", n_repeating, w_repeating);
+      DEBUG_MSG (ARABIC, nullptr, "rest of word:    count=%d width %d", start - context, w_total);
+      DEBUG_MSG (ARABIC, nullptr, "fixed tiles:     count=%d width=%d", n_fixed, w_fixed);
+      DEBUG_MSG (ARABIC, nullptr, "repeating tiles: count=%d width=%d", n_repeating, w_repeating);
 
       /* Number of additional times to repeat each repeating tile. */
       int n_copies = 0;
@@ -559,7 +559,7 @@
       if (step == MEASURE)
       {
 	extra_glyphs_needed += n_copies * n_repeating;
-	DEBUG_MSG (ARABIC, NULL, "will add extra %d copies of repeating tiles", n_copies);
+	DEBUG_MSG (ARABIC, nullptr, "will add extra %d copies of repeating tiles", n_copies);
       }
       else
       {
@@ -572,7 +572,7 @@
 	  if (info[k - 1].arabic_shaping_action() == STCH_REPEATING)
 	    repeat += n_copies;
 
-	  DEBUG_MSG (ARABIC, NULL, "appending %d copies of glyph %d; j=%d",
+	  DEBUG_MSG (ARABIC, nullptr, "appending %d copies of glyph %d; j=%d",
 		     repeat, info[k - 1].codepoint, j);
 	  for (unsigned int n = 0; n < repeat; n++)
 	  {
@@ -691,16 +691,16 @@
 {
   "arabic",
   collect_features_arabic,
-  NULL, /* override_features */
+  nullptr, /* override_features */
   data_create_arabic,
   data_destroy_arabic,
-  NULL, /* preprocess_text */
+  nullptr, /* preprocess_text */
   postprocess_glyphs_arabic,
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
-  NULL, /* decompose */
-  NULL, /* compose */
+  nullptr, /* decompose */
+  nullptr, /* compose */
   setup_masks_arabic,
-  NULL, /* disable_otl */
+  nullptr, /* disable_otl */
   reorder_marks_arabic,
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
diff --git a/src/hb-ot-shape-complex-default.cc b/src/hb-ot-shape-complex-default.cc
index 857980c..99b53a5 100644
--- a/src/hb-ot-shape-complex-default.cc
+++ b/src/hb-ot-shape-complex-default.cc
@@ -30,18 +30,18 @@
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default =
 {
   "default",
-  NULL, /* collect_features */
-  NULL, /* override_features */
-  NULL, /* data_create */
-  NULL, /* data_destroy */
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* collect_features */
+  nullptr, /* override_features */
+  nullptr, /* data_create */
+  nullptr, /* data_destroy */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
-  NULL, /* decompose */
-  NULL, /* compose */
-  NULL, /* setup_masks */
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* decompose */
+  nullptr, /* compose */
+  nullptr, /* setup_masks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-hangul.cc b/src/hb-ot-shape-complex-hangul.cc
index 63850d3..0f3337f 100644
--- a/src/hb-ot-shape-complex-hangul.cc
+++ b/src/hb-ot-shape-complex-hangul.cc
@@ -80,7 +80,7 @@
 {
   hangul_shape_plan_t *hangul_plan = (hangul_shape_plan_t *) calloc (1, sizeof (hangul_shape_plan_t));
   if (unlikely (!hangul_plan))
-    return NULL;
+    return nullptr;
 
   for (unsigned int i = 0; i < HANGUL_FEATURE_COUNT; i++)
     hangul_plan->mask_array[i] = plan->map.get_1_mask (hangul_features[i]);
@@ -420,13 +420,13 @@
   data_create_hangul,
   data_destroy_hangul,
   preprocess_text_hangul,
-  NULL, /* postprocess_glyphs */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
-  NULL, /* decompose */
-  NULL, /* compose */
+  nullptr, /* decompose */
+  nullptr, /* compose */
   setup_masks_hangul,
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-hebrew.cc b/src/hb-ot-shape-complex-hebrew.cc
index b8ddadc..fccd76a 100644
--- a/src/hb-ot-shape-complex-hebrew.cc
+++ b/src/hb-ot-shape-complex-hebrew.cc
@@ -170,18 +170,18 @@
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hebrew =
 {
   "hebrew",
-  NULL, /* collect_features */
-  NULL, /* override_features */
-  NULL, /* data_create */
-  NULL, /* data_destroy */
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* collect_features */
+  nullptr, /* override_features */
+  nullptr, /* data_create */
+  nullptr, /* data_destroy */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
-  NULL, /* decompose */
+  nullptr, /* decompose */
   compose_hebrew,
-  NULL, /* setup_masks */
+  nullptr, /* setup_masks */
   disable_otl_hebrew,
-  NULL, /* reorder_marks */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index c985026..324333c 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -435,7 +435,7 @@
   map->add_gsub_pause (initial_reordering);
   for (; i < INDIC_BASIC_FEATURES; i++) {
     map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
-    map->add_gsub_pause (NULL);
+    map->add_gsub_pause (nullptr);
   }
   map->add_gsub_pause (final_reordering);
   for (; i < INDIC_NUM_FEATURES; i++) {
@@ -533,7 +533,7 @@
 {
   indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t));
   if (unlikely (!indic_plan))
-    return NULL;
+    return nullptr;
 
