Add function to compare two buffers
Based on patch from Jonathan Kew.
Needs more cleaning up and documentation.
New API:
hb_buffer_diff_flags_t
hb_buffer_diff()
diff --git a/src/hb-buffer.h b/src/hb-buffer.h
index 1d40747..abb1ea3 100644
--- a/src/hb-buffer.h
+++ b/src/hb-buffer.h
@@ -466,6 +466,45 @@
/*
+ * Compare buffers
+ */
+
+typedef enum { /*< flags >*/
+ HB_BUFFER_DIFF_FLAG_EQUAL = 0x0000,
+
+ /* Buffers with different content_type cannot be meaningfully compared
+ * in any further detail. */
+ HB_BUFFER_DIFF_FLAG_CONTENT_TYPE_MISMATCH = 0X0001,
+
+ /* For buffers with differing length, the per-glyph comparison is not
+ * attempted, though we do still scan reference for dottedcircle / .notdef
+ * glyphs. */
+ HB_BUFFER_DIFF_FLAG_LENGTH_MISMATCH = 0X0002,
+
+ /* We want to know if dottedcircle / .notdef glyphs are present in the
+ * reference, as we may not care so much about other differences in this
+ * case. */
+ HB_BUFFER_DIFF_FLAG_NOTDEF_PRESENT = 0x0004,
+ HB_BUFFER_DIFF_FLAG_DOTTED_CIRCLE_PRESENT = 0x0008,
+
+ /* If the buffers have the same length, we compare them glyph-by-glyph
+ * and report which aspect(s) of the glyph info/position are different. */
+ HB_BUFFER_DIFF_FLAG_CODEPOINT_MISMATCH = 0x0010,
+ HB_BUFFER_DIFF_FLAG_CLUSTER_MISMATCH = 0x0010,
+ HB_BUFFER_DIFF_FLAG_MASK_MISMATCH = 0x0040,
+ HB_BUFFER_DIFF_FLAG_POSITION_MISMATCH = 0x0080
+
+} hb_buffer_diff_flags_t;
+
+/* Compare the contents of two buffers, report types of differences. */
+hb_buffer_diff_flags_t
+hb_buffer_diff (hb_buffer_t *buffer,
+ hb_buffer_t *reference,
+ hb_codepoint_t dottedcircle_glyph,
+ unsigned int position_fuzz);
+
+
+/*
* Debugging.
*/
