aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/api
diff options
context:
space:
mode:
Diffstat (limited to 'src/liblzma/api')
-rw-r--r--src/liblzma/api/lzma.h4
-rw-r--r--src/liblzma/api/lzma/base.h38
-rw-r--r--src/liblzma/api/lzma/bcj.h4
-rw-r--r--src/liblzma/api/lzma/block.h4
-rw-r--r--src/liblzma/api/lzma/container.h26
-rw-r--r--src/liblzma/api/lzma/filter.h51
-rw-r--r--src/liblzma/api/lzma/hardware.h3
-rw-r--r--src/liblzma/api/lzma/index.h28
-rw-r--r--src/liblzma/api/lzma/index_hash.h2
-rw-r--r--src/liblzma/api/lzma/lzma.h46
-rw-r--r--src/liblzma/api/lzma/stream_flags.h4
-rw-r--r--src/liblzma/api/lzma/vli.h31
12 files changed, 134 insertions, 107 deletions
diff --git a/src/liblzma/api/lzma.h b/src/liblzma/api/lzma.h
index fb593a35..fb874c3e 100644
--- a/src/liblzma/api/lzma.h
+++ b/src/liblzma/api/lzma.h
@@ -60,8 +60,8 @@
*
* Some could argue that liblzma API should provide all the required types,
* for example lzma_uint64, LZMA_UINT64_C(n), and LZMA_UINT64_MAX. This was
- * seen unnecessary mess, since most systems already provide all the necessary
- * types and macros in the standard headers.
+ * seen as an unnecessary mess, since most systems already provide all the
+ * necessary types and macros in the standard headers.
*
* Note that liblzma API still has lzma_bool, because using stdbool.h would
* break C89 and C++ programs on many systems. sizeof(bool) in C99 isn't
diff --git a/src/liblzma/api/lzma/base.h b/src/liblzma/api/lzma/base.h
index 993626a4..fc165ab7 100644
--- a/src/liblzma/api/lzma/base.h
+++ b/src/liblzma/api/lzma/base.h
@@ -281,21 +281,21 @@ typedef enum {
* Using LZMA_SYNC_FLUSH very often can dramatically reduce
* the compression ratio. With some filters (for example,
* LZMA2), fine-tuning the compression options may help
- * mitigate this problem significantly.
+ * mitigate this problem significantly (for example,
+ * match finder with LZMA2).
*
* Decoders don't support LZMA_SYNC_FLUSH.
*/
LZMA_FULL_FLUSH = 2,
/**<
- * \brief Make all the input available at output
+ * \brief Finish encoding of the current Block
*
- * Finish encoding of the current Block. All the input
- * data going to the current Block must have been given
- * to the encoder (the last bytes can still be pending in
- * next_in). Call lzma_code() with LZMA_FULL_FLUSH until
- * it returns LZMA_STREAM_END. Then continue normally with
- * LZMA_RUN or finish the Stream with LZMA_FINISH.
+ * All the input data going to the current Block must have
+ * been given to the encoder (the last bytes can still be
+ * pending in* next_in). Call lzma_code() with LZMA_FULL_FLUSH
+ * until it returns LZMA_STREAM_END. Then continue normally
+ * with LZMA_RUN or finish the Stream with LZMA_FINISH.
*
* This action is currently supported only by Stream encoder
* and easy encoder (which uses Stream encoder). If there is
@@ -306,12 +306,12 @@ typedef enum {
/**<
* \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
- * until it returns LZMA_STREAM_END. Once LZMA_FINISH has
- * been used, the amount of input must no longer be changed
- * by the application.
+ * 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 until it returns
+ * LZMA_STREAM_END. Once LZMA_FINISH has been used,
+ * the amount of input must no longer be changed by
+ * the application.
