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/*
*******************************************************************************
*
* © 2016 and later: Unicode, Inc. and others.
* License & terms of use: http://www.unicode.org/copyright.html
*
*******************************************************************************
*******************************************************************************
*
* Copyright (C) 2003-2006, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
* file name: uit_len8.c
* encoding: UTF-8
* tab size: 8 (not used)
* indentation:4
*
* created on: 2003feb10
* created by: Markus W. Scherer
*
* This file contains the implementation of the "lenient UTF-8" UCharIterator
* as used in the uciter8 sample code.
* UTF-8-style macros are defined as well as the UCharIterator.
* The macros are incomplete (do not assemble code points from pairs of
* surrogates, see comment below)
* but sufficient for the iterator.
*/
#include <string.h>
#include "unicode/utypes.h"
#include "unicode/uiter.h"
/* lenient UTF-8/CESU-8 macros ---------------------------------------------- */
/*
* This code leniently reads 8-bit Unicode strings,
* which could contain a mix of UTF-8 and CESU-8.
* More precisely:
* - supplementary code points may be encoded with dedicated 4-byte sequences
* (UTF-8 style)
* - supplementary code points may be encoded with
* pairs of 3-byte sequences, one for each surrogate of the UTF-16 form
* (CESU-8 style)
* - single surrogates are allowed, encoded with their "natural" 3-byte sequences
*
* Limitation:
* Right now, the macros do not attempt to assemble code points from pairs of
* separately encoded surrogates.
* This would not be sufficient for processing based on these macros,
* but it is sufficient for a UCharIterator that returns only UChars anyway.
*
* The code is copied and modified from utf_impl.c and utf8.h.
*
* Change 2006feb08: Much of the implementation code is replaced by calling
* the utf_impl.c functions which accept a new "strict" parameter value
* of -2 implementing exactly this leniency.
*/
#define L8_NEXT(s, i, length, c) { \
(c)=(uint8_t)(s)[(i)++]; \
if((c)>=0x80) { \
if(U8_IS_LEAD(c)) { \
(c)=utf8_nextCharSafeBody((const uint8_t *)s, &(i), (int32_t)(length), c, -2); \
} else { \
(c)=U_SENTINEL; \
} \
} \
}
#define L8_PREV(s, start, i, c) { \
(c)=(uint8_t)(s)[--(i)]; \
if((c)>=0x80) { \
if((c)<=0xbf) { \
(c)=utf8_prevCharSafeBody((const uint8_t *)s, start, &(i), c, -2); \
} else { \
(c)=U_SENTINEL; \
} \
} \
}
/* lenient-8 UCharIterator -------------------------------------------------- */
/*
* This is a copy of the UTF-8 UCharIterator in uiter.cpp,
* except that it uses the lenient-8-bit-Unicode macros above.
*/
/*
* Minimal implementation:
* Maintain a single-UChar buffer for an additional surrogate.
* The caller must not modify start and limit because they are used internally.
*
* Use UCharIterator fields as follows:
* context pointer to UTF-8 string
* length UTF-16 length of the string; -1 until lazy evaluation
* start current UTF-8 index
* index current UTF-16 index; may be -1="unknown" after setState()
* limit UTF-8 length of the string
* reservedField supplementary code point
*
* Since UCharIterator delivers 16-bit code units, the iteration can be
* currently in the middle of the byte sequence for a supplementary code point.
* In this case, reservedField will contain that code point and start will
* point to after the corresponding byte sequence. The UTF-16 index will be
* one less than what it would otherwise be corresponding to the UTF-8 index.
* Otherwise, reservedField will be 0.
*/
/*
* Possible optimization for NUL-terminated UTF-8 and UTF-16 strings:
* Add implementations that do not call strlen() for iteration but check for NUL.