   indic_plan->config = &indic_configs[0];
   for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
@@ -1848,14 +1848,14 @@
   override_features_indic,
   data_create_indic,
   data_destroy_indic,
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
   decompose_indic,
   compose_indic,
   setup_masks_indic,
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-myanmar.cc b/src/hb-ot-shape-complex-myanmar.cc
index 4081ed0..8b8e417 100644
--- a/src/hb-ot-shape-complex-myanmar.cc
+++ b/src/hb-ot-shape-complex-myanmar.cc
@@ -103,7 +103,7 @@
   for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
   {
     map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
-    map->add_gsub_pause (NULL);
+    map->add_gsub_pause (nullptr);
   }
   map->add_gsub_pause (final_reordering);
   for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
@@ -513,18 +513,18 @@
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar_old =
 {
   "default",
-  NULL, /* collect_features */
-  NULL, /* override_features */
-  NULL, /* data_create */
-  NULL, /* data_destroy */
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* collect_features */
+  nullptr, /* override_features */
+  nullptr, /* data_create */
+  nullptr, /* data_destroy */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
-  NULL, /* decompose */
-  NULL, /* compose */
-  NULL, /* setup_masks */
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* decompose */
+  nullptr, /* compose */
+  nullptr, /* setup_masks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
@@ -534,16 +534,16 @@
   "myanmar",
   collect_features_myanmar,
   override_features_myanmar,
-  NULL, /* data_create */
-  NULL, /* data_destroy */
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* data_create */
+  nullptr, /* data_destroy */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
-  NULL, /* decompose */
-  NULL, /* compose */
+  nullptr, /* decompose */
+  nullptr, /* compose */
   setup_masks_myanmar,
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
   false, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-private.hh b/src/hb-ot-shape-complex-private.hh
index 9792067..4951cb5 100644
--- a/src/hb-ot-shape-complex-private.hh
+++ b/src/hb-ot-shape-complex-private.hh
@@ -70,7 +70,7 @@
   /* collect_features()
    * Called during shape_plan().
    * Shapers should use plan->map to add their features and callbacks.
-   * May be NULL.
+   * May be nullptr.
    */
   void (*collect_features) (hb_ot_shape_planner_t *plan);
 
@@ -78,7 +78,7 @@
    * Called during shape_plan().
    * Shapers should use plan->map to override features and add callbacks after
    * common features are added.
-   * May be NULL.
+   * May be nullptr.
    */
   void (*override_features) (hb_ot_shape_planner_t *plan);
 
@@ -86,15 +86,15 @@
   /* data_create()
    * Called at the end of shape_plan().
    * Whatever shapers return will be accessible through plan->data later.
-   * If NULL is returned, means a plan failure.
+   * If nullptr is returned, means a plan failure.
    */
   void *(*data_create) (const hb_ot_shape_plan_t *plan);
 
   /* data_destroy()
    * Called when the shape_plan is being destroyed.
    * plan->data is passed here for destruction.
-   * If NULL is returned, means a plan failure.
-   * May be NULL.
+   * If nullptr is returned, means a plan failure.
+   * May be nullptr.
    */
   void (*data_destroy) (void *data);
 
@@ -102,7 +102,7 @@
   /* preprocess_text()
    * Called during shape().
    * Shapers can use to modify text before shaping starts.
-   * May be NULL.
+   * May be nullptr.
    */
   void (*preprocess_text) (const hb_ot_shape_plan_t *plan,
 			   hb_buffer_t              *buffer,
@@ -111,7 +111,7 @@
   /* postprocess_glyphs()
    * Called during shape().
    * Shapers can use to modify glyphs after shaping ends.
-   * May be NULL.
+   * May be nullptr.
    */
   void (*postprocess_glyphs) (const hb_ot_shape_plan_t *plan,
 			      hb_buffer_t              *buffer,
@@ -122,7 +122,7 @@
 
   /* decompose()
    * Called during shape()'s normalization.
-   * May be NULL.
+   * May be nullptr.
    */
   bool (*decompose) (const hb_ot_shape_normalize_context_t *c,
 		     hb_codepoint_t  ab,
@@ -131,7 +131,7 @@
 
   /* compose()
    * Called during shape()'s normalization.
-   * May be NULL.
+   * May be nullptr.
    */
   bool (*compose) (const hb_ot_shape_normalize_context_t *c,
 		   hb_codepoint_t  a,
@@ -142,7 +142,7 @@
    * Called during shape().
    * Shapers should use map to get feature masks and set on buffer.
    * Shapers may NOT modify characters.
-   * May be NULL.
+   * May be nullptr.
    */
   void (*setup_masks) (const hb_ot_shape_plan_t *plan,
 		       hb_buffer_t              *buffer,
@@ -152,14 +152,14 @@
    * Called during shape().
    * If set and returns true, GDEF/GSUB/GPOS of the font are ignored
    * and fallback operations used.
-   * May be NULL.
+   * May be nullptr.
    */
   bool (*disable_otl) (const hb_ot_shape_plan_t *plan);
 
   /* reorder_marks()
    * Called during shape().
    * Shapers can use to modify ordering of combining marks.
-   * May be NULL.
+   * May be nullptr.
    */
   void (*reorder_marks) (const hb_ot_shape_plan_t *plan,
 			 hb_buffer_t              *buffer,
@@ -286,7 +286,7 @@
 					      planner->map.script_index[0],
 					      planner->map.language_index[0],
 					      HB_TAG ('p','r','e','f'),
-					      NULL))
+					      nullptr))
 	return &_hb_ot_complex_shaper_indic;
       else
 	return &_hb_ot_complex_shaper_default;
diff --git a/src/hb-ot-shape-complex-thai.cc b/src/hb-ot-shape-complex-thai.cc
index 651c47f..58a0a41 100644
--- a/src/hb-ot-shape-complex-thai.cc
+++ b/src/hb-ot-shape-complex-thai.cc
@@ -97,7 +97,7 @@
     hb_codepoint_t u;
     hb_codepoint_t win_pua;
     hb_codepoint_t mac_pua;
-  } const *pua_mappings = NULL;
+  } const *pua_mappings = nullptr;
   static const thai_pua_mapping_t SD_mappings[] = {
     {0x0E48u, 0xF70Au, 0xF88Bu}, /* MAI EK */
     {0x0E49u, 0xF70Bu, 0xF88Eu}, /* MAI THO */
@@ -367,18 +367,18 @@
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
 {
   "thai",
-  NULL, /* collect_features */
-  NULL, /* override_features */
-  NULL, /* data_create */
-  NULL, /* data_destroy */
+  nullptr, /* collect_features */
+  nullptr, /* override_features */
+  nullptr, /* data_create */
+  nullptr, /* data_destroy */
   preprocess_text_thai,
-  NULL, /* postprocess_glyphs */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
-  NULL, /* decompose */
-  NULL, /* compose */
-  NULL, /* setup_masks */
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* decompose */
+  nullptr, /* compose */
+  nullptr, /* setup_masks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   false,/* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-tibetan.cc b/src/hb-ot-shape-complex-tibetan.cc
index a85ac0f..e87f1a4 100644
--- a/src/hb-ot-shape-complex-tibetan.cc
+++ b/src/hb-ot-shape-complex-tibetan.cc
@@ -48,17 +48,17 @@
 {
   "default",
   collect_features_tibetan,
-  NULL, /* override_features */
-  NULL, /* data_create */
-  NULL, /* data_destroy */
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* override_features */
+  nullptr, /* data_create */
+  nullptr, /* data_destroy */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
-  NULL, /* decompose */
-  NULL, /* compose */
-  NULL, /* setup_masks */
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* decompose */
+  nullptr, /* compose */
+  nullptr, /* setup_masks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-complex-use.cc b/src/hb-ot-shape-complex-use.cc
index 4bfbfb8..1f43ac7 100644
--- a/src/hb-ot-shape-complex-use.cc
+++ b/src/hb-ot-shape-complex-use.cc
@@ -144,7 +144,7 @@
   /* "Topographical features" */
   for (unsigned int i = 0; i < ARRAY_LENGTH (arabic_features); i++)
     map->add_feature (arabic_features[i], 1, F_NONE);
-  map->add_gsub_pause (NULL);
+  map->add_gsub_pause (nullptr);
 
