| // © 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) |
| */ |
| extern "C" U_EXPORT 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!=NULL) { |
| *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; |
| } |
