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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