   /* "Standard typographic presentation" and "Positional feature application" */
   for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
@@ -199,7 +199,7 @@
 {
   use_shape_plan_t *use_plan = (use_shape_plan_t *) calloc (1, sizeof (use_shape_plan_t));
   if (unlikely (!use_plan))
-    return NULL;
+    return nullptr;
 
   use_plan->rphf_mask = plan->map.get_1_mask (HB_TAG('r','p','h','f'));
 
@@ -209,7 +209,7 @@
     if (unlikely (!use_plan->arabic_plan))
     {
       free (use_plan);
-      return NULL;
+      return nullptr;
     }
   }
 
@@ -597,17 +597,17 @@
 {
   "use",
   collect_features_use,
-  NULL, /* override_features */
+  nullptr, /* override_features */
   data_create_use,
   data_destroy_use,
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
   decompose_use,
   compose_use,
   setup_masks_use,
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
   false, /* fallback_position */
 };
diff --git a/src/hb-ot-shape-private.hh b/src/hb-ot-shape-private.hh
index 594e54c..d0fe9e6 100644
--- a/src/hb-ot-shape-private.hh
+++ b/src/hb-ot-shape-private.hh
@@ -73,7 +73,7 @@
   hb_ot_shape_planner_t (const hb_shape_plan_t *master_plan) :
 			 face (master_plan->face_unsafe),
 			 props (master_plan->props),
-			 shaper (NULL),
+			 shaper (nullptr),
 			 map (face, &props) {}
   ~hb_ot_shape_planner_t (void) { map.finish (); }
 
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index 8fc9d46..9d1d6f7 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -70,7 +70,7 @@
   hb_ot_map_builder_t *map = &planner->map;
 
   map->add_global_bool_feature (HB_TAG('r','v','r','n'));
-  map->add_gsub_pause (NULL);
+  map->add_gsub_pause (nullptr);
 
   switch (props->direction) {
     case HB_DIRECTION_LTR:
@@ -176,7 +176,7 @@
 {
   hb_ot_shape_plan_t *plan = (hb_ot_shape_plan_t *) calloc (1, sizeof (hb_ot_shape_plan_t));
   if (unlikely (!plan))
-    return NULL;
+    return nullptr;
 
   hb_ot_shape_planner_t planner (shape_plan);
 
@@ -190,7 +190,7 @@
   if (plan->shaper->data_create) {
     plan->data = plan->shaper->data_create (plan);
     if (unlikely (!plan->data))
-      return NULL;
+      return nullptr;
   }
 
   return plan;
@@ -928,7 +928,7 @@
 {
   hb_ot_shape_plan_t plan;
 
-  const char *shapers[] = {"ot", NULL};
+  const char *shapers[] = {"ot", nullptr};
   hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached (font->face, &buffer->props,
 							     features, num_features, shapers);
 
diff --git a/src/hb-ot-tag.cc b/src/hb-ot-tag.cc
index 59b7d6a..64c6ce0 100644
--- a/src/hb-ot-tag.cc
+++ b/src/hb-ot-tag.cc
@@ -1020,7 +1020,7 @@
   unsigned int i;
 
   if (tag == HB_OT_TAG_DEFAULT_LANGUAGE)
-    return NULL;
+    return nullptr;
 
   /* struct LangTag has only room for 3-letter language tags. */
   switch (tag) {
diff --git a/src/hb-ot-var.cc b/src/hb-ot-var.cc
index 691196d..90ba0bd 100644
--- a/src/hb-ot-var.cc
+++ b/src/hb-ot-var.cc
@@ -130,7 +130,7 @@
   for (unsigned int i = 0; i < variations_length; i++)
   {
     unsigned int axis_index;
-    if (hb_ot_var_find_axis (face, variations[i].tag, &axis_index, NULL) &&
+    if (hb_ot_var_find_axis (face, variations[i].tag, &axis_index, nullptr) &&
 	axis_index < coords_length)
       coords[axis_index] = fvar.normalize_axis_value (axis_index, variations[i].value);
   }
diff --git a/src/hb-private.hh b/src/hb-private.hh
index 282c9fe..9691b08 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -200,13 +200,13 @@
 #  if defined(_WIN32_WCE)
      /* Some things not defined on Windows CE. */
 #    define vsnprintf _vsnprintf
-#    define getenv(Name) NULL
+#    define getenv(Name) nullptr
 #    if _WIN32_WCE < 0x800
 #      define setlocale(Category, Locale) "C"
 static int errno = 0; /* Use something better? */
 #    endif
 #  elif defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)
-#    define getenv(Name) NULL
+#    define getenv(Name) nullptr
 #  endif
 #  if defined(_MSC_VER) && _MSC_VER < 1900
 #    define snprintf _snprintf
@@ -241,11 +241,6 @@
 
