gfx/harfbuzz/src/hb-blob.h

   1 /*
   2  * Copyright © 2009  Red Hat, Inc.
   3  *
   4  *  This is part of HarfBuzz, a text shaping library.
   5  *
   6  * Permission is hereby granted, without written agreement and without
   7  * license or royalty fees, to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose, provided that the
   9  * above copyright notice and the following two paragraphs appear in
  10  * all copies of this software.
  11  *
  12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16  * DAMAGE.
  17  *
  18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23  *
  24  * Red Hat Author(s): Behdad Esfahbod
  25  */
  26
  27 #if !defined(HB_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
  28 #error "Include <hb.h> instead."
  29 #endif
  30
  31 #ifndef HB_BLOB_H
  32 #define HB_BLOB_H
  33
  34 #include "hb-common.h"
  35
  36 HB_BEGIN_DECLS
  37
  38
  39 /**
  40  * hb_memory_mode_t:
  41  * @HB_MEMORY_MODE_DUPLICATE: HarfBuzz immediately makes a copy of the data.
  42  * @HB_MEMORY_MODE_READONLY: HarfBuzz client will never modify the data,
  43  *     and HarfBuzz will never modify the data.
  44  * @HB_MEMORY_MODE_WRITABLE: HarfBuzz client made a copy of the data solely
  45  *     for HarfBuzz, so HarfBuzz may modify the data.
  46  * @HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE: See above
  47  *
  48  * Data type holding the memory modes available to
  49  * client programs.
  50  *
  51  * Regarding these various memory-modes:
  52  *
  53  * - In no case shall the HarfBuzz client modify memory
  54  *   that is passed to HarfBuzz in a blob.  If there is
  55  *   any such possibility, @HB_MEMORY_MODE_DUPLICATE should be used
  56  *   such that HarfBuzz makes a copy immediately,
  57  *
  58  * - Use @HB_MEMORY_MODE_READONLY otherwise, unless you really really
  59  *   really know what you are doing,
  60  *
  61  * - @HB_MEMORY_MODE_WRITABLE is appropriate if you really made a
  62  *   copy of data solely for the purpose of passing to
  63  *   HarfBuzz and doing that just once (no reuse!),
  64  *
  65  * - If the font is mmap()ed, it's okay to use
  66  *   @HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE, however, using that mode
  67  *   correctly is very tricky.  Use @HB_MEMORY_MODE_READONLY instead.
  68  **/
  69 typedef enum {
  70   HB_MEMORY_MODE_DUPLICATE,
  71   HB_MEMORY_MODE_READONLY,
  72   HB_MEMORY_MODE_WRITABLE,
  73   HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE
  74 } hb_memory_mode_t;
  75
  76 /**
  77  * hb_blob_t:
  78  *
  79  * Data type for blobs. A blob wraps a chunk of binary
  80  * data and facilitates its lifecycle management between
  81  * a client program and HarfBuzz.
  82  *
  83  **/
  84 typedef struct hb_blob_t hb_blob_t;
  85
  86 HB_EXTERN hb_blob_t *
  87 hb_blob_create (const char        *data,
  88                 unsigned int       length,
  89                 hb_memory_mode_t   mode,
  90                 void              *user_data,
  91                 hb_destroy_func_t  destroy);
  92
  93 HB_EXTERN hb_blob_t *
  94 hb_blob_create_or_fail (const char        *data,
  95                         unsigned int       length,
  96                         hb_memory_mode_t   mode,
  97                         void              *user_data,
  98                         hb_destroy_func_t  destroy);
  99
 100 HB_EXTERN hb_blob_t *
 101 hb_blob_create_from_file (const char *file_name);
 102
 103 HB_EXTERN hb_blob_t *
 104 hb_blob_create_from_file_or_fail (const char *file_name);
 105
 106 /* Always creates with MEMORY_MODE_READONLY.
 107  * Even if the parent blob is writable, we don't
 108  * want the user of the sub-blob to be able to
 109  * modify the parent data as that data may be
 110  * shared among multiple sub-blobs.
 111  */
 112 HB_EXTERN hb_blob_t *
 113 hb_blob_create_sub_blob (hb_blob_t    *parent,
 114                          unsigned int  offset,
 115                          unsigned int  length);
 116
 117 HB_EXTERN hb_blob_t *
 118 hb_blob_copy_writable_or_fail (hb_blob_t *blob);
 119
 120 HB_EXTERN hb_blob_t *
 121 hb_blob_get_empty (void);
 122
 123 HB_EXTERN hb_blob_t *
 124 hb_blob_reference (hb_blob_t *blob);
 125
 126 HB_EXTERN void
 127 hb_blob_destroy (hb_blob_t *blob);
 128
 129 HB_EXTERN hb_bool_t
 130 hb_blob_set_user_data (hb_blob_t          *blob,
 131                        hb_user_data_key_t *key,
 132                        void *              data,
 133                        hb_destroy_func_t   destroy,
 134                        hb_bool_t           replace);
 135
 136
 137 HB_EXTERN void *
 138 hb_blob_get_user_data (const hb_blob_t    *blob,
 139                        hb_user_data_key_t *key);
 140
 141
 142 HB_EXTERN void
 143 hb_blob_make_immutable (hb_blob_t *blob);
 144
 145 HB_EXTERN hb_bool_t
 146 hb_blob_is_immutable (hb_blob_t *blob);
 147
 148
 149 HB_EXTERN unsigned int
 150 hb_blob_get_length (hb_blob_t *blob);
 151
 152 HB_EXTERN const char *
 153 hb_blob_get_data (hb_blob_t *blob, unsigned int *length);
 154
 155 HB_EXTERN char *
 156 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length);
 157
 158 HB_END_DECLS
 159
 160 #endif /* HB_BLOB_H */