1 /*

     2 *******************************************************************************

     3 *

     4 *   Copyright (C) 1999-2005, International Business Machines

     5 *   Corporation and others.  All Rights Reserved.

     6 *

     7 *******************************************************************************

     8 *   file name:  utf16.h

     9 *   encoding:   US-ASCII

    10 *   tab size:   8 (not used)

    11 *   indentation:4

    12 *

    13 *   created on: 1999sep09

    14 *   created by: Markus W. Scherer

    15 */

    16 

    17 /**

    18  * \file

    19  * \brief C API: 16-bit Unicode handling macros

    20  * 

    21  * This file defines macros to deal with 16-bit Unicode (UTF-16) code units and strings.

    22  * utf16.h is included by utf.h after unicode/umachine.h

    23  * and some common definitions.

    24  *

    25  * For more information see utf.h and the ICU User Guide Strings chapter

    26  * (http://icu.sourceforge.net/userguide/strings.html).

    27  *

    28  * <em>Usage:</em>

    29  * ICU coding guidelines for if() statements should be followed when using these macros.

    30  * Compound statements (curly braces {}) must be used  for if-else-while... 

    31  * bodies and all macro statements should be terminated with semicolon.

    32  */

    33 

    34 #ifndef __UTF16_H__

    35 #define __UTF16_H__

    36 

    37 /* utf.h must be included first. */

    38 #ifndef __UTF_H__

    39 #   include "unicode/utf.h"

    40 #endif

    41 

    42 /* single-code point definitions -------------------------------------------- */

    43 

    44 /**

    45  * Does this code unit alone encode a code point (BMP, not a surrogate)?

    46  * @param c 16-bit code unit

    47  * @return TRUE or FALSE

    48  * @stable ICU 2.4

    49  */

    50 #define U16_IS_SINGLE(c) !U_IS_SURROGATE(c)

    51 

    52 /**

    53  * Is this code unit a lead surrogate (U+d800..U+dbff)?

    54  * @param c 16-bit code unit

    55  * @return TRUE or FALSE

    56  * @stable ICU 2.4

    57  */

    58 #define U16_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)

    59 

    60 /**

    61  * Is this code unit a trail surrogate (U+dc00..U+dfff)?

    62  * @param c 16-bit code unit

    63  * @return TRUE or FALSE

    64  * @stable ICU 2.4

    65  */

    66 #define U16_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)

    67 

    68 /**

    69  * Is this code unit a surrogate (U+d800..U+dfff)?

    70  * @param c 16-bit code unit

    71  * @return TRUE or FALSE

    72  * @stable ICU 2.4

    73  */

    74 #define U16_IS_SURROGATE(c) U_IS_SURROGATE(c)

    75 

    76 /**

    77  * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),

    78  * is it a lead surrogate?

    79  * @param c 16-bit code unit

    80  * @return TRUE or FALSE

    81  * @stable ICU 2.4

    82  */

    83 #define U16_IS_SURROGATE_LEAD(c) (((c)&0x400)==0)

    84 

    85 /**

    86  * Helper constant for U16_GET_SUPPLEMENTARY.

    87  * @internal

    88  */

    89 #define U16_SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000)

    90 

    91 /**

    92  * Get a supplementary code point value (U+10000..U+10ffff)

    93  * from its lead and trail surrogates.

    94  * The result is undefined if the input values are not

    95  * lead and trail surrogates.

    96  *

    97  * @param lead lead surrogate (U+d800..U+dbff)

    98  * @param trail trail surrogate (U+dc00..U+dfff)

    99  * @return supplementary code point (U+10000..U+10ffff)

   100  * @stable ICU 2.4

   101  */

   102 #define U16_GET_SUPPLEMENTARY(lead, trail) \

   103     (((UChar32)(lead)<<10UL)+(UChar32)(trail)-U16_SURROGATE_OFFSET)

   104 

   105 

   106 /**

   107  * Get the lead surrogate (0xd800..0xdbff) for a

   108  * supplementary code point (0x10000..0x10ffff).

   109  * @param supplementary 32-bit code point (U+10000..U+10ffff)

   110  * @return lead surrogate (U+d800..U+dbff) for supplementary

   111  * @stable ICU 2.4

   112  */

   113 #define U16_LEAD(supplementary) (UChar)(((supplementary)>>10)+0xd7c0)

   114 

   115 /**

   116  * Get the trail surrogate (0xdc00..0xdfff) for a

   117  * supplementary code point (0x10000..0x10ffff).

