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Diffstat (limited to 'intl/icu/source/common/utf_impl.cpp')
| -rw-r--r-- | intl/icu/source/common/utf_impl.cpp | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/intl/icu/source/common/utf_impl.cpp b/intl/icu/source/common/utf_impl.cpp new file mode 100644 index 0000000000..827a82daf4 --- /dev/null +++ b/intl/icu/source/common/utf_impl.cpp @@ -0,0 +1,329 @@ +// © 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +****************************************************************************** +* +* Copyright (C) 1999-2012, International Business Machines +* Corporation and others. All Rights Reserved. +* +****************************************************************************** +* file name: utf_impl.cpp +* encoding: UTF-8 +* 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. +*/ + +/* set import/export definitions */ +#ifndef U_UTF8_IMPL +# define U_UTF8_IMPL +#endif + +#include "unicode/utypes.h" +#include "unicode/utf.h" +#include "unicode/utf8.h" +#include "uassert.h" + +/* + * Table of the number of utf8 trail bytes, indexed by the lead byte. + * Used by the deprecated macro UTF8_COUNT_TRAIL_BYTES, defined in utf_old.h + * + * The current macro, U8_COUNT_TRAIL_BYTES, does _not_ use this table. + * + * Note that this table cannot be removed, even if UTF8_COUNT_TRAIL_BYTES were + * changed to no longer use it. References to the table from expansions of UTF8_COUNT_TRAIL_BYTES + * may exist in old client code that must continue to run with newer icu library versions. + * + * 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) + */ +U_CAPI 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, + + // illegal C0 & C1 + // 2-byte lead bytes C2..DF + 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, + + // 3-byte lead bytes E0..EF + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + // 4-byte lead bytes F0..F4 + // illegal F5..FF + 3, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 +}; + +static const UChar32 +utf8_errorValue[6]={ + // Same values as UTF8_ERROR_VALUE_1, UTF8_ERROR_VALUE_2, UTF_ERROR_VALUE, + // but without relying on the obsolete unicode/utf_old.h. + 0x15, 0x9f, 0xffff, + 0x10ffff +}; + +static UChar32 +errorValue(int32_t count, int8_t strict) { + if(strict>=0) { + return utf8_errorValue[count]; + } else if(strict==-3) { + return 0xfffd; + } else { + return U_SENTINEL; + } +} + +/* + * Handle the non-inline part of the U8_NEXT() and U8_NEXT_FFFD() macros + * and their obsolete sibling UTF8_NEXT_CHAR_SAFE(). + * + * U8_NEXT() supports NUL-terminated strings indicated via length<0. + * + * The "strict" parameter controls the error behavior: + * <0 "Safe" behavior of U8_NEXT(): + * -1: All illegal byte sequences yield U_SENTINEL=-1. + * -2: Same as -1, except 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. + * -3: All illegal byte sequences yield U+FFFD. + * 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. + * + * Note that a UBool is the same as an int8_t. + */ +U_CAPI UChar32 U_EXPORT2 +utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict) { + // *pi is one after byte c. + int32_t i=*pi; + // length can be negative for NUL-terminated strings: Read and validate one byte at a time. + if(i==length || c>0xf4) { + // end of string, or not a lead byte + } else if(c>=0xf0) { + // Test for 4-byte sequences first because + // U8_NEXT() handles shorter valid sequences inline. + uint8_t t1=s[i], t2, t3; + c&=7; + if(U8_IS_VALID_LEAD4_AND_T1(c, t1) && + ++i!=length && (t2=s[i]-0x80)<=0x3f && + ++i!=length && (t3=s[i]-0x80)<=0x3f) { + ++i; + c=(c<<18)|((t1&0x3f)<<12)|(t2<<6)|t3; + // strict: forbid non-characters like U+fffe + if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) { + *pi=i; + return c; + } + } + } else if(c>=0xe0) { + c&=0xf; + if(strict!=-2) { + uint8_t t1=s[i], t2; + if(U8_IS_VALID_LEAD3_AND_T1(c, t1) && + ++i!=length && (t2=s[i]-0x80)<=0x3f) { + ++i; + c=(c<<12)|((t1&0x3f)<<6)|t2; + // strict: forbid non-characters like U+fffe + if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) { + *pi=i; + return c; + } + } + } else { + // strict=-2 -> lenient: allow surrogates + uint8_t t1=s[i]-0x80, t2; + if(t1<=0x3f && (c>0 || t1>=0x20) && + ++i!