More documentation for burn_source

ZeroFourZero
Thomas Schmitt 15 years ago
parent f71c2079ff
commit 771e659a43
  1. 2
      cdrskin/cdrskin_timestamp.h
  2. 49
      libburn/libburn.h

@ -1 +1 @@
#define Cdrskin_timestamP "2007.10.03.112547"
#define Cdrskin_timestamP "2007.10.03.115550"

@ -319,29 +319,56 @@ struct burn_toc_entry
/** Data source interface for tracks.
This allows to use arbitrary program code as provider of track input data.
Objects compliant to this interface are either provided by the application
or by API calls of libburn. If provided by the application then the
functions (*read), (*get_size), (*set_size), (*free_data) MUST be
implemented by the application and attached to the object at creation time.
Function (*read_sub) MUST either be NULL or provided by the application.
or by API calls of libburn: burn_fd_source_new() , burn_file_source_new().
Those calls allow to use any file object as data source. Consider to feed
your data stream asynchronously into a file descriptor and to let libburn
handle the rest.
If you need to implement an own passive data producer by this interface,
then beware: it can do anything and it can spoil everything.
If implemented by the application then the functions (*read), (*get_size),
(*set_size), (*free_data) MUST be implemented and attached to the object
at creation time.
Function (*read_sub) is allowed to be NULL (or MUST be implemented).
burn_source.refcount MUST be handled properly: If not exactly as many
references are freed as have been obtained, then either memory leaks or
corrupted memory are the consequence.
All objects which are referred to by *data must be kept existent until
(*free_data) is called via burn_source_free() by the last referer.
With libburn provided burn_source objects the following rule applies:
Call burn_source_free() exactly once for every source obtained from
libburn API. You MUST NOT otherwise manipulate its refcount.
The following component description applies to application implemented
burn_source objects only. You need not to know it for API provided ones.
*/
struct burn_source {
/** Reference count for the data source. MUST be 1 when a new source
is created. Increment it to take more references for yourself. Use
burn_source_free() to destroy your references to it. */
is created and thus the first reference is handed out. Increment
it to take more references for yourself. Use burn_source_free()
to destroy your references to it. */
int refcount;
/** Read data from the source. Semantics like with read(2), but MUST
either deliver the full buffer as defined by size or MUST deliver
EOF (return -1) at the following call.
EOF (return 0) or failure (return -1) at this call or at the
next following call. I.e. the only incomplete buffer may be the
last one from that source.
libburn will read a single sector by each call to (*read).
The size of a sector depends on BURN_MODE_*. The known range is
2048 to 2352.
*/
int (*read)(struct burn_source *, unsigned char *buffer, int size);
/** Read subchannel data from the source (NULL if lib generated)
WARNING: This is an obscure feature with CD raw write modes.
Unless you checked the libburn code for correctness in that aspect
@ -350,12 +377,14 @@ struct burn_source {
*/
int (*read_sub)(struct burn_source *, unsigned char *buffer, int size);
/** Get the size of the source's data. Return 0 means unpredictable
size. If application provided (*get_size) allows return 0, then
the application MUST provide a fully functional (*set_size).
*/
off_t (*get_size)(struct burn_source *);
/** Program the reply of (*get_size) to a fixed value. It is advised
to implement this by a attribute off_t fixed_size; in *data .
The read() function does not have to take into respect this fake
@ -370,21 +399,24 @@ struct burn_source {
*/
int (*set_size)(struct burn_source *source, off_t size);
/** Clean up the source specific data. This function will be called
once by burn_source_free() when the last referer disposes the
source.
*/
void (*free_data)(struct burn_source *);
/** Next source, for when a source runs dry and padding is disabled
WARNING: This is an obscure feature. Set to NULL at creation and
from then on leave untouched and uninterpreted.
*/
struct burn_source *next;
/** Source specific data. Here the various source classes express their
specific properties and the instance objects store their individual
management data. E.g. a struct like this:
management data. E.g. data may point to a struct like this:
struct app_burn_source
{
struct my_app *app_handle;
@ -393,6 +425,7 @@ struct burn_source {
};
*/
void *data;
};

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