 /* Basics */
 
-
-#ifndef NULL
-# define NULL ((void *) 0)
-#endif
-
 #undef MIN
 template <typename Type>
 static inline Type MIN (const Type &a, const Type &b) { return a < b ? a : b; }
@@ -321,7 +316,7 @@
 /* Void! */
 struct _hb_void_t {};
 typedef const _hb_void_t *hb_void_t;
-#define HB_VOID ((const _hb_void_t *) NULL)
+#define HB_VOID ((const _hb_void_t *) nullptr)
 
 /* Return the number of 1 bits in mask. */
 static inline HB_CONST_FUNC unsigned int
@@ -387,7 +382,7 @@
 /* arrays and maps */
 
 
-#define HB_PREALLOCED_ARRAY_INIT {0, 0, NULL}
+#define HB_PREALLOCED_ARRAY_INIT {0, 0, nullptr}
 template <typename Type, unsigned int StaticSize=16>
 struct hb_prealloced_array_t
 {
@@ -412,7 +407,7 @@
 
     /* Need to reallocate */
     unsigned int new_allocated = allocated + (allocated >> 1) + 8;
-    Type *new_array = NULL;
+    Type *new_array = nullptr;
 
     if (array == static_array) {
       new_array = (Type *) calloc (new_allocated, sizeof (Type));
@@ -426,7 +421,7 @@
     }
 
     if (unlikely (!new_array))
-      return NULL;
+      return nullptr;
 
     array = new_array;
     allocated = new_allocated;
@@ -459,14 +454,14 @@
     for (unsigned int i = 0; i < len; i++)
       if (array[i] == v)
 	return &array[i];
-    return NULL;
+    return nullptr;
   }
   template <typename T>
   inline const Type *find (T v) const {
     for (unsigned int i = 0; i < len; i++)
       if (array[i] == v)
 	return &array[i];
-    return NULL;
+    return nullptr;
   }
 
   inline void qsort (void)
@@ -494,7 +489,7 @@
   {
     if (array != static_array)
       free (array);
-    array = NULL;
+    array = nullptr;
     allocated = len = 0;
   }
 };
@@ -528,7 +523,7 @@
 	old.finish ();
       }
       else {
-        item = NULL;
+        item = nullptr;
 	l.unlock ();
       }
     } else {
@@ -791,8 +786,8 @@
 		  const char *message HB_UNUSED,
 		  ...) {}
 
-#define DEBUG_MSG_LEVEL(WHAT, OBJ, LEVEL, LEVEL_DIR, ...)	_hb_debug_msg<HB_DEBUG_##WHAT> (#WHAT, (OBJ), NULL,    true, (LEVEL), (LEVEL_DIR), __VA_ARGS__)
-#define DEBUG_MSG(WHAT, OBJ, ...) 				_hb_debug_msg<HB_DEBUG_##WHAT> (#WHAT, (OBJ), NULL,    false, 0, 0, __VA_ARGS__)
+#define DEBUG_MSG_LEVEL(WHAT, OBJ, LEVEL, LEVEL_DIR, ...)	_hb_debug_msg<HB_DEBUG_##WHAT> (#WHAT, (OBJ), nullptr,    true, (LEVEL), (LEVEL_DIR), __VA_ARGS__)
+#define DEBUG_MSG(WHAT, OBJ, ...) 				_hb_debug_msg<HB_DEBUG_##WHAT> (#WHAT, (OBJ), nullptr,    false, 0, 0, __VA_ARGS__)
 #define DEBUG_MSG_FUNC(WHAT, OBJ, ...)				_hb_debug_msg<HB_DEBUG_##WHAT> (#WHAT, (OBJ), HB_FUNC, false, 0, 0, __VA_ARGS__)
 
 
@@ -851,7 +846,7 @@
   {
     _hb_warn_no_return<ret_t> (returned);
     if (!returned) {
-      _hb_debug_msg<max_level> (what, obj, NULL, true, plevel ? *plevel : 1, -1, " ");
+      _hb_debug_msg<max_level> (what, obj, nullptr, true, plevel ? *plevel : 1, -1, " ");
     }
     if (plevel) --*plevel;
   }
@@ -863,11 +858,11 @@
       return v;
     }
 
-    _hb_debug_msg<max_level> (what, obj, NULL, true, plevel ? *plevel : 1, -1,
+    _hb_debug_msg<max_level> (what, obj, nullptr, true, plevel ? *plevel : 1, -1,
 			      "return %s (line %d)",
 			      hb_printer_t<ret_t>().print (v), line);
     if (plevel) --*plevel;
-    plevel = NULL;
+    plevel = nullptr;
     returned = true;
     return v;
   }
@@ -989,7 +984,7 @@
 template <typename T> static inline void
 hb_stable_sort (T *array, unsigned int len, int(*compar)(const T *, const T *))
 {
-  hb_stable_sort (array, len, compar, (int *) NULL);
+  hb_stable_sort (array, len, compar, (int *) nullptr);
 }
 
 static inline hb_bool_t
diff --git a/src/hb-set-private.hh b/src/hb-set-private.hh
index 8cd02fb..fb45df9 100644
--- a/src/hb-set-private.hh
+++ b/src/hb-set-private.hh
@@ -355,7 +355,7 @@
   inline void init (const hb_set_t &set)
   {
     start = count = 0;
-    elts = NULL;
+    elts = nullptr;
 
     unsigned int max = set.get_max ();
     if (max == set.INVALID)
diff --git a/src/hb-shape-plan.cc b/src/hb-shape-plan.cc
index 5573cd2..e58f9ff 100644
--- a/src/hb-shape-plan.cc
+++ b/src/hb-shape-plan.cc
@@ -115,7 +115,7 @@
 {
   return hb_shape_plan_create2 (face, props,
 				user_features, num_user_features,
-				NULL, 0,
+				nullptr, 0,
 				shaper_list);
 }
 
