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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*
* Copyright (C) 1999-2012, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
* file name: utf16.h
* encoding: UTF-8
* tab size: 8 (not used)
* indentation:4
*
* created on: 1999sep09
* created by: Markus W. Scherer
*/
/**
* \file
* \brief C API: 16-bit Unicode handling macros
*
* This file defines macros to deal with 16-bit Unicode (UTF-16) code units and strings.
*
* For more information see utf.h and the ICU User Guide Strings chapter
* (https://unicode-org.github.io/icu/userguide/strings).
*
* <em>Usage:</em>
* ICU coding guidelines for if() statements should be followed when using these macros.
* Compound statements (curly braces {}) must be used for if-else-while...
* bodies and all macro statements should be terminated with semicolon.
*/
#ifndef __UTF16_H__
#define __UTF16_H__
#include <stdbool.h>
#include "unicode/umachine.h"
#ifndef __UTF_H__
# include "unicode/utf.h"
#endif
/* single-code point definitions -------------------------------------------- */
/**
* Does this code unit alone encode a code point (BMP, not a surrogate)?
* @param c 16-bit code unit
* @return true or false
* @stable ICU 2.4
*/
#define U16_IS_SINGLE(c) !U_IS_SURROGATE(c)
/**
* Is this code unit a lead surrogate (U+d800..U+dbff)?
* @param c 16-bit code unit
* @return true or false
* @stable ICU 2.4
*/
#define U16_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)
/**
* Is this code unit a trail surrogate (U+dc00..U+dfff)?
* @param c 16-bit code unit
* @return true or false
* @stable ICU 2.4
*/
#define U16_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)
/**
* Is this code unit a surrogate (U+d800..U+dfff)?
* @param c 16-bit code unit
* @return true or false
* @stable ICU 2.4
*/
#define U16_IS_SURROGATE(c) U_IS_SURROGATE(c)
/**
* Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),
* is it a lead surrogate?
* @param c 16-bit code unit
* @return true or false
* @stable ICU 2.4
*/
#define U16_IS_SURROGATE_LEAD(c) (((c)&0x400)==0)
/**
* Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),
* is it a trail surrogate?
* @param c 16-bit code unit
* @return true or false
* @stable ICU 4.2
*/
#define U16_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0)
/**
* Helper constant for U16_GET_SUPPLEMENTARY.
* @internal
*/
#define U16_SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000)
/**
* Get a supplementary code point value (U+10000..U+10ffff)
* from its lead and trail surrogates.
* The result is undefined if the input values are not
* lead and trail surrogates.
*
* @param lead lead surrogate (U+d800..U+dbff)
* @param trail trail surrogate (U+dc00..U+dfff)
* @return supplementary code point (U+10000..U+10ffff)
* @stable ICU 2.4
*/
#define U16_GET_SUPPLEMENTARY(lead, trail) \
(((UChar32)(lead)<<10UL)+(UChar32)(trail)-U16_SURROGATE_OFFSET)
/**
* Get the lead surrogate (0xd800..0xdbff) for a
* supplementary code point (0x10000..0x10ffff).
* @param supplementary 32-bit code point (U+10000..U+10ffff)
* @return lead surrogate (U+d800..U+dbff) for supplementary
* @stable ICU 2.4
*/
#define U16_LEAD(supplementary) (UChar)(((supplementary)>>10)+0xd7c0)
/**
* Get the trail surrogate (0xdc00..0xdfff) for a
* supplementary code point (0x10000..0x10ffff).
* @param supplementary 32-bit code point (U+10000..U+10ffff)
* @return trail surrogate (U+dc00..U+dfff) for supplementary
* @stable ICU 2.4
*/
#define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff)|0xdc00)
/**
* How many 16-bit code units are used to encode this Unicode code point? (1 or 2)
* The result is not defined if c is not a Unicode code point (U+0000..U+10ffff).
* @param c 32-bit code point
* @return 1 or 2
* @stable ICU 2.4
*/
#define U16_LENGTH(c) ((uint32_t)(c)<=0xffff ? 1 : 2)
/**
* The maximum number of 16-bit code units per Unicode code point (U+0000..U+10ffff).
* @return 2
* @stable ICU 2.4
*/
#define U16_MAX_LENGTH 2
/**
* Get a code point from a string at a random-access offset,
* without changing the offset.
