scuffed-code/icu4c/source/common/ucnvmbcs.c
2000-08-15 21:33:54 +00:00

1324 lines
52 KiB
C

/*
*******************************************************************************
*
* Copyright (C) 2000, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
* file name: ucnvmbcs.c
* encoding: US-ASCII
* tab size: 8 (not used)
* indentation:4
*
* created on: 2000jul03
* created by: Markus W. Scherer
*
* The current code in this file replaces the previous implementation
* of conversion code from multi-byte codepages to Unicode and back.
* This implementation supports the following:
* - legacy variable-length codepages with up to 4 bytes per character
* - all Unicode code points (up to 0x10ffff)
* - efficient distinction of unassigned vs. illegal byte sequences
* - it is possible in fromUnicode() to directly deal with simple
* stateful encodings
* - it is possible to convert Unicode code points other than U+0000
* to a single zero byte (but not as a fallback)
*
* Remaining limitations in fromUnicode:
* - byte sequences must not have leading zero bytes
* - no fallback mapping from Unicode to a zero byte
* - limitation to up to 4 bytes per character
*/
#include "unicode/utypes.h"
#include "unicode/ucnv.h"
#include "ucnv_bld.h"
#include "ucnvmbcs.h"
#include "ucnv_cnv.h"
/*
* Converting stateless codepage data
* (or codepage data with simple states) to Unicode.
*
* Data structure and algorithm for converting from complex legacy codepages
* to Unicode. (Designed before 2000-may-22.)
*
* The basic idea is that the structure of legacy codepages can be described
* with state tables.
* When reading a byte stream, each input byte causes a state transition.
* Some transitions result in the output of a code point, some result in
* "unassigned" or "illegal" output.
* This is used here for character conversion.
*
* The data structure begins with a state table consisting of a row
* per state, with 256 entries (columns) per row for each possible input
* byte value.
* Each entry is 32 bits wide, with the lower 7 bits containing the next state.
* State 0 is the initial state.
*
* Bit 31 of each entry indicates whether the state is
* terminal (bit 31 set) or not.
*
* Most of the time, the offset values of subsequent states are added
* up to a scalar value. This value will eventually be the index of
* the Unicode code point in a table that follows the state table.
* The effect is that the code points for final state table rows
* are contiguous. The code points of final state rows follow each other
* in the order of the references to those final states by previous
* states, etc.
*
* For some terminal states, the offset is itself the output Unicode
* code point (16 bits for a BMP code point or 20 bits for a code point
* that is written as a surrogate pair).
* For others, the code point in the Unicode table is stored with either
* one or two code units: one for BMP code points, two for a pair of
* surrogates.
* All code points for a final table take up the same number of code
* units, regardless of whether they all actually _use_ the same number
* of code units. This is necessary for simple array access.
*
* An additional feature comes in with what in ICU is called "fallback"
* mappings:
* In addition to round-trippable, precise, 1:1 mappings, there are often
* mappings defined between similar, though not the same, characters.
* Typically, such mappings occur only in fromUnicode mapping tables because
* Unicode has a superset repertoire of most other codepages. However, it
* is possible to provide such mappings in the toUnicode tables, too.
* In this case, the fallback mappings are partly integrated into the
* general state tables because the structure of the encoding includes their
* byte sequences. They are optional mappings when the main mapping is
* "unassigned", and are looked up by the scalar offset of the main mapping
* in a separate table. Only when the main mapping does not have such a
* scalar offset, i.e., in the case of action codes 5 of 6 below (valid-direct),
* would there need to be some different mechanism. Therefore, there are
* separate action codes 3 and 4 (fallback-direct) especially for that.
* The "unassigned" action code 2 cannot be used for fallback lookups because
* it also does not result in a scalar offset. This means that fallback mappings
* require to fit into either fallback-direct action codes or valid-single or
* valid-pair codes that result in scalar offsets.
* "Unassigned" really means "structurally unassigned".