*
* When decoding, using LZMA_FINISH is optional unless the
* LZMA_CONCATENATED flag was used when the decoder was
@@ -554,11 +554,11 @@ extern LZMA_API(void) lzma_end(lzma_stream *strm) lzma_nothrow;
* this may give misleading information if decoding .xz Streams that have
* multiple Blocks, because each Block can have different memory requirements.
*
- * \return Rough estimate of how much memory is currently allocated
- * for the filter decoders. If no filter chain is currently
- * allocated, some non-zero value is still returned, which is
- * less than or equal to what any filter chain would indicate
- * as its memory requirement.
+ * \return How much memory is currently allocated for the filter
+ * decoders. If no filter chain is currently allocated,
+ * some non-zero value is still returned, which is less than
+ * or equal to what any filter chain would indicate as its
+ * memory requirement.
*
* If this function isn't supported by *strm or some other error
* occurs, zero is returned.
diff --git a/src/liblzma/api/lzma/bcj.h b/src/liblzma/api/lzma/bcj.h
index 82e4a440..8e37538a 100644
--- a/src/liblzma/api/lzma/bcj.h
+++ b/src/liblzma/api/lzma/bcj.h
@@ -31,7 +31,7 @@
#define LZMA_FILTER_IA64 LZMA_VLI_C(0x06)
/**<
- * Filter for IA64 (Itanium) binaries.
+ * Filter for IA-64 (Itanium) binaries.
*/
#define LZMA_FILTER_ARM LZMA_VLI_C(0x07)
@@ -41,7 +41,7 @@
#define LZMA_FILTER_ARMTHUMB LZMA_VLI_C(0x08)
/**<
- * Filter for ARMThumb binaries.
+ * Filter for ARM-Thumb binaries.
*/
#define LZMA_FILTER_SPARC LZMA_VLI_C(0x09)
diff --git a/src/liblzma/api/lzma/block.h b/src/liblzma/api/lzma/block.h
index 8e681ed2..3019bf91 100644
--- a/src/liblzma/api/lzma/block.h
+++ b/src/liblzma/api/lzma/block.h
@@ -318,8 +318,8 @@ extern LZMA_API(lzma_ret) lzma_block_header_encode(
* The size of the Block Header must have already been decoded with
* lzma_block_header_size_decode() macro and stored to block->header_size.
*
- * block->filters must have been allocated, but not necessarily initialized.
- * Possible existing filter options are _not_ freed.
+ * block->filters must have been allocated, but they don't need to be
+ * initialized (possible existing filter options are not freed).
*
* \param block Destination for Block options.
* \param allocator lzma_allocator for custom allocator functions.
diff --git a/src/liblzma/api/lzma/container.h b/src/liblzma/api/lzma/container.h
index 0d907650..83e70b44 100644
--- a/src/liblzma/api/lzma/container.h
+++ b/src/liblzma/api/lzma/container.h
@@ -55,13 +55,13 @@
*
* This flag doesn't affect the memory usage requirements of the decoder (at
* least not significantly). The memory usage of the encoder may be increased
- * a little but only at the lowest preset levels (0-2).
+ * a little but only at the lowest preset levels (0-3).
*/
#define LZMA_PRESET_EXTREME (UINT32_C(1) << 31)
/**
- * \brief Calculate rough memory usage of easy encoder
+ * \brief Calculate approximate memory usage of easy encoder
*
* This function is a wrapper for lzma_raw_encoder_memusage().
*
@@ -72,7 +72,7 @@ extern LZMA_API(uint64_t) lzma_easy_encoder_memusage(uint32_t preset)
/**
- * \brief Calculate rough decoder memory usage of a preset
+ * \brief Calculate approximate decoder memory usage of a preset
*
* This function is a wrapper for lzma_raw_decoder_memusage().
*
@@ -93,16 +93,19 @@ extern LZMA_API(uint64_t) lzma_easy_decoder_memusage(uint32_t preset)
* \param preset Compression preset to use. A preset consist of level
* number and zero or more flags. Usually flags aren't
* used, so preset is simply a number [0, 9] which match
- * the options -0 .. -9 of the xz command line tool.