   118  * @param supplementary 32-bit code point (U+10000..U+10ffff)

   119  * @return trail surrogate (U+dc00..U+dfff) for supplementary

   120  * @stable ICU 2.4

   121  */

   122 #define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff)|0xdc00)

   123 

   124 /**

   125  * How many 16-bit code units are used to encode this Unicode code point? (1 or 2)

   126  * The result is not defined if c is not a Unicode code point (U+0000..U+10ffff).

   127  * @param c 32-bit code point

   128  * @return 1 or 2

   129  * @stable ICU 2.4

   130  */

   131 #define U16_LENGTH(c) ((uint32_t)(c)<=0xffff ? 1 : 2)

   132 

   133 /**

   134  * The maximum number of 16-bit code units per Unicode code point (U+0000..U+10ffff).

   135  * @return 2

   136  * @stable ICU 2.4

   137  */

   138 #define U16_MAX_LENGTH 2

   139 

   140 /**

   141  * Get a code point from a string at a random-access offset,

   142  * without changing the offset.

   143  * "Unsafe" macro, assumes well-formed UTF-16.

   144  *

   145  * The offset may point to either the lead or trail surrogate unit

   146  * for a supplementary code point, in which case the macro will read

   147  * the adjacent matching surrogate as well.

   148  * The result is undefined if the offset points to a single, unpaired surrogate.

   149  * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.

   150  *

   151  * @param s const UChar * string

   152  * @param i string offset

   153  * @param c output UChar32 variable

   154  * @see U16_GET

   155  * @stable ICU 2.4

   156  */

   157 #define U16_GET_UNSAFE(s, i, c) { \

   158     (c)=(s)[i]; \

   159     if(U16_IS_SURROGATE(c)) { \

   160         if(U16_IS_SURROGATE_LEAD(c)) { \

   161             (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)+1]); \

   162         } else { \

   163             (c)=U16_GET_SUPPLEMENTARY((s)[(i)-1], (c)); \

   164         } \

   165     } \

   166 }

   167 

   168 /**

   169  * Get a code point from a string at a random-access offset,

   170  * without changing the offset.

   171  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   172  *

   173  * The offset may point to either the lead or trail surrogate unit

   174  * for a supplementary code point, in which case the macro will read

   175  * the adjacent matching surrogate as well.

   176  * If the offset points to a single, unpaired surrogate, then that itself

   177  * will be returned as the code point.

   178  * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.

   179  *

   180  * @param s const UChar * string

   181  * @param start starting string offset (usually 0)

   182  * @param i string offset, start<=i<length

   183  * @param length string length

   184  * @param c output UChar32 variable

   185  * @see U16_GET_UNSAFE

   186  * @stable ICU 2.4

   187  */

   188 #define U16_GET(s, start, i, length, c) { \

   189     (c)=(s)[i]; \

   190     if(U16_IS_SURROGATE(c)) { \

   191         uint16_t __c2; \

   192         if(U16_IS_SURROGATE_LEAD(c)) { \

   193             if((i)+1<(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \

   194                 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \

   195             } \

   196         } else { \

   197             if((i)-1>=(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \

   198                 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \

   199             } \

   200         } \

   201     } \

   202 }

   203 

   204 /* definitions with forward iteration --------------------------------------- */

   205 

   206 /**

   207  * Get a code point from a string at a code point boundary offset,

   208  * and advance the offset to the next code point boundary.

   209  * (Post-incrementing forward iteration.)

   210  * "Unsafe" macro, assumes well-formed UTF-16.

   211  *

   212  * The offset may point to the lead surrogate unit

   213  * for a supplementary code point, in which case the macro will read

   214  * the following trail surrogate as well.

   215  * If the offset points to a trail surrogate, then that itself

   216  * will be returned as the code point.

   217  * The result is undefined if the offset points to a single, unpaired lead surrogate.

   218  *

   219  * @param s const UChar * string

   220  * @param i string offset

   221  * @param c output UChar32 variable

   222  * @see U16_NEXT

   223  * @stable ICU 2.4

   224  */

   225 #define U16_NEXT_UNSAFE(s, i, c) { \

   226     (c)=(s)[(i)++]; \

   227     if(U16_IS_LEAD(c)) { \

   228         (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)++]); \

   229     } \

   230 }

   231 

   232 /**

   233  * Get a code point from a string at a code point boundary offset,

   234  * and advance the offset to the next code point boundary.

   235  * (Post-incrementing forward iteration.)

   236  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   237  *

   238  * The offset may point to the lead surrogate unit

   239  * for a supplementary code point, in which case the macro will read

   240  * the following trail surrogate as well.