*
* The interpretation of the bits in each entry is as follows:
*
* Bit 31 not set, not a terminal entry:
* 30..7 offset delta, to be added up
* 6..0 next state
*
* Bit 31 set, terminal entry:
* 30..27 action code:
* 0 illegal byte sequence
* 26..7 not used, 0
* 1 state change only
* 26..7 not used, 0
* useful for state changes in simple stateful encodings,
* at Shift-In/Shift-Out codes
* 2 unassigned byte sequence
* 26..7 not used, 0
* this does not contain a final offset delta because the main
* purpose of this action code is to save scalar offset values;
* therefore, fallback values cannot be assigned to byte
* sequences that result in this action code - use codes 5 or 6
* 3 valid byte sequence (fallback)
* 22..7 16-bit Unicode BMP code point as fallback result
* 4 valid byte sequence (fallback)
* 26..7 20-bit Unicode surrogate code point as fallback result
*
* action codes 5, 6, 7, and 8 result in precise-mapping Unicode code points
* 5 valid byte sequence
* 22..7 16-bit Unicode BMP code point
* never U+fffe or U+ffff (use action codes 0, 2, 3 or 4 for that)
* 6 valid byte sequence
* 26..7 20-bit Unicode surrogate code point
* never U+fffe or U+ffff (use action codes 0, 2, 3 or 4 for that)
*
* action codes 7 and 8 may result in U+fffe (unassigned), in which case the
* final offset is to be looked up in a special fallback table
* 7 valid byte sequence
* 26..16 not used, 0
* 15..7 final offset delta
* pointing to one 16-bit code unit
* which may be U+fffe (unassigned) or U+ffff (illegal)
* 8 valid byte sequence
* 26..16 not used, 0
* 15..7 final offset delta
* pointing to two 16-bit code units
* (UTF-16 surrogates)
* the first code unit either is a lead surrogate and indicates
* an assigned surrogate pair, or it is a single unit
* which may be U+fffe (unassigned) or U+ffff (illegal)
* (the final offset deltas are at most 255 * 2,
* times 2 because of storing code unit pairs)
* 9..15 reserved for future use
* current implementations will only perform a state change
* and ignore bits 26..7
* 6..0 next state (regardless of action code)
*
* An encoding with contiguous ranges of unassigned byte sequences, like
* Shift-JIS and especially EUC-TW, can be stored efficiently by having
* at least two states for the trail bytes:
* One trail byte state that results in code points, and one that only
* has "unassigned" and "illegal" terminal states.
*
* Note: partly by accident, this data structure supports simple stateless
* encodings without any additional logic.
* Especially simple Shift-In/Shift-Out schemes could be handled with
* appropriate state tables (especially EBCDIC_STATEFUL!).
*/
/* MBCS setup functions ----------------------------------------------------- */
U_CFUNC void
_MBCSLoad(UConverterSharedData *sharedData,
const uint8_t *raw,
UErrorCode *pErrorCode) {
UConverterMBCSTable *mbcsTable=&sharedData->table->mbcs;
_MBCSHeader *header=(_MBCSHeader *)raw;
if(header->version[0]!=1) {
*pErrorCode=U_INVALID_TABLE_FORMAT;
return;
}
mbcsTable->countStates=(uint8_t)header->countStates;
mbcsTable->countToUFallbacks=header->countToUFallbacks;
mbcsTable->stateTable=(const int32_t (*)[256])(raw+sizeof(_MBCSHeader));
mbcsTable->toUFallbacks=(const _MBCSToUFallback *)(mbcsTable->stateTable+header->countStates);
mbcsTable->unicodeCodeUnits=(const uint16_t *)(raw+header->offsetToUCodeUnits);
mbcsTable->fromUnicodeTable=(const uint16_t *)(raw+header->offsetFromUTable);
mbcsTable->fromUnicodeBytes=(const uint8_t *)(raw+header->offsetFromUBytes);
mbcsTable->outputType=(uint8_t)header->flags;
}
U_CFUNC void
_MBCSReset(UConverter *cnv) {
/* toUnicode */
cnv->toUnicodeStatus=0;
cnv->mode=0;
cnv->toULength=0;
/* fromUnicode */
cnv->fromUSurrogateLead=0;
}
U_CFUNC void
_MBCSOpen(UConverter *cnv,
const char *name,
const char *locale,
UErrorCode *pErrorCode) {
_MBCSReset(cnv);
}
/* MBCS-to-Unicode conversion functions ------------------------------------- */
static UChar32
_MBCSGetFallback(UConverterMBCSTable *mbcsTable, uint32_t offset) {
const _MBCSToUFallback *toUFallbacks;
uint32_t i, start, limit;
limit=mbcsTable->countToUFallbacks;
if(limit>0) {
/* do a binary search for the fallback mapping */
toUFallbacks=mbcsTable->toUFallbacks;
start=0;
while(start<limit-1) {
i=(start+limit)/2;
if(offset<toUFallbacks[i].offset) {
limit=i;
} else {
start=i;
}
}
/* did we really find it? */
if(offset==toUFallbacks[start].offset) {
return toUFallbacks[start].codePoint;
}
}
return 0xfffe;
}
U_CFUNC void
_MBCSToUnicodeWithOffsets(UConverterToUnicodeArgs *pArgs,
UErrorCode *pErrorCode) {
/* set up the local pointers */
UConverter *cnv=pArgs->converter;
const uint8_t *source=(const uint8_t *)pArgs->source,
*sourceLimit=(const uint8_t *)pArgs->sourceLimit;
UChar *target=pArgs->target;
const UChar *targetLimit=pArgs->targetLimit;
int32_t *offsets=pArgs->offsets;
const int32_t (*stateTable)[256]=cnv->sharedData->table->mbcs.stateTable;
const uint16_t (*unicodeCodeUnits)=cnv->sharedData->table->mbcs.unicodeCodeUnits;
/* get the converter state from UConverter */
uint32_t offset=cnv->toUnicodeStatus;
uint8_t state=(uint8_t)(cnv->mode);
int8_t byteIndex=cnv->toULength;
uint8_t *bytes=cnv->toUBytes;
/* sourceIndex=-1 if the current character began in the previous buffer */
int32_t sourceIndex=byteIndex==0 ? 0 : -1,
nextSourceIndex=0;
/* conversion loop */
int32_t entry;
UChar c;
uint8_t b;
UConverterCallbackReason reason;
while(source<sourceLimit) {
/*
* This following test is to see if available input would overflow the output.
