| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| // -- This file was mechanically generated: Do not edit! -- // |
| |
| package java.nio.charset; |
| |
| import java.nio.Buffer; |
| import java.nio.ByteBuffer; |
| import java.nio.CharBuffer; |
| import java.nio.BufferOverflowException; |
| import java.nio.BufferUnderflowException; |
| import java.lang.ref.WeakReference; |
| import java.nio.charset.CoderMalfunctionError; // javadoc |
| import java.util.Arrays; |
| import java.util.Objects; |
| |
| |
| /** |
| * An engine that can transform a sequence of bytes in a specific charset into a sequence of |
| * sixteen-bit Unicode characters. |
| * |
| * <a id="steps"></a> |
| * |
| * <p> The input byte sequence is provided in a byte buffer or a series |
| * of such buffers. The output character sequence is written to a character buffer |
| * or a series of such buffers. A decoder should always be used by making |
| * the following sequence of method invocations, hereinafter referred to as a |
| * <i>decoding operation</i>: |
| * |
| * <ol> |
| * |
| * <li><p> Reset the decoder via the {@link #reset reset} method, unless it |
| * has not been used before; </p></li> |
| * |
| * <li><p> Invoke the {@link #decode decode} method zero or more times, as |
| * long as additional input may be available, passing {@code false} for the |
| * {@code endOfInput} argument and filling the input buffer and flushing the |
| * output buffer between invocations; </p></li> |
| * |
| * <li><p> Invoke the {@link #decode decode} method one final time, passing |
| * {@code true} for the {@code endOfInput} argument; and then </p></li> |
| * |
| * <li><p> Invoke the {@link #flush flush} method so that the decoder can |
| * flush any internal state to the output buffer. </p></li> |
| * |
| * </ol> |
| * |
| * Each invocation of the {@link #decode decode} method will decode as many |
| * bytes as possible from the input buffer, writing the resulting characters |
| * to the output buffer. The {@link #decode decode} method returns when more |
| * input is required, when there is not enough room in the output buffer, or |
| * when a decoding error has occurred. In each case a {@link CoderResult} |
| * object is returned to describe the reason for termination. An invoker can |
| * examine this object and fill the input buffer, flush the output buffer, or |
| * attempt to recover from a decoding error, as appropriate, and try again. |
| * |
| * <a id="ce"></a> |
| * |
| * <p> There are two general types of decoding errors. If the input byte |
| * sequence is not legal for this charset then the input is considered <i>malformed</i>. If |
| * the input byte sequence is legal but cannot be mapped to a valid |
| * Unicode character then an <i>unmappable character</i> has been encountered. |
| * |
| * <a id="cae"></a> |
| * |
| * <p> How a decoding error is handled depends upon the action requested for |
| * that type of error, which is described by an instance of the {@link |
| * CodingErrorAction} class. The possible error actions are to {@linkplain |
| * CodingErrorAction#IGNORE ignore} the erroneous input, {@linkplain |
| * CodingErrorAction#REPORT report} the error to the invoker via |
| * the returned {@link CoderResult} object, or {@linkplain CodingErrorAction#REPLACE |
| * replace} the erroneous input with the current value of the |
| * replacement string. The replacement |
| * |
| |
| |
| |
| |
| |
| * has the initial value <code>"\uFFFD"</code>; |
| |
| * |
| * its value may be changed via the {@link #replaceWith(java.lang.String) |
| * replaceWith} method. |
| * |
| * <p> The default action for malformed-input and unmappable-character errors |
| * is to {@linkplain CodingErrorAction#REPORT report} them. The |
| * malformed-input error action may be changed via the {@link |
| * #onMalformedInput(CodingErrorAction) onMalformedInput} method; the |
| * unmappable-character action may be changed via the {@link |
| * #onUnmappableCharacter(CodingErrorAction) onUnmappableCharacter} method. |
| * |
| * <p> This class is designed to handle many of the details of the decoding |
| * process, including the implementation of error actions. A decoder for a |
| * specific charset, which is a concrete subclass of this class, need only |
| * implement the abstract {@link #decodeLoop decodeLoop} method, which |
| * encapsulates the basic decoding loop. A subclass that maintains internal |
| * state should, additionally, override the {@link #implFlush implFlush} and |
