diff options
Diffstat (limited to 'java/core/src/main/java/com/google/protobuf/Utf8.java')
| -rw-r--r-- | java/core/src/main/java/com/google/protobuf/Utf8.java | 478 |
1 files changed, 477 insertions, 1 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/Utf8.java b/java/core/src/main/java/com/google/protobuf/Utf8.java index 1b136144..de75fe6b 100644 --- a/java/core/src/main/java/com/google/protobuf/Utf8.java +++ b/java/core/src/main/java/com/google/protobuf/Utf8.java @@ -34,11 +34,15 @@ import static com.google.protobuf.UnsafeUtil.addressOffset; import static com.google.protobuf.UnsafeUtil.hasUnsafeArrayOperations; import static com.google.protobuf.UnsafeUtil.hasUnsafeByteBufferOperations; import static java.lang.Character.MAX_SURROGATE; +import static java.lang.Character.MIN_HIGH_SURROGATE; +import static java.lang.Character.MIN_LOW_SURROGATE; +import static java.lang.Character.MIN_SUPPLEMENTARY_CODE_POINT; import static java.lang.Character.MIN_SURROGATE; import static java.lang.Character.isSurrogatePair; import static java.lang.Character.toCodePoint; import java.nio.ByteBuffer; +import java.util.Arrays; /** * A set of low-level, high-performance static utility methods related @@ -289,7 +293,7 @@ final class Utf8 { if (Character.MIN_SURROGATE <= c && c <= Character.MAX_SURROGATE) { // Check that we have a well-formed surrogate pair. int cp = Character.codePointAt(sequence, i); - if (cp < Character.MIN_SUPPLEMENTARY_CODE_POINT) { + if (cp < MIN_SUPPLEMENTARY_CODE_POINT) { throw new UnpairedSurrogateException(i, utf16Length); } i++; @@ -331,6 +335,26 @@ final class Utf8 { } /** + * Decodes the given UTF-8 portion of the {@link ByteBuffer} into a {@link String}. + * + * @throws InvalidProtocolBufferException if the input is not valid UTF-8. + */ + static String decodeUtf8(ByteBuffer buffer, int index, int size) + throws InvalidProtocolBufferException { + return processor.decodeUtf8(buffer, index, size); + } + + /** + * Decodes the given UTF-8 encoded byte array slice into a {@link String}. + * + * @throws InvalidProtocolBufferException if the input is not valid UTF-8. + */ + static String decodeUtf8(byte[] bytes, int index, int size) + throws InvalidProtocolBufferException { + return processor.decodeUtf8(bytes, index, size); + } + + /** * Encodes the given characters to the target {@link ByteBuffer} using UTF-8 encoding. * * <p>Selects an optimal algorithm based on the type of {@link ByteBuffer} (i.e. heap or direct) @@ -610,6 +634,116 @@ final class Utf8 { } /** + * Decodes the given byte array slice into a {@link String}. + * + * @throws InvalidProtocolBufferException if the byte array slice is not valid UTF-8. + */ + abstract String decodeUtf8(byte[] bytes, int index, int size) + throws InvalidProtocolBufferException; + + /** + * Decodes the given portion of the {@link ByteBuffer} into a {@link String}. + * + * @throws InvalidProtocolBufferException if the portion of the buffer is not valid UTF-8. + */ + final String decodeUtf8(ByteBuffer buffer, int index, int size) + throws InvalidProtocolBufferException { + if (buffer.hasArray()) { + final int offset = buffer.arrayOffset(); + return decodeUtf8(buffer.array(), offset + index, size); + } else if (buffer.isDirect()) { + return decodeUtf8Direct(buffer, index, size); + } + return decodeUtf8Default(buffer, index, size); + } + + /** + * Decodes direct {@link ByteBuffer} instances into {@link String}. + */ + abstract String decodeUtf8Direct(ByteBuffer buffer, int index, int size) + throws InvalidProtocolBufferException; + + /** + * Decodes {@link ByteBuffer} instances using the {@link ByteBuffer} API rather than + * potentially faster approaches. + */ + final String decodeUtf8Default(ByteBuffer buffer, int index, int size) + throws InvalidProtocolBufferException { + // Bitwise OR combines the sign bits so any negative value fails the check. + if ((index | size | buffer.limit() - index - size) < 0) { + throw new ArrayIndexOutOfBoundsException( + String.format("buffer limit=%d, index=%d, limit=%d", buffer.limit(), index, size)); + } + + int offset = index; + final int limit = offset + size; + + // The longest possible resulting String is the same as the number of input bytes, when it is + // all ASCII. For other cases, this over-allocates and we will truncate in the end. + char[] resultArr = new char[size]; + int resultPos = 0; + + // Optimize for 100% ASCII (Hotspot loves small simple top-level loops like this). + // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII). + while (offset < limit) { + byte b = buffer.get(offset); + if (!DecodeUtil.isOneByte(b)) { + break; + } + offset++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + + while (offset < limit) { + byte byte1 = buffer.get(offset++); + if (DecodeUtil.isOneByte(byte1)) { + DecodeUtil.handleOneByte(byte1, resultArr, resultPos++); + // It's common for there to be multiple ASCII characters in a run mixed in, so add an + // extra optimized loop to take care of these runs. + while (offset < limit) { + byte b = buffer.get(offset); + if (!DecodeUtil.isOneByte(b)) { + break; + } + offset++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + } else if (DecodeUtil.isTwoBytes(byte1)) { + if (offset >= limit) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleTwoBytes( + byte1, /* byte2 */ buffer.get(offset++), resultArr, resultPos++); + } else if (DecodeUtil.isThreeBytes(byte1)) { + if (offset >= limit - 1) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleThreeBytes( + byte1, + /* byte2 */ buffer.get(offset++), + /* byte3 */ buffer.get(offset++), + resultArr, + resultPos++); + } else { + if (offset >= limit - 2) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleFourBytes( + byte1, + /* byte2 */ buffer.get(offset++), + /* byte3 */ buffer.get(offset++), + /* byte4 */ buffer.get(offset++), + resultArr, + resultPos++); + // 4-byte case requires two chars. + resultPos++; + } + } + + return new String(resultArr, 0, resultPos); + } + + /** * Encodes an input character sequence ({@code in}) to UTF-8 in the target array ({@code out}). * For a string, this method is similar to * <pre>{@code @@ -851,6 +985,88 @@ final class Utf8 { } @Override + String decodeUtf8(byte[] bytes, int index, int size) throws InvalidProtocolBufferException { + // Bitwise OR combines the sign bits so any negative value fails the check. + if ((index | size | bytes.length - index - size) < 0) { + throw new ArrayIndexOutOfBoundsException( + String.format("buffer length=%d, index=%d, size=%d", bytes.length, index, size)); + } + + int offset = index; + final int limit = offset + size; + + // The longest possible resulting String is the same as the number of input bytes, when it is + // all ASCII. For other cases, this over-allocates and we will truncate in the end. + char[] resultArr = new char[size]; + int resultPos = 0; + + // Optimize for 100% ASCII (Hotspot loves small simple top-level loops like this). + // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII). + while (offset < limit) { + byte b = bytes[offset]; + if (!DecodeUtil.isOneByte(b)) { + break; + } + offset++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + + while (offset < limit) { + byte byte1 = bytes[offset++]; + if (DecodeUtil.isOneByte(byte1)) { + DecodeUtil.handleOneByte(byte1, resultArr, resultPos++); + // It's common for there to be multiple ASCII characters in a run mixed in, so add an + // extra optimized loop to take care of these runs. + while (offset < limit) { + byte b = bytes[offset]; + if (!DecodeUtil.isOneByte(b)) { + break; + } + offset++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + } else if (DecodeUtil.isTwoBytes(byte1)) { + if (offset >= limit) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleTwoBytes(byte1, /* byte2 */ bytes[offset++], resultArr, resultPos++); + } else if (DecodeUtil.isThreeBytes(byte1)) { + if (offset >= limit - 1) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleThreeBytes( + byte1, + /* byte2 */ bytes[offset++], + /* byte3 */ bytes[offset++], + resultArr, + resultPos++); + } else { + if (offset >= limit - 2) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleFourBytes( + byte1, + /* byte2 */ bytes[offset++], + /* byte3 */ bytes[offset++], + /* byte4 */ bytes[offset++], + resultArr, + resultPos++); + // 4-byte case requires two chars. + resultPos++; + } + } + + return new String(resultArr, 0, resultPos); + } + + @Override + String decodeUtf8Direct(ByteBuffer buffer, int index, int size) + throws InvalidProtocolBufferException { + // For safe processing, we have to use the ByteBufferAPI. + return decodeUtf8Default(buffer, index, size); + } + + @Override int encodeUtf8(CharSequence in, byte[] out, int offset, int length) { int utf16Length = in.length(); int j = offset; @@ -996,6 +1212,7 @@ final class Utf8 { @Override int partialIsValidUtf8(int state, byte[] bytes, final int index, final int limit) { + // Bitwise OR combines the sign bits so any negative value fails the check. if ((index | limit | bytes.length - limit) < 0) { throw new ArrayIndexOutOfBoundsException( String.format("Array length=%d, index=%d, limit=%d", bytes.length, index, limit)); @@ -1091,6 +1308,7 @@ final