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| -rw-r--r-- | intl/icu/source/common/ucnvbocu.cpp | 1413 |
1 files changed, 1413 insertions, 0 deletions
diff --git a/intl/icu/source/common/ucnvbocu.cpp b/intl/icu/source/common/ucnvbocu.cpp new file mode 100644 index 0000000000..007722e474 --- /dev/null +++ b/intl/icu/source/common/ucnvbocu.cpp @@ -0,0 +1,1413 @@ +// © 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +****************************************************************************** +* +* Copyright (C) 2002-2016, International Business Machines +* Corporation and others. All Rights Reserved. +* +****************************************************************************** +* file name: ucnvbocu.cpp +* encoding: UTF-8 +* tab size: 8 (not used) +* indentation:4 +* +* created on: 2002mar27 +* created by: Markus W. Scherer +* +* This is an implementation of the Binary Ordered Compression for Unicode, +* in its MIME-friendly form as defined in http://www.unicode.org/notes/tn6/ +*/ + +#include "unicode/utypes.h" + +#if !UCONFIG_NO_CONVERSION && !UCONFIG_ONLY_HTML_CONVERSION + +#include "unicode/ucnv.h" +#include "unicode/ucnv_cb.h" +#include "unicode/utf16.h" +#include "putilimp.h" +#include "ucnv_bld.h" +#include "ucnv_cnv.h" +#include "uassert.h" + +/* BOCU-1 constants and macros ---------------------------------------------- */ + +/* + * BOCU-1 encodes the code points of a Unicode string as + * a sequence of byte-encoded differences (slope detection), + * preserving lexical order. + * + * Optimize the difference-taking for runs of Unicode text within + * small scripts: + * + * Most small scripts are allocated within aligned 128-blocks of Unicode + * code points. Lexical order is preserved if the "previous code point" state + * is always moved into the middle of such a block. + * + * Additionally, "prev" is moved from anywhere in the Unihan and Hangul + * areas into the middle of those areas. + * + * C0 control codes and space are encoded with their US-ASCII bytes. + * "prev" is reset for C0 controls but not for space. + */ + +/* initial value for "prev": middle of the ASCII range */ +#define BOCU1_ASCII_PREV 0x40 + +/* bounding byte values for differences */ +#define BOCU1_MIN 0x21 +#define BOCU1_MIDDLE 0x90 +#define BOCU1_MAX_LEAD 0xfe +#define BOCU1_MAX_TRAIL 0xff +#define BOCU1_RESET 0xff + +/* number of lead bytes */ +#define BOCU1_COUNT (BOCU1_MAX_LEAD-BOCU1_MIN+1) + +/* adjust trail byte counts for the use of some C0 control byte values */ +#define BOCU1_TRAIL_CONTROLS_COUNT 20 +#define BOCU1_TRAIL_BYTE_OFFSET (BOCU1_MIN-BOCU1_TRAIL_CONTROLS_COUNT) + +/* number of trail bytes */ +#define BOCU1_TRAIL_COUNT ((BOCU1_MAX_TRAIL-BOCU1_MIN+1)+BOCU1_TRAIL_CONTROLS_COUNT) + +/* + * number of positive and negative single-byte codes + * (counting 0==BOCU1_MIDDLE among the positive ones) + */ +#define BOCU1_SINGLE 64 + +/* number of lead bytes for positive and negative 2/3/4-byte sequences */ +#define BOCU1_LEAD_2 43 +#define BOCU1_LEAD_3 3 +#define BOCU1_LEAD_4 1 + +/* The difference value range for single-byters. */ +#define BOCU1_REACH_POS_1 (BOCU1_SINGLE-1) +#define BOCU1_REACH_NEG_1 (-BOCU1_SINGLE) + +/* The difference value range for double-byters. */ +#define BOCU1_REACH_POS_2 (BOCU1_REACH_POS_1+BOCU1_LEAD_2*BOCU1_TRAIL_COUNT) +#define BOCU1_REACH_NEG_2 (BOCU1_REACH_NEG_1-BOCU1_LEAD_2*BOCU1_TRAIL_COUNT) + +/* The difference value range for 3-byters. */ +#define BOCU1_REACH_POS_3 \ + (BOCU1_REACH_POS_2+BOCU1_LEAD_3*BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT) + +#define BOCU1_REACH_NEG_3 (BOCU1_REACH_NEG_2-BOCU1_LEAD_3*BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT) + +/* The lead byte start values. */ +#define BOCU1_START_POS_2 (BOCU1_MIDDLE+BOCU1_REACH_POS_1+1) +#define BOCU1_START_POS_3 (BOCU1_START_POS_2+BOCU1_LEAD_2) +#define BOCU1_START_POS_4 (BOCU1_START_POS_3+BOCU1_LEAD_3) + /* ==BOCU1_MAX_LEAD */ + +#define BOCU1_START_NEG_2 (BOCU1_MIDDLE+BOCU1_REACH_NEG_1) +#define BOCU1_START_NEG_3 (BOCU1_START_NEG_2-BOCU1_LEAD_2) +#define BOCU1_START_NEG_4 (BOCU1_START_NEG_3-BOCU1_LEAD_3) + /* ==BOCU1_MIN+1 */ + +/* The length of a byte sequence, according to the lead byte (!=BOCU1_RESET). */ +#define BOCU1_LENGTH_FROM_LEAD(lead) \ + ((BOCU1_START_NEG_2<=(lead) && (lead)<BOCU1_START_POS_2) ? 1 : \ + (BOCU1_START_NEG_3<=(lead) && (lead)<BOCU1_START_POS_3) ? 2 : \ + (BOCU1_START_NEG_4<=(lead) && (lead)<BOCU1_START_POS_4) ? 