Handling of .xz Index lists. More...
Data Structures | |
struct | lzma_index_record |
Index Record and its location. More... | |
Typedefs | |
typedef struct lzma_index_s | lzma_index |
Opaque data type to hold the Index. | |
Functions | |
uint64_t | lzma_index_memusage (lzma_vli record_count) lzma_nothrow |
Calculate memory usage for Index with given number of Records. | |
lzma_index * | lzma_index_init (lzma_index *i, lzma_allocator *allocator) lzma_nothrow |
Allocate and initialize a new lzma_index structure. | |
void | lzma_index_end (lzma_index *i, lzma_allocator *allocator) lzma_nothrow |
Deallocate the Index. | |
lzma_ret | lzma_index_append (lzma_index *i, lzma_allocator *allocator, lzma_vli unpadded_size, lzma_vli uncompressed_size) lzma_nothrow lzma_attr_warn_unused_result |
Add a new Record to an Index. | |
lzma_vli | lzma_index_count (const lzma_index *i) lzma_nothrow lzma_attr_pure |
Get the number of Records. | |
lzma_vli | lzma_index_size (const lzma_index *i) lzma_nothrow lzma_attr_pure |
Get the size of the Index field as bytes. | |
lzma_vli | lzma_index_total_size (const lzma_index *i) lzma_nothrow lzma_attr_pure |
Get the total size of the Blocks. | |
lzma_vli | lzma_index_stream_size (const lzma_index *i) lzma_nothrow lzma_attr_pure |
Get the total size of the Stream. | |
lzma_vli | lzma_index_file_size (const lzma_index *i) lzma_nothrow lzma_attr_pure |
Get the total size of the file. | |
lzma_vli | lzma_index_uncompressed_size (const lzma_index *i) lzma_nothrow lzma_attr_pure |
Get the uncompressed size of the Stream. | |
lzma_bool | lzma_index_read (lzma_index *i, lzma_index_record *record) lzma_nothrow lzma_attr_warn_unused_result |
Get the next Record from the Index. | |
void | lzma_index_rewind (lzma_index *i) lzma_nothrow |
Rewind the Index. | |
lzma_bool | lzma_index_locate (lzma_index *i, lzma_index_record *record, lzma_vli target) lzma_nothrow |
Locate a Record. | |
lzma_ret | lzma_index_cat (lzma_index *lzma_restrict dest, lzma_index *lzma_restrict src, lzma_allocator *allocator, lzma_vli padding) lzma_nothrow lzma_attr_warn_unused_result |
Concatenate Indexes of two Streams. | |
lzma_index * | lzma_index_dup (const lzma_index *i, lzma_allocator *allocator) lzma_nothrow lzma_attr_warn_unused_result |
Duplicate an Index list. | |
lzma_bool | lzma_index_equal (const lzma_index *a, const lzma_index *b) lzma_nothrow lzma_attr_pure |
Compare if two Index lists are identical. | |
lzma_ret | lzma_index_encoder (lzma_stream *strm, lzma_index *i) lzma_nothrow lzma_attr_warn_unused_result |
Initialize .xz Index encoder. | |
lzma_ret | lzma_index_decoder (lzma_stream *strm, lzma_index **i, uint64_t memlimit) lzma_nothrow lzma_attr_warn_unused_result |
Initialize .xz Index decoder. | |
lzma_ret | lzma_index_buffer_encode (lzma_index *i, uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow |
Single-call .xz Index encoder. | |
lzma_ret | lzma_index_buffer_decode (lzma_index **i, uint64_t *memlimit, lzma_allocator *allocator, const uint8_t *in, size_t *in_pos, size_t in_size) lzma_nothrow |
Single-call .xz Index decoder. |
Handling of .xz Index lists.
typedef struct lzma_index_s lzma_index |
Opaque data type to hold the Index.
uint64_t lzma_index_memusage | ( | lzma_vli | record_count | ) |
Calculate memory usage for Index with given number of Records.
On disk, the size of the Index field depends on both the number of Records stored and how big values the Records store (due to variable-length integer encoding). When the Index is kept in lzma_index structure, the memory usage depends only on the number of Records stored in the Index. The size in RAM is almost always a lot bigger than in encoded form on disk.
This function calculates an approximate amount of memory needed hold the given number of Records in lzma_index structure. This value may vary between liblzma versions if the internal implementation is modified.
If you want to know how much memory an existing lzma_index structure is using, use lzma_index_memusage(lzma_index_count(i)).
References INDEX_GROUP_SIZE, and LZMA_VLI_MAX.