=length && (t2=s[i]-0x80)<=0x3f) { + *pi=i+1; + return (c<<12)|(t1<<6)|t2; + } + } + } else if(c>=0xc2) { + uint8_t t1=s[i]-0x80; + if(t1<=0x3f) { + *pi=i+1; + return ((c-0xc0)<<6)|t1; + } + } // else 0x80<=c<0xc2 is not a lead byte + + /* error handling */ + c=errorValue(i-*pi, strict); + *pi=i; + return c; +} + +U_CAPI int32_t U_EXPORT2 +utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError) { + if((uint32_t)(c)<=0x7ff) { + if((i)+1<(length)) { + (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); + (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); + return i; + } + } else if((uint32_t)(c)<=0xffff) { + /* Starting with Unicode 3.2, surrogate code points must not be encoded in UTF-8. */ + if((i)+2<(length) && !U_IS_SURROGATE(c)) { + (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); + (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); + (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); + return i; + } + } else if((uint32_t)(c)<=0x10ffff) { + if((i)+3<(length)) { + (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); + (s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80); + (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); + (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); + return i; + } + } + /* c>0x10ffff or not enough space, write an error value */ + if(pIsError!=nullptr) { + *pIsError=true; + } else { + length-=i; + if(length>0) { + int32_t offset; + if(length>3) { + length=3; + } + s+=i; + offset=0; + c=utf8_errorValue[length-1]; + U8_APPEND_UNSAFE(s, offset, c); + i=i+offset; + } + } + return i; +} + +U_CAPI UChar32 U_EXPORT2 +utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, UBool strict) { + // *pi is the index of byte c. + int32_t i=*pi; + if(U8_IS_TRAIL(c) && i>start) { + uint8_t b1=s[--i]; + if(U8_IS_LEAD(b1)) { + if(b1<0xe0) { + *pi=i; + return ((b1-0xc0)<<6)|(c&0x3f); + } else if(b1<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(b1, c) : U8_IS_VALID_LEAD4_AND_T1(b1, c)) { + // Truncated 3- or 4-byte sequence. + *pi=i; + return errorValue(1, strict); + } + } else if(U8_IS_TRAIL(b1) && i>start) { + // Extract the value bits from the last trail byte. + c&=0x3f; + uint8_t b2=s[--i]; + if(0xe0<=b2 && b2<=0xf4) { + if(b2<0xf0) { + b2&=0xf; + if(strict!=-2) { + if(U8_IS_VALID_LEAD3_AND_T1(b2, b1)) { + *pi=i; + c=(b2<<12)|((b1&0x3f)<<6)|c; + if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) { + return c; + } else { + // strict: forbid non-characters like U+fffe + return errorValue(2, strict); + } + } + } else { + // strict=-2 -> lenient: allow surrogates + b1-=0x80; + if((b2>0 || b1>=0x20)) { + *pi=i; + return (b2<<12)|(b1<<6)|c; + } + } + } else if(U8_IS_VALID_LEAD4_AND_T1(b2, b1)) { + // Truncated 4-byte sequence. + *pi=i; + return errorValue(2, strict); + } + } else if(U8_IS_TRAIL(b2) && i>start) { + uint8_t b3=s[--i]; + if(0xf0<=b3 && b3<=0xf4) { + b3&=7; + if(U8_IS_VALID_LEAD4_AND_T1(b3, b2)) { + *pi=i; + c=(b3<<18)|((b2&0x3f)<<12)|((b1&0x3f)<<6)|c; + if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) { + return c; + } else { + // strict: forbid non-characters like U+fffe + return errorValue(3, strict); + } + } + } + } + } + } + return errorValue(0, strict); +} + +U_CAPI int32_t U_EXPORT2 +utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i) { + // Same as utf8_prevCharSafeBody(..., strict=-1) minus assembling code points. + int32_t orig_i=i; + uint8_t c=s[i]; + if(U8_IS_TRAIL(c) && i>start) { + uint8_t b1=s[--i]; + if(U8_IS_LEAD(b1)) { + if(b1<0xe0 || + (b1<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(b1, c) : U8_IS_VALID_LEAD4_AND_T1(b1, c))) { + return i; + } + } else if(U8_IS_TRAIL(b1) && i>start) { + uint8_t b2=s[--i]; + if(0xe0<=b2 && b2<=0xf4) { + if(b2<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(b2, b1) : U8_IS_VALID_LEAD4_AND_T1(b2, b1)) { + return i; + } + } else if(U8_IS_TRAIL(b2) && i>start) { + uint8_t b3=s[--i]; + if(0xf0<=b3 && b3<=0xf4 && U8_IS_VALID_LEAD4_AND_T1(b3, b2)) { + return i; + } + } + } + } + return orig_i; +} |