* "Unsafe" macro, assumes well-formed UTF-16.
*
* The offset may point to either the lead or trail surrogate unit
* for a supplementary code point, in which case the macro will read
* the adjacent matching surrogate as well.
* The result is undefined if the offset points to a single, unpaired surrogate.
* Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.
*
* @param s const UChar * string
* @param i string offset
* @param c output UChar32 variable
* @see U16_GET
* @stable ICU 2.4
*/
#define U16_GET_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[i]; \
if(U16_IS_SURROGATE(c)) { \
if(U16_IS_SURROGATE_LEAD(c)) { \
(c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)+1]); \
} else { \
(c)=U16_GET_SUPPLEMENTARY((s)[(i)-1], (c)); \
} \
} \
} UPRV_BLOCK_MACRO_END
/**
* Get a code point from a string at a random-access offset,
* without changing the offset.
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The offset may point to either the lead or trail surrogate unit
* for a supplementary code point, in which case the macro will read
* the adjacent matching surrogate as well.
*
* The length can be negative for a NUL-terminated string.
*
* If the offset points to a single, unpaired surrogate, then
* c is set to that unpaired surrogate.
* Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.
*
* @param s const UChar * string
* @param start starting string offset (usually 0)
* @param i string offset, must be start<=i<length
* @param length string length
* @param c output UChar32 variable
* @see U16_GET_UNSAFE
* @stable ICU 2.4
*/
#define U16_GET(s, start, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[i]; \
if(U16_IS_SURROGATE(c)) { \
uint16_t __c2; \
if(U16_IS_SURROGATE_LEAD(c)) { \
if((i)+1!=(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \
(c)=U16_GET_SUPPLEMENTARY((c), __c2); \
} \
} else { \
if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
(c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
} \
} \
} \
} UPRV_BLOCK_MACRO_END
/**
* Get a code point from a string at a random-access offset,
* without changing the offset.
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The offset may point to either the lead or trail surrogate unit
* for a supplementary code point, in which case the macro will read
* the adjacent matching surrogate as well.
*
* The length can be negative for a NUL-terminated string.
*
* If the offset points to a single, unpaired surrogate, then
* c is set to U+FFFD.
* Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT_OR_FFFD.
*
* @param s const UChar * string
* @param start starting string offset (usually 0)
* @param i string offset, must be start<=i<length
* @param length string length
* @param c output UChar32 variable
* @see U16_GET_UNSAFE
* @stable ICU 60
*/
#define U16_GET_OR_FFFD(s, start, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[i]; \
if(U16_IS_SURROGATE(c)) { \
uint16_t __c2; \
if(U16_IS_SURROGATE_LEAD(c)) { \
if((i)+1!=(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \
(c)=U16_GET_SUPPLEMENTARY((c), __c2); \
} else { \
(c)=0xfffd; \
} \
} else { \
if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
(c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
} else { \
(c)=0xfffd; \
} \
} \
} \
} UPRV_BLOCK_MACRO_END
/* definitions with forward iteration --------------------------------------- */
/**
* Get a code point from a string at a code point boundary offset,
* and advance the offset to the next code point boundary.
* (Post-incrementing forward iteration.)
* "Unsafe" macro, assumes well-formed UTF-16.
*
* The offset may point to the lead surrogate unit
* for a supplementary code point, in which case the macro will read
* the following trail surrogate as well.
* If the offset points to a trail surrogate, then that itself
* will be returned as the code point.
* The result is undefined if the offset points to a single, unpaired lead surrogate.
*
* @param s const UChar * string
* @param i string offset
* @param c output UChar32 variable
* @see U16_NEXT
* @stable ICU 2.4
*/
#define U16_NEXT_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[(i)++]; \
if(U16_IS_LEAD(c)) { \
(c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)++]); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Get a code point from a string at a code point boundary offset,
* and advance the offset to the next code point boundary.
* (Post-incrementing forward iteration.)
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The length can be negative for a NUL-terminated string.
*
* The offset may point to the lead surrogate unit
* for a supplementary code point, in which case the macro will read
* the following trail surrogate as well.
* If the offset points to a trail surrogate or
* to a single, unpaired lead surrogate, then c is set to that unpaired surrogate.