Referenced by lzma_index_buffer_decode().
lzma_index* lzma_index_init | ( | lzma_index * | i, | |
lzma_allocator * | allocator | |||
) |
Allocate and initialize a new lzma_index structure.
If i is NULL, a new lzma_index structure is allocated, initialized, and a pointer to it returned. If allocation fails, NULL is returned.
If i is non-NULL, it is reinitialized and the same pointer returned. In this case, return value cannot be NULL or a different pointer than the i that was given as an argument.
References lzma_alloc().
Referenced by lzma_stream_buffer_encode().
void lzma_index_end | ( | lzma_index * | i, | |
lzma_allocator * | allocator | |||
) |
Deallocate the Index.
If i is NULL, this does nothing.
Referenced by lzma_index_buffer_decode(), lzma_index_dup(), and lzma_stream_buffer_encode().
lzma_ret lzma_index_append | ( | lzma_index * | i, | |
lzma_allocator * | allocator, | |||
lzma_vli | unpadded_size, | |||
lzma_vli | uncompressed_size | |||
) |
Add a new Record to an Index.
i | Pointer to a lzma_index structure | |
allocator | Pointer to lzma_allocator, or NULL to use malloc() | |
unpadded_size | Unpadded Size of a Block. This can be calculated with lzma_block_unpadded_size() after encoding or decoding the Block. | |
uncompressed_size | Uncompressed Size of a Block. This can be taken directly from lzma_block structure after encoding or decoding the Block. |
Appending a new Record does not affect the read position.
References index_append_real(), LZMA_DATA_ERROR, lzma_index_file_size(), lzma_index_size(), LZMA_OK, LZMA_PROG_ERROR, LZMA_VLI_MAX, and lzma_vli_size().
Referenced by lzma_stream_buffer_encode().
lzma_vli lzma_index_count | ( | const lzma_index * | i | ) |
Get the number of Records.
lzma_vli lzma_index_size | ( | const lzma_index * | i | ) |
Get the size of the Index field as bytes.
This is needed to verify the Backward Size field in the Stream Footer.
Referenced by lzma_index_append(), lzma_index_buffer_encode(), and lzma_stream_buffer_encode().
lzma_vli lzma_index_total_size | ( | const lzma_index * | i | ) |
Get the total size of the Blocks.
This doesn't include the Stream Header, Stream Footer, Stream Padding, or Index fields.
lzma_vli lzma_index_stream_size | ( | const lzma_index * | i | ) |
Get the total size of the Stream.
If multiple Indexes have been combined, this works as if the Blocks were in a single Stream.
References LZMA_STREAM_HEADER_SIZE.
lzma_vli lzma_index_file_size | ( | const lzma_index * | i | ) |
Get the total size of the file.
When no Indexes have been combined with lzma_index_cat(), this function is identical to lzma_index_stream_size(). If multiple Indexes have been combined, this includes also the headers of each separate Stream and the possible Stream Padding fields.
References LZMA_STREAM_HEADER_SIZE.
Referenced by lzma_index_append().
lzma_vli lzma_index_uncompressed_size | ( | const lzma_index * | i | ) |
Get the uncompressed size of the Stream.
lzma_bool lzma_index_read | ( | lzma_index * | i, | |
lzma_index_record * | record | |||
) |
Get the next Record from the Index.
References init_current(), next_group(), and set_info().
void lzma_index_rewind | ( | lzma_index * | i | ) |
Rewind the Index.
Rewind the Index so that next call to lzma_index_read() will return the first Record.
lzma_bool lzma_index_locate | ( | lzma_index * | i, | |
lzma_index_record * | record, | |||
lzma_vli | target | |||
) |
Locate a Record.
When the Index is available, it is possible to do random-access reading with granularity of Block size.
i | Pointer to lzma_index structure | |
record | Pointer to a structure to hold the search results | |
target | Uncompressed target offset which the caller would like to locate from the Stream |
If the target is smaller than the uncompressed size of the Stream (can be checked with lzma_index_uncompressed_size()):
If target is greater than the uncompressed size of the Stream, *record and the read position are not modified, and this function returns true.
References init_current(), next_group(), previous_group(), and set_info().
lzma_ret lzma_index_cat | ( | lzma_index *lzma_restrict | dest, | |
lzma_index *lzma_restrict | src, | |||
lzma_allocator * | allocator, | |||
lzma_vli | padding | |||
) |
Concatenate Indexes of two Streams.
