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