@@ -128,7 +128,7 @@
 		       unsigned int                   num_coords,
 		       const char * const            *shaper_list)
 {
-  DEBUG_MSG_FUNC (SHAPE_PLAN, NULL,
+  DEBUG_MSG_FUNC (SHAPE_PLAN, nullptr,
 		  "face=%p num_features=%d num_coords=%d shaper_list=%p",
 		  face,
 		  num_user_features,
@@ -136,8 +136,8 @@
 		  shaper_list);
 
   hb_shape_plan_t *shape_plan;
-  hb_feature_t *features = NULL;
-  int *coords = NULL;
+  hb_feature_t *features = nullptr;
+  int *coords = nullptr;
 
   if (unlikely (!face))
     face = hb_face_get_empty ();
@@ -196,16 +196,16 @@
     HB_OBJECT_HEADER_STATIC,
 
     true, /* default_shaper_list */
-    NULL, /* face */
+    nullptr, /* face */
     HB_SEGMENT_PROPERTIES_DEFAULT, /* props */
 
-    NULL, /* shaper_func */
-    NULL, /* shaper_name */
+    nullptr, /* shaper_func */
+    nullptr, /* shaper_name */
 
-    NULL, /* user_features */
+    nullptr, /* user_features */
     0,    /* num_user_featurs */
 
-    NULL, /* coords */
+    nullptr, /* coords */
     0,    /* num_coords */
 
     {
@@ -470,7 +470,7 @@
 {
   return hb_shape_plan_create_cached2 (face, props,
 				       user_features, num_user_features,
-				       NULL, 0,
+				       nullptr, 0,
 				       shaper_list);
 }
 
@@ -483,7 +483,7 @@
 			      unsigned int                   num_coords,
 			      const char * const            *shaper_list)
 {
-  DEBUG_MSG_FUNC (SHAPE_PLAN, NULL,
+  DEBUG_MSG_FUNC (SHAPE_PLAN, nullptr,
 		  "face=%p num_features=%d shaper_list=%p",
 		  face,
 		  num_user_features,
@@ -494,7 +494,7 @@
     shaper_list,
     user_features,
     num_user_features,
-    NULL
+    nullptr
   };
 
   if (shaper_list) {
diff --git a/src/hb-shape.cc b/src/hb-shape.cc
index f080a15..39355b3 100644
--- a/src/hb-shape.cc
+++ b/src/hb-shape.cc
@@ -76,7 +76,7 @@
     /* Not found; allocate one. */
     shaper_list = (const char **) calloc (1 + HB_SHAPERS_COUNT, sizeof (const char *));
     if (unlikely (!shaper_list)) {
-      static const char *nil_shaper_list[] = {NULL};
+      static const char *nil_shaper_list[] = {nullptr};
       return nil_shaper_list;
     }
 
@@ -84,9 +84,9 @@
     unsigned int i;
     for (i = 0; i < HB_SHAPERS_COUNT; i++)
       shaper_list[i] = shapers[i].name;
-    shaper_list[i] = NULL;
+    shaper_list[i] = nullptr;
 
-    if (!hb_atomic_ptr_cmpexch (&static_shaper_list, NULL, shaper_list)) {
+    if (!hb_atomic_ptr_cmpexch (&static_shaper_list, nullptr, shaper_list)) {
       free (shaper_list);
       goto retry;
     }
@@ -157,5 +157,5 @@
 	  const hb_feature_t  *features,
 	  unsigned int         num_features)
 {
-  hb_shape_full (font, buffer, features, num_features, NULL);
+  hb_shape_full (font, buffer, features, num_features, nullptr);
 }
diff --git a/src/hb-shaper-private.hh b/src/hb-shaper-private.hh
index 2481ef8..ce2d9f2 100644
--- a/src/hb-shaper-private.hh
+++ b/src/hb-shaper-private.hh
@@ -100,7 +100,7 @@
     /* Drop and recreate. */ \
     /* If someone dropped it in the mean time, throw it away and don't touch it. \
      * Otherwise, destruct it. */ \
-    if (hb_atomic_ptr_cmpexch (&HB_SHAPER_DATA (shaper, object), data, NULL)) { \
+    if (hb_atomic_ptr_cmpexch (&HB_SHAPER_DATA (shaper, object), data, nullptr)) { \
       HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data); \
     } \
     goto retry; \
@@ -109,7 +109,7 @@
     data = HB_SHAPER_DATA_CREATE_FUNC (shaper, object) (object); \
     if (unlikely (!data)) \
       data = (HB_SHAPER_DATA_TYPE (shaper, object) *) HB_SHAPER_DATA_INVALID; \
-    if (!hb_atomic_ptr_cmpexch (&HB_SHAPER_DATA (shaper, object), NULL, data)) { \
+    if (!hb_atomic_ptr_cmpexch (&HB_SHAPER_DATA (shaper, object), nullptr, data)) { \
       if (data && \
 	  data != HB_SHAPER_DATA_INVALID && \
 	  data != HB_SHAPER_DATA_SUCCEEDED) \
@@ -117,7 +117,7 @@
       goto retry; \
     } \
   } \
-  return data != NULL && !HB_SHAPER_DATA_IS_INVALID (data); \
+  return data != nullptr && !HB_SHAPER_DATA_IS_INVALID (data); \
 }
 
 
diff --git a/src/hb-shaper.cc b/src/hb-shaper.cc
index b25566d..2c44cf2 100644
--- a/src/hb-shaper.cc
+++ b/src/hb-shaper.cc
@@ -59,14 +59,14 @@
   {
     char *env = getenv ("HB_SHAPER_LIST");
     if (!env || !*env) {
-      (void) hb_atomic_ptr_cmpexch (&static_shapers, NULL, &all_shapers[0]);
+      (void) hb_atomic_ptr_cmpexch (&static_shapers, nullptr, &all_shapers[0]);
       return (const hb_shaper_pair_t *) all_shapers;
     }
 