*/
static int32_t U_CALLCONV
lenient8IteratorGetIndex(UCharIterator *iter, UCharIteratorOrigin origin) {
switch(origin) {
case UITER_ZERO:
case UITER_START:
return 0;
case UITER_CURRENT:
if(iter->index<0) {
/* the current UTF-16 index is unknown after setState(), count from the beginning */
const uint8_t *s;
UChar32 c;
int32_t i, limit, index;
s=(const uint8_t *)iter->context;
i=index=0;
limit=iter->start; /* count up to the UTF-8 index */
while(i<limit) {
L8_NEXT(s, i, limit, c);
if(c<=0xffff) {
++index;
} else {
index+=2;
}
}
iter->start=i; /* just in case setState() did not get us to a code point boundary */
if(i==iter->limit) {
iter->length=index; /* in case it was <0 or wrong */
}
if(iter->reservedField!=0) {
--index; /* we are in the middle of a supplementary code point */
}
iter->index=index;
}
return iter->index;
case UITER_LIMIT:
case UITER_LENGTH:
if(iter->length<0) {
const uint8_t *s;
UChar32 c;
int32_t i, limit, length;
s=(const uint8_t *)iter->context;
if(iter->index<0) {
/*
* the current UTF-16 index is unknown after setState(),
* we must first count from the beginning to here
*/
i=length=0;
limit=iter->start;
/* count from the beginning to the current index */
while(i<limit) {
L8_NEXT(s, i, limit, c);
if(c<=0xffff) {
++length;
} else {
length+=2;
}
}
/* assume i==limit==iter->start, set the UTF-16 index */
iter->start=i; /* just in case setState() did not get us to a code point boundary */
iter->index= iter->reservedField!=0 ? length-1 : length;
} else {
i=iter->start;
length=iter->index;
if(iter->reservedField!=0) {
++length;
}
}
/* count from the current index to the end */
limit=iter->limit;
while(i<limit) {
L8_NEXT(s, i, limit, c);
if(c<=0xffff) {
++length;
} else {
length+=2;
}
}
iter->length=length;
}
return iter->length;
default:
/* not a valid origin */
/* Should never get here! */
return -1;
}
}
static int32_t U_CALLCONV
lenient8IteratorMove(UCharIterator *iter, int32_t delta, UCharIteratorOrigin origin) {
const uint8_t *s;
UChar32 c;
int32_t pos; /* requested UTF-16 index */
int32_t i; /* UTF-8 index */
UBool havePos;
/* calculate the requested UTF-16 index */
switch(origin) {
case UITER_ZERO:
case UITER_START:
pos=delta;
havePos=true;
/* iter->index<0 (unknown) is possible */
break;
case UITER_CURRENT:
if(iter->index>=0) {
pos=iter->index+delta;
havePos=true;
} else {
/* the current UTF-16 index is unknown after setState(), use only delta */
pos=0;
havePos=false;
}
break;
case UITER_LIMIT:
case UITER_LENGTH:
if(iter->length>=0) {
pos=iter->length+delta;
havePos=true;
} else {
/* pin to the end, avoid counting the length */
iter->index=-1;
iter->start=iter->limit;
iter->reservedField=0;
if(delta>=0) {
return UITER_UNKNOWN_INDEX;
} else {
/* the current UTF-16 index is unknown, use only delta */
pos=0;
havePos=false;
}
}
break;
default:
return -1; /* Error */
}
if(havePos) {
/* shortcuts: pinning to the edges of the string */
if(pos<=0) {
iter->index=iter->start=iter->reservedField=0;
return 0;
} else if(iter->length>=0 && pos>=iter->length) {
iter->index=iter->length;
iter->start=iter->limit;
iter->reservedField=0;
return iter->index;
}
/* minimize the number of L8_NEXT/PREV operations */
if(iter->index<0 || pos<iter->index/2) {
/* go forward from the start instead of backward from the current index */
iter->index=iter->start=iter->reservedField=0;
