scuffed-code/icu4c/source/common/unicode/utf8.h
2000-02-09 19:42:15 +00:00

297 lines
8.3 KiB
C

/*
*******************************************************************************
*
* Copyright (C) 1999-2000, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
* file name: utf8.h
* encoding: US-ASCII
* tab size: 8 (not used)
* indentation:4
*
* created on: 1999sep13
* created by: Markus W. Scherer
*
* This file defines macros to deal with UTF-8 code units and code points.
* Signatures and semantics are the same as for the similarly named macros
* in utf16.h.
* utf8.h is included by utf.h after unicode/umachine.h
* and some common definitions.
*/
#ifndef __UTF8_H__
#define __UTF8_H__
/* internal definitions ----------------------------------------------------- */
U_CAPI uint8_t U_EXPORT2
utf8_countTrailBytes[256];
/*
* Count the trail bytes for a lead byte -
* this macro should be used so that the assembler code
* that is mentioned in utf_impl.c could be used here.
*/
#define UTF8_COUNT_TRAIL_BYTES(leadByte) (utf8_countTrailBytes[(uint8_t)leadByte])
/* use a macro here, too - there may be a simpler way with some machines */
#define UTF8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countTrailBytes)))-1)
U_CAPI UChar32 U_EXPORT2
utf8_nextCharSafeBody(const uint8_t *s, UTextOffset *pi, UTextOffset length, UChar32 c, bool_t strict);
U_CAPI UTextOffset U_EXPORT2
utf8_appendCharSafeBody(uint8_t *s, UTextOffset i, UTextOffset length, UChar32 c);
U_CAPI UChar32 U_EXPORT2
utf8_prevCharSafeBody(const uint8_t *s, UTextOffset *pi, UChar32 c, bool_t strict);
U_CAPI UTextOffset U_EXPORT2
utf8_back1SafeBody(const uint8_t *s, UTextOffset i);
/*
* For the semantics of all of these macros, see utf16.h.
* The UTF-8 macros favor sequences more the shorter they are.
* Sometimes, only the single-byte case is covered by a macro,
* while longer sequences are handled by a function call.
*/
/* single-code point definitions -------------------------------------------- */
/* classes of code unit values */
#define UTF8_IS_SINGLE(uchar) ((uchar)&0x80==0)
#define UTF8_IS_LEAD(uchar) ((uchar)>=0xc0)
#define UTF8_IS_TRAIL(uchar) ((uchar)&0xc0==0x80)
/* number of code units per code point */
#define UTF8_NEED_MULTIPLE_UCHAR(c) ((uint32_t)(c)>0x7f)
/*
* ICU does not deal with code points >0x10ffff
* unless necessary for advancing in the byte stream.
*/
#if 1
# define UTF8_CHAR_LENGTH(c) \
((uint32_t)(c)<=0x7f ? 1 : \
((uint32_t)(c)<=0x7ff ? 2 : \
((uint32_t)(c)<=0xffff ? 3 : 4) \
) \
)
#else
/* this has an illegal branch for 7 bytes to be consistent with UTF8_COUNT_TRAIL_BYTES() */
# define UTF8_CHAR_LENGTH(c) \
((uint32_t)(c)<=0x7f ? 1 : \
((uint32_t)(c)<=0x7ff ? 2 : \
((uint32_t)(c)<=0xffff ? 3 : \
((uint32_t)(c)<=0x10ffff ? 4 : \
((uint32_t)(c)<=0x3ffffff ? 5 : \
((uint32_t)(c)<=0x7fffffff ? 6 : 7) \
) \
) \
) \
) \
)
#endif
#define UTF8_MAX_CHAR_LENGTH 4
/* average number of code units compared to UTF-16 */
#define UTF8_ARRAY_SIZE(size) ((5*(size))/2)
#define UTF8_GET_CHAR_UNSAFE(s, i, c) { \
UTextOffset I=(UTextOffset)(i); \
UTF8_SET_CHAR_START_UNSAFE(s, I); \
UTF8_NEXT_CHAR_UNSAFE(s, I, c); \
}
#define UTF8_GET_CHAR_SAFE(s, i, length, c, strict) { \
UTextOffset I=(UTextOffset)(i); \
UTF8_SET_CHAR_START_SAFE(s, I); \
UTF8_NEXT_CHAR_SAFE(s, I, length, c, strict); \
}
/* definitions with forward iteration --------------------------------------- */
/*
* Read a Unicode scalar value from an array of UTF-8 bytes.
* Only values <=0x10ffff are accepted, and if an error occurs,
* then c will be set such that UTF_IS_ERROR(c).
* The _UNSAFE macro is fast and does not check for errors.
* The _SAFE macro checks for errors and optionally for
* irregular sequences, too, i.e., for sequences that
* are longer than necessary, such as <c0 80> instead of <0>.
* The strict checks also check for surrogates and
* for 0xXXXXfffe and 0xXXXXffff.
