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This commit is contained in:
Lasse Collin 2008-09-06 23:42:50 +03:00
parent 0a31ed9d5e
commit 32fe5fa541
5 changed files with 65 additions and 39 deletions

View file

@ -243,10 +243,19 @@ typedef enum {
/**
* \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
@ -262,21 +271,37 @@ typedef enum {
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
*
* \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.
* 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.
*
* 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
@ -291,6 +316,11 @@ typedef enum {
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
@ -402,35 +432,30 @@ typedef struct lzma_internal_s lzma_internal;
* - 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. */

View file

@ -1,5 +1,5 @@
/**
* \file lzma/FIXME.h
* \file lzma/container.h
* \brief File formats
*
* \author Copyright (C) 1999-2008 Igor Pavlov
@ -255,7 +255,9 @@ extern lzma_ret lzma_auto_decoder(
/**
* \brief Initializes decoder for LZMA_Alone file
*
* The LZMA_Alone decoder supports LZMA_SYNC_FLUSH. FIXME
* Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH.
* There is no need to use LZMA_FINISH, but allowing it may simplify
* certain types of applications.
*
* \return - LZMA_OK
* - LZMA_MEM_ERROR

View file

@ -143,8 +143,7 @@ fill_window(lzma_coder *coder, lzma_allocator *allocator, const uint8_t *in,
coder->mf.read_pos -= pending;
// Call the skip function directly instead of using
// lz_dict_skip(), since we don't want to touch
// mf->read_ahead.
// mf_skip(), since we don't want to touch mf->read_ahead.
coder->mf.skip(&coder->mf, pending);
}

View file

@ -95,12 +95,12 @@ struct lzma_mf_s {
//////////////////
/// 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;
@ -117,7 +117,7 @@ struct lzma_mf_s {
/// 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
@ -177,10 +177,10 @@ typedef struct {
// 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.
//

View file

@ -244,7 +244,7 @@ do { \
///
/// \param len_limit Don't look for matches longer than len_limit.
/// \param pos lzma_mf.read_pos + lzma_mf.offset
/// \param cur Pointer to current byte (lzma_dict_ptr(mf))
/// \param cur Pointer to current byte (mf_ptr(mf))
/// \param cur_match Start position of the current match candidate
/// \param loops Maximum length of the hash chain
/// \param son lzma_mf.son (contains the hash chain)