harfbuzz/src/hb-blob.h

161 lines
4.6 KiB
C

/*
* Copyright © 2009 Red Hat, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Red Hat Author(s): Behdad Esfahbod
*/
#if !defined(HB_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
#error "Include <hb.h> instead."
#endif
#ifndef HB_BLOB_H
#define HB_BLOB_H
#include "hb-common.h"
HB_BEGIN_DECLS
/**
* hb_memory_mode_t:
* @HB_MEMORY_MODE_DUPLICATE: HarfBuzz immediately makes a copy of the data.
* @HB_MEMORY_MODE_READONLY: HarfBuzz client will never modify the data,
* and HarfBuzz will never modify the data.
* @HB_MEMORY_MODE_WRITABLE: HarfBuzz client made a copy of the data solely
* for HarfBuzz, so HarfBuzz may modify the data.
* @HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE: See above
*
* Data type holding the memory modes available to
* client programs.
*
* Regarding these various memory-modes:
*
* - In no case shall the HarfBuzz client modify memory
* that is passed to HarfBuzz in a blob. If there is
* any such possibility, @HB_MEMORY_MODE_DUPLICATE should be used
* such that HarfBuzz makes a copy immediately,
*
* - Use @HB_MEMORY_MODE_READONLY otherwise, unless you really really
* really know what you are doing,
*
* - @HB_MEMORY_MODE_WRITABLE is appropriate if you really made a
* copy of data solely for the purpose of passing to
* HarfBuzz and doing that just once (no reuse!),
*
* - If the font is mmap()ed, it's okay to use
* @HB_MEMORY_READONLY_MAY_MAKE_WRITABLE, however, using that mode
* correctly is very tricky. Use @HB_MEMORY_MODE_READONLY instead.
**/
typedef enum {
HB_MEMORY_MODE_DUPLICATE,
HB_MEMORY_MODE_READONLY,
HB_MEMORY_MODE_WRITABLE,
HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE
} hb_memory_mode_t;
/**
* hb_blob_t:
*
* Data type for blobs. A blob wraps a chunk of binary
* data and facilitates its lifecycle management between
* a client program and HarfBuzz.
*
**/
typedef struct hb_blob_t hb_blob_t;
HB_EXTERN hb_blob_t *
hb_blob_create (const char *data,
unsigned int length,
hb_memory_mode_t mode,
void *user_data,
hb_destroy_func_t destroy);
HB_EXTERN hb_blob_t *
hb_blob_create_or_fail (const char *data,
unsigned int length,
hb_memory_mode_t mode,
void *user_data,
hb_destroy_func_t destroy);
HB_EXTERN hb_blob_t *
hb_blob_create_from_file (const char *file_name);
HB_EXTERN hb_blob_t *
hb_blob_create_from_file_or_fail (const char *file_name);
/* Always creates with MEMORY_MODE_READONLY.
* Even if the parent blob is writable, we don't
* want the user of the sub-blob to be able to
* modify the parent data as that data may be
* shared among multiple sub-blobs.
*/
HB_EXTERN hb_blob_t *
hb_blob_create_sub_blob (hb_blob_t *parent,
unsigned int offset,
unsigned int length);
HB_EXTERN hb_blob_t *
hb_blob_copy_writable_or_fail (hb_blob_t *blob);
HB_EXTERN hb_blob_t *
hb_blob_get_empty (void);
HB_EXTERN hb_blob_t *
hb_blob_reference (hb_blob_t *blob);
HB_EXTERN void
hb_blob_destroy (hb_blob_t *blob);
HB_EXTERN hb_bool_t
hb_blob_set_user_data (hb_blob_t *blob,
hb_user_data_key_t *key,
void * data,
hb_destroy_func_t destroy,
hb_bool_t replace);
HB_EXTERN void *
hb_blob_get_user_data (hb_blob_t *blob,
hb_user_data_key_t *key);
HB_EXTERN void
hb_blob_make_immutable (hb_blob_t *blob);
HB_EXTERN hb_bool_t
hb_blob_is_immutable (hb_blob_t *blob);
HB_EXTERN unsigned int
hb_blob_get_length (hb_blob_t *blob);
HB_EXTERN const char *
hb_blob_get_data (hb_blob_t *blob, unsigned int *length);
HB_EXTERN char *
hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length);
HB_END_DECLS
#endif /* HB_BLOB_H */