*/
#define UTF8_NEXT_CHAR_UNSAFE(s, i, c) { \
(c)=(s)[(i)++]; \
if((c)&0x80) { \
uint8_t count=UTF8_COUNT_TRAIL_BYTES(c); \
UTF8_MASK_LEAD_BYTE(c, count); \
switch(count) { \
/* each following branch falls through to the next one */ \
case 3: \
(c)=((c)<<6)|((s)[(i)++]&0x3f); \
case 2: \
(c)=((c)<<6)|((s)[(i)++]&0x3f); \
case 1: \
(c)=((c)<<6)|((s)[(i)++]&0x3f); \
/* no other branches to optimize switch() */ \
break; \
} \
} \
}
#define UTF8_APPEND_CHAR_UNSAFE(s, i, c) { \
if((uint32_t)(c)<=0x7f) { \
(s)[(i)++]=(uint8_t)(c); \
} else { \
if((uint32_t)(c)<=0x7ff) { \
(s)[(i)++]=(uint8_t)((c)>>6)|0xc0; \
} else { \
if((uint32_t)(c)<=0xffff) { \
(s)[(i)++]=(uint8_t)((c)>>12)|0xe0; \
} else { \
(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; \
} \
}
#define UTF8_FWD_1_UNSAFE(s, i) { \
(i)+=1+UTF8_COUNT_TRAIL_BYTES((s)[i]); \
}
#define UTF8_FWD_N_UNSAFE(s, i, n) { \
UTextOffset N=(n); \
while(N>0) { \
UTF8_FWD_1_UNSAFE(s, i); \
--N; \
} \
}
#define UTF8_SET_CHAR_START_UNSAFE(s, i) { \
while(UTF8_IS_TRAIL((s)[i])) { --(i); } \
}
#define UTF8_NEXT_CHAR_SAFE(s, i, length, c, strict) { \
(c)=(s)[(i)++]; \
if((c)&0x80) { \
(c)=utf8_nextCharSafeBody(s, &(i), (UTextOffset)(length), c, strict); \
} \
}
#define UTF8_APPEND_CHAR_SAFE(s, i, length, c) { \
if((uint32_t)(c)<=0x7f) { \
(s)[(i)++]=(uint8_t)(c); \
} else { \
(i)=utf8_appendCharSafeBody(s, (UTextOffset)(i), (UTextOffset)(length), c); \
} \
}
#define UTF8_FWD_1_SAFE(s, i, length) { \
if((i)<(length)) { \
uint8_t b=(s)[(i)++]; \
if(b&0x80) { \
uint8_t count=UTF8_COUNT_TRAIL_BYTES(b); \
if((i)+count>(length)) { \
count=(length)-(i); \
} \
while(count>0 && UTF8_IS_TRAIL((s)[i])) { \
++(i); \
--count; \
} \
} \
} \
}
#define UTF8_FWD_N_SAFE(s, i, length, n) { \
UTextOffset N=(n); \
while(N>0 && (i)<(length)) { \
UTF8_FWD_1_SAFE(s, i, length); \
--N; \
} \
}
#define UTF8_SET_CHAR_START_SAFE(s, i) { \
if((s)[(i)]&0x80) { \
(i)=utf8_back1SafeBody(s, (UTextOffset)(i)); \
} \
}
/* definitions with backward iteration -------------------------------------- */
#define UTF8_PREV_CHAR_UNSAFE(s, i, c) { \
(c)=(s)[--(i)]; \
if((c)&0x80) { \
uint8_t b, count=1, shift=6; \
\
/* c must be a trail byte */ \
(c)&=0x3f; \
for(;;) { \
b=(s)[--(i)]; \
if(b>=0xc0) { \
UTF8_MASK_LEAD_BYTE(b, count); \
(c)|=(UChar32)b<<shift; \
break; \
} else { \
(c)|=(UChar32)(b&0x3f)<<shift; \
++count; \
shift+=6; \
} \
} \
} \
}
#define UTF8_BACK_1_UNSAFE(s, i) { \
while(UTF8_IS_TRAIL((s)[--(i)])) {} \
}
#define UTF8_BACK_N_UNSAFE(s, i, n) { \
UTextOffset N=(n); \
while(N>0) { \
UTF8_BACK_1_UNSAFE(s, i); \
--N; \
} \
}
#define UTF8_SET_CHAR_LIMIT_UNSAFE(s, i) { \
UTF8_BACK_1_UNSAFE(s, i); \
UTF8_FWD_1_UNSAFE(s, i); \
}
#define UTF8_PREV_CHAR_SAFE(s, i, c, strict) { \
(c)=(s)[--(i)]; \
if((c)&0x80) { \
(c)=utf8_prevCharSafeBody(s, &(i), c, strict); \
} \
}
#define UTF8_BACK_1_SAFE(s, i) { \
if((i)>0) { \
--(i); \
if((s)[(i)]&0x80) { \
(i)=utf8_back1SafeBody(s, (UTextOffset)(i)); \
} \
} \
}
#define UTF8_BACK_N_SAFE(s, i, n) { \
UTextOffset N=(n); \
while(N>0 && (i)>0) { \
UTF8_BACK_1_SAFE(s, i); \
--N; \
} \
}
#define UTF8_SET_CHAR_LIMIT_SAFE(s, i, length) { \
UTF8_BACK_1_SAFE(s, i); \
UTF8_FWD_1_SAFE(s, i, length); \
}
#endif