| * {@link #implReset implReset} methods. |
| * |
| * <p> Instances of this class are not safe for use by multiple concurrent |
| * threads. </p> |
| * |
| * |
| * @author Mark Reinhold |
| * @author JSR-51 Expert Group |
| * @since 1.4 |
| * |
| * @see ByteBuffer |
| * @see CharBuffer |
| * @see Charset |
| * @see CharsetEncoder |
| */ |
| |
| public abstract class CharsetDecoder { |
| |
| private final Charset charset; |
| private final float averageCharsPerByte; |
| private final float maxCharsPerByte; |
| |
| private String replacement; |
| private CodingErrorAction malformedInputAction |
| = CodingErrorAction.REPORT; |
| private CodingErrorAction unmappableCharacterAction |
| = CodingErrorAction.REPORT; |
| |
| // Internal states |
| // |
| private static final int ST_RESET = 0; |
| private static final int ST_CODING = 1; |
| private static final int ST_END = 2; |
| private static final int ST_FLUSHED = 3; |
| |
| private int state = ST_RESET; |
| |
| private static String stateNames[] |
| = { "RESET", "CODING", "CODING_END", "FLUSHED" }; |
| |
| |
| /** |
| * Initializes a new decoder. The new decoder will have the given |
| * chars-per-byte and replacement values. |
| * |
| * @param cs |
| * The charset that created this decoder |
| * |
| * @param averageCharsPerByte |
| * A positive float value indicating the expected number of |
| * characters that will be produced for each input byte |
| * |
| * @param maxCharsPerByte |
| * A positive float value indicating the maximum number of |
| * characters that will be produced for each input byte |
| * |
| * @param replacement |
| * The initial replacement; must not be {@code null}, must have |
| * non-zero length, must not be longer than maxCharsPerByte, |
| * and must be {@linkplain #isLegalReplacement legal} |
| * |
| * @throws IllegalArgumentException |
| * If the preconditions on the parameters do not hold |
| */ |
| private |
| CharsetDecoder(Charset cs, |
| float averageCharsPerByte, |
| float maxCharsPerByte, |
| String replacement) |
| { |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| this.charset = cs; |
| // Use !(a > 0.0f) rather than (a <= 0.0f) to exclude NaN values |
| if (!(averageCharsPerByte > 0.0f)) |
| throw new IllegalArgumentException("Non-positive " |
| + "averageCharsPerByte"); |
| // Use !(a > 0.0f) rather than (a <= 0.0f) to exclude NaN values |
| if (!(maxCharsPerByte > 0.0f)) |
| throw new IllegalArgumentException("Non-positive " |
| + "maxCharsPerByte"); |
| if (averageCharsPerByte > maxCharsPerByte) |
| throw new IllegalArgumentException("averageCharsPerByte" |
| + " exceeds " |
| + "maxCharsPerByte"); |
| this.replacement = replacement; |
| this.averageCharsPerByte = averageCharsPerByte; |
| this.maxCharsPerByte = maxCharsPerByte; |
| |
| |
| |
| // Android-removed |
| // replaceWith(replacement); |
| |
| |
| |
| |
| |
| |
| |
| |
| } |
| |
| /** |
| * Initializes a new decoder. The new decoder will have the given |
| * chars-per-byte values and its replacement will be the |
| * string <code>"\uFFFD"</code>. |
| * |
| * @param cs |
| * The charset that created this decoder |
| * |
| * @param averageCharsPerByte |
| * A positive float value indicating the expected number of |
| * characters that will be produced for each input byte |
| * |
| * @param maxCharsPerByte |
| * A positive float value indicating the maximum number of |
| * characters that will be produced for each input byte |
| * |
| * @throws IllegalArgumentException |
| * If the preconditions on the parameters do not hold |
| */ |
| protected CharsetDecoder(Charset cs, |
| float averageCharsPerByte, |
| float maxCharsPerByte) |
| { |
| this(cs, |
| averageCharsPerByte, maxCharsPerByte, |
| "\uFFFD"); |
| } |
| |
| /** |
| * Returns the charset that created this decoder. |
| * |
| * @return This decoder's charset |
| */ |
| public final Charset charset() { |
| return charset; |
| } |
| |
| /** |
| * Returns this decoder's replacement value. |
| * |
| * @return This decoder's current replacement, |
| * which is never {@code null} and is never empty |
| */ |
| public final String replacement() { |
| |
| return replacement; |
| |
| |
| |
| |
| } |
| |
| /** |
| * Changes this decoder's replacement value. |
| * |
| * <p> This method invokes the {@link #implReplaceWith implReplaceWith} |
| * method, passing the new replacement, after checking that the new |
| * replacement is acceptable. </p> |
| * |