* It does not catch output of more than one code unit that
* overflows as a result of a surrogate pair or callback output
* from the last source byte.
* Therefore, those situations also test for overflows and will
* then break the loop, too.
*/
if(target<targetLimit) {
bytes[byteIndex++]=b=*source++;
++nextSourceIndex;
entry=stateTable[state][b];
if(entry>=0) {
/*
* bit 31 is not set, bits:
* 30..7 offset delta
* 6..0 next state
*/
state=(uint8_t)(entry&0x7f);
offset+=entry>>7;
} else {
/*
* bit 31 is set, bits:
* 30..27 action code
* (do not mask out bit 31 for speed, include it in action values)
* 26..7 depend on the action code
* 6..0 next state
*/
/* set the next state early so that we can reuse the entry variable */
state=(uint8_t)(entry&0x7f); /* typically 0 */
/* switch per action code */
switch((uint32_t)entry>>27U) {
case 16|MBCS_STATE_ILLEGAL:
/* bits 26..7 are not used, 0 */
/* callback(illegal) */
reason=UCNV_ILLEGAL;
*pErrorCode=U_ILLEGAL_CHAR_FOUND;
goto callback;
case 16|MBCS_STATE_CHANGE_ONLY:
/* bits 26..7 are not used, 0 */
/*
* This serves as a state change without any output.
* It is useful for reading simple stateful encodings,
* for example using just Shift-In/Shift-Out codes.
* The 21 unused bits may later be used for more sophisticated
* state transitions.
*/
break;
case 16|MBCS_STATE_UNASSIGNED:
/* bits 26..7 are not used, 0 */
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
case 16|MBCS_STATE_FALLBACK_DIRECT_16:
/* bits 26..23 are not used, 0 */
/* bits 22..7 contain the Unicode BMP code point */
if(!cnv->useFallback) {
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
}
/* fall through to the MBCS_STATE_VALID_DIRECT_16 branch */
case 16|MBCS_STATE_VALID_DIRECT_16:
/* bits 26..23 are not used, 0 */
/* bits 22..7 contain the Unicode BMP code point */
/* output BMP code point */
*target++=(UChar)(entry>>7);
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
break;
case 16|MBCS_STATE_FALLBACK_DIRECT_20:
/* bits 26..7 contain the Unicode surrogate code point minus 0x10000 */
if(!cnv->useFallback) {
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
}
/* fall through to the MBCS_STATE_VALID_DIRECT_20 branch */
case 16|MBCS_STATE_VALID_DIRECT_20:
/* bits 26..7 contain the Unicode surrogate code point minus 0x10000 */
entry=(entry>>7)&0xfffff;
/* output surrogate pair */
*target++=(UChar)(0xd800|(UChar)(entry>>10));
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
c=(UChar)(0xdc00|(UChar)(entry&0x3ff));
if(target<targetLimit) {
*target++=c;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
} else {
/* target overflow */
cnv->UCharErrorBuffer[0]=c;
cnv->UCharErrorBufferLength=1;
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
offset=0;
byteIndex=0;
goto endloop;
}
break;
case 16|MBCS_STATE_VALID_16:
/* bits 26..16 are not used, 0 */
/* bits 15..7 contain the final offset delta to one 16-bit code unit */
offset+=(uint16_t)entry>>7;
c=unicodeCodeUnits[offset];
if(c<0xfffe) {
/* output BMP code point */
*target++=c;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
} else if(c==0xfffe) {
if(cnv->useFallback && (entry=(int32_t)_MBCSGetFallback(&cnv->sharedData->table->mbcs, offset))!=0xfffe) {
goto output32;
}
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
} else {
/* callback(illegal) */
reason=UCNV_ILLEGAL;
*pErrorCode=U_ILLEGAL_CHAR_FOUND;
goto callback;
}
break;
case 16|MBCS_STATE_VALID_16_PAIR:
/* bits 26..16 are not used, 0 */
/* bits 15..7 contain the final offset delta to two 16-bit code units */
offset+=(uint16_t)entry>>7;
c=unicodeCodeUnits[offset++];
if(UTF_IS_FIRST_SURROGATE(c)) {
*target++=c;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
if(target<targetLimit) {
*target++=unicodeCodeUnits[offset];
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
} else {
/* target overflow */
cnv->UCharErrorBuffer[0]=unicodeCodeUnits[offset];
cnv->UCharErrorBufferLength=1;
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
offset=0;
byteIndex=0;
goto endloop;
}
} else if(c<0xfffe) {
/* output BMP code point */
*target++=c;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
} else if(c==0xfffe) {
/*
* For the fallback, we need to restore the offset that
* we had before the unicodeCodeUnits[offset++] above that incremented it!