     /* Not found; allocate one. */
     shapers = (hb_shaper_pair_t *) calloc (1, sizeof (all_shapers));
     if (unlikely (!shapers)) {
-      (void) hb_atomic_ptr_cmpexch (&static_shapers, NULL, &all_shapers[0]);
+      (void) hb_atomic_ptr_cmpexch (&static_shapers, nullptr, &all_shapers[0]);
       return (const hb_shaper_pair_t *) all_shapers;
     }
 
@@ -97,7 +97,7 @@
 	p = end + 1;
     }
 
-    if (!hb_atomic_ptr_cmpexch (&static_shapers, NULL, shapers)) {
+    if (!hb_atomic_ptr_cmpexch (&static_shapers, nullptr, shapers)) {
       free (shapers);
       goto retry;
     }
diff --git a/src/hb-ucdn.cc b/src/hb-ucdn.cc
index d41cf5b..c237ee8 100644
--- a/src/hb-ucdn.cc
+++ b/src/hb-ucdn.cc
@@ -238,7 +238,7 @@
   static const hb_unicode_funcs_t _hb_ucdn_unicode_funcs = {
     HB_OBJECT_HEADER_STATIC,
 
-    NULL, /* parent */
+    nullptr, /* parent */
     true, /* immutable */
     {
 #define HB_UNICODE_FUNC_IMPLEMENT(name) hb_ucdn_##name,
diff --git a/src/hb-unicode.cc b/src/hb-unicode.cc
index d553a71..726baeb 100644
--- a/src/hb-unicode.cc
+++ b/src/hb-unicode.cc
@@ -188,7 +188,7 @@
 const hb_unicode_funcs_t _hb_unicode_funcs_nil = {
   HB_OBJECT_HEADER_STATIC,
 
-  NULL, /* parent */
+  nullptr, /* parent */
   true, /* immutable */
   {
 #define HB_UNICODE_FUNC_IMPLEMENT(name) hb_unicode_##name##_nil,
@@ -365,7 +365,7 @@
   } else {									\
     ufuncs->func.name = ufuncs->parent->func.name;				\
     ufuncs->user_data.name = ufuncs->parent->user_data.name;			\
-    ufuncs->destroy.name = NULL;						\
+    ufuncs->destroy.name = nullptr;						\
   }										\
 }
 
diff --git a/src/hb-uniscribe.cc b/src/hb-uniscribe.cc
index 8599106..b19c394 100644
--- a/src/hb-uniscribe.cc
+++ b/src/hb-uniscribe.cc
@@ -202,9 +202,9 @@
   inline void init (void)
   {
     HMODULE hinstLib;
-    this->ScriptItemizeOpenType = NULL;
-    this->ScriptShapeOpenType   = NULL;
-    this->ScriptPlaceOpenType   = NULL;
+    this->ScriptItemizeOpenType = nullptr;
+    this->ScriptShapeOpenType   = nullptr;
+    this->ScriptPlaceOpenType   = nullptr;
 
     hinstLib = GetModuleHandle (TEXT ("usp10.dll"));
     if (hinstLib)
@@ -217,7 +217,7 @@
 	!this->ScriptShapeOpenType   ||
 	!this->ScriptPlaceOpenType)
     {
-      DEBUG_MSG (UNISCRIBE, NULL, "OpenType versions of functions not found; falling back.");
+      DEBUG_MSG (UNISCRIBE, nullptr, "OpenType versions of functions not found; falling back.");
       this->ScriptItemizeOpenType = hb_ScriptItemizeOpenType;
       this->ScriptShapeOpenType   = hb_ScriptShapeOpenType;
       this->ScriptPlaceOpenType   = hb_ScriptPlaceOpenType;
@@ -242,11 +242,11 @@
   {
     funcs = (hb_uniscribe_shaper_funcs_t *) calloc (1, sizeof (hb_uniscribe_shaper_funcs_t));
     if (unlikely (!funcs))
-      return NULL;
+      return nullptr;
 
     funcs->init ();
 
-    if (!hb_atomic_ptr_cmpexch (&uniscribe_funcs, NULL, funcs)) {
+    if (!hb_atomic_ptr_cmpexch (&uniscribe_funcs, nullptr, funcs)) {
       free (funcs);
       goto retry;
     }
@@ -369,7 +369,7 @@
   if (!new_sfnt_data)
   {
     hb_blob_destroy (blob);
-    return NULL;
+    return nullptr;
   }
 
   memcpy(new_sfnt_data, orig_sfnt_data, length);
@@ -417,7 +417,7 @@
     {
       free (new_sfnt_data);
       hb_blob_destroy (blob);
-      return NULL;
+      return nullptr;
     }
   }
 
@@ -427,7 +427,7 @@
 
   hb_blob_destroy (blob);
   return hb_blob_create ((const char *) new_sfnt_data, new_length,
-			 HB_MEMORY_MODE_WRITABLE, NULL, free);
+			 HB_MEMORY_MODE_WRITABLE, nullptr, free);
 }
 
 hb_uniscribe_shaper_face_data_t *
@@ -435,13 +435,13 @@
 {
   hb_uniscribe_shaper_face_data_t *data = (hb_uniscribe_shaper_face_data_t *) calloc (1, sizeof (hb_uniscribe_shaper_face_data_t));
   if (unlikely (!data))
-    return NULL;
+    return nullptr;
 
   data->funcs = hb_uniscribe_shaper_get_funcs ();
   if (unlikely (!data->funcs))
   {
     free (data);
-    return NULL;
+    return nullptr;
   }
 
   hb_blob_t *blob = hb_face_reference_blob (face);
@@ -452,18 +452,18 @@
   if (unlikely (!blob))
   {
     free (data);
-    return NULL;
+    return nullptr;
   }
 
