| /* |
| ****************************************************************************** |
| * |
| * Copyright (C) 1999-2006, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| * |
| ****************************************************************************** |
| * file name: utf_impl.c |
| * encoding: US-ASCII |
| * tab size: 8 (not used) |
| * indentation:4 |
| * |
| * created on: 1999sep13 |
| * created by: Markus W. Scherer |
| * |
| * This file provides implementation functions for macros in the utfXX.h |
| * that would otherwise be too long as macros. |
| */ |
| |
| #include <stddef.h> |
| |
| #include "lib/fxl/third_party/icu/icu_utf.h" |
| |
| namespace fxl_icu { |
| |
| /** |
| * UTF8_ERROR_VALUE_1 and UTF8_ERROR_VALUE_2 are special error values for UTF-8, |
| * which need 1 or 2 bytes in UTF-8: |
| * \code |
| * U+0015 = NAK = Negative Acknowledge, C0 control character |
| * U+009f = highest C1 control character |
| * \endcode |
| * |
| * These are used by UTF8_..._SAFE macros so that they can return an error value |
| * that needs the same number of code units (bytes) as were seen by |
| * a macro. They should be tested with UTF_IS_ERROR() or UTF_IS_VALID(). |
| * |
| * @deprecated ICU 2.4. Obsolete, see utf_old.h. |
| */ |
| #define FXL_UTF8_ERROR_VALUE_1 0x15 |
| |
| /** |
| * See documentation on UTF8_ERROR_VALUE_1 for details. |
| * |
| * @deprecated ICU 2.4. Obsolete, see utf_old.h. |
| */ |
| #define FXL_UTF8_ERROR_VALUE_2 0x9f |
| |
| /** |
| * Error value for all UTFs. This code point value will be set by macros with e> |
| * checking if an error is detected. |
| * |
| * @deprecated ICU 2.4. Obsolete, see utf_old.h. |
| */ |
| #define FXL_UTF_ERROR_VALUE 0xffff |
| |
| /* |
| * This table could be replaced on many machines by |
| * a few lines of assembler code using an |
| * "index of first 0-bit from msb" instruction and |
| * one or two more integer instructions. |
| * |
| * For example, on an i386, do something like |
| * - MOV AL, leadByte |
| * - NOT AL (8-bit, leave b15..b8==0..0, reverse only b7..b0) |
| * - MOV AH, 0 |
| * - BSR BX, AX (16-bit) |
| * - MOV AX, 6 (result) |
| * - JZ finish (ZF==1 if leadByte==0xff) |
| * - SUB AX, BX (result) |
| * -finish: |
| * (BSR: Bit Scan Reverse, scans for a 1-bit, starting from the MSB) |
| * |
| * In Unicode, all UTF-8 byte sequences with more than 4 bytes are illegal; |
| * lead bytes above 0xf4 are illegal. |
| * We keep them in this table for skipping long ISO 10646-UTF-8 sequences. |
| */ |
| const uint8_t utf8_countTrailBytes[256] = |
| { |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| |
| 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, |
| 3, 3, /* illegal in Unicode */ |
| 4, 4, 4, 4, /* illegal in Unicode */ |
| 5, 5, /* illegal in Unicode */ |
| 0, 0 /* illegal bytes 0xfe and 0xff */ |
| }; |
| |
| static const UChar32 utf8_minLegal[4] = {0, 0x80, 0x800, 0x10000}; |
| |
| static const UChar32 utf8_errorValue[6] = {FXL_UTF8_ERROR_VALUE_1, |
| FXL_UTF8_ERROR_VALUE_2, |
| FXL_UTF_ERROR_VALUE, |
| 0x10ffff, |
| 0x3ffffff, |
| 0x7fffffff}; |
| |
| /* |
| * Handle the non-inline part of the U8_NEXT() macro and its obsolete sibling |
| * UTF8_NEXT_CHAR_SAFE(). |
| * |
| * The "strict" parameter controls the error behavior: |
| * <0 "Safe" behavior of U8_NEXT(): All illegal byte sequences yield a negative |
| * code point result. |
| * 0 Obsolete "safe" behavior of UTF8_NEXT_CHAR_SAFE(..., FALSE): |