*/
if(cnv->useFallback && (entry=(int32_t)_MBCSGetFallback(&cnv->sharedData->table->mbcs, offset-1))!=0xfffe) {
goto output32;
}
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
} else {
/* callback(illegal) */
reason=UCNV_ILLEGAL;
*pErrorCode=U_ILLEGAL_CHAR_FOUND;
goto callback;
}
break;
default:
/* reserved, must never occur */
/* bits 26..7 are not used, 0 */
break;
}
/* normal end of action codes: prepare for a new character */
offset=0;
byteIndex=0;
sourceIndex=nextSourceIndex;
continue;
/*
* Markus Scherer 2000-jul-05
*
* The following is extremely ugly, and I apologize for it:
* Several places in the above switch statement need to call
* a callback function or output a 32-bit code point,
* each of which is an involved process with
* a couple dozen of statements.
*
* I could do this in a function call, but I fear that then
* the compiler does not keep the frequently used variables in
* registers because the function call would need them on the stack
* for input and output.
*
* I could do this with a macro, but that is harder to debug and
* bloats the compiled code.
*
* I could just copy and paste the code, but that would also bloat
* the program size, make the pieces harder to maintain, and make
* the switch statement extremely long and clumsy.
*
* Therefore, those places goto here and do it all in one place,
* while the normal processing has a continue above and skips this
* part.
* This actually _saves_ goto statements, too:
* Since it is not possible in C to break a loop from within a switch
* statement, the callback code in the switch statement would have to
* goto behind the loop. Here, it can break if necessary.
*/
output32:
/* output a 32-bit (21-bit) Unicode code point stored in entry */
if(entry<=0xffff) {
/* output BMP code point */
*target++=(UChar)entry;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
} else {
/* output surrogate pair */
*target++=(UChar)(0xd7c0+(entry>>10));
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
c=(UChar)(0xdc00|(UChar)(entry&0x3ff));
if(target<targetLimit) {
*target++=c;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
} else {
/* target overflow */
cnv->UCharErrorBuffer[0]=c;
cnv->UCharErrorBufferLength=1;
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
offset=0;
byteIndex=0;
break;
}
}
/* same as normal end of action codes: prepare for a new character */
offset=0;
byteIndex=0;
sourceIndex=nextSourceIndex;
continue;
callback:
/* call the callback function with all the preparations and post-processing */
/* update the arguments structure */
pArgs->source=(const char *)source;
pArgs->target=target;
pArgs->offsets=offsets;
/* copy the current bytes to invalidCharBuffer */
for(b=0; b<(uint8_t)byteIndex; ++b) {
cnv->invalidCharBuffer[b]=(char)bytes[b];
}
cnv->invalidCharLength=byteIndex;
/* set the converter state in UConverter to deal with the next character */
cnv->toUnicodeStatus=0;
cnv->mode=state;
cnv->toULength=0;
/* call the callback function */
cnv->fromCharErrorBehaviour(cnv->toUContext, pArgs, (const char *)bytes, byteIndex, reason, pErrorCode);
/* get the converter state from UConverter */
offset=cnv->toUnicodeStatus;
state=(uint8_t)cnv->mode;
byteIndex=cnv->toULength;
/* update target and deal with offsets if necessary */
if(offsets!=NULL) {
/* add the sourceIndex to the relative offsets that the callback wrote */
if(sourceIndex>=0) {
while(target<pArgs->target) {
*offsets+=sourceIndex;
++offsets;
++target;
}
} else {
/* sourceIndex==-1, set -1 offsets */
while(target<pArgs->target) {
*offsets=-1;
++offsets;
++target;
}
}
} else {
target=pArgs->target;
}
/* update the source pointer and index */
sourceIndex=nextSourceIndex+((const uint8_t *)pArgs->source-source);
source=(const uint8_t *)pArgs->source;
/* break on error */
if(U_FAILURE(*pErrorCode)) {
offset=0;
state=0;
byteIndex=0;
break;
}
/*
* If the callback overflowed the target, then we need to
* stop here with an overflow indication.
*/
if(cnv->UCharErrorBufferLength>0) {
/* target is full */
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
break;
}
/*
* We do not need to repeat the statements from the normal
* end of the action codes because we already updated all the
* necessary variables.
*/
}
} else {
/* target is full */
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
break;
}
}
endloop:
if(pArgs->flush && source>=sourceLimit) {
/* reset the state for the next conversion */
if(byteIndex>0 && U_SUCCESS(*pErrorCode)) {
/* a character byte sequence remains incomplete */
*pErrorCode=U_TRUNCATED_CHAR_FOUND;
}
cnv->toUnicodeStatus=0;
cnv->mode=0;
cnv->toULength=0;
} else {
/* set the converter state back into UConverter */
cnv->toUnicodeStatus=offset;
cnv->mode=state;
cnv->toULength=byteIndex;
}
/* write back the updated pointers */
pArgs->source=(const char *)source;
pArgs->target=target;
pArgs->offsets=offsets;
}
U_CFUNC void
_MBCSToUnicode(UConverterToUnicodeArgs *pArgs,
UErrorCode *pErrorCode) {
_MBCSToUnicodeWithOffsets(pArgs, pErrorCode);
}
/*
* This is a simple, interim implementation of GetNextUChar()
* that allows to concentrate on testing one single implementation
* of the ToUnicode conversion before it gets copied to
* multiple version that are then optimized for their needs
* (with vs. without offsets and getNextUChar).
