// © 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 … /* bounding byte values for differences */ #define BOCU1_MIN … #define BOCU1_MIDDLE … #define BOCU1_MAX_LEAD … #define BOCU1_MAX_TRAIL … #define BOCU1_RESET … /* number of lead bytes */ #define BOCU1_COUNT … /* adjust trail byte counts for the use of some C0 control byte values */ #define BOCU1_TRAIL_CONTROLS_COUNT … #define BOCU1_TRAIL_BYTE_OFFSET … /* number of trail bytes */ #define BOCU1_TRAIL_COUNT … /* * number of positive and negative single-byte codes * (counting 0==BOCU1_MIDDLE among the positive ones) */ #define BOCU1_SINGLE … /* number of lead bytes for positive and negative 2/3/4-byte sequences */ #define BOCU1_LEAD_2 … #define BOCU1_LEAD_3 … #define BOCU1_LEAD_4 … /* The difference value range for single-byters. */ #define BOCU1_REACH_POS_1 … #define BOCU1_REACH_NEG_1 … /* The difference value range for double-byters. */ #define BOCU1_REACH_POS_2 … #define BOCU1_REACH_NEG_2 … /* The difference value range for 3-byters. */ #define BOCU1_REACH_POS_3 … #define BOCU1_REACH_NEG_3 … /* The lead byte start values. */ #define BOCU1_START_POS_2 … #define BOCU1_START_POS_3 … #define BOCU1_START_POS_4 … /* ==BOCU1_MAX_LEAD */ #define BOCU1_START_NEG_2 … #define BOCU1_START_NEG_3 … #define BOCU1_START_NEG_4 … /* ==BOCU1_MIN+1 */ /* The length of a byte sequence, according to the lead byte (!=BOCU1_RESET). */ #define BOCU1_LENGTH_FROM_LEAD … /* The length of a byte sequence, according to its packed form. */ #define BOCU1_LENGTH_FROM_PACKED … /* * 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 … /* * 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 … /* Faster versions of packDiff() for single-byte-encoded diff values. */ /** Is a diff value encodable in a single byte? */ #define DIFF_IS_SINGLE … /** Encode a diff value in a single byte. */ #define PACK_SINGLE_DIFF … /** Is a diff value encodable in two bytes? */ #define DIFF_IS_DOUBLE … /* BOCU-1 implementation functions ------------------------------------------ */ #define BOCU1_SIMPLE_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 … /* * 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; } /* * 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; } /* 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
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