| /* |
| * Copyright (C) 2007 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "UTF8.h" |
| |
| namespace WTF { |
| namespace Unicode { |
| |
| inline int inlineUTF8SequenceLengthNonASCII(char b0) |
| { |
| if ((b0 & 0xC0) != 0xC0) |
| return 0; |
| if ((b0 & 0xE0) == 0xC0) |
| return 2; |
| if ((b0 & 0xF0) == 0xE0) |
| return 3; |
| if ((b0 & 0xF8) == 0xF0) |
| return 4; |
| return 0; |
| } |
| |
| inline int inlineUTF8SequenceLength(char b0) |
| { |
| return (b0 & 0x80) == 0 ? 1 : inlineUTF8SequenceLengthNonASCII(b0); |
| } |
| |
| int UTF8SequenceLength(char b0) |
| { |
| return (b0 & 0x80) == 0 ? 1 : inlineUTF8SequenceLengthNonASCII(b0); |
| } |
| |
| int decodeUTF8Sequence(const char* sequence) |
| { |
| // Handle 0-byte sequences (never valid). |
| const unsigned char b0 = sequence[0]; |
| const int length = inlineUTF8SequenceLength(b0); |
| if (length == 0) |
| return -1; |
| |
| // Handle 1-byte sequences (plain ASCII). |
| const unsigned char b1 = sequence[1]; |
| if (length == 1) { |
| if (b1) |
| return -1; |
| return b0; |
| } |
| |
| // Handle 2-byte sequences. |
| if ((b1 & 0xC0) != 0x80) |
| return -1; |
| const unsigned char b2 = sequence[2]; |
| if (length == 2) { |
| if (b2) |
| return -1; |
| const int c = ((b0 & 0x1F) << 6) | (b1 & 0x3F); |
| if (c < 0x80) |
| return -1; |
| return c; |
| } |
| |
| // Handle 3-byte sequences. |
| if ((b2 & 0xC0) != 0x80) |
| return -1; |
| const unsigned char b3 = sequence[3]; |
| if (length == 3) { |
| if (b3) |
| return -1; |
| const int c = ((b0 & 0xF) << 12) | ((b1 & 0x3F) << 6) | (b2 & 0x3F); |
| if (c < 0x800) |
| return -1; |
| // UTF-16 surrogates should never appear in UTF-8 data. |
| if (c >= 0xD800 && c <= 0xDFFF) |
| return -1; |
| return c; |
| } |
| |
| // Handle 4-byte sequences. |
| if ((b3 & 0xC0) != 0x80) |
| return -1; |
| const unsigned char b4 = sequence[4]; |
| if (length == 4) { |
| if (b4) |
| return -1; |
| const int c = ((b0 & 0x7) << 18) | ((b1 & 0x3F) << 12) | ((b2 & 0x3F) << 6) | (b3 & 0x3F); |
| if (c < 0x10000 || c > 0x10FFFF) |
| return -1; |
| return c; |
| } |
| |
| return -1; |
| } |
| |
| // Once the bits are split out into bytes of UTF-8, this is a mask OR-ed |
| // into the first byte, depending on how many bytes follow. There are |
| // as many entries in this table as there are UTF-8 sequence types. |
| // (I.e., one byte sequence, two byte... etc.). Remember that sequencs |
| // for *legal* UTF-8 will be 4 or fewer bytes total. |
| static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC }; |
| |
| ConversionResult convertUTF16ToUTF8( |
| const UChar** sourceStart, const UChar* sourceEnd, |
| char** targetStart, char* targetEnd, bool strict) |
| { |
| ConversionResult result = conversionOK; |
| const UChar* source = *sourceStart; |
| char* target = *targetStart; |
| while (source < sourceEnd) { |
| UChar32 ch; |
| unsigned short bytesToWrite = 0; |
| const UChar32 byteMask = 0xBF; |
| const UChar32 byteMark = 0x80; |
| const UChar* oldSource = source; // In case we have to back up because of target overflow. |
| ch = static_cast<unsigned short>(*source++); |
| // If we have a surrogate pair, convert to UChar32 first. |
| if (ch >= 0xD800 && ch <= 0xDBFF) { |
| // If the 16 bits following the high surrogate are in the source buffer... |
| if (source < sourceEnd) { |
| UChar32 ch2 = static_cast<unsigned short>(*source); |
| // If it's a low surrogate, convert to UChar32. |
| if (ch2 >= 0xDC00 && ch2 <= 0xDFFF) { |
| ch = ((ch - 0xD800) << 10) + (ch2 - 0xDC00) + 0x0010000; |
| ++source; |
| } else if (strict) { // it's an unpaired high surrogate |
| --source; // return to the illegal value itself |
| result = sourceIllegal; |
| break; |
| } |
| } else { // We don't have the 16 bits following the high surrogate. |
| --source; // return to the high surrogate |
| result = sourceExhausted; |
| break; |
| } |
| } else if (strict) { |
| // UTF-16 surrogate values are illegal in UTF-32 |
| if (ch >= 0xDC00 && ch <= 0xDFFF) { |
| --source; // return to the illegal value itself |
| result = sourceIllegal; |
| break; |
| } |
| } |
| // Figure out how many bytes the result will require |
| if (ch < (UChar32)0x80) { |
| bytesToWrite = 1; |
| } else if (ch < (UChar32)0x800) { |
| bytesToWrite = 2; |
| } else if (ch < (UChar32)0x10000) { |
| bytesToWrite = 3; |
| } else if (ch < (UChar32)0x110000) { |
| bytesToWrite = 4; |
| } else { |
| bytesToWrite = 3; |
| ch = 0xFFFD; |