*/
U_CFUNC UChar32
_MBCSGetNextUChar(UConverterToUnicodeArgs *pArgs,
UErrorCode *pErrorCode) {
UChar buffer[UTF_MAX_CHAR_LENGTH];
const char *realLimit=pArgs->sourceLimit;
pArgs->target=buffer;
pArgs->targetLimit=buffer+UTF_MAX_CHAR_LENGTH;
while(pArgs->source<realLimit) {
/* feed in one byte at a time to make sure to get only one character out */
pArgs->sourceLimit=pArgs->source+1;
pArgs->flush= (UBool)(pArgs->sourceLimit==realLimit);
_MBCSToUnicode(pArgs, pErrorCode);
if(U_FAILURE(*pErrorCode) && *pErrorCode!=U_BUFFER_OVERFLOW_ERROR) {
return 0xffff;
} else if(pArgs->target!=buffer) {
if(*pErrorCode==U_BUFFER_OVERFLOW_ERROR) {
*pErrorCode=U_ZERO_ERROR;
}
return ucnv_getUChar32KeepOverflow(pArgs->converter, buffer, pArgs->target-buffer);
}
}
/* no output because of empty input or only state changes and skipping callbacks */
*pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;
return 0xffff;
}
/*
* This is a simple version of getNextUChar() that is used
* by other converter implementations.
* It does not use state from the converter, nor error codes,
* and does not provide fallback mappings.
*
* Return value:
* U+fffe unassigned
* U+ffff illegal
* otherwise the Unicode code point
*/
U_CFUNC UChar32
_MBCSSimpleGetNextUChar(UConverterSharedData *sharedData,
const char **pSource, const char *sourceLimit) {
/* set up the local pointers */
const uint8_t *source=(const uint8_t *)*pSource;
const int32_t (*stateTable)[256]=sharedData->table->mbcs.stateTable;
const uint16_t (*unicodeCodeUnits)=sharedData->table->mbcs.unicodeCodeUnits;
/* converter state */
uint32_t offset=0;
uint8_t state=0;
/* conversion loop */
int32_t entry;
if(source>=(const uint8_t *)sourceLimit) {
/* no input at all: "unassigned" */
return 0xfffe;
}
do {
entry=stateTable[state][*source++];
if(entry>=0) {
/*
* bit 31 is not set, bits:
* 30..7 offset delta
* 6..0 next state
*/
state=(uint8_t)(entry&0x7f);
offset+=entry>>7;
} else {
/*
* bit 31 is set, bits:
* 30..27 action code
* (do not mask out bit 31 for speed, include it in action values)
* 26..7 depend on the action code
* 6..0 next state
*/
*pSource=(const char *)source;
/* switch per action code */
switch((uint32_t)entry>>27U) {
case 16|MBCS_STATE_ILLEGAL:
/* bits 26..7 are not used, 0 */
return 0xffff;
case 16|MBCS_STATE_CHANGE_ONLY:
/* bits 26..7 are not used, 0 */
/*
* This serves as a state change without any output.
* It is useful for reading simple stateful encodings,
* for example using just Shift-In/Shift-Out codes.
* The 21 unused bits may later be used for more sophisticated
* state transitions.