+ * the options -0 ... -9 of the xz command line tool.
* Additional flags can be be set using bitwise-or with
* the preset level number, e.g. 6 | LZMA_PRESET_EXTREME.
* \param check Integrity check type to use. See check.h for available
- * checks. If you are unsure, use LZMA_CHECK_CRC32.
+ * checks. The xz command line tool defaults to
+ * LZMA_CHECK_CRC64, which is a good choice if you are
+ * unsure. LZMA_CHECK_CRC32 is good too as long as the
+ * uncompressed file is not many gigabytes.
*
* \return - LZMA_OK: Initialization succeeded. Use lzma_code() to
* encode your data.
* - LZMA_MEM_ERROR: Memory allocation failed.
- * - LZMA_OPTIONS_ERROR: The given compression level is not
+ * - LZMA_OPTIONS_ERROR: The given compression preset is not
* supported by this build of liblzma.
* - LZMA_UNSUPPORTED_CHECK: The given check type is not
* supported by this liblzma build.
@@ -310,7 +313,8 @@ extern LZMA_API(lzma_ret) lzma_stream_buffer_encode(
* \brief Initialize .xz Stream decoder
*
* \param strm Pointer to properly prepared lzma_stream
- * \param memlimit Rough memory usage limit as bytes
+ * \param memlimit Memory usage limit as bytes. Use UINT64_MAX
+ * to effectively disable the limiter.
* \param flags Bitwise-or of zero or more of the decoder flags:
* LZMA_TELL_NO_CHECK, LZMA_TELL_UNSUPPORTED_CHECK,
* LZMA_TELL_ANY_CHECK, LZMA_CONCATENATED
@@ -318,6 +322,7 @@ extern LZMA_API(lzma_ret) lzma_stream_buffer_encode(
* \return - LZMA_OK: Initialization was successful.
* - LZMA_MEM_ERROR: Cannot allocate memory.
* - LZMA_OPTIONS_ERROR: Unsupported flags
+ * - LZMA_PROG_ERROR
*/
extern LZMA_API(lzma_ret) lzma_stream_decoder(
lzma_stream *strm, uint64_t memlimit, uint32_t flags)
@@ -332,12 +337,14 @@ extern LZMA_API(lzma_ret) lzma_stream_decoder(
* of the input file has been detected.
*
* \param strm Pointer to properly prepared lzma_stream
- * \param memlimit Rough memory usage limit as bytes
+ * \param memlimit Memory usage limit as bytes. Use UINT64_MAX
+ * to effectively disable the limiter.
* \param flags Bitwise-or of flags, or zero for no flags.
*
* \return - LZMA_OK: Initialization was successful.
* - LZMA_MEM_ERROR: Cannot allocate memory.
* - LZMA_OPTIONS_ERROR: Unsupported flags
+ * - LZMA_PROG_ERROR
*/
extern LZMA_API(lzma_ret) lzma_auto_decoder(
lzma_stream *strm, uint64_t memlimit, uint32_t flags)
@@ -353,6 +360,7 @@ extern LZMA_API(lzma_ret) lzma_auto_decoder(
*
* \return - LZMA_OK
* - LZMA_MEM_ERROR
+ * - LZMA_PROG_ERROR
*/
extern LZMA_API(lzma_ret) lzma_alone_decoder(
lzma_stream *strm, uint64_t memlimit)
@@ -379,7 +387,7 @@ extern LZMA_API(lzma_ret) lzma_alone_decoder(
* won't be read is in[in_size].
* \param out Beginning of the output buffer
* \param out_pos The next byte will be written to out[*out_pos].
- * *out_pos is updated only if encoding succeeds.
+ * *out_pos is updated only if decoding succeeds.
* \param out_size Size of the out buffer; the first byte into
* which no data is written to is out[out_size].