3 : 4) + +/* The length of a byte sequence, according to its packed form. */ +#define BOCU1_LENGTH_FROM_PACKED(packed) \ + ((uint32_t)(packed)<0x04000000 ? (packed)>>24 : 4) + +/* + * 12 commonly used C0 control codes (and space) are only used to encode + * themselves directly, + * which makes BOCU-1 MIME-usable and reasonably safe for + * ASCII-oriented software. + * + * These controls are + * 0 NUL + * + * 7 BEL + * 8 BS + * + * 9 TAB + * a LF + * b VT + * c FF + * d CR + * + * e SO + * f SI + * + * 1a SUB + * 1b ESC + * + * The other 20 C0 controls are also encoded directly (to preserve order) + * but are also used as trail bytes in difference encoding + * (for better compression). + */ +#define BOCU1_TRAIL_TO_BYTE(t) ((t)>=BOCU1_TRAIL_CONTROLS_COUNT ? (t)+BOCU1_TRAIL_BYTE_OFFSET : bocu1TrailToByte[t]) + +/* + * Byte value map for control codes, + * from external byte values 0x00..0x20 + * to trail byte values 0..19 (0..0x13) as used in the difference calculation. + * External byte values that are illegal as trail bytes are mapped to -1. + */ +static const int8_t +bocu1ByteToTrail[BOCU1_MIN]={ +/* 0 1 2 3 4 5 6 7 */ + -1, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, -1, + +/* 8 9 a b c d e f */ + -1, -1, -1, -1, -1, -1, -1, -1, + +/* 10 11 12 13 14 15 16 17 */ + 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, + +/* 18 19 1a 1b 1c 1d 1e 1f */ + 0x0e, 0x0f, -1, -1, 0x10, 0x11, 0x12, 0x13, + +/* 20 */ + -1 +}; + +/* + * Byte value map for control codes, + * from trail byte values 0..19 (0..0x13) as used in the difference calculation + * to external byte values 0x00..0x20. + */ +static const int8_t +bocu1TrailToByte[BOCU1_TRAIL_CONTROLS_COUNT]={ +/* 0 1 2 3 4 5 6 7 */ + 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x10, 0x11, + +/* 8 9 a b c d e f */ + 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, + +/* 10 11 12 13 */ + 0x1c, 0x1d, 0x1e, 0x1f +}; + +/** + * Integer division and modulo with negative numerators + * yields negative modulo results and quotients that are one more than + * what we need here. + * This macro adjust the results so that the modulo-value m is always >=0. + * + * For positive n, the if() condition is always false. + * + * @param n Number to be split into quotient and rest. + * Will be modified to contain the quotient. + * @param d Divisor. + * @param m Output variable for the rest (modulo result). + */ +#define NEGDIVMOD(n, d, m) UPRV_BLOCK_MACRO_BEGIN { \ + (m)=(n)%(d); \ + (n)/=(d); \ + if((m)<0) { \ + --(n); \ + (m)+=(d); \ + } \ +} UPRV_BLOCK_MACRO_END + +/* Faster versions of packDiff() for single-byte-encoded diff values. */ + +/** Is a diff value encodable in a single byte? */ +#define DIFF_IS_SINGLE(diff) (BOCU1_REACH_NEG_1<=(diff) && (diff)<=BOCU1_REACH_POS_1) + +/** Encode a diff value in a single byte. */ +#define PACK_SINGLE_DIFF(diff) (BOCU1_MIDDLE+(diff)) + +/** Is a diff value encodable in two bytes? */ +#define DIFF_IS_DOUBLE(diff) (BOCU1_REACH_NEG_2<=(diff) && (diff)<=BOCU1_REACH_POS_2) + +/* BOCU-1 implementation functions ------------------------------------------ */ + +#define BOCU1_SIMPLE_PREV(c) (((c)&~0x7f)+BOCU1_ASCII_PREV) + +/** + * Compute the next "previous" value for differencing + * from the current code point. + * + * @param c current code point, 0x3040..0xd7a3 (rest handled by macro below) + * @return "previous code point" state value + */ +static inline int32_t +bocu1Prev(int32_t c) { + /* compute new prev */ + if(/* 0x3040<=c && */ c<=0x309f) { + /* Hiragana is not 128-aligned */ + return 0x3070; + } else if(0x4e00<=c && c<=0x9fa5) { + /* CJK Unihan */ + return 0x4e00-BOCU1_REACH_NEG_2; + } else if(0xac00<=c /* && c<=0xd7a3 */) { + /* Korean Hangul */ + return (0xd7a3+0xac00)/2; + } else { + /* mostly small scripts */ + return BOCU1_SIMPLE_PREV(c); + } +} + +/** Fast version of bocu1Prev() for most scripts. */ +#define BOCU1_PREV(c) ((c)<0x3040 || (c)>0xd7a3 ? BOCU1_SIMPLE_PREV(c) : bocu1Prev(c)) + +/* + * The BOCU-1 converter uses the standard setup code in ucnv.c/ucnv_bld.c. + * The UConverter fields are used as follows: + * + * fromUnicodeStatus encoder's prev (0 will be interpreted as BOCU1_ASCII_PREV) + * + * toUnicodeStatus decoder's prev (0 will be interpreted as BOCU1_ASCII_PREV) + * mode decoder's incomplete (diff<<2)|count (ignored when toULength==0) + */ + +/* BOCU-1-from-Unicode conversion functions --------------------------------- */ + +/** + * Encode a difference -0x10ffff..0x10ffff in 1..4 bytes + * and return a packed integer with them. + * + * The encoding favors small absolute differences with short encodings + * to compress runs of same-script characters. + * + * Optimized version with unrolled loops and fewer floating-point operations + * than the standard