Concatenating Indexes is useful when doing random-access reading in multi-Stream .xz file, or when combining multiple Streams into single Stream.
dest | Destination Index after which src is appended | |
src | Source Index. If this function succeeds, the memory allocated for src is freed or moved to be part of dest. | |
allocator | Custom memory allocator; can be NULL to use malloc() and free(). | |
padding | Size of the Stream Padding field between Streams. This must be a multiple of four. |
lzma_index* lzma_index_dup | ( | const lzma_index * | i, | |
lzma_allocator * | allocator | |||
) |
Duplicate an Index list.
Makes an identical copy of the Index. Also the read position is copied.
References lzma_index_s::current, lzma_index_s::group, lzma_index_s::head, lzma_index_group_s::last, lzma_alloc(), lzma_index_end(), lzma_index_group_s::next, lzma_index_group_s::paddings, lzma_index_group_s::prev, lzma_index_s::tail, lzma_index_group_s::uncompressed_sums, and lzma_index_group_s::unpadded_sums.
lzma_bool lzma_index_equal | ( | const lzma_index * | a, | |
const lzma_index * | b | |||
) |
Compare if two Index lists are identical.
Read positions are not compared.
References lzma_index_group_s::last, lzma_index_group_s::next, lzma_index_group_s::paddings, lzma_index_group_s::uncompressed_sums, and lzma_index_group_s::unpadded_sums.
lzma_ret lzma_index_encoder | ( | lzma_stream * | strm, | |
lzma_index * | i | |||
) |
Initialize .xz Index encoder.
strm | Pointer to properly prepared lzma_stream | |
i | Pointer to lzma_index which should be encoded. The read position will be at the end of the Index after lzma_code() has returned LZMA_STREAM_END. |
The only valid action value for lzma_code() is LZMA_RUN.
References lzma_next_strm_init, LZMA_OK, and LZMA_RUN.
lzma_ret lzma_index_decoder | ( | lzma_stream * | strm, | |
lzma_index ** | i, | |||
uint64_t | memlimit | |||
) |
Initialize .xz Index decoder.
strm | Pointer to properly prepared lzma_stream | |
i | Pointer to a pointer that will be made to point to the final decoded Index once lzma_code() has returned LZMA_STREAM_END. That is, lzma_index_decoder() always takes care of allocating a new lzma_index structure, and *i doesn't need to be initialized by the caller. | |
memlimit | How much memory the resulting Index is allowed to require. |
The only valid action value for lzma_code() is LZMA_RUN.
References lzma_next_strm_init, LZMA_OK, and LZMA_RUN.
lzma_ret lzma_index_buffer_encode | ( | lzma_index * | i, | |
uint8_t * | out, | |||
size_t * | out_pos, | |||
size_t | out_size | |||
) |
Single-call .xz Index encoder.
i | Index to be encoded. The read position will be at the end of the Index if encoding succeeds, or at unspecified position in case an error occurs. | |
out | Beginning of the output buffer | |
out_pos | The next byte will be written to out[*out_pos]. *out_pos is updated only if encoding succeeds. | |
out_size | Size of the out buffer; the first byte into which no data is written to is out[out_size]. |
References LZMA_BUF_ERROR, lzma_index_size(), LZMA_OK, LZMA_PROG_ERROR, LZMA_RUN, and LZMA_STREAM_END.
Referenced by lzma_stream_buffer_encode().
lzma_ret lzma_index_buffer_decode | ( | lzma_index ** | i, | |
uint64_t * | memlimit, | |||
lzma_allocator * | allocator, | |||
const uint8_t * | in, | |||
size_t * | in_pos, | |||
size_t | in_size | |||
) |
Single-call .xz Index decoder.
i | Pointer to a pointer that will be made to point to the final decoded Index if decoding is successful. That is, lzma_index_buffer_decode() always takes care of allocating a new lzma_index structure, and *i doesn't need to be initialized by the caller. | |
memlimit | Pointer to how much memory the resulting Index is allowed to require. The value pointed by this pointer is modified if and only if LZMA_MEMLIMIT_ERROR is returned. | |
allocator | Pointer to lzma_allocator, or NULL to use malloc() | |
in | Beginning of the input buffer | |
in_pos | The next byte will be read from in[*in_pos]. *in_pos is updated only if decoding succeeds. | |
in_size | Size of the input buffer; the first byte that won't be read is in[in_size]. |
References lzma_coder_s::count, LZMA_DATA_ERROR, lzma_index_end(), lzma_index_memusage(), LZMA_OK, LZMA_PROG_ERROR, LZMA_RUN, LZMA_STREAM_END, and return_if_error.