index_hash.c File Reference

Validates Index by using a hash function. More...

#include "common.h"
#include "index.h"
#include "check.h"

Go to the source code of this file.

Classes
struct	lzma_index_hash_info
struct	lzma_index_hash_s

Functions
	LZMA_API (lzma_index_hash *)
	LZMA_API (void)
	LZMA_API (lzma_vli)
	Calculate approximate memory usage of easy encoder. More...
static lzma_ret	hash_append (lzma_index_hash_info *info, lzma_vli unpadded_size, lzma_vli uncompressed_size)
	Updates the sizes and the hash without any validation. More...
	LZMA_API (lzma_ret)

Detailed Description

Validates Index by using a hash function.

Definition in file index_hash.c.

Function Documentation

hash_append()

static lzma_ret hash_append ( lzma_index_hash_info *  info, lzma_vli  unpadded_size, lzma_vli  uncompressed_size  )

static

Updates the sizes and the hash without any validation.

Definition at line 126 of file index_hash.c.

{
    info->blocks_size += vli_ceil4(unpadded_size);
    info->uncompressed_size += uncompressed_size;
    info->index_list_size += lzma_vli_size(unpadded_size)
            + lzma_vli_size(uncompressed_size);
    ++info->count;
 
    const lzma_vli sizes[2] = { unpadded_size, uncompressed_size };
    lzma_check_update(&info->check, LZMA_CHECK_BEST,
            (const uint8_t *)(sizes), sizeof(sizes));
 
    return LZMA_OK;
}

References info(), LZMA_CHECK_BEST, lzma_check_update(), LZMA_OK, uncompressed_size, unpadded_size, and vli_ceil4().

Referenced by LZMA_API().

LZMA_API() [1/4]

LZMA_API

(

lzma_index_hash *

)

Definition at line 72 of file index_hash.c.

{
    if (index_hash == NULL) {
        index_hash = lzma_alloc(sizeof(lzma_index_hash), allocator);
        if (index_hash == NULL)
            return NULL;
    }
 
    index_hash->sequence = SEQ_BLOCK;
    index_hash->blocks.blocks_size = 0;
    index_hash->blocks.uncompressed_size = 0;
    index_hash->blocks.count = 0;
    index_hash->blocks.index_list_size = 0;
    index_hash->records.blocks_size = 0;
    index_hash->records.uncompressed_size = 0;
    index_hash->records.count = 0;
    index_hash->records.index_list_size = 0;
    index_hash->unpadded_size = 0;
    index_hash->uncompressed_size = 0;
    index_hash->pos = 0;
    index_hash->crc32 = 0;
 
    // These cannot fail because LZMA_CHECK_BEST is known to be supported.
    (void)lzma_check_init(&index_hash->blocks.check, LZMA_CHECK_BEST);
    (void)lzma_check_init(&index_hash->records.check, LZMA_CHECK_BEST);
 
    return index_hash;
}

References allocator, lzma_index_hash_s::blocks, lzma_index_hash_info::blocks_size, lzma_index_hash_info::check, lzma_index_hash_info::count, lzma_index_hash_s::crc32, lzma_index_hash_info::index_list_size, lzma_alloc(), LZMA_CHECK_BEST, lzma_check_init(), NULL, lzma_index_hash_s::pos, lzma_index_hash_s::records, lzma_index_hash_s::sequence, lzma_index_hash_info::uncompressed_size, lzma_index_hash_s::uncompressed_size, and lzma_index_hash_s::unpadded_size.

LZMA_API() [2/4]

LZMA_API

(

lzma_ret

)

Definition at line 143 of file index_hash.c.

{
    // Validate the arguments.
    if (index_hash->sequence != SEQ_BLOCK
            || unpadded_size < UNPADDED_SIZE_MIN
            || unpadded_size > UNPADDED_SIZE_MAX
            || uncompressed_size > LZMA_VLI_MAX)
        return LZMA_PROG_ERROR;
 
    // Update the hash.
    return_if_error(hash_append(&index_hash->blocks,
            unpadded_size, uncompressed_size));
 