*/
if(source==(const uint8_t *)sourceLimit) {
/* if there are only state changes, then return "unassigned" */
return 0xfffe;
}
break;
case 16|MBCS_STATE_UNASSIGNED:
/* bits 26..7 are not used, 0 */
return 0xfffe;
case 16|MBCS_STATE_FALLBACK_DIRECT_16:
/* bits 26..23 are not used, 0 */
/* bits 22..7 contain the Unicode BMP code point */
return 0xfffe;
case 16|MBCS_STATE_VALID_DIRECT_16:
/* bits 26..23 are not used, 0 */
/* bits 22..7 contain the Unicode BMP code point */
/* output BMP code point */
return (UChar)(entry>>7);
case 16|MBCS_STATE_FALLBACK_DIRECT_20:
/* bits 26..7 contain the Unicode surrogate code point minus 0x10000 */
return 0xfffe;
case 16|MBCS_STATE_VALID_DIRECT_20:
/* bits 26..7 contain the Unicode surrogate code point minus 0x10000 */
return 0x10000+((entry>>7)&0xfffff);
case 16|MBCS_STATE_VALID_16:
/* bits 26..16 are not used, 0 */
/* bits 15..7 contain the final offset delta to one 16-bit code unit */
offset+=(uint16_t)entry>>7;
return unicodeCodeUnits[offset];
case 16|MBCS_STATE_VALID_16_PAIR:
/* bits 26..16 are not used, 0 */
/* bits 15..7 contain the final offset delta to two 16-bit code units */
offset+=(uint16_t)entry>>7;
entry=unicodeCodeUnits[offset++];
if(UTF_IS_FIRST_SURROGATE(entry)) {
return UTF16_GET_PAIR_VALUE(entry, unicodeCodeUnits[offset]);
} else {
return (UChar32)entry;
}
default:
/* reserved, must never occur */
/* bits 26..7 are not used, 0 */
break;
}
/* state change only - prepare for a new character */
state=(uint8_t)(entry&0x7f); /* typically 0 */
offset=0;
}
} while(source<(const uint8_t *)sourceLimit);
*pSource=(const char *)source;
return 0xffff;
}
/* MBCS-from-Unicode conversion functions ----------------------------------- */
U_CFUNC void
_MBCSFromUnicodeWithOffsets(UConverterFromUnicodeArgs *pArgs,
UErrorCode *pErrorCode) {
/* set up the local pointers */
UConverter *cnv=pArgs->converter;
const UChar *source=pArgs->source,
*sourceLimit=pArgs->sourceLimit;
uint8_t *target=(uint8_t *)pArgs->target;
int32_t targetCapacity=pArgs->targetLimit-pArgs->target;
int32_t *offsets=pArgs->offsets;
const uint16_t *table=cnv->sharedData->table->mbcs.fromUnicodeTable;
const uint8_t *bytes=cnv->sharedData->table->mbcs.fromUnicodeBytes;
uint8_t outputType=cnv->sharedData->table->mbcs.outputType;
/* get the converter state from UConverter */
UChar32 c=cnv->fromUSurrogateLead;
/* sourceIndex=-1 if the current character began in the previous buffer */
int32_t sourceIndex= c==0 ? 0 : -1,
nextSourceIndex=0;
/* conversion loop */
UConverterCallbackReason reason;
uint32_t i;
uint32_t value;
int32_t length;
/*
* This is another piece of ugly code:
* A goto into the loop if the converter state contains a first surrogate
* from the previous function call.
* It saves me to check in each loop iteration a check of if(c==0)
* and duplicating the trail-surrogate-handling code in the else
* branch of that check.
* I could not find any other way to get around this other than
* using a function call for the conversion and callback, which would
* be even more inefficient.
*
* Markus Scherer 2000-jul-19
*/
if(c!=0 && targetCapacity>0) {
goto getTrail;
}
while(source<sourceLimit) {
/*
* This following test is to see if available input would overflow the output.
* It does not catch output of more than one byte that
* overflows as a result of a multi-byte character or callback output
* from the last source character.
* Therefore, those situations also test for overflows and will
* then break the loop, too.
*/
if(targetCapacity>0) {
/*
* Get a correct Unicode code point:
* a single UChar for a BMP code point or
* a matched surrogate pair for a "surrogate code point".
*/
c=*source++;
++nextSourceIndex;
if(UTF_IS_SURROGATE(c)) {
if(UTF_IS_SURROGATE_FIRST(c)) {
getTrail:
if(source<sourceLimit) {
/* test the following code unit */
UChar trail=*source;
if(UTF_IS_SECOND_SURROGATE(trail)) {
++source;
++nextSourceIndex;
c=UTF16_GET_PAIR_VALUE(c, trail);
/* convert this surrogate code point */
/* exit this condition tree */
} else {
/* this is an unmatched lead code unit (1st surrogate) */
/* callback(illegal) */
reason=UCNV_ILLEGAL;
*pErrorCode=U_ILLEGAL_CHAR_FOUND;
goto callback;
}
} else {
/* no more input */
break;
}
} else {
/* this is an unmatched trail code unit (2nd surrogate) */
/* callback(illegal) */
reason=UCNV_ILLEGAL;
*pErrorCode=U_ILLEGAL_CHAR_FOUND;
goto callback;
}
}
/* convert the Unicode code point in c into codepage bytes */
/*
* The basic lookup is a triple-stage compact array lookup:
*
* Bits 21..10 (0x440 different values because Unicode code points
* reach up to 0x10ffff) are used as an index into table[],
* then bits 9..4 are added to that and together multiplied by 2
* to be used as an index into a second table that starts at table+0x440.
*
* In that second table, there will be two 16-bit values
* (and therefore we multiplied by two in the previous step):
* One 16-bit value stores a bit for each of the 16 Unicode code points
* that are grouped here to indicate if it is assigned or not.
* If it is not assigned, there may still be a codepage character
* stored in the third stage: a fallback value. It is used only when
* fallbacks are turned on for the converter. If the code point is
* unassigned and fallbacks not used or there is no fallback character
* (all bytes 0), then the callback function is called.
*
* The second value in the second table (stage) is an index into
* the third table. It is multiplied by 16*(bytes stored per character)
* to get to the first of 16 characters. At last, bits 3..0 of
* the Unicode code point are multiplied by (bytes stored per character)
* and added to that index for the address of the output codepage
* character.