class Utf8 { @Override int partialIsValidUtf8Direct( final int state, ByteBuffer buffer, final int index, final int limit) { + // Bitwise OR combines the sign bits so any negative value fails the check. if ((index | limit | buffer.limit() - limit) < 0) { throw new ArrayIndexOutOfBoundsException( String.format("buffer limit=%d, index=%d, limit=%d", buffer.limit(), index, limit)); @@ -1185,6 +1403,157 @@ final class Utf8 { } @Override + String decodeUtf8(byte[] bytes, int index, int size) throws InvalidProtocolBufferException { + if ((index | size | bytes.length - index - size) < 0) { + throw new ArrayIndexOutOfBoundsException( + String.format("buffer length=%d, index=%d, size=%d", bytes.length, index, size)); + } + + int offset = index; + final int limit = offset + size; + + // The longest possible resulting String is the same as the number of input bytes, when it is + // all ASCII. For other cases, this over-allocates and we will truncate in the end. + char[] resultArr = new char[size]; + int resultPos = 0; + + // Optimize for 100% ASCII (Hotspot loves small simple top-level loops like this). + // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII). + while (offset < limit) { + byte b = UnsafeUtil.getByte(bytes, offset); + if (!DecodeUtil.isOneByte(b)) { + break; + } + offset++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + + while (offset < limit) { + byte byte1 = UnsafeUtil.getByte(bytes, offset++); + if (DecodeUtil.isOneByte(byte1)) { + DecodeUtil.handleOneByte(byte1, resultArr, resultPos++); + // It's common for there to be multiple ASCII characters in a run mixed in, so add an + // extra optimized loop to take care of these runs. + while (offset < limit) { + byte b = UnsafeUtil.getByte(bytes, offset); + if (!DecodeUtil.isOneByte(b)) { + break; + } + offset++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + } else if (DecodeUtil.isTwoBytes(byte1)) { + if (offset >= limit) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleTwoBytes( + byte1, /* byte2 */ UnsafeUtil.getByte(bytes, offset++), resultArr, resultPos++); + } else if (DecodeUtil.isThreeBytes(byte1)) { + if (offset >= limit - 1) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleThreeBytes( + byte1, + /* byte2 */ UnsafeUtil.getByte(bytes, offset++), + /* byte3 */ UnsafeUtil.getByte(bytes, offset++), + resultArr, + resultPos++); + } else { + if (offset >= limit - 2) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleFourBytes( + byte1, + /* byte2 */ UnsafeUtil.getByte(bytes, offset++), + /* byte3 */ UnsafeUtil.getByte(bytes, offset++), + /* byte4 */ UnsafeUtil.getByte(bytes, offset++), + resultArr, + resultPos++); + // 4-byte case requires two chars. + resultPos++; + } + } + + return new String(resultArr, 0, resultPos); + } + + @Override + String decodeUtf8Direct(ByteBuffer buffer, int index, int size) + throws InvalidProtocolBufferException { + // Bitwise OR combines the sign bits so any negative value fails the check. + if ((index | size | buffer.limit() - index - size) < 0) { + throw new ArrayIndexOutOfBoundsException( + String.format("buffer limit=%d, index=%d, limit=%d", buffer.limit(), index, size)); + } + long address = UnsafeUtil.addressOffset(buffer) + index; + final long addressLimit = address + size; + + // The longest possible resulting String is the same as the number of input bytes, when it is + // all ASCII. For other cases, this over-allocates and we will truncate in the end. + char[] resultArr = new char[size]; + int resultPos = 0; + + // Optimize for 100% ASCII (Hotspot loves small simple top-level loops like this). + // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII). + while (address < addressLimit) { + byte b = UnsafeUtil.getByte(address); + if (!DecodeUtil.isOneByte(b)) { + break; + } + address++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + + while (address < addressLimit) { + byte byte1 = UnsafeUtil.getByte(address++); + if (DecodeUtil.isOneByte(byte1)) { + DecodeUtil.handleOneByte(byte1, resultArr, resultPos++); + // It's common for there to be multiple ASCII characters in a run mixed in, so add an + // extra optimized loop to take care of these runs. + while (address < addressLimit) { + byte b = UnsafeUtil.getByte(address); + if (!DecodeUtil.isOneByte(b)) { + break; + } + address++; + DecodeUtil.handleOneByte(b, resultArr, resultPos++); + } + } else if (DecodeUtil.isTwoBytes(byte1)) { + if (address >= addressLimit) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleTwoBytes( + byte1, /* byte2 */ UnsafeUtil.getByte(address++), resultArr, resultPos++); + } else if (DecodeUtil.isThreeBytes(byte1)) { + if (address >= addressLimit - 1) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleThreeBytes( + byte1, + /* byte2 */ UnsafeUtil.getByte(address++), + /* byte3 */ UnsafeUtil.getByte(address++), + resultArr, + resultPos++); + } else { + if (address >= addressLimit - 2) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + DecodeUtil.handleFourBytes( + byte1, + /* byte2 */ UnsafeUtil.getByte(address++), + /* byte3 */ UnsafeUtil.getByte(address++), + /* byte4 */ UnsafeUtil.getByte(address++), + resultArr, + resultPos++); + // 4-byte case requires two chars. + resultPos++; + } + } + + return new String(resultArr, 0, resultPos); + } + + @Override int encodeUtf8(final CharSequence in, final byte[] out, final int offset, final int length) { long outIx = offset; final long outLimit = outIx + length; @@ -1554,5 +1923,112 @@ final class Utf8 { } } + /** + * Utility methods for decoding bytes into {@link String}. Callers are responsible for extracting + * bytes (possibly using Unsafe methods), and checking remaining bytes. All other UTF-8 validity + * checks and codepoint conversion happen in this class. + */ + private static class DecodeUtil { + + /** + * Returns whether this is a single-byte codepoint (i.e., ASCII) with the form '0XXXXXXX'. + */ + private static boolean isOneByte(byte b) { + return b >= 0; + } + + /** + * Returns whether this is a two-byte codepoint with the form '10XXXXXX'. + */ + private static boolean isTwoBytes(byte b) { + return b < (byte) 0xE0; + } + + /** + * Returns whether this is a three-byte codepoint with the form '110XXXXX'. + */ + private static boolean isThreeBytes(byte b) { + return b < (byte) 0xF0; + } + + private static void handleOneByte(byte byte1, char[] resultArr, int resultPos) { + resultArr[resultPos] = (char) byte1; + } + + private static void handleTwoBytes( + byte byte1, byte byte2, char[] resultArr, int resultPos) + throws InvalidProtocolBufferException { + // Simultaneously checks for illegal trailing-byte in leading position (<= '11000000') and + // overlong 2-byte, '11000001'. + if (byte1 < (byte) 0xC2 + || isNotTrailingByte(byte2)) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + resultArr[resultPos] = (char) (((byte1 & 0x1F) << 6) | trailingByteValue(byte2)); + } + + private static void handleThreeBytes( + byte byte1, byte byte2, byte byte3, char[] resultArr, int resultPos) + throws InvalidProtocolBufferException { + if (isNotTrailingByte(byte2) + // overlong? 5 most significant bits must not all be zero + || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0) + // check for illegal surrogate codepoints + || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0) + || isNotTrailingByte(byte3)) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + resultArr[resultPos] = (char) + (((byte1 & 0x0F) << 12) | (trailingByteValue(byte2) << 6) | trailingByteValue(byte3)); + } + + private static void handleFourBytes( + byte byte1, byte byte2, byte byte3, byte byte4, char[] resultArr, int resultPos) + throws InvalidProtocolBufferException{ + if (isNotTrailingByte(byte2) + // Check that 1 <= plane <= 16. Tricky optimized form of: + // valid 4-byte leading byte? + // if (byte1 > (byte) 0xF4 || + // overlong? 4 most significant bits must not all be zero + // byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 || + // codepoint larger than the highest code point (U+10FFFF)? + // byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F) + || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0 + || isNotTrailingByte(byte3) + || isNotTrailingByte(byte4)) { + throw InvalidProtocolBufferException.invalidUtf8(); + } + int codepoint = ((byte1 & 0x07) << 18) + | (trailingByteValue(byte2) << 12) + | (trailingByteValue(byte3) << 6) + | trailingByteValue(byte4); + resultArr[resultPos] = DecodeUtil.highSurrogate(codepoint); + resultArr[resultPos + 1] = DecodeUtil.lowSurrogate(codepoint); + } + + /** + * Returns whether the byte is not a valid continuation of the form '10XXXXXX'. + */ + private static boolean isNotTrailingByte(byte b) { + return b > (byte) 0xBF; + } + + /** + * Returns the actual value of the trailing byte (removes the prefix '10') for composition. + */ + private static int trailingByteValue(byte b) { + return b & 0x3F; + } + + private static char highSurrogate(int codePoint) { + return (char) ((MIN_HIGH_SURROGATE - (MIN_SUPPLEMENTARY_CODE_POINT >>> 10)) + + (codePoint >>> 10)); + } + + private static char lowSurrogate(int codePoint) { + return (char) (MIN_LOW_SURROGATE + (codePoint & 0x3ff)); + } + } + private Utf8() {} } |