} else if(iter->length>=0 && (iter->length-pos)<(pos-iter->index)) {
/*
* if we have the UTF-16 index and length and the new position is
* closer to the end than the current index,
* then go backward from the end instead of forward from the current index
*/
iter->index=iter->length;
iter->start=iter->limit;
iter->reservedField=0;
}
delta=pos-iter->index;
if(delta==0) {
return iter->index; /* nothing to do */
}
} else {
/* move relative to unknown UTF-16 index */
if(delta==0) {
return UITER_UNKNOWN_INDEX; /* nothing to do */
} else if(-delta>=iter->start) {
/* moving backwards by more UChars than there are UTF-8 bytes, pin to 0 */
iter->index=iter->start=iter->reservedField=0;
return 0;
} else if(delta>=(iter->limit-iter->start)) {
/* moving forward by more UChars than the remaining UTF-8 bytes, pin to the end */
iter->index=iter->length; /* may or may not be <0 (unknown) */
iter->start=iter->limit;
iter->reservedField=0;
return iter->index>=0 ? iter->index : UITER_UNKNOWN_INDEX;
}
}
/* delta!=0 */
/* move towards the requested position, pin to the edges of the string */
s=(const uint8_t *)iter->context;
pos=iter->index; /* could be <0 (unknown) */
i=iter->start;
if(delta>0) {
/* go forward */
int32_t limit=iter->limit;
if(iter->reservedField!=0) {
iter->reservedField=0;
++pos;
--delta;
}
while(delta>0 && i<limit) {
L8_NEXT(s, i, limit, c);
if(c<0xffff) {
++pos;
--delta;
} else if(delta>=2) {
pos+=2;
delta-=2;
} else /* delta==1 */ {
/* stop in the middle of a supplementary code point */
iter->reservedField=c;
++pos;
break; /* delta=0; */
}
}
if(i==limit) {
if(iter->length<0 && iter->index>=0) {
iter->length= iter->reservedField==0 ? pos : pos+1;
} else if(iter->index<0 && iter->length>=0) {
iter->index= iter->reservedField==0 ? iter->length : iter->length-1;
}
}
} else /* delta<0 */ {
/* go backward */
if(iter->reservedField!=0) {
iter->reservedField=0;
i-=4; /* we stayed behind the supplementary code point; go before it now */
--pos;
++delta;
}
while(delta<0 && i>0) {
L8_PREV(s, 0, i, c);
if(c<0xffff) {
--pos;
++delta;
} else if(delta<=-2) {
pos-=2;
delta+=2;
} else /* delta==-1 */ {
/* stop in the middle of a supplementary code point */
i+=4; /* back to behind this supplementary code point for consistent state */
iter->reservedField=c;
--pos;
break; /* delta=0; */
}
}
}
iter->start=i;
if(iter->index>=0) {
return iter->index=pos;
} else {
/* we started with index<0 (unknown) so pos is bogus */
if(i<=1) {
return iter->index=i; /* reached the beginning */
} else {
/* we still don't know the UTF-16 index */
return UITER_UNKNOWN_INDEX;
}
}
}
static UBool U_CALLCONV
lenient8IteratorHasNext(UCharIterator *iter) {
return iter->reservedField!=0 || iter->start<iter->limit;
}
static UBool U_CALLCONV
lenient8IteratorHasPrevious(UCharIterator *iter) {
return iter->start>0;
}
static UChar32 U_CALLCONV
lenient8IteratorCurrent(UCharIterator *iter) {
if(iter->reservedField!=0) {
return U16_TRAIL(iter->reservedField);
} else if(iter->start<iter->limit) {
const uint8_t *s=(const uint8_t *)iter->context;
UChar32 c;
int32_t i=iter->start;
L8_NEXT(s, i, iter->limit, c);
if(c<0) {
return 0xfffd;
} else if(c<=0xffff) {
return c;
} else {
return U16_LEAD(c);
}
} else {
return U_SENTINEL;
}
}
static UChar32 U_CALLCONV
lenient8IteratorNext(UCharIterator *iter) {
int32_t index;
if(iter->reservedField!=0) {
UChar trail=U16_TRAIL(iter->reservedField);
