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| hb_blob_t * | hb_blob_create () |
| hb_blob_t * | hb_blob_create_or_fail () |
| hb_blob_t * | hb_blob_create_from_file () |
| hb_blob_t * | hb_blob_create_from_file_or_fail () |
| hb_blob_t * | hb_blob_create_sub_blob () |
| hb_blob_t * | hb_blob_copy_writable_or_fail () |
| void | hb_blob_destroy () |
| const char * | hb_blob_get_data () |
| char * | hb_blob_get_data_writable () |
| hb_blob_t * | hb_blob_get_empty () |
| unsigned int | hb_blob_get_length () |
| void * | hb_blob_get_user_data () |
| hb_bool_t | hb_blob_is_immutable () |
| void | hb_blob_make_immutable () |
| hb_blob_t * | hb_blob_reference () |
| hb_bool_t | hb_blob_set_user_data () |
Blobs wrap a chunk of binary data to handle lifecycle management of data while it is passed between client and HarfBuzz. Blobs are primarily used to create font faces, but also to access font face tables, as well as pass around other binary data.
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);
Creates a new "blob" object wrapping data
. The mode
parameter is used
to negotiate ownership and lifecycle of data
.
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data |
Pointer to blob data. |
|
length |
Length of |
|
mode |
Memory mode for |
|
user_data |
Data parameter to pass to |
|
destroy |
Callback to call when |
[nullable] |
New blob, or the empty blob if something failed or if length
is
zero. Destroy with hb_blob_destroy().
Since: 0.9.2
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);
Creates a new "blob" object wrapping data
. The mode
parameter is used
to negotiate ownership and lifecycle of data
.
Note that this function returns a freshly-allocated empty blob even if length
is zero. This is in contrast to hb_blob_create(), which returns the singleton
empty blob (as returned by hb_blob_get_empty()) if length
is zero.
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data |
Pointer to blob data. |
|
length |
Length of |
|
mode |
Memory mode for |
|
user_data |
Data parameter to pass to |
|
destroy |
Callback to call when |
[nullable] |
Since: 2.8.2
hb_blob_t *
hb_blob_create_from_file (const char *file_name);
Creates a new blob containing the data from the specified binary font file.
Since: 1.7.7
hb_blob_t *
hb_blob_create_from_file_or_fail (const char *file_name);
Creates a new blob containing the data from the specified binary font file.
Since: 2.8.2
hb_blob_t * hb_blob_create_sub_blob (hb_blob_t *parent,unsigned int offset,unsigned int length);
Returns a blob that represents a range of bytes in parent
. The new
blob is always created with HB_MEMORY_MODE_READONLY, meaning that it
will never modify data in the parent blob. The parent data is not
expected to be modified, and will result in undefined behavior if it
is.
Makes parent
immutable.
parent |
Parent blob. |
|
offset |
Start offset of sub-blob within |
|
length |
Length of sub-blob. |
New blob, or the empty blob if something failed or if
length
is zero or offset
is beyond the end of parent
's data. Destroy
with hb_blob_destroy().
Since: 0.9.2
hb_blob_t *
hb_blob_copy_writable_or_fail (hb_blob_t *blob);
Makes a writable copy of blob
.
Since: 1.8.0
void
hb_blob_destroy (hb_blob_t *blob);
Decreases the reference count on blob
, and if it reaches zero, destroys
blob
, freeing all memory, possibly calling the destroy-callback the blob
was created for if it has not been called already.
See TODO:link object types for more information.
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Since: 0.9.2
const char * hb_blob_get_data (hb_blob_t *blob,unsigned int *length);
Fetches the data from a blob.
Since: 0.9.2
char * hb_blob_get_data_writable (hb_blob_t *blob,unsigned int *length);
Tries to make blob data writable (possibly copying it) and return pointer to data.
Fails if blob has been made immutable, or if memory allocation fails.
Since: 0.9.2
hb_blob_t *
hb_blob_get_empty (void);
Returns the singleton empty blob.
See TODO:link object types for more information.
Since: 0.9.2
unsigned int
hb_blob_get_length (hb_blob_t *blob);
Fetches the length of a blob's data.
Since: 0.9.2
void * hb_blob_get_user_data (hb_blob_t *blob,hb_user_data_key_t *key);
Fetches the user data associated with the specified key, attached to the specified font-functions structure.
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Since: 0.9.2
hb_bool_t
hb_blob_is_immutable (hb_blob_t *blob);
Tests whether a blob is immutable.
Since: 0.9.2
void
hb_blob_make_immutable (hb_blob_t *blob);
Makes a blob immutable.
Since: 0.9.2
hb_blob_t *
hb_blob_reference (hb_blob_t *blob);
Increases the reference count on blob
.
See TODO:link object types for more information.
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Since: 0.9.2
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);
Attaches a user-data key/data pair to the specified blob.
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blob |
An hb_blob_t |
|
key |
The user-data key to set |
|
data |
A pointer to the user data to set |
|
destroy |
A callback to call when |
[nullable] |
replace |
Whether to replace an existing data with the same key |
Since: 0.9.2
typedef struct hb_blob_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.
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.