*
* @param s const UChar * string
* @param i string offset, must be i<length
* @param length string length
* @param c output UChar32 variable
* @see U16_NEXT_UNSAFE
* @stable ICU 2.4
*/
#define U16_NEXT(s, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[(i)++]; \
if(U16_IS_LEAD(c)) { \
uint16_t __c2; \
if((i)!=(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \
++(i); \
(c)=U16_GET_SUPPLEMENTARY((c), __c2); \
} \
} \
} UPRV_BLOCK_MACRO_END
/**
* Get a code point from a string at a code point boundary offset,
* and advance the offset to the next code point boundary.
* (Post-incrementing forward iteration.)
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The length can be negative for a NUL-terminated string.
*
* The offset may point to the lead surrogate unit
* for a supplementary code point, in which case the macro will read
* the following trail surrogate as well.
* If the offset points to a trail surrogate or
* to a single, unpaired lead surrogate, then c is set to U+FFFD.
*
* @param s const UChar * string
* @param i string offset, must be i<length
* @param length string length
* @param c output UChar32 variable
* @see U16_NEXT_UNSAFE
* @stable ICU 60
*/
#define U16_NEXT_OR_FFFD(s, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[(i)++]; \
if(U16_IS_SURROGATE(c)) { \
uint16_t __c2; \
if(U16_IS_SURROGATE_LEAD(c) && (i)!=(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \
++(i); \
(c)=U16_GET_SUPPLEMENTARY((c), __c2); \
} else { \
(c)=0xfffd; \
} \
} \
} UPRV_BLOCK_MACRO_END
/**
* Append a code point to a string, overwriting 1 or 2 code units.
* The offset points to the current end of the string contents
* and is advanced (post-increment).
* "Unsafe" macro, assumes a valid code point and sufficient space in the string.
* Otherwise, the result is undefined.
*
* @param s const UChar * string buffer
* @param i string offset
* @param c code point to append
* @see U16_APPEND
* @stable ICU 2.4
*/
#define U16_APPEND_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \
if((uint32_t)(c)<=0xffff) { \
(s)[(i)++]=(uint16_t)(c); \
} else { \
(s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \
(s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Append a code point to a string, overwriting 1 or 2 code units.
* The offset points to the current end of the string contents
* and is advanced (post-increment).
* "Safe" macro, checks for a valid code point.
* If a surrogate pair is written, checks for sufficient space in the string.
* If the code point is not valid or a trail surrogate does not fit,
* then isError is set to true.
*
* @param s const UChar * string buffer
* @param i string offset, must be i<capacity
* @param capacity size of the string buffer
* @param c code point to append
* @param isError output UBool set to true if an error occurs, otherwise not modified
* @see U16_APPEND_UNSAFE
* @stable ICU 2.4
*/
#define U16_APPEND(s, i, capacity, c, isError) UPRV_BLOCK_MACRO_BEGIN { \
if((uint32_t)(c)<=0xffff) { \
(s)[(i)++]=(uint16_t)(c); \
} else if((uint32_t)(c)<=0x10ffff && (i)+1<(capacity)) { \
(s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \
(s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \
} else /* c>0x10ffff or not enough space */ { \
(isError)=true; \
} \
} UPRV_BLOCK_MACRO_END
/**
* Advance the string offset from one code point boundary to the next.
* (Post-incrementing iteration.)
* "Unsafe" macro, assumes well-formed UTF-16.
*
* @param s const UChar * string
* @param i string offset
* @see U16_FWD_1
* @stable ICU 2.4
*/
#define U16_FWD_1_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_LEAD((s)[(i)++])) { \
++(i); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Advance the string offset from one code point boundary to the next.
* (Post-incrementing iteration.)
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The length can be negative for a NUL-terminated string.
*
* @param s const UChar * string
* @param i string offset, must be i<length
* @param length string length
* @see U16_FWD_1_UNSAFE
* @stable ICU 2.4
*/
#define U16_FWD_1(s, i, length) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_LEAD((s)[(i)++]) && (i)!=(length) && U16_IS_TRAIL((s)[i])) { \
++(i); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Advance the string offset from one code point boundary to the n-th next one,
* i.e., move forward by n code points.
* (Post-incrementing iteration.)
* "Unsafe" macro, assumes well-formed UTF-16.
