ConvertUTF.h

   1 /*
   2  * Copyright 2001-2004 Unicode, Inc.
   3  *
   4  * Disclaimer
   5  *
   6  * This source code is provided as is by Unicode, Inc. No claims are
   7  * made as to fitness for any particular purpose. No warranties of any
   8  * kind are expressed or implied. The recipient agrees to determine
   9  * applicability of information provided. If this file has been
  10  * purchased on magnetic or optical media from Unicode, Inc., the
  11  * sole remedy for any claim will be exchange of defective media
  12  * within 90 days of receipt.
  13  *
  14  * Limitations on Rights to Redistribute This Code
  15  *
  16  * Unicode, Inc. hereby grants the right to freely use the information
  17  * supplied in this file in the creation of products supporting the
  18  * Unicode Standard, and to make copies of this file in any form
  19  * for internal or external distribution as long as this notice
  20  * remains attached.
  21  */
  22
  23 /* ---------------------------------------------------------------------
  24
  25     Conversions between UTF32, UTF-16, and UTF-8.  Header file.
  26
  27     Several funtions are included here, forming a complete set of
  28     conversions between the three formats.  UTF-7 is not included
  29     here, but is handled in a separate source file.
  30
  31     Each of these routines takes pointers to input buffers and output
  32     buffers.  The input buffers are const.
  33
  34     Each routine converts the text between *sourceStart and sourceEnd,
  35     putting the result into the buffer between *targetStart and
  36     targetEnd. Note: the end pointers are *after* the last item: e.g.
  37     *(sourceEnd - 1) is the last item.
  38
  39     The return result indicates whether the conversion was successful,
  40     and if not, whether the problem was in the source or target buffers.
  41     (Only the first encountered problem is indicated.)
  42
  43     After the conversion, *sourceStart and *targetStart are both
  44     updated to point to the end of last text successfully converted in
  45     the respective buffers.
  46
  47     Input parameters:
  48         sourceStart - pointer to a pointer to the source buffer.
  49                 The contents of this are modified on return so that
  50                 it points at the next thing to be converted.
  51         targetStart - similarly, pointer to pointer to the target buffer.
  52         sourceEnd, targetEnd - respectively pointers to the ends of the
  53                 two buffers, for overflow checking only.
  54
  55     These conversion functions take a ConversionFlags argument. When this
  56     flag is set to strict, both irregular sequences and isolated surrogates
  57     will cause an error.  When the flag is set to lenient, both irregular
  58     sequences and isolated surrogates are converted.
  59
  60     Whether the flag is strict or lenient, all illegal sequences will cause
  61     an error return. This includes sequences such as: <F4 90 80 80>, <C0 80>,
  62     or <A0> in UTF-8, and values above 0x10FFFF in UTF-32. Conformant code
  63     must check for illegal sequences.
  64
  65     When the flag is set to lenient, characters over 0x10FFFF are converted
  66     to the replacement character; otherwise (when the flag is set to strict)
  67     they constitute an error.
  68
  69     Output parameters:
  70         The value "sourceIllegal" is returned from some routines if the input
  71         sequence is malformed.  When "sourceIllegal" is returned, the source
  72         value will point to the illegal value that caused the problem. E.g.,
  73         in UTF-8 when a sequence is malformed, it points to the start of the
  74         malformed sequence.
  75
  76     Author: Mark E. Davis, 1994.
  77     Rev History: Rick McGowan, fixes & updates May 2001.
  78                  Fixes & updates, Sept 2001.
  79
  80 ------------------------------------------------------------------------ */
  81
  82 /* ---------------------------------------------------------------------
  83     The following 4 definitions are compiler-specific.
  84     The C standard does not guarantee that wchar_t has at least
  85     16 bits, so wchar_t is no less portable than unsigned short!
  86     All should be unsigned values to avoid sign extension during
  87     bit mask & shift operations.
  88 ------------------------------------------------------------------------ */
  89
  90 typedef unsigned long   UTF32;  /* at least 32 bits */
  91 typedef unsigned short  UTF16;  /* at least 16 bits */
  92 typedef unsigned char   UTF8;   /* typically 8 bits */
  93 typedef unsigned char   Boolean; /* 0 or 1 */
  94
  95 /* Some fundamental constants */
  96 #define UNI_REPLACEMENT_CHAR (UTF32)0x0000FFFD
  97 #define UNI_MAX_BMP (UTF32)0x0000FFFF
  98 #define UNI_MAX_UTF16 (UTF32)0x0010FFFF
  99 #define UNI_MAX_UTF32 (UTF32)0x7FFFFFFF
 100 #define UNI_MAX_LEGAL_UTF32 (UTF32)0x0010FFFF
 101
 102 typedef enum {
 103         conversionOK,           /* conversion successful */
 104         sourceExhausted,        /* partial character in source, but hit end */
 105         targetExhausted,        /* insuff. room in target for conversion */
 106         sourceIllegal           /* source sequence is illegal/malformed */
 107 } ConversionResult;
 108
 109 typedef enum {
 110         strictConversion = 0,
 111         lenientConversion
 112 } ConversionFlags;
 113
 114 /* This is for C++ and does no harm in C */
 115 #ifdef __cplusplus
 116 extern "C" {
 117 #endif
 118
 119 ConversionResult ConvertUTF8toUTF16 (
 120                 const UTF8** sourceStart, const UTF8* sourceEnd,
 121                 UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags);
 122
 123 ConversionResult ConvertUTF16toUTF8 (
 124                 const UTF16** sourceStart, const UTF16* sourceEnd,
 125                 UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags);
 126
 127 ConversionResult ConvertUTF8toUTF32 (
 128                 const UTF8** sourceStart, const UTF8* sourceEnd,
 129                 UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags);
 130
 131 ConversionResult ConvertUTF32toUTF8 (
 132                 const UTF32** sourceStart, const UTF32* sourceEnd,
 133                 UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags);
 134
 135 ConversionResult ConvertUTF16toUTF32 (
 136                 const UTF16** sourceStart, const UTF16* sourceEnd,
 137                 UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags);
 138
 139 ConversionResult ConvertUTF32toUTF16 (
 140                 const UTF32** sourceStart, const UTF32* sourceEnd,
 141                 UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags);
 142
 143 Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd);
 144
 145 #ifdef __cplusplus
 146 }
 147 #endif
 148
 149 /* --------------------------------------------------------------------- */