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_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_from_file (const char *file_name);
95 
96 /* Always creates with MEMORY_MODE_READONLY.
97  * Even if the parent blob is writable, we don't
98  * want the user of the sub-blob to be able to
99  * modify the parent data as that data may be
100  * shared among multiple sub-blobs.
101  */
102 HB_EXTERN hb_blob_t *
103 hb_blob_create_sub_blob (hb_blob_t    *parent,
104 			 unsigned int  offset,
105 			 unsigned int  length);
106 
107 HB_EXTERN hb_blob_t *
108 hb_blob_copy_writable_or_fail (hb_blob_t *blob);
109 
110 HB_EXTERN hb_blob_t *
111 hb_blob_get_empty (void);
112 
113 HB_EXTERN hb_blob_t *
114 hb_blob_reference (hb_blob_t *blob);
115 
116 HB_EXTERN void
117 hb_blob_destroy (hb_blob_t *blob);
118 
119 HB_EXTERN hb_bool_t
120 hb_blob_set_user_data (hb_blob_t          *blob,
121 		       hb_user_data_key_t *key,
122 		       void *              data,
123 		       hb_destroy_func_t   destroy,
124 		       hb_bool_t           replace);
125 
126 
127 HB_EXTERN void *
128 hb_blob_get_user_data (hb_blob_t          *blob,
129 		       hb_user_data_key_t *key);
130 
131 
132 HB_EXTERN void
133 hb_blob_make_immutable (hb_blob_t *blob);
134 
135 HB_EXTERN hb_bool_t
136 hb_blob_is_immutable (hb_blob_t *blob);
137 
138 
139 HB_EXTERN unsigned int
140 hb_blob_get_length (hb_blob_t *blob);
141 
142 HB_EXTERN const char *
143 hb_blob_get_data (hb_blob_t *blob, unsigned int *length);
144 
145 HB_EXTERN char *
146 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length);
147 
148 HB_END_DECLS
149 
150 #endif /* HB_BLOB_H */
151