/**
* \brief The `action' argument for lzma_code()
+ *
+ * After the first use of LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, or LZMA_FINISH,
+ * the same `action' must is used until lzma_code() returns LZMA_STREAM_END.
+ * Also, the amount of input (that is, strm->avail_in) must not be modified
+ * by the application until lzma_code() returns LZMA_STREAM_END. Changing the
+ * `action' or modifying the amount of input will make lzma_code() return
+ * LZMA_PROG_ERROR.
*/
typedef enum {
LZMA_RUN = 0,
/**<
+ * \brief Continue coding
+ *
* Encoder: Encode as much input as possible. Some internal
* buffering will probably be done (depends on the filter
* chain in use), which causes latency: the input used won't
LZMA_SYNC_FLUSH = 1,
/**<
- * Encoder: Makes all the data given to liblzma via next_in
- * available in next_out without resetting the filters. Call
- * lzma_code() with LZMA_SYNC_FLUSH until it returns
- * LZMA_STREAM_END. Then continue encoding normally.
+ * \brief Make all the input available at output
+ *
+ * Normally the encoder introduces some latency.
+ * LZMA_SYNC_FLUSH forces all the buffered data to be
+ * available at output without resetting the internal
+ * state of the encoder. This way it is possible to use
+ * compressed stream for example for communication over
+ * network.
+ *
+ * Only some filters support LZMA_SYNC_FLUSH. Trying to use
+ * LZMA_SYNC_FLUSH with filters that don't support it will
+ * make lzma_code() return LZMA_HEADER_ERROR. For example,
+ * LZMA1 doesn't support LZMA_SYNC_FLUSH but LZMA2 does.
*
- * \note Synchronous flushing is supported only by
- * some filters. Using LZMA_SYNC_FLUSH with
- * which such filters will make lzma_code()
- * return LZMA_HEADER_ERROR.
+ * Using LZMA_SYNC_FLUSH very often can dramatically reduce
+ * the compression ratio. With some filters (for example,
+ * LZMA2), finetuning the compression options may help
+ * mitigate this problem significantly.
*
* Decoders don't support LZMA_SYNC_FLUSH.
*/
LZMA_FULL_FLUSH = 2,
/**<
+ * \brief Make all the input available at output
+ *
+ * This is like LZMA_SYNC_FLUSH except that this resets the
+ * internal encoder state.
+ *
+ *
+ *
* Finishes encoding of the current Data Block. All the input
* data going to the current Data Block must have been given
* to the encoder (the last bytes can still be pending in
LZMA_FINISH = 3
/**<
+ * \brief Finish the coding operation
+ *
+ *
+ *
+ *
* Finishes the coding operation. All the input data must
* have been given to the encoder (the last bytes can still
* be pending in next_in). Call lzma_code() with LZMA_FINISH
* - defining custom memory hander functions; and
* - holding a pointer to coder-specific internal data structures.
*
- * When a new lzma_stream structure is allocated (either as automatic variable
- * on stack or dynamically with malloc()), the new lzma_stream structure must
- * be initialized to LZMA_STREAM_INIT.
+ * The typical usage
*
- * Before initializing a coder (for example, with lzma_stream_decoder()),
+ * - After allocating lzma_stream (on stack or with malloc()), it must be
+ * initialized to LZMA_STREAM_INIT (see LZMA_STREAM_INIT for details).
*
+ * - Initialize a coder to the lzma_stream, for example by using
+ * lzma_easy_encoder() or lzma_auto_decoder(). In contrast to zlib,
+ * strm->next_in and strm->next_out are ignored by all initialization
+ * functions, thus it is safe to not initialize them yet. The
+ * initialization functions always set strm->total_in and strm->total_out
+ * to zero.
*
- * Before calling any of the lzma_*_init() functions the first time,
- * the application must reset lzma_stream to LZMA_STREAM_INIT. The
- * lzma_*_init() function will verify the options, allocate internal
- * data structures and store pointer to them into `internal'. Finally
- * total_in and total_out are reset to zero. In contrast to zlib,
- * next_in and avail_in are ignored by the initialization functions.
+ * - Use lzma_code() to do the actual work.
*
- * The actual coding is done with the lzma_code() function. Application
- * must update next_in, avail_in, next_out, and avail_out between
- * calls to lzma_decode() just like with zlib.
+ * - Once the coding has been finished, the existing lzma_stream can be
+ * reused. It is OK to reuse lzma_stream with different initialization
+ * function without calling lzma_end() first. Old allocations are
+ * automatically freed.
*
- * In contrast to zlib, even the decoder requires that there always
- * is at least one byte space in next_out; if avail_out == 0,
- * LZMA_BUF_ERROR is returned immediatelly. This shouldn't be a problem
- * for most applications that already use zlib, but it's still worth
- * checking your application.
+ * - Finally, use lzma_end() to free the allocated memory.
*
* Application may modify values of total_in and total_out as it wants.
* They are updated by liblzma to match the amount of data read and
* written, but liblzma doesn't use the values internally.
- *
- * Application must not touch the `internal' pointer.
*/
typedef struct {
const uint8_t *next_in; /**< Pointer to the next input byte. */
//////////////////
/// Find matches. Returns the number of distance-length pairs written
- /// to the matches array. This is called only via lzma_mf_find.
+ /// to the matches array. This is called only via lzma_mf_find().
uint32_t (*find)(lzma_mf *mf, lzma_match *matches);
/// Skips num bytes. This is like find() but doesn't make the
/// distance-length pairs available, thus being a little faster.
- /// This is called only via mf_skip function.
+ /// This is called only via mf_skip().
void (*skip)(lzma_mf *mf, uint32_t num);
uint32_t *hash;
/// Maximum length of a match supported by the LZ-based encoder.
/// If the longest match found by the match finder is find_len_max,
- /// lz_dict_find() tries to expand it up to match_len_max bytes.
+ /// mf_find() tries to expand it up to match_len_max bytes.
uint32_t match_len_max;
/// When running out of input, binary tree match finders need to know
// also take longer.
//
// A single encoder loop in the LZ-based encoder may call the match finder
-// (lz_dict_find() or lz_dict_skip()) at maximum of after_size times.
-// In other words, a single encoder loop may advance lz_dict.read_pos at
+// (mf_find() or mf_skip()) at maximum of after_size times.
+// In other words, a single encoder loop may advance lzma_mf.read_pos at
// maximum of after_size times. Since matches are looked up to
-// lz_dict.buffer[lz_dict.read_pos + match_len_max - 1], the total
+// lzma_mf.buffer[lzma_mf.read_pos + match_len_max - 1], the total
// amount of extra buffer needed after dictionary_size becomes
// after_size + match_len_max.
//
projects / platform / upstream / xz.git / commitdiff