| * @param newReplacement The new replacement; must not be |
| * {@code null}, must have non-zero length, |
| |
| * and must not be longer than the value returned by the |
| * {@link #maxCharsPerByte() maxCharsPerByte} method |
| |
| |
| |
| |
| |
| |
| * |
| * @return This decoder |
| * |
| * @throws IllegalArgumentException |
| * If the preconditions on the parameter do not hold |
| */ |
| public final CharsetDecoder replaceWith(String newReplacement) { |
| if (newReplacement == null) |
| throw new IllegalArgumentException("Null replacement"); |
| int len = newReplacement.length(); |
| if (len == 0) |
| throw new IllegalArgumentException("Empty replacement"); |
| if (len > maxCharsPerByte) |
| throw new IllegalArgumentException("Replacement too long"); |
| |
| this.replacement = newReplacement; |
| |
| |
| |
| |
| |
| |
| implReplaceWith(this.replacement); |
| return this; |
| } |
| |
| /** |
| * Reports a change to this decoder's replacement value. |
| * |
| * <p> The default implementation of this method does nothing. This method |
| * should be overridden by decoders that require notification of changes to |
| * the replacement. </p> |
| * |
| * @param newReplacement The replacement value |
| */ |
| protected void implReplaceWith(String newReplacement) { |
| } |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| /** |
| * Returns this decoder's current action for malformed-input errors. |
| * |
| * @return The current malformed-input action, which is never {@code null} |
| */ |
| public CodingErrorAction malformedInputAction() { |
| return malformedInputAction; |
| } |
| |
| /** |
| * Changes this decoder's action for malformed-input errors. |
| * |
| * <p> This method invokes the {@link #implOnMalformedInput |
| * implOnMalformedInput} method, passing the new action. </p> |
| * |
| * @param newAction The new action; must not be {@code null} |
| * |
| * @return This decoder |
| * |
| * @throws IllegalArgumentException |
| * If the precondition on the parameter does not hold |
| */ |
| public final CharsetDecoder onMalformedInput(CodingErrorAction newAction) { |
| if (newAction == null) |
| throw new IllegalArgumentException("Null action"); |
| malformedInputAction = newAction; |
| implOnMalformedInput(newAction); |
| return this; |
| } |
| |
| /** |
| * Reports a change to this decoder's malformed-input action. |
| * |
| * <p> The default implementation of this method does nothing. This method |
| * should be overridden by decoders that require notification of changes to |
| * the malformed-input action. </p> |
| * |
| * @param newAction The new action |
| */ |
| protected void implOnMalformedInput(CodingErrorAction newAction) { } |
| |
| /** |
| * Returns this decoder's current action for unmappable-character errors. |
| * |
| * @return The current unmappable-character action, which is never |
| * {@code null} |
| */ |
| public CodingErrorAction unmappableCharacterAction() { |
| return unmappableCharacterAction; |
| } |
| |
| /** |
| * Changes this decoder's action for unmappable-character errors. |
| * |
| * <p> This method invokes the {@link #implOnUnmappableCharacter |
| * implOnUnmappableCharacter} method, passing the new action. </p> |
| * |
| * @param newAction The new action; must not be {@code null} |
| * |
| * @return This decoder |
| * |
| * @throws IllegalArgumentException |
| * If the precondition on the parameter does not hold |
| */ |
| public final CharsetDecoder onUnmappableCharacter(CodingErrorAction |
| newAction) |
| { |
| if (newAction == null) |
| throw new IllegalArgumentException("Null action"); |
| unmappableCharacterAction = newAction; |
| implOnUnmappableCharacter(newAction); |
| return this; |
| } |
| |
| /** |
| * Reports a change to this decoder's unmappable-character action. |
| * |
| * <p> The default implementation of this method does nothing. This method |
| * should be overridden by decoders that require notification of changes to |
| * the unmappable-character action. </p> |
| * |
| * @param newAction The new action |
| */ |
| protected void implOnUnmappableCharacter(CodingErrorAction newAction) { } |
| |
| /** |
| * Returns the average number of characters that will be produced for each |
| * byte of input. This heuristic value may be used to estimate the size |
| * of the output buffer required for a given input sequence. |
| * |
| * @return The average number of characters produced |
| * per byte of input |
| */ |
| public final float averageCharsPerByte() { |