*
diff --git a/src/liblzma/api/lzma/filter.h b/src/liblzma/api/lzma/filter.h
index 038a9339..efd036f7 100644
--- a/src/liblzma/api/lzma/filter.h
+++ b/src/liblzma/api/lzma/filter.h
@@ -1,6 +1,6 @@
/**
* \file lzma/filter.h
- * \brief Common filter related types
+ * \brief Common filter related types and functions
*/
/*
@@ -59,11 +59,6 @@ typedef struct {
* If the filter doesn't need options, set this to NULL. If id is
* set to LZMA_VLI_UNKNOWN, options is ignored, and thus
* doesn't need be initialized.
- *
- * Some filters support changing the options in the middle of
- * the encoding process. These filters store the pointer of the
- * options structure and communicate with the application via
- * modifications of the options structure.
*/
void *options;
@@ -126,15 +121,16 @@ extern LZMA_API(lzma_ret) lzma_filters_copy(const lzma_filter *src,
/**
- * \brief Calculate rough memory requirements for raw encoder
+ * \brief Calculate approximate memory requirements for raw encoder
*
- * Because the calculation is rough, this function can be used to calculate
- * the memory requirements for Block and Stream encoders too.
+ * This function can be used to calculate the memory requirements for
+ * Block and Stream encoders too because Block and Stream encoders don't
+ * need significantly more memory than raw encoder.
*
* \param filters Array of filters terminated with
* .id == LZMA_VLI_UNKNOWN.
*
- * \return Rough number of bytes of memory required for the given
+ * \return Number of bytes of memory required for the given
* filter chain when encoding.
*/
extern LZMA_API(uint64_t) lzma_raw_encoder_memusage(const lzma_filter *filters)
@@ -142,15 +138,16 @@ extern LZMA_API(uint64_t) lzma_raw_encoder_memusage(const lzma_filter *filters)
/**
- * \brief Calculate rough memory requirements for raw decoder
+ * \brief Calculate approximate memory requirements for raw decoder
*
- * Because the calculation is rough, this function can be used to calculate
- * the memory requirements for Block and Stream decoders too.
+ * This function can be used to calculate the memory requirements for
+ * Block and Stream decoders too because Block and Stream decoders don't
+ * need significantly more memory than raw decoder.
*
* \param filters Array of filters terminated with
* .id == LZMA_VLI_UNKNOWN.
*
- * \return Rough number of bytes of memory required for the given
+ * \return Number of bytes of memory required for the given
* filter chain when decoding.
*/
extern LZMA_API(uint64_t) lzma_raw_decoder_memusage(const lzma_filter *filters)
@@ -251,7 +248,8 @@ extern LZMA_API(lzma_ret) lzma_filters_update(
*
* \note There is no function to calculate how big output buffer
* would surely be big enough. (lzma_stream_buffer_bound()
- * works only for lzma_stream_buffer_encode().)
+ * works only for lzma_stream_buffer_encode(); raw encoder
+ * won't necessarily meet that bound.)
*/
extern LZMA_API(lzma_ret) lzma_raw_buffer_encode(
const lzma_filter *filters, lzma_allocator *allocator,
@@ -323,9 +321,10 @@ extern LZMA_API(lzma_ret) lzma_properties_size(
* succeeds but using the same options to initialize the encoder
* will fail.
*
- * \note It is OK to skip calling this function if
- * lzma_properties_size() indicated that the size
- * of the Filter Properties field is zero.
+ * \note If lzma_properties_size() indicated that the size
+ * of the Filter Properties field is zero, calling
+ * lzma_properties_encode() is not required, but it
+ * won't do any harm either.
*/
extern LZMA_API(lzma_ret) lzma_properties_encode(
const lzma_filter *filter, uint8_t *props) lzma_nothrow;
@@ -364,11 +363,11 @@ extern LZMA_API(lzma_ret) lzma_properties_decode(
* memory to hold the encoded Filter Flags.