*
* For EUC encodings that use only either 0x8e or 0x8f as the first
* byte of their longest byte sequences, the first two bytes in
* this third stage indicate with their 7th bits whether these bytes
* are to be written directly or actually need to be preceeded by
* one of the two Single-Shift codes. With this, the third stage
* stores one byte fewer per character than the actual maximum length of
* EUC byte sequences.
*
* Other than that, leading zero bytes are removed and the other
* bytes output. A single zero byte may be output if the "assigned"
* bit in stage 2 was on or also if the Unicode code point is U+0000.
* The data structure does not support zero byte output as a fallback
* for other code points, and also does not allow output of leading zeros.
*/
i=0x440+2*((uint32_t)table[c>>10]+((c>>4)&0x3f));
/* is this code point assigned, or do we use fallbacks? */
if((table[i++]&(1<<(c&0xf)))!=0 || cnv->useFallback) {
const uint8_t *p;
/* get the bytes and the length for the output */
switch(outputType) {
case MBCS_OUTPUT_1:
p=bytes+(16*(uint32_t)table[i]+(c&0xf));
value=*p;
length=1;
break;
case MBCS_OUTPUT_2:
p=bytes+(16*(uint32_t)table[i]+(c&0xf))*2;
if(U_IS_BIG_ENDIAN) {
value=*(uint16_t *)p;
} else {
value=((uint32_t)*p<<8)|p[1];
}
if(value<=0xff) {
length=1;
} else {
length=2;
}
break;
case MBCS_OUTPUT_3:
p=bytes+(16*(uint32_t)table[i]+(c&0xf))*3;
value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
if(value<=0xff) {
length=1;
} else if(value<=0xffff) {
length=2;
} else {
length=3;
}
break;
case MBCS_OUTPUT_4:
p=bytes+(16*(uint32_t)table[i]+(c&0xf))*4;
if(U_IS_BIG_ENDIAN) {
value=*(uint32_t *)p;
} else {
value=((uint32_t)*p<<24)|((uint32_t)p[1]<<16)|((uint32_t)p[2]<<8)|p[3];
}
if(value<=0xff) {
length=1;
} else if(value<=0xffff) {
length=2;
} else if(value<=0xffffff) {
length=3;
} else {
length=4;
}
break;
case MBCS_OUTPUT_3_EUC:
p=bytes+(16*(uint32_t)table[i]+(c&0xf))*2;
if(U_IS_BIG_ENDIAN) {
value=*(uint16_t *)p;
} else {
value=((uint32_t)*p<<8)|p[1];
}
/* EUC 16-bit fixed-length representation */
if(value<=0xff) {
length=1;
} else if((value&0x8000)==0) {
value|=0x8e8000;
length=3;
} else if((value&0x80)==0) {
value|=0x8f0080;
length=3;
} else {
length=2;
}
break;
case MBCS_OUTPUT_4_EUC:
p=bytes+(16*(uint32_t)table[i]+(c&0xf))*3;
value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
/* EUC 16-bit fixed-length representation applied to the first two bytes */
if(value<=0xff) {
length=1;
} else if(value<=0xffff) {
length=2;
} else if((value&0x800000)==0) {
value|=0x8e800000;
length=4;
} else if((value&0x8000)==0) {
value|=0x8f008000;
length=4;
} else {
length=3;
}
break;
default:
/* must not occur */
/*
* To avoid compiler warnings that value & length may be
* used without having been initialized, we set them here.
* In reality, this is unreachable code.
* Not having a default branch also causes warnings with
* some compilers.
*/
value=0;
length=0;
break;
}
/* is the codepage value really an "unassigned" indicator? */
if(value==0 && c!=0 && (table[i-1]&(1<<(c&0xf)))==0) {
/*
* We allow a 0 byte output if the Unicode code point is
* U+0000 and also if the "assigned" bit is set for this entry.
* There is no way with this data structure for fallback output
* for other than U+0000 to be a zero byte.
*/
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
}
} else {
/* callback(unassigned) */
reason=UCNV_UNASSIGNED;
*pErrorCode=U_INVALID_CHAR_FOUND;
goto callback;
}
/* write the output character bytes from value and length */
if(length==1) {
/* this is easy because we know that there is enough space */
*target++=(uint8_t)value;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
--targetCapacity;
} else {
/* from the first if in the loop we know that available>0 */
if(length<=targetCapacity) {
switch(length) {
/* each branch falls through to the next one */
case 4:
*target++=(uint8_t)(value>>24);
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
case 3:
*target++=(uint8_t)(value>>16);
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
case 2:
*target++=(uint8_t)(value>>8);
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
/* case 1: covered by above, but all branches also have to output this byte */
*target++=(uint8_t)value;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
default:
/* will never occur */
break;
}
targetCapacity-=length;
} else {
uint8_t *p;
/*
* 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<=available<length<=4 */
length-=targetCapacity;
p=(uint8_t *)cnv->charErrorBuffer;
switch(length) {
/* each branch falls through to the next one */
case 3:
*p++=(uint8_t)(value>>16);
case 2:
*p++=(uint8_t)(value>>8);
case 1:
*p=(uint8_t)value;
default:
/* will never occur */
break;
}
cnv->charErrorBufferLength=(int8_t)length;
/* now output what fits into the regular target */
value>>=8*length; /* length was reduced by available */
switch(targetCapacity) {
/* each branch falls through to the next one */
case 3:
*target++=(uint8_t)(value>>16);
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
case 2:
*target++=(uint8_t)(value>>8);
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
case 1:
*target++=(uint8_t)value;
if(offsets!=NULL) {
*offsets++=sourceIndex;
}
default:
/* will never occur */
break;
}
/* target overflow */
targetCapacity=0;
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
c=0;
break;
}
}
/* normal end of conversion: prepare for a new character */
c=0;
sourceIndex=nextSourceIndex;
continue;
/*
* This is the same ugly trick as in ToUnicode(), for the
* same reasons...