| return averageCharsPerByte; |
| } |
| |
| /** |
| * Returns the maximum number of characters that will be produced for each |
| * byte of input. This value may be used to compute the worst-case size |
| * of the output buffer required for a given input sequence. This value |
| * accounts for any necessary content-independent prefix or suffix |
| |
| |
| |
| |
| * characters. |
| |
| * |
| * @return The maximum number of characters that will be produced per |
| * byte of input |
| */ |
| public final float maxCharsPerByte() { |
| return maxCharsPerByte; |
| } |
| |
| // Android-changed: Keep compat behavior. Document NPE thrown for null arguments. |
| /** |
| * Decodes as many bytes as possible from the given input buffer, |
| * writing the results to the given output buffer. |
| * |
| * <p> The buffers are read from, and written to, starting at their current |
| * positions. At most {@link Buffer#remaining in.remaining()} bytes |
| * will be read and at most {@link Buffer#remaining out.remaining()} |
| * characters will be written. The buffers' positions will be advanced to |
| * reflect the bytes read and the characters written, but their marks and |
| * limits will not be modified. |
| * |
| * <p> In addition to reading bytes from the input buffer and writing |
| * characters to the output buffer, this method returns a {@link CoderResult} |
| * object to describe its reason for termination: |
| * |
| * <ul> |
| * |
| * <li><p> {@link CoderResult#UNDERFLOW} indicates that as much of the |
| * input buffer as possible has been decoded. If there is no further |
| * input then the invoker can proceed to the next step of the |
| * <a href="#steps">decoding operation</a>. Otherwise this method |
| * should be invoked again with further input. </p></li> |
| * |
| * <li><p> {@link CoderResult#OVERFLOW} indicates that there is |
| * insufficient space in the output buffer to decode any more bytes. |
| * This method should be invoked again with an output buffer that has |
| * more {@linkplain Buffer#remaining remaining} characters. This is |
| * typically done by draining any decoded characters from the output |
| * buffer. </p></li> |
| * |
| * <li><p> A {@linkplain CoderResult#malformedForLength |
| * malformed-input} result indicates that a malformed-input |
| * error has been detected. The malformed bytes begin at the input |
| * buffer's (possibly incremented) position; the number of malformed |
| * bytes may be determined by invoking the result object's {@link |
| * CoderResult#length() length} method. This case applies only if the |
| * {@linkplain #onMalformedInput malformed action} of this decoder |
| * is {@link CodingErrorAction#REPORT}; otherwise the malformed input |
| * will be ignored or replaced, as requested. </p></li> |
| * |
| * <li><p> An {@linkplain CoderResult#unmappableForLength |
| * unmappable-character} result indicates that an |
| * unmappable-character error has been detected. The bytes that |
| * decode the unmappable character begin at the input buffer's (possibly |
| * incremented) position; the number of such bytes may be determined |
| * by invoking the result object's {@link CoderResult#length() length} |
| * method. This case applies only if the {@linkplain #onUnmappableCharacter |
| * unmappable action} of this decoder is {@link |
| * CodingErrorAction#REPORT}; otherwise the unmappable character will be |
| * ignored or replaced, as requested. </p></li> |
| * |
| * </ul> |
| * |
| * In any case, if this method is to be reinvoked in the same decoding |
| * operation then care should be taken to preserve any bytes remaining |
| * in the input buffer so that they are available to the next invocation. |
| * |
| * <p> The {@code endOfInput} parameter advises this method as to whether |
| * the invoker can provide further input beyond that contained in the given |
| * input buffer. If there is a possibility of providing additional input |
| * then the invoker should pass {@code false} for this parameter; if there |
| * is no possibility of providing further input then the invoker should |
| * pass {@code true}. It is not erroneous, and in fact it is quite |
| * common, to pass {@code false} in one invocation and later discover that |
| * no further input was actually available. It is critical, however, that |
| * the final invocation of this method in a sequence of invocations always |
| * pass {@code true} so that any remaining undecoded input will be treated |
| * as being malformed. |