packDiff(). + * + * @param diff difference value -0x10ffff..0x10ffff + * @return + * 0x010000zz for 1-byte sequence zz + * 0x0200yyzz for 2-byte sequence yy zz + * 0x03xxyyzz for 3-byte sequence xx yy zz + * 0xwwxxyyzz for 4-byte sequence ww xx yy zz (ww>0x03) + */ +static int32_t +packDiff(int32_t diff) { + int32_t result, m; + + U_ASSERT(!DIFF_IS_SINGLE(diff)); /* assume we won't be called where diff==BOCU1_REACH_NEG_1=-64 */ + if(diff>=BOCU1_REACH_NEG_1) { + /* mostly positive differences, and single-byte negative ones */ +#if 0 /* single-byte case handled in macros, see below */ + if(diff<=BOCU1_REACH_POS_1) { + /* single byte */ + return 0x01000000|(BOCU1_MIDDLE+diff); + } else +#endif + if(diff<=BOCU1_REACH_POS_2) { + /* two bytes */ + diff-=BOCU1_REACH_POS_1+1; + result=0x02000000; + + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + result|=BOCU1_TRAIL_TO_BYTE(m); + + result|=(BOCU1_START_POS_2+diff)<<8; + } else if(diff<=BOCU1_REACH_POS_3) { + /* three bytes */ + diff-=BOCU1_REACH_POS_2+1; + result=0x03000000; + + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + result|=BOCU1_TRAIL_TO_BYTE(m); + + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + result|=BOCU1_TRAIL_TO_BYTE(m)<<8; + + result|=(BOCU1_START_POS_3+diff)<<16; + } else { + /* four bytes */ + diff-=BOCU1_REACH_POS_3+1; + + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + result=BOCU1_TRAIL_TO_BYTE(m); + + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + result|=BOCU1_TRAIL_TO_BYTE(m)<<8; + + /* + * We know that / and % would deliver quotient 0 and rest=diff. + * Avoid division and modulo for performance. + */ + result|=BOCU1_TRAIL_TO_BYTE(diff)<<16; + + result|=((uint32_t)BOCU1_START_POS_4)<<24; + } + } else { + /* two- to four-byte negative differences */ + if(diff>=BOCU1_REACH_NEG_2) { + /* two bytes */ + diff-=BOCU1_REACH_NEG_1; + result=0x02000000; + + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + result|=BOCU1_TRAIL_TO_BYTE(m); + + result|=(BOCU1_START_NEG_2+diff)<<8; + } else if(diff>=BOCU1_REACH_NEG_3) { + /* three bytes */ + diff-=BOCU1_REACH_NEG_2; + result=0x03000000; + + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + result|=BOCU1_TRAIL_TO_BYTE(m); + + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + result|=BOCU1_TRAIL_TO_BYTE(m)<<8; + + result|=(BOCU1_START_NEG_3+diff)<<16; + } else { + /* four bytes */ + diff-=BOCU1_REACH_NEG_3; + + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + result=BOCU1_TRAIL_TO_BYTE(m); + + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + result|=BOCU1_TRAIL_TO_BYTE(m)<<8; + + /* + * We know that NEGDIVMOD would deliver + * quotient -1 and rest=diff+BOCU1_TRAIL_COUNT. + * Avoid division and modulo for performance. + */ + m=diff+BOCU1_TRAIL_COUNT; + result|=BOCU1_TRAIL_TO_BYTE(m)<<16; + + result|=BOCU1_MIN<<24; + } + } + return result; +} + + +static void U_CALLCONV +_Bocu1FromUnicodeWithOffsets(UConverterFromUnicodeArgs *pArgs, + UErrorCode *pErrorCode) { + UConverter *cnv; + const char16_t *source, *sourceLimit; + uint8_t *target; + int32_t targetCapacity; + int32_t *offsets; + + int32_t prev, c, diff; + + int32_t sourceIndex, nextSourceIndex; + + /* set up the local pointers */ + cnv=pArgs->converter; + source=pArgs->source; + sourceLimit=pArgs->sourceLimit; + target=(uint8_t *)pArgs->target; + targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target); + offsets=pArgs->offsets; + + /* get the converter state from UConverter */ + c=cnv->fromUChar32; + prev=(int32_t)cnv->fromUnicodeStatus; + if(prev==0) { + prev=BOCU1_ASCII_PREV; + } + + /* sourceIndex=-1 if the current character began in the previous buffer */ + sourceIndex= c==0 ? 0 : -1; + nextSourceIndex=0; + + /* conversion loop */ + if(c!=0 && targetCapacity>0) { + goto getTrail; + } + +fastSingle: + /* fast loop for single-byte differences */ + /* use only one loop counter variable, targetCapacity, not also source */ + diff=(int32_t)(sourceLimit-source); + if(targetCapacity>diff) { + targetCapacity=diff; + } + while(targetCapacity>0 && (c=*source)<0x3000) { + if(c<=0x20) { + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(uint8_t)c; + *offsets++=nextSourceIndex++; + ++source; + --targetCapacity; + } else { + diff=c-prev; + if(DIFF_IS_SINGLE(diff)) { + prev=BOCU1_SIMPLE_PREV(c); + *target++=(uint8_t)PACK_SINGLE_DIFF(diff); + *offsets++=nextSourceIndex++; + ++source; + --targetCapacity; + } else { + break; + } + } + } + /* restore real values */ + targetCapacity=(int32_t)((const uint8_t *)pArgs->targetLimit-target); + sourceIndex=nextSourceIndex; /* wrong if offsets==nullptr but does not matter */ + + /* regular loop for all cases */ + while(source<sourceLimit) { + if(targetCapacity>0) { + c=*source++; + ++nextSourceIndex; + + if(c<=0x20) { + /* + * ISO C0 control & space: + * Encode directly for MIME compatibility, + * and reset state except for space, to not disrupt compression. + */ + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(uint8_t)c; + *offsets++=sourceIndex; + --targetCapacity; + + sourceIndex=nextSourceIndex; + continue; + } + + if(U16_IS_LEAD(c)) { +getTrail: + if(source<sourceLimit) { + /* test the following code unit */ + char16_t trail=*source; + if(U16_IS_TRAIL(trail)) { + ++source; + ++nextSourceIndex; + c=U16_GET_SUPPLEMENTARY(c, trail); + } + } else { + /* no more input */ + c=-c; /* negative lead surrogate as "incomplete" indicator to avoid c=0 everywhere else */ + break; + } + } + + /* + * all other Unicode code points c==U+0021..U+10ffff + * are encoded with the difference c-prev + * + * a new prev is computed from c, + * placed in the middle of a 0x80-block (for most small scripts) or + * in the middle of the Unihan and Hangul blocks + * to statistically minimize the following difference + */ + diff=c-prev; + prev=BOCU1_PREV(c); + if(DIFF_IS_SINGLE(diff)) { + *target++=(uint8_t)PACK_SINGLE_DIFF(diff); + *offsets++=sourceIndex; + --targetCapacity; + sourceIndex=nextSourceIndex; + if(c<0x3000) { + goto fastSingle; + } + } else if(DIFF_IS_DOUBLE(diff) && 2<=targetCapacity) { + /* optimize 2-byte case */ + int32_t m; + + if(diff>=0) { + diff-=BOCU1_REACH_POS_1+1; + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + diff+=BOCU1_START_POS_2; + } else { + diff-=BOCU1_REACH_NEG_1; + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + diff+=BOCU1_START_NEG_2; + } + *target++=(uint8_t)diff; + *target++=(uint8_t)BOCU1_TRAIL_TO_BYTE(m); + *offsets++=sourceIndex; + *offsets++=sourceIndex; + targetCapacity-=2; + sourceIndex=nextSourceIndex; + } else { + int32_t length; /* will be 2..4 */ + + diff=packDiff(diff); + length=BOCU1_LENGTH_FROM_PACKED(diff); + + /* write the output character bytes from diff and length */ + /* from the first if in the loop we know that targetCapacity>0 */ + if(length<=targetCapacity) { + switch(length) { + /* each branch falls through to the next one */ + case 4: + *target++=(uint8_t)(diff>>24); + *offsets++=sourceIndex; + U_FALLTHROUGH; + case 3: + *target++=(uint8_t)(diff>>16); + *offsets++=sourceIndex; + U_FALLTHROUGH; + case 2: + *target++=(uint8_t)(diff>>8); + *offsets++=sourceIndex; + /* case 1: handled above */ + *target++=(uint8_t)diff; + *offsets++=sourceIndex; + U_FALLTHROUGH; + default: + /* will never occur */ + break; + } + targetCapacity-=length; + sourceIndex=nextSourceIndex; + } else { + uint8_t *charErrorBuffer; + + /* + * We actually do this backwards here: + * In order to save an intermediate variable, we output + * first to the overflow buffer what does not fit into the + * regular target. + */ + /* we know that 1<=targetCapacity<length<=4 */ + length-=targetCapacity; + charErrorBuffer=(uint8_t *)cnv->charErrorBuffer; + switch(length) { + /* each branch falls through to the next one */ + case 3: + *charErrorBuffer++=(uint8_t)(diff>>16); + U_FALLTHROUGH; + case 2: + *charErrorBuffer++=(uint8_t)(diff>>8); + U_FALLTHROUGH; + case 1: + *charErrorBuffer=(uint8_t)diff; + U_FALLTHROUGH; + default: + /* will never occur */ + break; + } + cnv->charErrorBufferLength=(int8_t)length; + + /* now output what fits into the regular target */ + diff>>=8*length; /* length was reduced by targetCapacity */ + switch(targetCapacity) { + /* each branch falls through to the next one */ + case 3: + *target++=(uint8_t)(diff>>16); + *offsets++=sourceIndex; + U_FALLTHROUGH; + case 2: + *target++=(uint8_t)(diff>>8); + *offsets++=sourceIndex; + U_FALLTHROUGH; + case 1: + *target++=(uint8_t)diff; + *offsets++=sourceIndex; + U_FALLTHROUGH; + default: + /* will never occur */ + break; + } + + /* target overflow */ + targetCapacity=0; + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + } + } else { + /* target is full */ + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + } + + /* set the converter state back into UConverter */ + cnv->fromUChar32= c<0 ? -c : 0; + cnv->fromUnicodeStatus=(uint32_t)prev; + + /* write back the updated pointers */ + pArgs->source=source; + pArgs->target=(char *)target; + pArgs->offsets=offsets; +} + +/* + * Identical to _Bocu1FromUnicodeWithOffsets but without offset handling. + * If a change is made in the original function, then either + * change this function the same way or + * re-copy the original function and remove the variables + * offsets, sourceIndex, and nextSourceIndex. + */ +static void U_CALLCONV +_Bocu1FromUnicode(UConverterFromUnicodeArgs *pArgs, + UErrorCode *pErrorCode) { + UConverter *cnv; + const char16_t *source, *sourceLimit; + uint8_t *target; + int32_t targetCapacity; + + int32_t prev, c, diff; + + /* set up the local pointers */ + cnv=pArgs->converter; + source=pArgs->source; + sourceLimit=pArgs->sourceLimit; + target=(uint8_t *)pArgs->target; + targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target); + + /* get the converter state from UConverter */ + c=cnv->fromUChar32; + prev=(int32_t)cnv->fromUnicodeStatus; + if(prev==0) { + prev=BOCU1_ASCII_PREV; + } + + /* conversion loop */ + if(c!=0 && targetCapacity>0) { + goto getTrail; + } + +fastSingle: + /* fast loop for single-byte differences */ + /* use only one loop counter variable, targetCapacity, not also source */ + diff=(int32_t)(sourceLimit-source); + if(targetCapacity>diff) { + targetCapacity=diff; + } + while(targetCapacity>0 && (c=*source)<0x3000) { + if(c<=0x20) { + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(uint8_t)c; + } else { + diff=c-prev; + if(DIFF_IS_SINGLE(diff)) { + prev=BOCU1_SIMPLE_PREV(c); + *target++=(uint8_t)PACK_SINGLE_DIFF(diff); + } else { + break; + } + } + ++source; + --targetCapacity; + } + /* restore real values */ + targetCapacity=(int32_t)((const uint8_t *)pArgs->targetLimit-target); + + /* regular loop for all cases */ + while(source<sourceLimit) { + if(targetCapacity>0) { + c=*source++; + + if(c<=0x20) { + /* + * ISO C0 control & space: + * Encode directly for MIME compatibility, + * and reset state except for space, to not disrupt compression. + */ + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(uint8_t)c; + --targetCapacity; + continue; + } + + if(U16_IS_LEAD(c)) { +getTrail: + if(source<sourceLimit) { + /* test the following code unit */ + char16_t trail=*source; + if(U16_IS_TRAIL(trail)) { + ++source; + c=U16_GET_SUPPLEMENTARY(c, trail); + } + } else { + /* no more input */ + c=-c; /* negative lead surrogate as "incomplete" indicator to avoid c=0 everywhere else */ + break; + } + } + + /* + * all other Unicode code points c==U+0021..U+10ffff + * are encoded with the difference c-prev + * + * a new prev is computed from c, + * placed in the middle of a 0x80-block (for most small scripts) or + * in the middle of the Unihan and Hangul blocks + * to statistically minimize the following difference + */ + diff=c-prev; + prev=BOCU1_PREV(c); + if(DIFF_IS_SINGLE(diff)) { + *target++=(uint8_t)PACK_SINGLE_DIFF(diff); + --targetCapacity; + if(c<0x3000) { + goto fastSingle; + } + } else if(DIFF_IS_DOUBLE(diff) && 2<=targetCapacity) { + /* optimize 2-byte case */ + int32_t m; + + if(diff>=0) { + diff-=BOCU1_REACH_POS_1+1; + m=diff%BOCU1_TRAIL_COUNT; + diff/=BOCU1_TRAIL_COUNT; + diff+=BOCU1_START_POS_2; + } else { + diff-=BOCU1_REACH_NEG_1; + NEGDIVMOD(diff, BOCU1_TRAIL_COUNT, m); + diff+=BOCU1_START_NEG_2; + } + *target++=(uint8_t)diff; + *target++=(uint8_t)BOCU1_TRAIL_TO_BYTE(m); + targetCapacity-=2; + } else { + int32_t length; /* will be 2..4 */ + + diff=packDiff(diff); + length=BOCU1_LENGTH_FROM_PACKED(diff); + + /* write the output character bytes from diff and length */ + /* from the first if in the loop we know that targetCapacity>0 */ + if(length<=targetCapacity) { + switch(length) { + /* each branch falls through to the next one */ + case 4: + *target++=(uint8_t)(diff>>24); + U_FALLTHROUGH; + case 3: + *target++=(uint8_t)(diff>>16); + /* case 2: handled above */ + *target++=(uint8_t)(diff>>8); + /* case 1: handled above */ + *target++=(uint8_t)diff; + U_FALLTHROUGH; + default: + /* will never occur */ + break; + } + targetCapacity-=length; + } else { + uint8_t *charErrorBuffer; + + /* + * We actually do this backwards here: + * In order to save an intermediate variable, we output + * first to the overflow buffer what does not fit into the + * regular target. + */ + /* we know that 1<=targetCapacity<length<=4 */ + length-=targetCapacity; + charErrorBuffer=(uint8_t *)cnv->charErrorBuffer; + switch(length) { + /* each branch falls through to the next one */ + case 3: + *charErrorBuffer++=(uint8_t)(diff>>16); + U_FALLTHROUGH; + case 2: + *charErrorBuffer++=(uint8_t)(diff>>8); + U_FALLTHROUGH; + case 1: + *charErrorBuffer=(uint8_t)diff; + U_FALLTHROUGH; + default: + /* will never occur */ + break; + } + cnv->charErrorBufferLength=(int8_t)length; + + /* now output what fits into the regular target */ + diff>>=8*length; /* length was reduced by targetCapacity */ + switch(targetCapacity) { + /* each branch falls through