282 lines
8.6 KiB
C
282 lines
8.6 KiB
C
/*
|
|
*******************************************************************************
|
|
*
|
|
* Copyright (C) 1999-2000, International Business Machines
|
|
* Corporation and others. All Rights Reserved.
|
|
*
|
|
*******************************************************************************
|
|
* file name: utf_impl.c
|
|
* encoding: US-ASCII
|
|
* tab size: 8 (not used)
|
|
* indentation:4
|
|
*
|
|
* created on: 1999sep13
|
|
* created by: Markus W. Scherer
|
|
*
|
|
* This file provides implementation functions for macros in the utfXX.h
|
|
* that would otherwise be too long as macros.
|
|
*/
|
|
|
|
#include "unicode/umachine.h"
|
|
#include "unicode/utf.h"
|
|
|
|
/*
|
|
* This table could be replaced on many machines by
|
|
* a few lines of assembler code using an
|
|
* "index of first 0-bit from msb" instruction and
|
|
* one or two more integer instructions.
|
|
*
|
|
* For example, on an i386, do something like
|
|
* - MOV AL, leadByte
|
|
* - NOT AL (8-bit, leave b15..b8==0..0, reverse only b7..b0)
|
|
* - MOV AH, 0
|
|
* - BSR BX, AX (16-bit)
|
|
* - MOV AX, 6 (result)
|
|
* - JZ finish (ZF==1 if leadByte==0xff)
|
|
* - SUB AX, BX (result)
|
|
* -finish:
|
|
* (BSR: Bit Scan Reverse, scans for a 1-bit, starting from the MSB)
|
|
*/
|
|
U_CAPI uint8_t U_EXPORT2
|
|
utf8_countTrailBytes[256]={
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
|
|
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
|
|
3, 3, 3, 3, 3, 3, 3, 3,
|
|
4, 4, 4, 4,
|
|
5, 5,
|
|
0, 0 /* illegal bytes 0xfe and 0xff */
|
|
};
|
|
|
|
static UChar32
|
|
utf8_minRegular[4]={ 0, 0x80, 0x800, 0x10000 };
|
|
|
|
static UChar32
|
|
utf8_errorValue[6]={
|
|
UTF8_ERROR_VALUE_1, UTF8_ERROR_VALUE_2, UTF_ERROR_VALUE, 0x10ffff,
|
|
0x3ffffff, 0x7fffffff
|
|
};
|
|
|
|
U_CAPI UChar32 U_EXPORT2
|
|
utf8_nextCharSafeBody(const uint8_t *s, UTextOffset *pi, UTextOffset length, UChar32 c, bool_t strict) {
|
|
UTextOffset i=*pi;
|
|
uint8_t count=UTF8_COUNT_TRAIL_BYTES(c);
|
|
if((i)+count<=(length)) {
|
|
uint8_t trail, illegal=0;
|
|
|
|
UTF8_MASK_LEAD_BYTE((c), count);
|
|
/* count==0 for illegally leading trail bytes and the illegal bytes 0xfe and 0xff */
|
|
switch(count) {
|
|
/* each branch falls through to the next one */
|
|
case 5:
|
|
trail=s[(i)++];
|
|
(c)=((c)<<6)|(trail&0x3f);
|
|
illegal|=(trail&0xc0)^0x80;
|
|
case 4:
|
|
trail=s[(i)++];
|
|
(c)=((c)<<6)|(trail&0x3f);
|
|
illegal|=(trail&0xc0)^0x80;
|
|
case 3:
|
|
trail=s[(i)++];
|
|
(c)=((c)<<6)|(trail&0x3f);
|
|
if(c<0x110) {
|
|
illegal|=(trail&0xc0)^0x80;
|
|
} else {
|
|
/* code point>0x10ffff, outside Unicode */
|
|
i+=2;
|
|
illegal=1;
|
|
break;
|
|
}
|
|
case 2:
|
|
trail=s[(i)++];
|
|
(c)=((c)<<6)|(trail&0x3f);
|
|
illegal|=(trail&0xc0)^0x80;
|
|
case 1:
|
|
trail=s[(i)++];
|
|
(c)=((c)<<6)|(trail&0x3f);
|
|
illegal|=(trail&0xc0)^0x80;
|
|
break;
|
|
case 0:
|
|
illegal=1;
|
|
/* no default branch to optimize switch() - all values are covered */
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* All the error handling should return a value
|
|
* that needs count bytes so that UTF8_GET_CHAR_SAFE() works right.