| * |
| * <p> This method works by invoking the {@link #decodeLoop decodeLoop} |
| * method, interpreting its results, handling error conditions, and |
| * reinvoking it as necessary. </p> |
| * |
| * |
| * @param in |
| * The input byte buffer |
| * |
| * @param out |
| * The output character buffer |
| * |
| * @param endOfInput |
| * {@code true} if, and only if, the invoker can provide no |
| * additional input bytes beyond those in the given buffer |
| * |
| * @return A coder-result object describing the reason for termination |
| * |
| * @throws IllegalStateException |
| * If a decoding operation is already in progress and the previous |
| * step was an invocation neither of the {@link #reset reset} |
| * method, nor of this method with a value of {@code false} for |
| * the {@code endOfInput} parameter, nor of this method with a |
| * value of {@code true} for the {@code endOfInput} parameter |
| * but a return value indicating an incomplete decoding operation |
| * |
| * @throws CoderMalfunctionError |
| * If an invocation of the decodeLoop method threw |
| * an unexpected exception |
| * |
| * @throws NullPointerException if input or output buffer is null |
| */ |
| public final CoderResult decode(ByteBuffer in, CharBuffer out, |
| boolean endOfInput) |
| { |
| // Android-added: Keep compat behavior. libcore throws NPE for null arguments. |
| Objects.requireNonNull(in, "in"); |
| Objects.requireNonNull(out, "out"); |
| |
| int newState = endOfInput ? ST_END : ST_CODING; |
| if ((state != ST_RESET) && (state != ST_CODING) |
| && !(endOfInput && (state == ST_END))) |
| throwIllegalStateException(state, newState); |
| state = newState; |
| |
| for (;;) { |
| |
| CoderResult cr; |
| try { |
| cr = decodeLoop(in, out); |
| } catch (RuntimeException x) { |
| throw new CoderMalfunctionError(x); |
| } |
| |
| if (cr.isOverflow()) |
| return cr; |
| |
| if (cr.isUnderflow()) { |
| if (endOfInput && in.hasRemaining()) { |
| cr = CoderResult.malformedForLength(in.remaining()); |
| // Fall through to malformed-input case |
| } else { |
| return cr; |
| } |
| } |
| |
| CodingErrorAction action = null; |
| if (cr.isMalformed()) |
| action = malformedInputAction; |
| else if (cr.isUnmappable()) |
| action = unmappableCharacterAction; |
| else |
| assert false : cr.toString(); |
| |
| if (action == CodingErrorAction.REPORT) |
| return cr; |
| |
| if (action == CodingErrorAction.REPLACE) { |
| if (out.remaining() < replacement.length()) |
| return CoderResult.OVERFLOW; |
| out.put(replacement); |
| } |
| |
| if ((action == CodingErrorAction.IGNORE) |
| || (action == CodingErrorAction.REPLACE)) { |
| // Skip erroneous input either way |
| in.position(in.position() + cr.length()); |
| continue; |
| } |
| |
| assert false; |
| } |
| |
| } |
| |
| /** |
| * Flushes this decoder. |
| * |
| * <p> Some decoders maintain internal state and may need to write some |
| * final characters to the output buffer once the overall input sequence has |
| * been read. |
| * |
| * <p> Any additional output is written to the output buffer beginning at |
| * its current position. At most {@link Buffer#remaining out.remaining()} |
| * characters will be written. The buffer's position will be advanced |
| * appropriately, but its mark and limit will not be modified. |
| * |
| * <p> If this method completes successfully then it returns {@link |
| * CoderResult#UNDERFLOW}. If there is insufficient room in the output |
| * buffer then it returns {@link CoderResult#OVERFLOW}. If this happens |
| * then this method must be invoked again, with an output buffer that has |
| * more room, in order to complete the current <a href="#steps">decoding |
| * operation</a>. |
| * |
| * <p> If this decoder has already been flushed then invoking this method |
| * has no effect. |
| * |
| * <p> This method invokes the {@link #implFlush implFlush} method to |
| * perform the actual flushing operation. </p> |
| * |
| * @param out |
| * The output character buffer |
| * |
| * @return A coder-result object, either {@link CoderResult#UNDERFLOW} or |
| * {@link CoderResult#OVERFLOW} |
| * |
| * @throws IllegalStateException |
| * If the previous step of the current decoding operation was an |
| * invocation neither of the {@link #flush flush} method nor of |
| * the three-argument {@link |
| * #decode(ByteBuffer,CharBuffer,boolean) decode} method |
| * with a value of {@code true} for the {@code endOfInput} |
| * parameter |
| */ |