   DWORD num_fonts_installed;
-  data->fh = AddFontMemResourceEx ((void *) hb_blob_get_data (blob, NULL),
+  data->fh = AddFontMemResourceEx ((void *) hb_blob_get_data (blob, nullptr),
 				   hb_blob_get_length (blob),
 				   0, &num_fonts_installed);
   if (unlikely (!data->fh))
   {
     DEBUG_MSG (UNISCRIBE, face, "Face AddFontMemResourceEx() failed");
     free (data);
-    return NULL;
+    return nullptr;
   }
 
   return data;
@@ -509,11 +509,11 @@
 hb_uniscribe_shaper_font_data_t *
 _hb_uniscribe_shaper_font_data_create (hb_font_t *font)
 {
-  if (unlikely (!hb_uniscribe_shaper_face_data_ensure (font->face))) return NULL;
+  if (unlikely (!hb_uniscribe_shaper_face_data_ensure (font->face))) return nullptr;
 
   hb_uniscribe_shaper_font_data_t *data = (hb_uniscribe_shaper_font_data_t *) calloc (1, sizeof (hb_uniscribe_shaper_font_data_t));
   if (unlikely (!data))
-    return NULL;
+    return nullptr;
 
   int font_size = font->face->get_upem (); /* Default... */
   /* No idea if the following is even a good idea. */
@@ -525,25 +525,25 @@
   data->x_mult = (double) font->x_scale / font_size;
   data->y_mult = (double) font->y_scale / font_size;
 
-  data->hdc = GetDC (NULL);
+  data->hdc = GetDC (nullptr);
 
   if (unlikely (!populate_log_font (&data->log_font, font, font_size))) {
     DEBUG_MSG (UNISCRIBE, font, "Font populate_log_font() failed");
     _hb_uniscribe_shaper_font_data_destroy (data);
-    return NULL;
+    return nullptr;
   }
 
   data->hfont = CreateFontIndirectW (&data->log_font);
   if (unlikely (!data->hfont)) {
     DEBUG_MSG (UNISCRIBE, font, "Font CreateFontIndirectW() failed");
     _hb_uniscribe_shaper_font_data_destroy (data);
-     return NULL;
+     return nullptr;
   }
 
   if (!SelectObject (data->hdc, data->hfont)) {
     DEBUG_MSG (UNISCRIBE, font, "Font SelectObject() failed");
     _hb_uniscribe_shaper_font_data_destroy (data);
-     return NULL;
+     return nullptr;
   }
 
   return data;
@@ -553,7 +553,7 @@
 _hb_uniscribe_shaper_font_data_destroy (hb_uniscribe_shaper_font_data_t *data)
 {
   if (data->hdc)
-    ReleaseDC (NULL, data->hdc);
+    ReleaseDC (nullptr, data->hdc);
   if (data->hfont)
     DeleteObject (data->hfont);
   if (data->script_cache)
@@ -564,7 +564,7 @@
 LOGFONTW *
 hb_uniscribe_font_get_logfontw (hb_font_t *font)
 {
-  if (unlikely (!hb_uniscribe_shaper_font_data_ensure (font))) return NULL;
+  if (unlikely (!hb_uniscribe_shaper_font_data_ensure (font))) return nullptr;
   hb_uniscribe_shaper_font_data_t *font_data =  HB_SHAPER_DATA_GET (font);
   return &font_data->log_font;
 }
@@ -572,7 +572,7 @@
 HFONT
 hb_uniscribe_font_get_hfont (hb_font_t *font)
 {
-  if (unlikely (!hb_uniscribe_shaper_font_data_ensure (font))) return NULL;
+  if (unlikely (!hb_uniscribe_shaper_font_data_ensure (font))) return nullptr;
   hb_uniscribe_shaper_font_data_t *font_data =  HB_SHAPER_DATA_GET (font);
   return font_data->hfont;
 }
@@ -738,7 +738,7 @@
 
 #define FAIL(...) \
   HB_STMT_START { \
-    DEBUG_MSG (UNISCRIBE, NULL, __VA_ARGS__); \
+    DEBUG_MSG (UNISCRIBE, nullptr, __VA_ARGS__); \
     return false; \
   } HB_STMT_END;
 
@@ -960,7 +960,7 @@
 				     /* out */
 				     advances + glyphs_offset,
 				     offsets + glyphs_offset,
-				     NULL);
+				     nullptr);
     if (unlikely (FAILED (hr)))
       FAIL ("ScriptPlaceOpenType() failed: 0x%08xL", hr);
 
diff --git a/src/main.cc b/src/main.cc
index f9708cc..93c3b46 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -47,11 +47,11 @@
     exit (1);
   }
 
-  const char *font_data = NULL;
+  const char *font_data = nullptr;
   int len = 0;
 
 #ifdef HAVE_GLIB
-  GMappedFile *mf = g_mapped_file_new (argv[1], false, NULL);
+  GMappedFile *mf = g_mapped_file_new (argv[1], false, nullptr);
   font_data = g_mapped_file_get_contents (mf);
   len = g_mapped_file_get_length (mf);
 #else
diff --git a/src/test-buffer-serialize.cc b/src/test-buffer-serialize.cc
index 18c46e9..c52d88a 100644
--- a/src/test-buffer-serialize.cc
+++ b/src/test-buffer-serialize.cc
@@ -45,7 +45,7 @@
 int
 main (int argc, char **argv)
 {
-  hb_blob_t *blob = NULL;
+  hb_blob_t *blob = nullptr;
 
   if (argc != 2) {
     fprintf (stderr, "usage: %s font-file\n", argv[0]);
@@ -61,7 +61,7 @@
     hb_memory_mode_t mm;
 