*
* \param size Pointer to integer to hold the calculated size
- * \param filters Filter ID and associated options whose encoded
+ * \param filter Filter ID and associated options whose encoded
* size is to be calculated
*
* \return - LZMA_OK: *size set successfully. Note that this doesn't
- * guarantee that filters->options is valid, thus
+ * guarantee that filter->options is valid, thus
* lzma_filter_flags_encode() may still fail.
* - LZMA_OPTIONS_ERROR: Unknown Filter ID or unsupported options.
* - LZMA_PROG_ERROR: Invalid options
@@ -377,7 +376,7 @@ extern LZMA_API(lzma_ret) lzma_properties_decode(
* you need to loop over every lzma_filter entry.
*/
extern LZMA_API(lzma_ret) lzma_filter_flags_size(
- uint32_t *size, const lzma_filter *filters)
+ uint32_t *size, const lzma_filter *filter)
lzma_nothrow lzma_attr_warn_unused_result;
@@ -387,7 +386,7 @@ extern LZMA_API(lzma_ret) lzma_filter_flags_size(
* In contrast to some functions, this doesn't allocate the needed buffer.
* This is due to how this function is used internally by liblzma.
*
- * \param filters Filter ID and options to be encoded
+ * \param filter Filter ID and options to be encoded
* \param out Beginning of the output buffer
* \param out_pos out[*out_pos] is the next write position. This
* is updated by the encoder.
@@ -399,7 +398,7 @@ extern LZMA_API(lzma_ret) lzma_filter_flags_size(
* buffer space (you should have checked it with
* lzma_filter_flags_size()).
*/
-extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filters,
+extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filter,
uint8_t *out, size_t *out_pos, size_t out_size)
lzma_nothrow lzma_attr_warn_unused_result;
@@ -407,8 +406,8 @@ extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filters,
/**
* \brief Decode Filter Flags from given buffer
*
- * The decoded result is stored into *filters. filters->options is
- * initialized but the old value is NOT free()d.
+ * The decoded result is stored into *filter. The old value of
+ * filter->options is not free()d.
*
* \return - LZMA_OK
* - LZMA_OPTIONS_ERROR
@@ -416,6 +415,6 @@ extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filters,
* - LZMA_PROG_ERROR
*/
extern LZMA_API(lzma_ret) lzma_filter_flags_decode(
- lzma_filter *filters, lzma_allocator *allocator,
+ lzma_filter *filter, lzma_allocator *allocator,
const uint8_t *in, size_t *in_pos, size_t in_size)
lzma_nothrow lzma_attr_warn_unused_result;
diff --git a/src/liblzma/api/lzma/hardware.h b/src/liblzma/api/lzma/hardware.h
index f44cb602..e7dd03c3 100644
--- a/src/liblzma/api/lzma/hardware.h
+++ b/src/liblzma/api/lzma/hardware.h
@@ -39,8 +39,7 @@
*
* This function may be useful when determining a reasonable memory
* usage limit for decompressing or how much memory it is OK to use
- * for compressing. For example, the default limit used by the xz
- * command line tool is 40 % of RAM.
+ * for compressing.
*
* \return On success, the total amount of physical memory in bytes
* is returned. If the amount of RAM cannot be determined,
diff --git a/src/liblzma/api/lzma/index.h b/src/liblzma/api/lzma/index.h
index 5ea12e35..16bacc28 100644
--- a/src/liblzma/api/lzma/index.h
+++ b/src/liblzma/api/lzma/index.h
@@ -136,6 +136,13 @@ typedef struct {
*
* This offset is relative to the beginning of the lzma_index
* (i.e. usually the beginning of the .xz file).
+ *
+ * When doing random-access reading, it is possible that
+ * the target offset is not exactly at Block boundary. One
+ * will need to compare the target offset against
+ * uncompressed_file_offset or uncompressed_stream_offset,
+ * and possibly decode and throw away some amount of data
+ * before reaching the target offset.