   241  * If the offset points to a trail surrogate or

   242  * to a single, unpaired lead surrogate, then that itself

   243  * will be returned as the code point.

   244  *

   245  * @param s const UChar * string

   246  * @param i string offset, i<length

   247  * @param length string length

   248  * @param c output UChar32 variable

   249  * @see U16_NEXT_UNSAFE

   250  * @stable ICU 2.4

   251  */

   252 #define U16_NEXT(s, i, length, c) { \

   253     (c)=(s)[(i)++]; \

   254     if(U16_IS_LEAD(c)) { \

   255         uint16_t __c2; \

   256         if((i)<(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \

   257             ++(i); \

   258             (c)=U16_GET_SUPPLEMENTARY((c), __c2); \

   259         } \

   260     } \

   261 }

   262 

   263 /**

   264  * Append a code point to a string, overwriting 1 or 2 code units.

   265  * The offset points to the current end of the string contents

   266  * and is advanced (post-increment).

   267  * "Unsafe" macro, assumes a valid code point and sufficient space in the string.

   268  * Otherwise, the result is undefined.

   269  *

   270  * @param s const UChar * string buffer

   271  * @param i string offset

   272  * @param c code point to append

   273  * @see U16_APPEND

   274  * @stable ICU 2.4

   275  */

   276 #define U16_APPEND_UNSAFE(s, i, c) { \

   277     if((uint32_t)(c)<=0xffff) { \

   278         (s)[(i)++]=(uint16_t)(c); \

   279     } else { \

   280         (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \

   281         (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \

   282     } \

   283 }

   284 

   285 /**

   286  * Append a code point to a string, overwriting 1 or 2 code units.

   287  * The offset points to the current end of the string contents

   288  * and is advanced (post-increment).

   289  * "Safe" macro, checks for a valid code point.

   290  * If a surrogate pair is written, checks for sufficient space in the string.

   291  * If the code point is not valid or a trail surrogate does not fit,

   292  * then isError is set to TRUE.

   293  *

   294  * @param s const UChar * string buffer

   295  * @param i string offset, i<length

   296  * @param capacity size of the string buffer

   297  * @param c code point to append

   298  * @param isError output UBool set to TRUE if an error occurs, otherwise not modified

   299  * @see U16_APPEND_UNSAFE

   300  * @stable ICU 2.4

   301  */

   302 #define U16_APPEND(s, i, capacity, c, isError) { \

   303     if((uint32_t)(c)<=0xffff) { \

   304         (s)[(i)++]=(uint16_t)(c); \

   305     } else if((uint32_t)(c)<=0x10ffff && (i)+1<(capacity)) { \

   306         (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \

   307         (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \

   308     } else /* c>0x10ffff or not enough space */ { \

   309         (isError)=TRUE; \

   310     } \

   311 }

   312 

   313 /**

   314  * Advance the string offset from one code point boundary to the next.

   315  * (Post-incrementing iteration.)

   316  * "Unsafe" macro, assumes well-formed UTF-16.

   317  *

   318  * @param s const UChar * string

   319  * @param i string offset

   320  * @see U16_FWD_1

   321  * @stable ICU 2.4

   322  */

   323 #define U16_FWD_1_UNSAFE(s, i) { \

   324     if(U16_IS_LEAD((s)[(i)++])) { \

   325         ++(i); \

   326     } \

   327 }

   328 

   329 /**

   330  * Advance the string offset from one code point boundary to the next.

   331  * (Post-incrementing iteration.)

   332  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   333  *

   334  * @param s const UChar * string

   335  * @param i string offset, i<length

   336  * @param length string length

   337  * @see U16_FWD_1_UNSAFE

   338  * @stable ICU 2.4

   339  */

   340 #define U16_FWD_1(s, i, length) { \

   341     if(U16_IS_LEAD((s)[(i)++]) && (i)<(length) && U16_IS_TRAIL((s)[i])) { \

   342         ++(i); \

   343     } \

   344 }

   345 

   346 /**

   347  * Advance the string offset from one code point boundary to the n-th next one,

   348  * i.e., move forward by n code points.

   349  * (Post-incrementing iteration.)

   350  * "Unsafe" macro, assumes well-formed UTF-16.