 #ifdef HAVE_GLIB
-    GMappedFile *mf = g_mapped_file_new (argv[1], false, NULL);
+    GMappedFile *mf = g_mapped_file_new (argv[1], false, nullptr);
     font_data = g_mapped_file_get_contents (mf);
     len = g_mapped_file_get_length (mf);
     destroy = (hb_destroy_func_t) g_mapped_file_unref;
@@ -86,7 +86,7 @@
 
   hb_face_t *face = hb_face_create (blob, 0 /* first face */);
   hb_blob_destroy (blob);
-  blob = NULL;
+  blob = nullptr;
 
   unsigned int upem = hb_face_get_upem (face);
   hb_font_t *font = hb_font_create (face);
@@ -115,7 +115,7 @@
       ret = false;
 
     hb_buffer_serialize_glyphs (buf, 0, hb_buffer_get_length (buf),
-				out, sizeof (out), NULL,
+				out, sizeof (out), nullptr,
 				font, HB_BUFFER_SERIALIZE_FORMAT_JSON,
 				HB_BUFFER_SERIALIZE_FLAG_DEFAULT);
     puts (out);
diff --git a/src/test-size-params.cc b/src/test-size-params.cc
index 35d9e3c..faa8280 100644
--- a/src/test-size-params.cc
+++ b/src/test-size-params.cc
@@ -43,7 +43,7 @@
 int
 main (int argc, char **argv)
 {
-  hb_blob_t *blob = NULL;
+  hb_blob_t *blob = nullptr;
 
   if (argc != 2) {
     fprintf (stderr, "usage: %s font-file\n", argv[0]);
@@ -59,7 +59,7 @@
     hb_memory_mode_t mm;
 
 #ifdef HAVE_GLIB
-    GMappedFile *mf = g_mapped_file_new (argv[1], false, NULL);
+    GMappedFile *mf = g_mapped_file_new (argv[1], false, nullptr);
     font_data = g_mapped_file_get_contents (mf);
     len = g_mapped_file_get_length (mf);
     destroy = (hb_destroy_func_t) g_mapped_file_unref;
@@ -85,7 +85,7 @@
   /* Create the face */
   hb_face_t *face = hb_face_create (blob, 0 /* first face */);
   hb_blob_destroy (blob);
-  blob = NULL;
+  blob = nullptr;
 
   unsigned int p[5];
   bool ret = hb_ot_layout_get_size_params (face, p, p+1, p+2, p+3, p+4);
diff --git a/src/test-would-substitute.cc b/src/test-would-substitute.cc
index 8ea87cd..cad5b5a 100644
--- a/src/test-would-substitute.cc
+++ b/src/test-would-substitute.cc
@@ -47,7 +47,7 @@
 int
 main (int argc, char **argv)
 {
-  hb_blob_t *blob = NULL;
+  hb_blob_t *blob = nullptr;
 
   if (argc != 4 && argc != 5) {
     fprintf (stderr, "usage: %s font-file lookup-index first-glyph [second-glyph]\n", argv[0]);
@@ -63,7 +63,7 @@
     hb_memory_mode_t mm;
 
 #ifdef HAVE_GLIB
-    GMappedFile *mf = g_mapped_file_new (argv[1], false, NULL);
+    GMappedFile *mf = g_mapped_file_new (argv[1], false, nullptr);
     font_data = g_mapped_file_get_contents (mf);
     len = g_mapped_file_get_length (mf);
     destroy = (hb_destroy_func_t) g_mapped_file_unref;
@@ -89,7 +89,7 @@
   /* Create the face */
   hb_face_t *face = hb_face_create (blob, 0 /* first face */);
   hb_blob_destroy (blob);
-  blob = NULL;
+  blob = nullptr;
 
   hb_font_t *font = hb_font_create (face);
 #ifdef HAVE_FREETYPE
@@ -102,5 +102,5 @@
       (argc > 4 &&
        !hb_font_glyph_from_string (font, argv[4], -1, &glyphs[1])))
     return 2;
-  return !hb_ot_layout_lookup_would_substitute (face, strtol (argv[2], NULL, 0), glyphs, len, false);
+  return !hb_ot_layout_lookup_would_substitute (face, strtol (argv[2], nullptr, 0), glyphs, len, false);
 }
diff --git a/src/test.cc b/src/test.cc
index 0c90f8f..2c24fda 100644
--- a/src/test.cc
+++ b/src/test.cc
@@ -46,7 +46,7 @@
 int
 main (int argc, char **argv)
 {
-  hb_blob_t *blob = NULL;
+  hb_blob_t *blob = nullptr;
 
   if (argc != 2) {
     fprintf (stderr, "usage: %s font-file.ttf\n", argv[0]);
@@ -62,7 +62,7 @@
     hb_memory_mode_t mm;
 
 #ifdef HAVE_GLIB
-    GMappedFile *mf = g_mapped_file_new (argv[1], false, NULL);
+    GMappedFile *mf = g_mapped_file_new (argv[1], false, nullptr);
     font_data = g_mapped_file_get_contents (mf);
     len = g_mapped_file_get_length (mf);
     destroy = (hb_destroy_func_t) g_mapped_file_unref;
@@ -90,7 +90,7 @@
   /* Create the face */
   hb_face_t *face = hb_face_create (blob, 0 /* first face */);
   hb_blob_destroy (blob);
-  blob = NULL;
+  blob = nullptr;
   unsigned int upem = hb_face_get_upem (face);
 
   hb_font_t *font = hb_font_create (face);
@@ -105,11 +105,11 @@
   hb_buffer_add_utf8 (buffer, "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xb0\xe0\xa5\x8d\xe0\xa4\x95", -1, 0, -1);
   hb_buffer_guess_segment_properties (buffer);
 
-  hb_shape (font, buffer, NULL, 0);
+  hb_shape (font, buffer, nullptr, 0);
 
   unsigned int count = hb_buffer_get_length (buffer);
-  hb_glyph_info_t *infos = hb_buffer_get_glyph_infos (buffer, NULL);
-  hb_glyph_position_t *positions = hb_buffer_get_glyph_positions (buffer, NULL);
+  hb_glyph_info_t *infos = hb_buffer_get_glyph_infos (buffer, nullptr);
+  hb_glyph_position_t *positions = hb_buffer_get_glyph_positions (buffer, nullptr);
 
   for (unsigned int i = 0; i < count; i++)
   {