*/
lzma_vli uncompressed_file_offset;
@@ -166,14 +173,8 @@ typedef struct {
* \brief Uncompressed size of this Block
*
* You should pass this to the Block decoder if you will
- * decode this Block.
- *
- * When doing random-access reading, it is possible that
- * the target offset is not exactly at Block boundary. One
- * will need to compare the target offset against
- * uncompressed_file_offset or uncompressed_stream_offset,
- * and possibly decode and throw away some amount of data
- * before reaching the target offset.
+ * decode this Block. It will allow the Block decoder to
+ * validate the uncompressed size.
*/
lzma_vli uncompressed_size;
@@ -181,7 +182,8 @@ typedef struct {
* \brief Unpadded size of this Block
*
* You should pass this to the Block decoder if you will
- * decode this Block.
+ * decode this Block. It will allow the Block decoder to
+ * validate the unpadded size.
*/
lzma_vli unpadded_size;
@@ -583,7 +585,9 @@ extern LZMA_API(lzma_index *) lzma_index_dup(
* \param strm Pointer to properly prepared lzma_stream
* \param i Pointer to lzma_index which should be encoded.
*
- * The only valid action value for lzma_code() is LZMA_RUN.
+ * The valid `action' values for lzma_code() are LZMA_RUN and LZMA_FINISH.
+ * It is enough to use only one of them (you can choose freely; use LZMA_RUN
+ * to support liblzma versions older than 5.0.0).
*
* \return - LZMA_OK: Initialization succeeded, continue with lzma_code().
* - LZMA_MEM_ERROR
@@ -608,7 +612,9 @@ extern LZMA_API(lzma_ret) lzma_index_encoder(
* \param memlimit How much memory the resulting lzma_index is
* allowed to require.
*
- * The only valid action value for lzma_code() is LZMA_RUN.
+ * The valid `action' values for lzma_code() are LZMA_RUN and LZMA_FINISH.
+ * It is enough to use only one of them (you can choose freely; use LZMA_RUN
+ * to support liblzma versions older than 5.0.0).
*
* \return - LZMA_OK: Initialization succeeded, continue with lzma_code().
* - LZMA_MEM_ERROR
diff --git a/src/liblzma/api/lzma/index_hash.h b/src/liblzma/api/lzma/index_hash.h
index 94726e7b..fa2e048d 100644
--- a/src/liblzma/api/lzma/index_hash.h
+++ b/src/liblzma/api/lzma/index_hash.h
@@ -1,6 +1,6 @@
/**
* \file lzma/index_hash.h
- * \brief Validates Index by using a hash function
+ * \brief Validate Index by using a hash function
*
* Hashing makes it possible to use constant amount of memory to validate
* Index of arbitrary size.
diff --git a/src/liblzma/api/lzma/lzma.h b/src/liblzma/api/lzma/lzma.h
index 9d31a5ce..ae577282 100644
--- a/src/liblzma/api/lzma/lzma.h
+++ b/src/liblzma/api/lzma/lzma.h
@@ -46,6 +46,10 @@
* Match finder has major effect on both speed and compression ratio.
* Usually hash chains are faster than binary trees.
*
+ * If you will use LZMA_SYNC_FLUSH often, the hash chains may be a better
+ * choice, because binary trees get much higher compression ratio penalty
+ * with LZMA_SYNC_FLUSH.
+ *
* The memory usage formulas are only rough estimates, which are closest to
* reality when dict_size is a power of two. The formulas are more complex
* in reality, and can also change a little between liblzma versions. Use
@@ -173,6 +177,7 @@ extern LZMA_API(lzma_bool) lzma_mode_is_supported(lzma_mode mode)
* Since LZMA1 and LZMA2 share most of the code, it's simplest to share
* the options structure too. For encoding, all but the reserved variables
* need to be initialized unless specifically mentioned otherwise.