   351  *

   352  * @param s const UChar * string

   353  * @param i string offset

   354  * @param n number of code points to skip

   355  * @see U16_FWD_N

   356  * @stable ICU 2.4

   357  */

   358 #define U16_FWD_N_UNSAFE(s, i, n) { \

   359     int32_t __N=(n); \

   360     while(__N>0) { \

   361         U16_FWD_1_UNSAFE(s, i); \

   362         --__N; \

   363     } \

   364 }

   365 

   366 /**

   367  * Advance the string offset from one code point boundary to the n-th next one,

   368  * i.e., move forward by n code points.

   369  * (Post-incrementing iteration.)

   370  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   371  *

   372  * @param s const UChar * string

   373  * @param i string offset, i<length

   374  * @param length string length

   375  * @param n number of code points to skip

   376  * @see U16_FWD_N_UNSAFE

   377  * @stable ICU 2.4

   378  */

   379 #define U16_FWD_N(s, i, length, n) { \

   380     int32_t __N=(n); \

   381     while(__N>0 && (i)<(length)) { \

   382         U16_FWD_1(s, i, length); \

   383         --__N; \

   384     } \

   385 }

   386 

   387 /**

   388  * Adjust a random-access offset to a code point boundary

   389  * at the start of a code point.

   390  * If the offset points to the trail surrogate of a surrogate pair,

   391  * then the offset is decremented.

   392  * Otherwise, it is not modified.

   393  * "Unsafe" macro, assumes well-formed UTF-16.

   394  *

   395  * @param s const UChar * string

   396  * @param i string offset

   397  * @see U16_SET_CP_START

   398  * @stable ICU 2.4

   399  */

   400 #define U16_SET_CP_START_UNSAFE(s, i) { \

   401     if(U16_IS_TRAIL((s)[i])) { \

   402         --(i); \

   403     } \

   404 }

   405 

   406 /**

   407  * Adjust a random-access offset to a code point boundary

   408  * at the start of a code point.

   409  * If the offset points to the trail surrogate of a surrogate pair,

   410  * then the offset is decremented.

   411  * Otherwise, it is not modified.

   412  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   413  *

   414  * @param s const UChar * string

   415  * @param start starting string offset (usually 0)

   416  * @param i string offset, start<=i

   417  * @see U16_SET_CP_START_UNSAFE

   418  * @stable ICU 2.4

   419  */

   420 #define U16_SET_CP_START(s, start, i) { \

   421     if(U16_IS_TRAIL((s)[i]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \

   422         --(i); \

   423     } \

   424 }

   425 

   426 /* definitions with backward iteration -------------------------------------- */

   427 

   428 /**

   429  * Move the string offset from one code point boundary to the previous one

   430  * and get the code point between them.

   431  * (Pre-decrementing backward iteration.)

   432  * "Unsafe" macro, assumes well-formed UTF-16.

   433  *

   434  * The input offset may be the same as the string length.

   435  * If the offset is behind a trail surrogate unit

   436  * for a supplementary code point, then the macro will read

   437  * the preceding lead surrogate as well.

   438  * If the offset is behind a lead surrogate, then that itself

   439  * will be returned as the code point.

   440  * The result is undefined if the offset is behind a single, unpaired trail surrogate.

   441  *

   442  * @param s const UChar * string

   443  * @param i string offset

   444  * @param c output UChar32 variable

   445  * @see U16_PREV

   446  * @stable ICU 2.4

   447  */

   448 #define U16_PREV_UNSAFE(s, i, c) { \

   449     (c)=(s)[--(i)]; \

   450     if(U16_IS_TRAIL(c)) { \

   451         (c)=U16_GET_SUPPLEMENTARY((s)[--(i)], (c)); \

   452     } \

   453 }

   454 

   455 /**

   456  * Move the string offset from one code point boundary to the previous one

   457  * and get the code point between them.

   458  * (Pre-decrementing backward iteration.)

   459  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   460  *

   461  * The input offset may be the same as the string length.

   462  * If the offset is behind a trail surrogate unit

   463  * for a supplementary code point, then the macro will read

   464  * the preceding lead surrogate as well.

   465  * If the offset is behind a lead surrogate or behind a single, unpaired

   466  * trail surrogate, then that itself

   467  * will be returned as the code point.

   468  *

   469  * @param s const UChar * string

   470  * @param start starting string offset (usually 0)

   471  * @param i string offset, start<=i

   472  * @param c output UChar32 variable

   473  * @see U16_PREV_UNSAFE

   474  * @stable ICU 2.4

   475  */

   476 #define U16_PREV(s, start, i, c) { \

   477     (c)=(s)[--(i)]; \

   478     if(U16_IS_TRAIL(c)) { \

   479         uint16_t __c2; \

   480         if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \

   481             --(i); \

   482             (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \

   483         } \

   484     } \

   485 }

   486 

   487 /**

   488  * Move the string offset from one code point boundary to the previous one.