*/
callback:
/* call the callback function with all the preparations and post-processing */
/* update the arguments structure */
pArgs->source=source;
pArgs->target=(char *)target;
pArgs->offsets=offsets;
/* set the converter state in UConverter to deal with the next character */
cnv->fromUSurrogateLead=0;
/* write the code point as code units */
i=0;
UTF_APPEND_CHAR_UNSAFE(cnv->invalidUCharBuffer, i, c);
cnv->invalidUCharLength=(int8_t)i;
/* call the callback function */
cnv->fromUCharErrorBehaviour(cnv->fromUContext, pArgs, cnv->invalidUCharBuffer, i, c, reason, pErrorCode);
/* get the converter state from UConverter */
c=cnv->fromUSurrogateLead;
/* update target and deal with offsets if necessary */
if(offsets!=NULL) {
/* add the sourceIndex to the relative offsets that the callback wrote */
if(sourceIndex>=0) {
while(target<(const uint8_t *)pArgs->target) {
*offsets+=sourceIndex;
++offsets;
++target;
}
} else {
/* sourceIndex==-1, set -1 offsets */
while(target<(uint8_t *)pArgs->target) {
*offsets=-1;
++offsets;
++target;
}
}
} else {
target=(uint8_t *)pArgs->target;
}
/* update the source pointer and index */
sourceIndex=nextSourceIndex+(pArgs->source-source);
source=pArgs->source;
targetCapacity=(uint8_t *)pArgs->targetLimit-target;
/* break on error */
if(U_FAILURE(*pErrorCode)) {
c=0;
break;
}
/*
* If the callback overflowed the target, then we need to
* stop here with an overflow indication.
*/
if(cnv->charErrorBufferLength>0) {
/* target is full */
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
break;
}
/*
* We do not need to repeat the statements from the normal
* end of the conversion because we already updated all the
* necessary variables.
*/
} else {
/* target is full */
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
break;
}
}
if(pArgs->flush && source>=sourceLimit) {
/* reset the state for the next conversion */
if(c!=0 && U_SUCCESS(*pErrorCode)) {
/* a character byte sequence remains incomplete */
*pErrorCode=U_TRUNCATED_CHAR_FOUND;
}
cnv->fromUSurrogateLead=0;
} else {
/* set the converter state back into UConverter */
cnv->fromUSurrogateLead=(UChar)c;
}
/* write back the updated pointers */
pArgs->source=source;
pArgs->target=(char *)target;
pArgs->offsets=offsets;
}
U_CFUNC void
_MBCSFromUnicode(UConverterFromUnicodeArgs *pArgs,
UErrorCode *pErrorCode) {
_MBCSFromUnicodeWithOffsets(pArgs, pErrorCode);
}
static void
_MBCSGetStarters(const UConverter* cnv,
UBool starters[256],
UErrorCode *pErrorCode) {
const int32_t *state0=cnv->sharedData->table->mbcs.stateTable[0];
int i;
for(i=0; i<256; ++i) {
/* all bytes that cause a state transition from state 0 are lead bytes */
starters[i]= (UBool)(state0[i]>=0);
}
}
/*
* This is an internal function that allows other converter implementations
* to check whether a byte is a lead byte.
*/
U_CFUNC UBool
_MBCSIsLeadByte(UConverterSharedData *sharedData, char byte) {
return (UBool)(sharedData->table->mbcs.stateTable[0][(uint8_t)byte]>=0);
}
static const UConverterImpl _MBCSImpl={
UCNV_MBCS,
_MBCSLoad,
NULL,
_MBCSOpen,
NULL,
_MBCSReset,
_MBCSToUnicode,
_MBCSToUnicodeWithOffsets,
_MBCSFromUnicode,
_MBCSFromUnicodeWithOffsets,
_MBCSGetNextUChar,
_MBCSGetStarters
};
/* Static data is in tools/makeconv/ucnvstat.c for data-based
* converters. Be sure to update it as well.
*/
const UConverterSharedData _MBCSData={
sizeof(UConverterSharedData), 1,
NULL, NULL, NULL, FALSE, &_MBCSImpl,
0
};