+ * lzma_lzma_preset() can be used to get a good starting point.
*
* For raw decoding, both LZMA1 and LZMA2 need dict_size, preset_dict, and
* preset_dict_size (if preset_dict != NULL). LZMA1 needs also lc, lp, and pb.
@@ -255,7 +260,13 @@ typedef struct {
* eight-bit byte (also known as `literal') are taken into
* account when predicting the bits of the next literal.
*
- * \todo Example
+ * E.g. in typical English text, an upper-case letter is
+ * often followed by a lower-case letter, and a lower-case
+ * letter is usually followed by another lower-case letter.
+ * In the US-ASCII character set, the highest three bits are 010
+ * for upper-case letters and 011 for lower-case letters.
+ * When lc is at least 3, the literal coding can take advantage of
+ * this property in the uncompressed data.
*
* There is a limit that applies to literal context bits and literal
* position bits together: lc + lp <= 4. Without this limit the
@@ -275,12 +286,9 @@ typedef struct {
/**
* \brief Number of literal position bits
*
- * How many of the lowest bits of the current position (number
- * of bytes from the beginning of the uncompressed data) in the
- * uncompressed data is taken into account when predicting the
- * bits of the next literal (a single eight-bit byte).
- *
- * \todo Example
+ * lp affects what kind of alignment in the uncompressed data is
+ * assumed when encoding literals. A literal is a single 8-bit byte.
+ * See pb below for more information about alignment.
*/
uint32_t lp;
# define LZMA_LP_DEFAULT 0
@@ -288,14 +296,22 @@ typedef struct {
/**
* \brief Number of position bits
*
- * How many of the lowest bits of the current position in the
- * uncompressed data is taken into account when estimating
- * probabilities of matches. A match is a sequence of bytes for
- * which a matching sequence is found from the dictionary and
- * thus can be stored as distance-length pair.
+ * pb affects what kind of alignment in the uncompressed data is
+ * assumed in general. The default means four-byte alignment
+ * (2^ pb =2^2=4), which is often a good choice when there's
+ * no better guess.
+ *
+ * When the aligment is known, setting pb accordingly may reduce
+ * the file size a little. E.g. with text files having one-byte
+ * alignment (US-ASCII, ISO-8859-*, UTF-8), setting pb=0 can
+ * improve compression slightly. For UTF-16 text, pb=1 is a good
+ * choice. If the alignment is an odd number like 3 bytes, pb=0
+ * might be the best choice.
*
- * Example: If most of the matches occur at byte positions of
- * 8 * n + 3, that is, 3, 11, 19, ... set pb to 3, because 2**3 == 8.
+ * Even though the assumed alignment can be adjusted with pb and
+ * lp, LZMA1 and LZMA2 still slightly favor 16-byte alignment.
+ * It might be worth taking into account when designing file formats
+ * that are likely to be often compressed with LZMA1 or LZMA2.
*/
uint32_t pb;
# define LZMA_PB_MIN 0
@@ -346,7 +362,7 @@ typedef struct {
*
* Setting depth to zero tells liblzma to use an automatic default
* value, that depends on the selected match finder and nice_len.
- * The default is in the range [10, 200] or so (it may vary between
+ * The default is in the range [4, 200] or so (it may vary between
* liblzma versions).
*
* Using a bigger depth value than the default can increase
diff --git a/src/liblzma/api/lzma/stream_flags.h b/src/liblzma/api/lzma/stream_flags.h
index d255bdda..c6e73037 100644
--- a/src/liblzma/api/lzma/stream_flags.h
+++ b/src/liblzma/api/lzma/stream_flags.h
@@ -148,7 +148,7 @@ extern LZMA_API(lzma_ret) lzma_stream_footer_encode(
/**
* \brief Decode Stream Header
*
- * \param options Stream Header options to be encoded.
+ * \param options Target for the decoded Stream Header options.
* \param in Beginning of the input buffer of
* LZMA_STREAM_HEADER_SIZE bytes.