   489  * (Pre-decrementing backward iteration.)

   490  * The input offset may be the same as the string length.

   491  * "Unsafe" macro, assumes well-formed UTF-16.

   492  *

   493  * @param s const UChar * string

   494  * @param i string offset

   495  * @see U16_BACK_1

   496  * @stable ICU 2.4

   497  */

   498 #define U16_BACK_1_UNSAFE(s, i) { \

   499     if(U16_IS_TRAIL((s)[--(i)])) { \

   500         --(i); \

   501     } \

   502 }

   503 

   504 /**

   505  * Move the string offset from one code point boundary to the previous one.

   506  * (Pre-decrementing backward iteration.)

   507  * The input offset may be the same as the string length.

   508  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   509  *

   510  * @param s const UChar * string

   511  * @param start starting string offset (usually 0)

   512  * @param i string offset, start<=i

   513  * @see U16_BACK_1_UNSAFE

   514  * @stable ICU 2.4

   515  */

   516 #define U16_BACK_1(s, start, i) { \

   517     if(U16_IS_TRAIL((s)[--(i)]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \

   518         --(i); \

   519     } \

   520 }

   521 

   522 /**

   523  * Move the string offset from one code point boundary to the n-th one before it,

   524  * i.e., move backward by n code points.

   525  * (Pre-decrementing backward iteration.)

   526  * The input offset may be the same as the string length.

   527  * "Unsafe" macro, assumes well-formed UTF-16.

   528  *

   529  * @param s const UChar * string

   530  * @param i string offset

   531  * @param n number of code points to skip

   532  * @see U16_BACK_N

   533  * @stable ICU 2.4

   534  */

   535 #define U16_BACK_N_UNSAFE(s, i, n) { \

   536     int32_t __N=(n); \

   537     while(__N>0) { \

   538         U16_BACK_1_UNSAFE(s, i); \

   539         --__N; \

   540     } \

   541 }

   542 

   543 /**

   544  * Move the string offset from one code point boundary to the n-th one before it,

   545  * i.e., move backward by n code points.

   546  * (Pre-decrementing backward iteration.)

   547  * The input offset may be the same as the string length.

   548  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   549  *

   550  * @param s const UChar * string

   551  * @param start start of string

   552  * @param i string offset, i<length

   553  * @param n number of code points to skip

   554  * @see U16_BACK_N_UNSAFE

   555  * @stable ICU 2.4

   556  */

   557 #define U16_BACK_N(s, start, i, n) { \

   558     int32_t __N=(n); \

   559     while(__N>0 && (i)>(start)) { \

   560         U16_BACK_1(s, start, i); \

   561         --__N; \

   562     } \

   563 }

   564 

   565 /**

   566  * Adjust a random-access offset to a code point boundary after a code point.

   567  * If the offset is behind the lead surrogate of a surrogate pair,

   568  * then the offset is incremented.

   569  * Otherwise, it is not modified.

   570  * The input offset may be the same as the string length.

   571  * "Unsafe" macro, assumes well-formed UTF-16.

   572  *

   573  * @param s const UChar * string

   574  * @param i string offset

   575  * @see U16_SET_CP_LIMIT

   576  * @stable ICU 2.4

   577  */

   578 #define U16_SET_CP_LIMIT_UNSAFE(s, i) { \

   579     if(U16_IS_LEAD((s)[(i)-1])) { \

   580         ++(i); \

   581     } \

   582 }

   583 

   584 /**

   585  * Adjust a random-access offset to a code point boundary after a code point.

   586  * If the offset is behind the lead surrogate of a surrogate pair,

   587  * then the offset is incremented.

   588  * Otherwise, it is not modified.

   589  * The input offset may be the same as the string length.

   590  * "Safe" macro, handles unpaired surrogates and checks for string boundaries.

   591  *

   592  * @param s const UChar * string

   593  * @param start starting string offset (usually 0)

   594  * @param i string offset, start<=i<=length

   595  * @param length string length

   596  * @see U16_SET_CP_LIMIT_UNSAFE

   597  * @stable ICU 2.4

   598  */

   599 #define U16_SET_CP_LIMIT(s, start, i, length) { \

   600     if((start)<(i) && (i)<(length) && U16_IS_LEAD((s)[(i)-1]) && U16_IS_TRAIL((s)[i])) { \

   601         ++(i); \

   602     } \

   603 }

   604 

   605 #endif