    // Validate the properties of *info are still in allowed limits.
    if (index_hash->blocks.blocks_size > LZMA_VLI_MAX
            || index_hash->blocks.uncompressed_size > LZMA_VLI_MAX
            || index_size(index_hash->blocks.count,
                    index_hash->blocks.index_list_size)
                > LZMA_BACKWARD_SIZE_MAX
            || index_stream_size(index_hash->blocks.blocks_size,
                    index_hash->blocks.count,
                    index_hash->blocks.index_list_size)
                > LZMA_VLI_MAX)
        return LZMA_DATA_ERROR;
 
    return LZMA_OK;
}

References lzma_index_hash_s::blocks, lzma_index_hash_info::blocks_size, lzma_index_hash_info::count, hash_append(), lzma_index_hash_info::index_list_size, index_size(), index_stream_size(), LZMA_BACKWARD_SIZE_MAX, LZMA_DATA_ERROR, LZMA_OK, LZMA_PROG_ERROR, LZMA_VLI_MAX, return_if_error, lzma_index_hash_s::sequence, lzma_index_hash_info::uncompressed_size, uncompressed_size, unpadded_size, UNPADDED_SIZE_MAX, and UNPADDED_SIZE_MIN.

LZMA_API() [3/4]

LZMA_API

(

uint64_t

)

Calculate approximate memory usage of easy encoder.

Get the total amount of physical memory (RAM) in bytes.

Calculate approximate memory usage of multithreaded .xz encoder.

Calculate approximate decoder memory usage of a preset.

This function is a wrapper for lzma_raw_encoder_memusage().

Parameters

preset

Compression preset (level and possible flags)

Returns

Number of bytes of memory required for the given preset when encoding. If an error occurs, for example due to unsupported preset, UINT64_MAX is returned.

This function is a wrapper for lzma_raw_decoder_memusage().

Parameters

preset

Compression preset (level and possible flags)

Returns

Number of bytes of memory required to decompress a file that was compressed using the given preset. If an error occurs, for example due to unsupported preset, UINT64_MAX is returned.

Since doing the encoding in threaded mode doesn't affect the memory requirements of single-threaded decompressor, you can use lzma_easy_decoder_memusage(options->preset) or lzma_raw_decoder_memusage(options->filters) to calculate the decompressor memory requirements.

Parameters

options

Compression options

Returns

Number of bytes of memory required for encoding with the given options. If an error occurs, for example due to unsupported preset or filter chain, UINT64_MAX is returned.

Calculate approximate memory usage of easy encoder.

Get the uncompressed size of the file.

Get the total size of the file.

Get the total size of the Blocks.

Get the total size of the Stream.

Get the size of the Index field as bytes.

Get the number of Blocks.

Get the number of Streams.

Calculate the memory usage of an existing lzma_index.

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/Blocks stored in the Index(es), and in case of concatenated lzma_indexes, the number of Streams. The size in RAM is almost always significantly bigger than in the encoded form on disk.

This function calculates an approximate amount of memory needed hold the given number of Streams and Blocks in lzma_index structure. This value may vary between CPU architectures and also between liblzma versions if the internal implementation is modified.

This is a shorthand for lzma_index_memusage(lzma_index_stream_count(i), lzma_index_block_count(i)).

This returns the total number of Blocks in lzma_index. To get number of Blocks in individual Streams, use lzma_index_iter.

This is needed to verify the Backward Size field in the Stream Footer.

If multiple lzma_indexes have been combined, this works as if the Blocks were in a single Stream. This is useful if you are going to combine Blocks from multiple Streams into a single new Stream.

This doesn't include the Stream Header, Stream Footer, Stream Padding, or Index fields.

When no lzma_indexes have been combined with lzma_index_cat() and there is no Stream Padding, this function is identical to lzma_index_stream_size(). If multiple lzma_indexes have been combined, this includes also the headers of each separate Stream and the possible Stream Padding fields.

Definition at line 113 of file index_hash.c.

{
    // Get the size of the Index from ->blocks instead of ->records for
    // cases where application wants to know the Index Size before
    // decoding the Index.
    return index_size(index_hash->blocks.count,
            index_hash->blocks.index_list_size);
}

References lzma_index_hash_s::blocks, lzma_index_hash_info::count, lzma_index_hash_info::index_list_size, and index_size().

LZMA_API() [4/4]

LZMA_API

(

void

)

Definition at line 104 of file index_hash.c.

{
    lzma_free(index_hash, allocator);
    return;
}

References allocator, and lzma_free().