| public final CoderResult flush(CharBuffer out) { |
| if (state == ST_END) { |
| CoderResult cr = implFlush(out); |
| if (cr.isUnderflow()) |
| state = ST_FLUSHED; |
| return cr; |
| } |
| |
| if (state != ST_FLUSHED) |
| throwIllegalStateException(state, ST_FLUSHED); |
| |
| return CoderResult.UNDERFLOW; // Already flushed |
| } |
| |
| /** |
| * Flushes this decoder. |
| * |
| * <p> The default implementation of this method does nothing, and always |
| * returns {@link CoderResult#UNDERFLOW}. This method should be overridden |
| * by decoders that may need to write final characters to the output buffer |
| * once the entire input sequence has been read. </p> |
| * |
| * @param out |
| * The output character buffer |
| * |
| * @return A coder-result object, either {@link CoderResult#UNDERFLOW} or |
| * {@link CoderResult#OVERFLOW} |
| */ |
| protected CoderResult implFlush(CharBuffer out) { |
| return CoderResult.UNDERFLOW; |
| } |
| |
| /** |
| * Resets this decoder, clearing any internal state. |
| * |
| * <p> This method resets charset-independent state and also invokes the |
| * {@link #implReset() implReset} method in order to perform any |
| * charset-specific reset actions. </p> |
| * |
| * @return This decoder |
| * |
| */ |
| public final CharsetDecoder reset() { |
| implReset(); |
| state = ST_RESET; |
| return this; |
| } |
| |
| /** |
| * Resets this decoder, clearing any charset-specific internal state. |
| * |
| * <p> The default implementation of this method does nothing. This method |
| * should be overridden by decoders that maintain internal state. </p> |
| */ |
| protected void implReset() { } |
| |
| /** |
| * Decodes one or more bytes into one or more characters. |
| * |
| * <p> This method encapsulates the basic decoding loop, decoding as many |
| * bytes as possible until it either runs out of input, runs out of room |
| * in the output buffer, or encounters a decoding error. This method is |
| * invoked by the {@link #decode decode} method, which handles result |
| * interpretation and error recovery. |
| * |
| * <p> The buffers are read from, and written to, starting at their current |
| * positions. At most {@link Buffer#remaining in.remaining()} bytes |
| * will be read, and at most {@link Buffer#remaining out.remaining()} |
| * characters will be written. The buffers' positions will be advanced to |
| * reflect the bytes read and the characters written, but their marks and |
| * limits will not be modified. |
| * |
| * <p> This method returns a {@link CoderResult} object to describe its |
| * reason for termination, in the same manner as the {@link #decode decode} |
| * method. Most implementations of this method will handle decoding errors |
| * by returning an appropriate result object for interpretation by the |
| * {@link #decode decode} method. An optimized implementation may instead |
| * examine the relevant error action and implement that action itself. |
| * |
| * <p> An implementation of this method may perform arbitrary lookahead by |
| * returning {@link CoderResult#UNDERFLOW} until it receives sufficient |
| * input. </p> |
| * |
| * @param in |
| * The input byte buffer |
| * |
| * @param out |
| * The output character buffer |
| * |
| * @return A coder-result object describing the reason for termination |
| */ |
| protected abstract CoderResult decodeLoop(ByteBuffer in, |
| CharBuffer out); |
| |
| // Android-changed: Document CoderMalfunctionError and NPE thrown for null input buffer. |
| /** |
| * Convenience method that decodes the remaining content of a single input |
| * byte buffer into a newly-allocated character buffer. |
| * |
| * <p> This method implements an entire <a href="#steps">decoding |
| * operation</a>; that is, it resets this decoder, then it decodes the |
| * bytes in the given byte buffer, and finally it flushes this |
| * decoder. This method should therefore not be invoked if a decoding |
| * operation is already in progress. </p> |
| * |
| * @param in |
| * The input byte buffer |
| * |
| * @return A newly-allocated character buffer containing the result of the |
| * decoding operation. The buffer's position will be zero and its |
| * limit will follow the last character written. |
| * |
| * @throws IllegalStateException |
| * If a decoding operation is already in progress |
| * |
| * @throws MalformedInputException |
| * If the byte sequence starting at the input buffer's current |
| * position is not legal for this charset and the current malformed-input action |