| * All illegal byte sequences yield a positive code point such that this |
| * result code point would be encoded with the same number of bytes as |
| * the illegal sequence. |
| * >0 Obsolete "strict" behavior of UTF8_NEXT_CHAR_SAFE(..., TRUE): |
| * Same as the obsolete "safe" behavior, but non-characters are also treated |
| * like illegal sequences. |
| * |
| * The special negative (<0) value -2 is used for lenient treatment of surrogate |
| * code points as legal. Some implementations use this for roundtripping of |
| * Unicode 16-bit strings that are not well-formed UTF-16, that is, they |
| * contain unpaired surrogates. |
| * |
| * Note that a UBool is the same as an int8_t. |
| */ |
| UChar32 utf8_nextCharSafeBody(const uint8_t* s, |
| size_t* pi, |
| size_t length, |
| UChar32 c, |
| UBool strict) { |
| size_t i = *pi; |
| uint8_t count = FXL_U8_COUNT_TRAIL_BYTES(c); |
| if ((i) + count <= (length)) { |
| uint8_t trail, illegal = 0; |
| |
| FXL_U8_MASK_LEAD_BYTE((c), count); |
| /* count==0 for illegally leading trail bytes and the illegal bytes 0xfe and |
| * 0xff */ |
| switch (count) { |
| /* each branch falls through to the next one */ |
| case 5: |
| case 4: |
| /* count>=4 is always illegal: no more than 3 trail bytes in Unicode's |
| * UTF-8 */ |
| illegal = 1; |
| break; |
| case 3: |
| trail = s[(i)++]; |
| (c) = ((c) << 6) | (trail & 0x3f); |
| if (c < 0x110) { |
| illegal |= (trail & 0xc0) ^ 0x80; |
| } else { |
| /* code point>0x10ffff, outside Unicode */ |
| illegal = 1; |
| break; |
| } |
| case 2: |
| trail = s[(i)++]; |
| (c) = ((c) << 6) | (trail & 0x3f); |
| illegal |= (trail & 0xc0) ^ 0x80; |
| case 1: |
| trail = s[(i)++]; |
| (c) = ((c) << 6) | (trail & 0x3f); |
| illegal |= (trail & 0xc0) ^ 0x80; |
| break; |
| case 0: |
| if (strict >= 0) { |
| return FXL_UTF8_ERROR_VALUE_1; |
| } else { |
| return FXL_U_SENTINEL; |
| } |
| /* no default branch to optimize switch() - all values are covered */ |
| } |
| |
| /* |
| * All the error handling should return a value |
| * that needs count bytes so that UTF8_GET_CHAR_SAFE() works right. |
| * |
| * Starting with Unicode 3.0.1, non-shortest forms are illegal. |
| * Starting with Unicode 3.2, surrogate code points must not be |
| * encoded in UTF-8, and there are no irregular sequences any more. |
| * |
| * U8_ macros (new in ICU 2.4) return negative values for error conditions. |
| */ |
| |
| /* correct sequence - all trail bytes have (b7..b6)==(10)? */ |
| /* illegal is also set if count>=4 */ |
| if (illegal || (c) < utf8_minLegal[count] || |
| (FXL_U_IS_SURROGATE(c) && strict != -2)) { |
| /* error handling */ |
| uint8_t errorCount = count; |
| /* don't go beyond this sequence */ |
| i = *pi; |
| while (count > 0 && FXL_U8_IS_TRAIL(s[i])) { |
| ++(i); |
| --count; |
| } |
| if (strict >= 0) { |
| c = utf8_errorValue[errorCount - count]; |
| } else { |
| c = FXL_U_SENTINEL; |
| } |
| } else if ((strict) > 0 && FXL_U_IS_UNICODE_NONCHAR(c)) { |
| /* strict: forbid non-characters like U+fffe */ |
| c = utf8_errorValue[count]; |
| } |
| } else /* too few bytes left */ { |
| /* error handling */ |
| size_t i0 = i; |
| /* don't just set (i)=(length) in case there is an illegal sequence */ |
| while ((i) < (length) && FXL_U8_IS_TRAIL(s[i])) { |
| ++(i); |
| } |
| if (strict >= 0) { |
| c = utf8_errorValue[i - i0]; |
| } else { |
| c = FXL_U_SENTINEL; |
| } |
| } |
| *pi = i; |
| return c; |
| } |
| |
| } // namespace fxl_icu |