*
* @param s const UChar * string
* @param i string offset
* @param n number of code points to skip
* @see U16_FWD_N
* @stable ICU 2.4
*/
#define U16_FWD_N_UNSAFE(s, i, n) UPRV_BLOCK_MACRO_BEGIN { \
int32_t __N=(n); \
while(__N>0) { \
U16_FWD_1_UNSAFE(s, i); \
--__N; \
} \
} UPRV_BLOCK_MACRO_END
/**
* Advance the string offset from one code point boundary to the n-th next one,
* i.e., move forward by n code points.
* (Post-incrementing iteration.)
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The length can be negative for a NUL-terminated string.
*
* @param s const UChar * string
* @param i int32_t string offset, must be i<length
* @param length int32_t string length
* @param n number of code points to skip
* @see U16_FWD_N_UNSAFE
* @stable ICU 2.4
*/
#define U16_FWD_N(s, i, length, n) UPRV_BLOCK_MACRO_BEGIN { \
int32_t __N=(n); \
while(__N>0 && ((i)<(length) || ((length)<0 && (s)[i]!=0))) { \
U16_FWD_1(s, i, length); \
--__N; \
} \
} UPRV_BLOCK_MACRO_END
/**
* Adjust a random-access offset to a code point boundary
* at the start of a code point.
* If the offset points to the trail surrogate of a surrogate pair,
* then the offset is decremented.
* Otherwise, it is not modified.
* "Unsafe" macro, assumes well-formed UTF-16.
*
* @param s const UChar * string
* @param i string offset
* @see U16_SET_CP_START
* @stable ICU 2.4
*/
#define U16_SET_CP_START_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_TRAIL((s)[i])) { \
--(i); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Adjust a random-access offset to a code point boundary
* at the start of a code point.
* If the offset points to the trail surrogate of a surrogate pair,
* then the offset is decremented.
* Otherwise, it is not modified.
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* @param s const UChar * string
* @param start starting string offset (usually 0)
* @param i string offset, must be start<=i
* @see U16_SET_CP_START_UNSAFE
* @stable ICU 2.4
*/
#define U16_SET_CP_START(s, start, i) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_TRAIL((s)[i]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \
--(i); \
} \
} UPRV_BLOCK_MACRO_END
/* definitions with backward iteration -------------------------------------- */
/**
* Move the string offset from one code point boundary to the previous one
* and get the code point between them.
* (Pre-decrementing backward iteration.)
* "Unsafe" macro, assumes well-formed UTF-16.
*
* The input offset may be the same as the string length.
* If the offset is behind a trail surrogate unit
* for a supplementary code point, then the macro will read
* the preceding lead surrogate as well.
* If the offset is behind a lead surrogate, then that itself
* will be returned as the code point.
* The result is undefined if the offset is behind a single, unpaired trail surrogate.
*
* @param s const UChar * string
* @param i string offset
* @param c output UChar32 variable
* @see U16_PREV
* @stable ICU 2.4
*/
#define U16_PREV_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[--(i)]; \
if(U16_IS_TRAIL(c)) { \
(c)=U16_GET_SUPPLEMENTARY((s)[--(i)], (c)); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Move the string offset from one code point boundary to the previous one
* and get the code point between them.
* (Pre-decrementing backward iteration.)
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The input offset may be the same as the string length.
* If the offset is behind a trail surrogate unit
* for a supplementary code point, then the macro will read
* the preceding lead surrogate as well.
* If the offset is behind a lead surrogate or behind a single, unpaired
* trail surrogate, then c is set to that unpaired surrogate.
*
* @param s const UChar * string
* @param start starting string offset (usually 0)
* @param i string offset, must be start<i
* @param c output UChar32 variable
* @see U16_PREV_UNSAFE
* @stable ICU 2.4
*/
#define U16_PREV(s, start, i, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[--(i)]; \
if(U16_IS_TRAIL(c)) { \
uint16_t __c2; \
if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
--(i); \
(c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
} \
} \
} UPRV_BLOCK_MACRO_END
/**
* Move the string offset from one code point boundary to the previous one
* and get the code point between them.
* (Pre-decrementing backward iteration.)
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The input offset may be the same as the string length.
* If the offset is behind a trail surrogate unit
* for a supplementary code point, then the macro will read
* the preceding lead surrogate as well.
* If the offset is behind a lead surrogate or behind a single, unpaired
* trail surrogate, then c is set to U+FFFD.