| * is {@link CodingErrorAction#REPORT} |
| * |
| * @throws UnmappableCharacterException |
| * If the byte sequence starting at the input buffer's current |
| * position cannot be mapped to an equivalent character sequence and |
| * the current unmappable-character action is {@link |
| * CodingErrorAction#REPORT} |
| * |
| * @throws CoderMalfunctionError |
| * If an invocation of the decodeLoop method threw |
| * an unexpected exception |
| * |
| * @throws NullPointerException if input buffer is null |
| */ |
| public final CharBuffer decode(ByteBuffer in) |
| throws CharacterCodingException |
| { |
| int n = (int)(in.remaining() * averageCharsPerByte()); |
| CharBuffer out = CharBuffer.allocate(n); |
| |
| if ((n == 0) && (in.remaining() == 0)) |
| return out; |
| reset(); |
| for (;;) { |
| CoderResult cr = in.hasRemaining() ? |
| decode(in, out, true) : CoderResult.UNDERFLOW; |
| if (cr.isUnderflow()) |
| cr = flush(out); |
| |
| if (cr.isUnderflow()) |
| break; |
| if (cr.isOverflow()) { |
| n = 2*n + 1; // Ensure progress; n might be 0! |
| CharBuffer o = CharBuffer.allocate(n); |
| out.flip(); |
| o.put(out); |
| out = o; |
| continue; |
| } |
| cr.throwException(); |
| } |
| out.flip(); |
| return out; |
| } |
| |
| |
| |
| /** |
| * Tells whether or not this decoder implements an auto-detecting charset. |
| * |
| * <p> The default implementation of this method always returns |
| * {@code false}; it should be overridden by auto-detecting decoders to |
| * return {@code true}. </p> |
| * |
| * @return {@code true} if, and only if, this decoder implements an |
| * auto-detecting charset |
| */ |
| public boolean isAutoDetecting() { |
| return false; |
| } |
| |
| /** |
| * Tells whether or not this decoder has yet detected a |
| * charset <i>(optional operation)</i>. |
| * |
| * <p> If this decoder implements an auto-detecting charset then at a |
| * single point during a decoding operation this method may start returning |
| * {@code true} to indicate that a specific charset has been detected in |
| * the input byte sequence. Once this occurs, the {@link #detectedCharset |
| * detectedCharset} method may be invoked to retrieve the detected charset. |
| * |
| * <p> That this method returns {@code false} does not imply that no bytes |
| * have yet been decoded. Some auto-detecting decoders are capable of |
| * decoding some, or even all, of an input byte sequence without fixing on |
| * a particular charset. |
| * |
| * <p> The default implementation of this method always throws an {@link |
| * UnsupportedOperationException}; it should be overridden by |
| * auto-detecting decoders to return {@code true} once the input charset |
| * has been determined. </p> |
| * |
| * @return {@code true} if, and only if, this decoder has detected a |
| * specific charset |
| * |
| * @throws UnsupportedOperationException |
| * If this decoder does not implement an auto-detecting charset |
| */ |
| public boolean isCharsetDetected() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Retrieves the charset that was detected by this |
| * decoder <i>(optional operation)</i>. |
| * |
| * <p> If this decoder implements an auto-detecting charset then this |
| * method returns the actual charset once it has been detected. After that |
| * point, this method returns the same value for the duration of the |
| * current decoding operation. If not enough input bytes have yet been |
| * read to determine the actual charset then this method throws an {@link |
| * IllegalStateException}. |
| * |
| * <p> The default implementation of this method always throws an {@link |
| * UnsupportedOperationException}; it should be overridden by |
| * auto-detecting decoders to return the appropriate value. </p> |
| * |
| * @return The charset detected by this auto-detecting decoder, |
| * or {@code null} if the charset has not yet been determined |
| * |
| * @throws IllegalStateException |
| * If insufficient bytes have been read to determine a charset |
| * |
| * @throws UnsupportedOperationException |
| * If this decoder does not implement an auto-detecting charset |
| */ |
| public Charset detectedCharset() { |
| throw new UnsupportedOperationException(); |
| } |
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| private void throwIllegalStateException(int from, int to) { |
| throw new IllegalStateException("Current state = " + stateNames[from] |
| + ", new state = " + stateNames[to]); |
| } |
| |
| } |