to the next one */ + case 3: + *target++=(uint8_t)(diff>>16); + U_FALLTHROUGH; + case 2: + *target++=(uint8_t)(diff>>8); + U_FALLTHROUGH; + case 1: + *target++=(uint8_t)diff; + U_FALLTHROUGH; + default: + /* will never occur */ + break; + } + + /* target overflow */ + targetCapacity=0; + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + } + } else { + /* target is full */ + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + } + + /* set the converter state back into UConverter */ + cnv->fromUChar32= c<0 ? -c : 0; + cnv->fromUnicodeStatus=(uint32_t)prev; + + /* write back the updated pointers */ + pArgs->source=source; + pArgs->target=(char *)target; +} + +/* BOCU-1-to-Unicode conversion functions ----------------------------------- */ + +/** + * Function for BOCU-1 decoder; handles multi-byte lead bytes. + * + * @param b lead byte; + * BOCU1_MIN<=b<BOCU1_START_NEG_2 or BOCU1_START_POS_2<=b<BOCU1_MAX_LEAD + * @return (diff<<2)|count + */ +static inline int32_t +decodeBocu1LeadByte(int32_t b) { + int32_t diff, count; + + if(b>=BOCU1_START_NEG_2) { + /* positive difference */ + if(b<BOCU1_START_POS_3) { + /* two bytes */ + diff=((int32_t)b-BOCU1_START_POS_2)*BOCU1_TRAIL_COUNT+BOCU1_REACH_POS_1+1; + count=1; + } else if(b<BOCU1_START_POS_4) { + /* three bytes */ + diff=((int32_t)b-BOCU1_START_POS_3)*BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT+BOCU1_REACH_POS_2+1; + count=2; + } else { + /* four bytes */ + diff=BOCU1_REACH_POS_3+1; + count=3; + } + } else { + /* negative difference */ + if(b>=BOCU1_START_NEG_3) { + /* two bytes */ + diff=((int32_t)b-BOCU1_START_NEG_2)*BOCU1_TRAIL_COUNT+BOCU1_REACH_NEG_1; + count=1; + } else if(b>BOCU1_MIN) { + /* three bytes */ + diff=((int32_t)b-BOCU1_START_NEG_3)*BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT+BOCU1_REACH_NEG_2; + count=2; + } else { + /* four bytes */ + diff=-BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT+BOCU1_REACH_NEG_3; + count=3; + } + } + + /* return the state for decoding the trail byte(s) */ + return ((uint32_t)diff<<2)|count; +} + +/** + * Function for BOCU-1 decoder; handles multi-byte trail bytes. + * + * @param count number of remaining trail bytes including this one + * @param b trail byte + * @return new delta for diff including b - <0 indicates an error + * + * @see decodeBocu1 + */ +static inline int32_t +decodeBocu1TrailByte(int32_t count, int32_t b) { + if(b<=0x20) { + /* skip some C0 controls and make the trail byte range contiguous */ + b=bocu1ByteToTrail[b]; + /* b<0 for an illegal trail byte value will result in return<0 below */ +#if BOCU1_MAX_TRAIL<0xff + } else if(b>BOCU1_MAX_TRAIL) { + return -99; +#endif + } else { + b-=BOCU1_TRAIL_BYTE_OFFSET; + } + + /* add trail byte into difference and decrement count */ + if(count==1) { + return b; + } else if(count==2) { + return b*BOCU1_TRAIL_COUNT; + } else /* count==3 */ { + return b*(BOCU1_TRAIL_COUNT*BOCU1_TRAIL_COUNT); + } +} + +static void U_CALLCONV +_Bocu1ToUnicodeWithOffsets(UConverterToUnicodeArgs *pArgs, + UErrorCode *pErrorCode) { + UConverter *cnv; + const uint8_t *source, *sourceLimit; + char16_t *target; + const char16_t *targetLimit; + int32_t *offsets; + + int32_t prev, count, diff, c; + + int8_t byteIndex; + uint8_t *bytes; + + int32_t sourceIndex, nextSourceIndex; + + /* set up the local pointers */ + cnv=pArgs->converter; + source=(const uint8_t *)pArgs->source; + sourceLimit=(const uint8_t *)pArgs->sourceLimit; + target=pArgs->target; + targetLimit=pArgs->targetLimit; + offsets=pArgs->offsets; + + /* get the converter state from UConverter */ + prev=(int32_t)cnv->toUnicodeStatus; + if(prev==0) { + prev=BOCU1_ASCII_PREV; + } + diff=cnv->mode; /* mode may be set to UCNV_SI by ucnv_bld.c but then toULength==0 */ + count=diff&3; + diff>>=2; + + byteIndex=cnv->toULength; + bytes=cnv->toUBytes; + + /* sourceIndex=-1 if the current character began in the previous buffer */ + sourceIndex=byteIndex==0 ? 