*
@@ -183,7 +183,7 @@ extern LZMA_API(lzma_ret) lzma_stream_header_decode(
/**
* \brief Decode Stream Footer
*
- * \param options Stream Header options to be encoded.
+ * \param options Target for the decoded Stream Header options.
* \param in Beginning of the input buffer of
* LZMA_STREAM_HEADER_SIZE bytes.
*
diff --git a/src/liblzma/api/lzma/vli.h b/src/liblzma/api/lzma/vli.h
index 57e3d388..9ad13f2e 100644
--- a/src/liblzma/api/lzma/vli.h
+++ b/src/liblzma/api/lzma/vli.h
@@ -29,7 +29,7 @@
/**
- * \brief Maximum supported value of variable-length integer
+ * \brief Maximum supported value of a variable-length integer
*/
#define LZMA_VLI_MAX (UINT64_MAX / 2)
@@ -39,11 +39,10 @@
#define LZMA_VLI_UNKNOWN UINT64_MAX
/**
- * \brief Maximum supported length of variable length integers
+ * \brief Maximum supported encoded length of variable length integers
*/
#define LZMA_VLI_BYTES_MAX 9
-
/**
* \brief VLI constant suffix
*/
@@ -53,19 +52,19 @@
/**
* \brief Variable-length integer type
*
- * This will always be unsigned integer. Valid VLI values are in the range
- * [0, LZMA_VLI_MAX]. Unknown value is indicated with LZMA_VLI_UNKNOWN,
- * which is the maximum value of the underlaying integer type.
+ * Valid VLI values are in the range [0, LZMA_VLI_MAX]. Unknown value is
+ * indicated with LZMA_VLI_UNKNOWN, which is the maximum value of the
+ * underlaying integer type.
*
- * In future, even if lzma_vli is defined to be something other than uint64_t,
- * it is guaranteed that 2 * LZMA_VLI_MAX will not overflow lzma_vli.
- * This simplifies integer overflow detection.
+ * lzma_vli will be uint64_t for the foreseeable future. If a bigger size
+ * is needed in the future, it is guaranteed that 2 * LZMA_VLI_MAX will
+ * not overflow lzma_vli. This simplifies integer overflow detection.
*/
typedef uint64_t lzma_vli;
/**
- * \brief Simple macro to validate variable-length integer
+ * \brief Validate a variable-length integer
*
* This is useful to test that application has given acceptable values
* for example in the uncompressed_size and compressed_size variables.
@@ -88,9 +87,9 @@ typedef uint64_t lzma_vli;
*
* \param vli Integer to be encoded
* \param vli_pos How many VLI-encoded bytes have already been written
- * out. When starting to encode a new integer, *vli_pos
- * must be set to zero. To use single-call encoding,
- * set vli_pos to NULL.
+ * out. When starting to encode a new integer in
+ * multi-call mode, *vli_pos must be set to zero.
+ * To use single-call encoding, set vli_pos to NULL.
* \param out Beginning of the output buffer
* \param out_pos The next byte will be written to out[*out_pos].
* \param out_size Size of the out buffer; the first byte into
@@ -126,9 +125,9 @@ extern LZMA_API(lzma_ret) lzma_vli_encode(lzma_vli vli, size_t *vli_pos,
* initialize it to zero when *vli_pos == 0, so
* application isn't required to initialize *vli.
* \param vli_pos How many bytes have already been decoded. When
- * starting to decode a new integer, *vli_pos must
- * be initialized to zero. To use single-call decoding,
- * set this to NULL.
+ * starting to decode a new integer in multi-call
+ * mode, *vli_pos must be initialized to zero. To
+ * use single-call decoding, set vli_pos to NULL.
* \param in Beginning of the input buffer
* \param in_pos The next byte will be read from in[*in_pos].
* \param in_size Size of the input buffer; the first byte that
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-20 20:26:13 +0000