iter->reservedField=0;
if((index=iter->index)>=0) {
iter->index=index+1;
}
return trail;
} else if(iter->start<iter->limit) {
const uint8_t *s=(const uint8_t *)iter->context;
UChar32 c;
L8_NEXT(s, iter->start, iter->limit, c);
if((index=iter->index)>=0) {
iter->index=++index;
if(iter->length<0 && iter->start==iter->limit) {
iter->length= c<=0xffff ? index : index+1;
}
} else if(iter->start==iter->limit && iter->length>=0) {
iter->index= c<=0xffff ? iter->length : iter->length-1;
}
if(c<0) {
return 0xfffd;
} else if(c<=0xffff) {
return c;
} else {
iter->reservedField=c;
return U16_LEAD(c);
}
} else {
return U_SENTINEL;
}
}
static UChar32 U_CALLCONV
lenient8IteratorPrevious(UCharIterator *iter) {
int32_t index;
if(iter->reservedField!=0) {
UChar lead=U16_LEAD(iter->reservedField);
iter->reservedField=0;
iter->start-=4; /* we stayed behind the supplementary code point; go before it now */
if((index=iter->index)>0) {
iter->index=index-1;
}
return lead;
} else if(iter->start>0) {
const uint8_t *s=(const uint8_t *)iter->context;
UChar32 c;
L8_PREV(s, 0, iter->start, c);
if((index=iter->index)>0) {
iter->index=index-1;
} else if(iter->start<=1) {
iter->index= c<=0xffff ? iter->start : iter->start+1;
}
if(c<0) {
return 0xfffd;
} else if(c<=0xffff) {
return c;
} else {
iter->start+=4; /* back to behind this supplementary code point for consistent state */
iter->reservedField=c;
return U16_TRAIL(c);
}
} else {
return U_SENTINEL;
}
}
static uint32_t U_CALLCONV
lenient8IteratorGetState(const UCharIterator *iter) {
uint32_t state=(uint32_t)(iter->start<<1);
if(iter->reservedField!=0) {
state|=1;
}
return state;
}
static void U_CALLCONV
lenient8IteratorSetState(UCharIterator *iter, uint32_t state, UErrorCode *pErrorCode) {
if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
/* do nothing */
} else if(iter==NULL) {
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
} else if(state==lenient8IteratorGetState(iter)) {
/* setting to the current state: no-op */
} else {
int32_t index=(int32_t)(state>>1); /* UTF-8 index */
state&=1; /* 1 if in surrogate pair, must be index>=4 */
if((state==0 ? index<0 : index<4) || iter->limit<index) {
*pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;
} else {
iter->start=index; /* restore UTF-8 byte index */
if(index<=1) {
iter->index=index;
} else {
iter->index=-1; /* unknown UTF-16 index */
}
if(state==0) {
iter->reservedField=0;
} else {
/* verified index>=4 above */
UChar32 c;
L8_PREV((const uint8_t *)iter->context, 0, index, c);
if(c<=0xffff) {
*pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;
} else {
iter->reservedField=c;
}
}
}
}
}
static const UCharIterator lenient8Iterator={
0, 0, 0, 0, 0, 0,
lenient8IteratorGetIndex,
lenient8IteratorMove,
lenient8IteratorHasNext,
lenient8IteratorHasPrevious,
lenient8IteratorCurrent,
lenient8IteratorNext,
lenient8IteratorPrevious,
NULL,
lenient8IteratorGetState,
lenient8IteratorSetState
};
U_CAPI void U_EXPORT2
uiter_setLenient8(UCharIterator *iter, const char *s, int32_t length) {
if(iter!=0) {
if(s!=0 && length>=-1) {
*iter=lenient8Iterator;
iter->context=s;
if(length>=0) {
iter->limit=length;
} else {
iter->limit=(int32_t)strlen(s);
}
iter->length= iter->limit<=1 ? iter->limit : -1;
} else {
/* set no-op iterator */
uiter_setString(iter, NULL, 0);
}
}
}
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