|
|
*/
|
|
|
|
/* correct sequence - all trail bytes have (b7..b6)==(10)? */
|
|
if(illegal) {
|
|
/* error handling */
|
|
uint8_t errorCount=count;
|
|
/* don't go beyond this sequence */
|
|
(i)-=count;
|
|
while(count>0 && UTF8_IS_TRAIL(s[i])) {
|
|
++(i);
|
|
--count;
|
|
}
|
|
c=utf8_errorValue[errorCount-count];
|
|
} else if((strict) &&
|
|
(UTF_IS_SURROGATE(c) ||
|
|
count>=4 || (c)<utf8_minRegular[count] ||
|
|
((c)&0xfffe)==0xfffe)
|
|
) {
|
|
/* irregular sequence */
|
|
c=utf8_errorValue[count];
|
|
}
|
|
} else /* too few bytes left */ {
|
|
/* error handling */
|
|
UTextOffset i0=i;
|
|
/* don't just set (i)=(length) in case there is an illegal sequence */
|
|
while((i)<(length) && UTF8_IS_TRAIL(s[i])) {
|
|
++(i);
|
|
}
|
|
c=utf8_errorValue[i-i0];
|
|
}
|
|
*pi=i;
|
|
return c;
|
|
}
|
|
|
|
U_CAPI UTextOffset U_EXPORT2
|
|
utf8_appendCharSafeBody(uint8_t *s, UTextOffset i, UTextOffset length, UChar32 c) {
|
|
if((c)<=0x7ff) {
|
|
if((i)+1<(length)) {
|
|
(s)[(i)++]=(uint8_t)((c)>>6)|0xc0;
|
|
(s)[(i)++]=(uint8_t)(c)&0x3f|0x80;
|
|
return i;
|
|
}
|
|
} else if((uint32_t)(c)<=0xffff) {
|
|
if((i)+2<(length)) {
|
|
(s)[(i)++]=(uint8_t)((c)>>12)|0xe0;
|
|
(s)[(i)++]=(uint8_t)((c)>>6)&0x3f|0x80;
|
|
(s)[(i)++]=(uint8_t)(c)&0x3f|0x80;
|
|
return i;
|
|
}
|
|
} else if((uint32_t)(c)<=0x10ffff) {
|
|
if((i)+3<(length)) {
|
|
(s)[(i)++]=(uint8_t)((c)>>18)|0xf0;
|
|
(s)[(i)++]=(uint8_t)((c)>>12)&0x3f|0x80;
|
|
(s)[(i)++]=(uint8_t)((c)>>6)&0x3f|0x80;
|
|
(s)[(i)++]=(uint8_t)(c)&0x3f|0x80;
|
|
return i;
|
|
}
|
|
}
|
|
/* c>0x10ffff or not enough space, write an error value */
|
|
length-=i;
|
|
if(length>0) {
|
|
if(length>3) {
|
|
length=3;
|
|
}
|
|
s+=i;
|
|
c=utf8_errorValue[length-1];
|
|
UTF8_APPEND_CHAR_SAFE(s, i, length, c);
|
|
}
|
|
return i;
|
|
}
|
|
|
|
U_CAPI UChar32 U_EXPORT2
|
|
utf8_prevCharSafeBody(const uint8_t *s, UTextOffset *pi, UChar32 c, bool_t strict) {
|
|
UTextOffset i=*pi;
|
|
if(UTF8_IS_TRAIL(c)) {
|
|
uint8_t b, count=1, shift=6;
|
|
|
|
c&=0x3f;
|
|
while(i>0 && count<6) {
|
|
b=s[--i];
|
|
if((uint8_t)(b-0x80)<0x7e) { /* 0x80<=b<0xfe */
|
|
if(b&0x40) {
|
|
/* lead byte */
|
|
uint8_t shouldCount=UTF8_COUNT_TRAIL_BYTES(b);
|
|
|
|
if(count==shouldCount) {
|
|
*pi=i;
|
|
UTF8_MASK_LEAD_BYTE(b, count);
|
|
c|=(UChar32)b<<shift;
|
|
if( c>0x10ffff ||
|
|
(strict) &&
|
|
(UTF_IS_SURROGATE(c) ||
|
|
count>=4 || (c)<utf8_minRegular[count] || ((c)&0xfffe)==0xfffe)
|
|
) {
|
|
/* irregular sequence */
|
|
} else {
|
|
return c;
|
|
}
|
|
} else {
|
|
/* the lead byte does not match the number of trail bytes */
|
|
/* only set the position to the lead byte if it would
|
|
include the trail byte that we started with */
|
|
if(count<shouldCount) {
|
|
*pi=i;
|
|
}
|
|
}
|
|
break;
|
|
} else {
|
|
/* trail byte */
|
|
c|=(UChar32)(b&0x3f)<<shift;
|
|
++count;
|
|
shift+=6;
|
|
}
|
|
} else {
|
|
/* single-byte character precedes trailing bytes */
|
|
break;
|
|
}
|
|
}
|
|
/* i==0 or count==6 - no lead byte in legal distance */
|
|
/* } else { called with single lead byte */
|
|
}
|
|
return UTF_ERROR_VALUE;
|
|
}
|
|
|
|
U_CAPI UTextOffset U_EXPORT2
|
|
utf8_back1SafeBody(const uint8_t *s, UTextOffset i) {
|
|
/* i had been decremented once before the function call */
|
|
UTextOffset I=i, Z;
|
|
uint8_t b;
|
|
|
|
/* read at most the 6 bytes s[Z] to s[i], inclusively */
|
|
if(I>5) {
|
|
Z=I-5;
|
|
} else {
|
|
Z=0;
|
|
}
|
|
|
|
/* return I if the sequence starting there is long enough to include i */
|
|
for(;;) {
|
|
b=s[I];
|
|
if((uint8_t)(b-0x80)>=0x7e) { /* not 0x80<=b<0xfe */
|
|
break;
|
|
} else if(b>=0xc0) {
|
|
if(UTF8_COUNT_TRAIL_BYTES(b)>=(i-I)) {
|
|
return I;
|
|
} else {
|
|
break;
|
|
}
|
|
} else if(Z<I) {
|
|
--I;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* return i itself to be consistent with the FWD_1 macro */
|
|
return i;
|
|
}
|