*
* @param s const UChar * string
* @param start starting string offset (usually 0)
* @param i string offset, must be start<i
* @param c output UChar32 variable
* @see U16_PREV_UNSAFE
* @stable ICU 60
*/
#define U16_PREV_OR_FFFD(s, start, i, c) UPRV_BLOCK_MACRO_BEGIN { \
(c)=(s)[--(i)]; \
if(U16_IS_SURROGATE(c)) { \
uint16_t __c2; \
if(U16_IS_SURROGATE_TRAIL(c) && (i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
--(i); \
(c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
} else { \
(c)=0xfffd; \
} \
} \
} UPRV_BLOCK_MACRO_END
/**
* Move the string offset from one code point boundary to the previous one.
* (Pre-decrementing backward iteration.)
* The input offset may be the same as the string length.
* "Unsafe" macro, assumes well-formed UTF-16.
*
* @param s const UChar * string
* @param i string offset
* @see U16_BACK_1
* @stable ICU 2.4
*/
#define U16_BACK_1_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_TRAIL((s)[--(i)])) { \
--(i); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Move the string offset from one code point boundary to the previous one.
* (Pre-decrementing backward iteration.)
* The input offset may be the same as the string length.
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* @param s const UChar * string
* @param start starting string offset (usually 0)
* @param i string offset, must be start<i
* @see U16_BACK_1_UNSAFE
* @stable ICU 2.4
*/
#define U16_BACK_1(s, start, i) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_TRAIL((s)[--(i)]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \
--(i); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Move the string offset from one code point boundary to the n-th one before it,
* i.e., move backward by n code points.
* (Pre-decrementing backward iteration.)
* The input offset may be the same as the string length.
* "Unsafe" macro, assumes well-formed UTF-16.
*
* @param s const UChar * string
* @param i string offset
* @param n number of code points to skip
* @see U16_BACK_N
* @stable ICU 2.4
*/
#define U16_BACK_N_UNSAFE(s, i, n) UPRV_BLOCK_MACRO_BEGIN { \
int32_t __N=(n); \
while(__N>0) { \
U16_BACK_1_UNSAFE(s, i); \
--__N; \
} \
} UPRV_BLOCK_MACRO_END
/**
* Move the string offset from one code point boundary to the n-th one before it,
* i.e., move backward by n code points.
* (Pre-decrementing backward iteration.)
* The input offset may be the same as the string length.
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* @param s const UChar * string
* @param start start of string
* @param i string offset, must be start<i
* @param n number of code points to skip
* @see U16_BACK_N_UNSAFE
* @stable ICU 2.4
*/
#define U16_BACK_N(s, start, i, n) UPRV_BLOCK_MACRO_BEGIN { \
int32_t __N=(n); \
while(__N>0 && (i)>(start)) { \
U16_BACK_1(s, start, i); \
--__N; \
} \
} UPRV_BLOCK_MACRO_END
/**
* Adjust a random-access offset to a code point boundary after a code point.
* If the offset is behind the lead surrogate of a surrogate pair,
* then the offset is incremented.
* Otherwise, it is not modified.
* The input offset may be the same as the string length.
* "Unsafe" macro, assumes well-formed UTF-16.
*
* @param s const UChar * string
* @param i string offset
* @see U16_SET_CP_LIMIT
* @stable ICU 2.4
*/
#define U16_SET_CP_LIMIT_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \
if(U16_IS_LEAD((s)[(i)-1])) { \
++(i); \
} \
} UPRV_BLOCK_MACRO_END
/**
* Adjust a random-access offset to a code point boundary after a code point.
* If the offset is behind the lead surrogate of a surrogate pair,
* then the offset is incremented.
* Otherwise, it is not modified.
* The input offset may be the same as the string length.
* "Safe" macro, handles unpaired surrogates and checks for string boundaries.
*
* The length can be negative for a NUL-terminated string.
*
* @param s const UChar * string
* @param start int32_t starting string offset (usually 0)
* @param i int32_t string offset, start<=i<=length
* @param length int32_t string length
* @see U16_SET_CP_LIMIT_UNSAFE
* @stable ICU 2.4
*/
#define U16_SET_CP_LIMIT(s, start, i, length) UPRV_BLOCK_MACRO_BEGIN { \
if((start)<(i) && ((i)<(length) || (length)<0) && U16_IS_LEAD((s)[(i)-1]) && U16_IS_TRAIL((s)[i])) { \
++(i); \
} \
} UPRV_BLOCK_MACRO_END
#endif