0 : -1; + nextSourceIndex=0; + + /* conversion "loop" similar to _SCSUToUnicodeWithOffsets() */ + if(count>0 && byteIndex>0 && target<targetLimit) { + goto getTrail; + } + +fastSingle: + /* fast loop for single-byte differences */ + /* use count as the only loop counter variable */ + diff=(int32_t)(sourceLimit-source); + count=(int32_t)(pArgs->targetLimit-target); + if(count>diff) { + count=diff; + } + while(count>0) { + if(BOCU1_START_NEG_2<=(c=*source) && c<BOCU1_START_POS_2) { + c=prev+(c-BOCU1_MIDDLE); + if(c<0x3000) { + *target++=(char16_t)c; + *offsets++=nextSourceIndex++; + prev=BOCU1_SIMPLE_PREV(c); + } else { + break; + } + } else if(c<=0x20) { + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(char16_t)c; + *offsets++=nextSourceIndex++; + } else { + break; + } + ++source; + --count; + } + sourceIndex=nextSourceIndex; /* wrong if offsets==nullptr but does not matter */ + + /* decode a sequence of single and lead bytes */ + while(source<sourceLimit) { + if(target>=targetLimit) { + /* target is full */ + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + + ++nextSourceIndex; + c=*source++; + if(BOCU1_START_NEG_2<=c && c<BOCU1_START_POS_2) { + /* Write a code point directly from a single-byte difference. */ + c=prev+(c-BOCU1_MIDDLE); + if(c<0x3000) { + *target++=(char16_t)c; + *offsets++=sourceIndex; + prev=BOCU1_SIMPLE_PREV(c); + sourceIndex=nextSourceIndex; + goto fastSingle; + } + } else if(c<=0x20) { + /* + * Direct-encoded C0 control code or space. + * Reset prev for C0 control codes but not for space. + */ + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(char16_t)c; + *offsets++=sourceIndex; + sourceIndex=nextSourceIndex; + continue; + } else if(BOCU1_START_NEG_3<=c && c<BOCU1_START_POS_3 && source<sourceLimit) { + /* Optimize two-byte case. */ + if(c>=BOCU1_MIDDLE) { + diff=((int32_t)c-BOCU1_START_POS_2)*BOCU1_TRAIL_COUNT+BOCU1_REACH_POS_1+1; + } else { + diff=((int32_t)c-BOCU1_START_NEG_2)*BOCU1_TRAIL_COUNT+BOCU1_REACH_NEG_1; + } + + /* trail byte */ + ++nextSourceIndex; + c=decodeBocu1TrailByte(1, *source++); + if(c<0 || (uint32_t)(c=prev+diff+c)>0x10ffff) { + bytes[0]=source[-2]; + bytes[1]=source[-1]; + byteIndex=2; + *pErrorCode=U_ILLEGAL_CHAR_FOUND; + break; + } + } else if(c==BOCU1_RESET) { + /* only reset the state, no code point */ + prev=BOCU1_ASCII_PREV; + sourceIndex=nextSourceIndex; + continue; + } else { + /* + * For multi-byte difference lead bytes, set the decoder state + * with the partial difference value from the lead byte and + * with the number of trail bytes. + */ + bytes[0]=(uint8_t)c; + byteIndex=1; + + diff=decodeBocu1LeadByte(c); + count=diff&3; + diff>>=2; +getTrail: + for(;;) { + if(source>=sourceLimit) { + goto endloop; + } + ++nextSourceIndex; + c=bytes[byteIndex++]=*source++; + + /* trail byte in any position */ + c=decodeBocu1TrailByte(count, c); + if(c<0) { + *pErrorCode=U_ILLEGAL_CHAR_FOUND; + goto endloop; + } + + diff+=c; + if(--count==0) { + /* final trail byte, deliver a code point */ + byteIndex=0; + c=prev+diff; + if((uint32_t)c>0x10ffff) { + *pErrorCode=U_ILLEGAL_CHAR_FOUND; + goto endloop; + } + break; + } + } + } + + /* calculate the next prev and output c */ + prev=BOCU1_PREV(c); + if(c<=0xffff) { + *target++=(char16_t)c; + *offsets++=sourceIndex; + } else { + /* output surrogate pair */ + *target++=U16_LEAD(c); + if(target<targetLimit) { + *target++=U16_TRAIL(c); + *offsets++=sourceIndex; + *offsets++=sourceIndex; + } else { + /* target overflow */ + *offsets++=sourceIndex; + cnv->UCharErrorBuffer[0]=U16_TRAIL(c); + cnv->UCharErrorBufferLength=1; + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + } + sourceIndex=nextSourceIndex; + } +endloop: + + if(*pErrorCode==U_ILLEGAL_CHAR_FOUND) { + /* set the converter state in UConverter to deal with the next character */ + cnv->toUnicodeStatus=BOCU1_ASCII_PREV; + cnv->mode=0; + } else { + /* set the converter state back into UConverter */ + cnv->toUnicodeStatus=(uint32_t)prev; + cnv->mode=(int32_t)((uint32_t)diff<<2)|count; + } + cnv->toULength=byteIndex; + + /* write back the updated pointers */ + pArgs->source=(const char *)source; + pArgs->target=target; + pArgs->offsets=offsets; + return; +} + +/* + * Identical to _Bocu1ToUnicodeWithOffsets but without offset handling. + * If a change is made in the original function, then either + * change this function the same way or + * re-copy the original function and remove the variables + * offsets, sourceIndex, and nextSourceIndex. + */ +static void U_CALLCONV +_Bocu1ToUnicode(UConverterToUnicodeArgs *pArgs, + UErrorCode *pErrorCode) { + UConverter *cnv; + const uint8_t *source, *sourceLimit; + char16_t *target; + const char16_t *targetLimit; + + int32_t prev, count, diff, c; + + int8_t byteIndex; + uint8_t *bytes; + + /* set up the local pointers */ + cnv=pArgs->converter; + source=(const uint8_t *)pArgs->source; + sourceLimit=(const uint8_t *)pArgs->sourceLimit; + target=pArgs->target; + targetLimit=pArgs->targetLimit; + + /* get the converter state from UConverter */ + prev=(int32_t)cnv->toUnicodeStatus; + if(prev==0) { + prev=BOCU1_ASCII_PREV; + } + diff=cnv->mode; /* mode may be set to UCNV_SI by ucnv_bld.c but then toULength==0 */ + count=diff&3; + diff>>=2; + + byteIndex=cnv->toULength; + bytes=cnv->toUBytes; + + /* conversion "loop" similar to _SCSUToUnicodeWithOffsets() */ + if(count>0 && byteIndex>0 && target<targetLimit) { + goto getTrail; + } + +fastSingle: + /* fast loop for single-byte differences */ + /* use count as the only loop counter variable */ + diff=(int32_t)(sourceLimit-source); + count=(int32_t)(pArgs->targetLimit-target); + if(count>diff) { + count=diff; + } + while(count>0) { + if(BOCU1_START_NEG_2<=(c=*source) && c<BOCU1_START_POS_2) { + c=prev+(c-BOCU1_MIDDLE); + if(c<0x3000) { + *target++=(char16_t)c; + prev=BOCU1_SIMPLE_PREV(c); + } else { + break; + } + } else if(c<=0x20) { + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(char16_t)c; + } else { + break; + } + ++source; + --count; + } + + /* decode a sequence of single and lead bytes */ + while(source<sourceLimit) { + if(target>=targetLimit) { + /* target is full */ + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + + c=*source++; + if(BOCU1_START_NEG_2<=c && c<BOCU1_START_POS_2) { + /* Write a code point directly from a single-byte difference. */ + c=prev+(c-BOCU1_MIDDLE); + if(c<0x3000) { + *target++=(char16_t)c; + prev=BOCU1_SIMPLE_PREV(c); + goto fastSingle; + } + } else if(c<=0x20) { + /* + * Direct-encoded C0 control code or space. + * Reset prev for C0 control codes but not for space. + */ + if(c!=0x20) { + prev=BOCU1_ASCII_PREV; + } + *target++=(char16_t)c; + continue; + } else if(BOCU1_START_NEG_3<=c && c<BOCU1_START_POS_3 && source<sourceLimit) { + /* Optimize two-byte case. */ + if(c>=BOCU1_MIDDLE) { + diff=((int32_t)c-BOCU1_START_POS_2)*BOCU1_TRAIL_COUNT+BOCU1_REACH_POS_1+1; + } else { + diff=((int32_t)c-BOCU1_START_NEG_2)*BOCU1_TRAIL_COUNT+BOCU1_REACH_NEG_1; + } + + /* trail byte */ + c=decodeBocu1TrailByte(1, *source++); + if(c<0 || (uint32_t)(c=prev+diff+c)>0x10ffff) { + bytes[0]=source[-2]; + bytes[1]=source[-1]; + byteIndex=2; + *pErrorCode=U_ILLEGAL_CHAR_FOUND; + break; + } + } else if(c==BOCU1_RESET) { + /* only reset the state, no code point */ + prev=BOCU1_ASCII_PREV; + continue; + } else { + /* + * For multi-byte difference lead bytes, set the decoder state + * with the partial difference value from the lead byte and + * with the number of trail bytes. + */ + bytes[0]=(uint8_t)c; + byteIndex=1; + + diff=decodeBocu1LeadByte(c); + count=diff&3; + diff>>=2; +getTrail: + for(;;) { + if(source>=sourceLimit) { + goto endloop; + } + c=bytes[byteIndex++]=*source++; + + /* trail byte in any position */ + c=decodeBocu1TrailByte(count, c); + if(c<0) { + *pErrorCode=U_ILLEGAL_CHAR_FOUND; + goto endloop; + } + + diff+=c; + if(--count==0) { + /* final trail byte, deliver a code point */ + byteIndex=0; + c=prev+diff; + if((uint32_t)c>0x10ffff) { + *pErrorCode=U_ILLEGAL_CHAR_FOUND; + goto endloop; + } + break; + } + } + } + + /* calculate the next prev and output c */ + prev=BOCU1_PREV(c); + if(c<=0xffff) { + *target++=(char16_t)c; + } else { + /* output surrogate pair */ + *target++=U16_LEAD(c); + if(target<targetLimit) { + *target++=U16_TRAIL(c); + } else { + /* target overflow */ + cnv->UCharErrorBuffer[0]=U16_TRAIL(c); + cnv->UCharErrorBufferLength=1; + *pErrorCode=U_BUFFER_OVERFLOW_ERROR; + break; + } + } + } +endloop: + + if(*pErrorCode==U_ILLEGAL_CHAR_FOUND) { + /* set the converter state in UConverter to deal with the next character */ + cnv->toUnicodeStatus=BOCU1_ASCII_PREV; + cnv->mode=0; + } else { + /* set the converter state back into UConverter */ + cnv->toUnicodeStatus=(uint32_t)prev; + cnv->mode=((uint32_t)diff<<2)|count; + } + cnv->toULength=byteIndex; + + /* write back the updated pointers */ + pArgs->source=(const char *)source; + pArgs->target=target; + return; +} + +/* miscellaneous ------------------------------------------------------------ */ + +static const UConverterImpl _Bocu1Impl={ + UCNV_BOCU1, + + nullptr, + nullptr, + + nullptr, + nullptr, + nullptr, + + _Bocu1ToUnicode, + _Bocu1ToUnicodeWithOffsets, + _Bocu1FromUnicode, + _Bocu1FromUnicodeWithOffsets, + nullptr, + + nullptr, + nullptr, + nullptr, + nullptr, + ucnv_getCompleteUnicodeSet, + + nullptr, + nullptr +}; + +static const UConverterStaticData _Bocu1StaticData={ + sizeof(UConverterStaticData), + "BOCU-1", + 1214, /* CCSID for BOCU-1 */ + UCNV_IBM, UCNV_BOCU1, + 1, 4, /* one char16_t generates at least 1 byte and at most 4 bytes */ + { 0x1a, 0, 0, 0 }, 1, /* BOCU-1 never needs to write a subchar */ + false, false, + 0, + 0, + { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } /* reserved */ +}; + +const UConverterSharedData _Bocu1Data= + UCNV_IMMUTABLE_SHARED_DATA_INITIALIZER(&_Bocu1StaticData, &_Bocu1Impl); + +#endif |