| } |
| |
| target += bytesToWrite; |
| if (target > targetEnd) { |
| source = oldSource; // Back up source pointer! |
| target -= bytesToWrite; |
| result = targetExhausted; |
| break; |
| } |
| switch (bytesToWrite) { // note: everything falls through. |
| case 4: *--target = (char)((ch | byteMark) & byteMask); ch >>= 6; |
| case 3: *--target = (char)((ch | byteMark) & byteMask); ch >>= 6; |
| case 2: *--target = (char)((ch | byteMark) & byteMask); ch >>= 6; |
| case 1: *--target = (char)(ch | firstByteMark[bytesToWrite]); |
| } |
| target += bytesToWrite; |
| } |
| *sourceStart = source; |
| *targetStart = target; |
| return result; |
| } |
| |
| // This must be called with the length pre-determined by the first byte. |
| // If presented with a length > 4, this returns false. The Unicode |
| // definition of UTF-8 goes up to 4-byte sequences. |
| static bool isLegalUTF8(const unsigned char* source, int length) |
| { |
| unsigned char a; |
| const unsigned char* srcptr = source + length; |
| switch (length) { |
| default: return false; |
| // Everything else falls through when "true"... |
| case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; |
| case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false; |
| case 2: if ((a = (*--srcptr)) > 0xBF) return false; |
| |
| switch (*source) { |
| // no fall-through in this inner switch |
| case 0xE0: if (a < 0xA0) return false; break; |
| case 0xED: if (a > 0x9F) return false; break; |
| case 0xF0: if (a < 0x90) return false; break; |
| case 0xF4: if (a > 0x8F) return false; break; |
| default: if (a < 0x80) return false; |
| } |
| |
| case 1: if (*source >= 0x80 && *source < 0xC2) return false; |
| } |
| if (*source > 0xF4) |
| return false; |
| return true; |
| } |
| |
| // Magic values subtracted from a buffer value during UTF8 conversion. |
| // This table contains as many values as there might be trailing bytes |
| // in a UTF-8 sequence. |
| static const UChar32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, |
| 0x03C82080UL, 0xFA082080UL, 0x82082080UL }; |
| |
| ConversionResult convertUTF8ToUTF16( |
| const char** sourceStart, const char* sourceEnd, |
| UChar** targetStart, UChar* targetEnd, bool strict) |
| { |
| ConversionResult result = conversionOK; |
| const char* source = *sourceStart; |
| UChar* target = *targetStart; |
| while (source < sourceEnd) { |
| UChar32 ch = 0; |
| int extraBytesToRead = UTF8SequenceLength(*source) - 1; |
| if (source + extraBytesToRead >= sourceEnd) { |
| result = sourceExhausted; |
| break; |
| } |
| // Do this check whether lenient or strict |
| if (!isLegalUTF8(reinterpret_cast<const unsigned char*>(source), extraBytesToRead + 1)) { |
| result = sourceIllegal; |
| break; |
| } |
| // The cases all fall through. |
| switch (extraBytesToRead) { |
| case 5: ch += static_cast<unsigned char>(*source++); ch <<= 6; // remember, illegal UTF-8 |
| case 4: ch += static_cast<unsigned char>(*source++); ch <<= 6; // remember, illegal UTF-8 |
| case 3: ch += static_cast<unsigned char>(*source++); ch <<= 6; |
| case 2: ch += static_cast<unsigned char>(*source++); ch <<= 6; |
| case 1: ch += static_cast<unsigned char>(*source++); ch <<= 6; |
| case 0: ch += static_cast<unsigned char>(*source++); |
| } |
| ch -= offsetsFromUTF8[extraBytesToRead]; |
| |
| if (target >= targetEnd) { |
| source -= (extraBytesToRead + 1); // Back up source pointer! |
| result = targetExhausted; break; |
| } |
| if (ch <= 0xFFFF) { |
| // UTF-16 surrogate values are illegal in UTF-32 |
| if (ch >= 0xD800 && ch <= 0xDFFF) { |
| if (strict) { |
| source -= (extraBytesToRead + 1); // return to the illegal value itself |
| result = sourceIllegal; |
| break; |
| } else |
| *target++ = 0xFFFD; |
| } else |
| *target++ = (UChar)ch; // normal case |
| } else if (ch > 0x10FFFF) { |
| if (strict) { |
| result = sourceIllegal; |
| source -= (extraBytesToRead + 1); // return to the start |
| break; // Bail out; shouldn't continue |
| } else |
| *target++ = 0xFFFD; |
| } else { |
| // target is a character in range 0xFFFF - 0x10FFFF |
| if (target + 1 >= targetEnd) { |
| source -= (extraBytesToRead + 1); // Back up source pointer! |
| result = targetExhausted; |
| break; |
| } |
| ch -= 0x0010000UL; |
| *target++ = (UChar)((ch >> 10) + 0xD800); |
| *target++ = (UChar)((ch & 0x03FF) + 0xDC00); |
| } |
| } |
| *sourceStart = source; |
| *targetStart = target; |
| return result; |
| } |
| |
| } |
| } |
