known_sizes.c File Reference

Encodes .lzma Stream with sizes known in Block Header. More...

#include "sysdefs.h"
#include "lzma.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/unistd.h>
#include <stdio.h>

Go to the source code of this file.

Macros
#define	BUFFER_SIZE   (1U << 20)

Functions
int	main (void)

Detailed Description

Encodes .lzma Stream with sizes known in Block Header.

The input file is encoded in RAM, and the known Compressed Size and/or Uncompressed Size values are stored in the Block Header. As of writing there's no such Stream encoder in liblzma.

Definition in file known_sizes.c.

Macro Definition Documentation

BUFFER_SIZE

#define BUFFER_SIZE   (1U << 20)

Definition at line 28 of file known_sizes.c.

Function Documentation

main()

int main

(

void

)

Definition at line 32 of file known_sizes.c.

{
    // Allocate the buffers.
    uint8_t *in = malloc(BUFFER_SIZE);
    uint8_t *out = malloc(BUFFER_SIZE);
    if (in == NULL || out == NULL)
        return 1;
 
    // Fill the input buffer.
    const size_t in_size = fread(in, 1, BUFFER_SIZE, stdin);
 
    // Filter setup
    lzma_options_lzma opt_lzma;
    if (lzma_lzma_preset(&opt_lzma, 1))
        return 1;
 
    lzma_filter filters[] = {
        {
            .id = LZMA_FILTER_LZMA2,
            .options = &opt_lzma
        },
        {
            .id = LZMA_VLI_UNKNOWN
        }
    };
 
    lzma_block block = {
        .check = LZMA_CHECK_CRC32,
        .compressed_size = BUFFER_SIZE, // Worst case reserve
        .uncompressed_size = in_size,
        .filters = filters,
    };
 
    lzma_stream strm = LZMA_STREAM_INIT;
    if (lzma_block_encoder(&strm, &block) != LZMA_OK)
        return 1;
 
    // Reserve space for Stream Header and Block Header. We need to
    // calculate the size of the Block Header first.
    if (lzma_block_header_size(&block) != LZMA_OK)
        return 1;
 
    size_t out_size = LZMA_STREAM_HEADER_SIZE + block.header_size;
 
    strm.next_in = in;
    strm.avail_in = in_size;
    strm.next_out = out + out_size;
    strm.avail_out = BUFFER_SIZE - out_size;
 
    if (lzma_code(&strm, LZMA_FINISH) != LZMA_STREAM_END)
        return 1;
 
    out_size += strm.total_out;
 
    if (lzma_block_header_encode(&block, out + LZMA_STREAM_HEADER_SIZE)
            != LZMA_OK)
        return 1;
 
    lzma_index *idx = lzma_index_init(NULL);
    if (idx == NULL)
        return 1;
 
    if (lzma_index_append(idx, NULL, block.header_size + strm.total_out,
            strm.total_in) != LZMA_OK)
        return 1;
 
    if (lzma_index_encoder(&strm, idx) != LZMA_OK)
        return 1;
 
    if (lzma_code(&strm, LZMA_RUN) != LZMA_STREAM_END)
        return 1;
 
    out_size += strm.total_out;
 
    lzma_end(&strm);
 
    lzma_index_end(idx, NULL);
 
    // Encode the Stream Header and Stream Footer. backwards_size is
    // needed only for the Stream Footer.
    lzma_stream_flags sf = {
        .backward_size = strm.total_out,
        .check = block.check,
    };
 
    if (lzma_stream_header_encode(&sf, out) != LZMA_OK)
        return 1;
 
    if (lzma_stream_footer_encode(&sf, out + out_size) != LZMA_OK)
        return 1;
 
    out_size += LZMA_STREAM_HEADER_SIZE;
 
    // Write out the file.
    fwrite(out, 1, out_size, stdout);
 
    return 0;
}

References lzma_stream::avail_in, lzma_stream::avail_out, lzma_stream_flags::backward_size, BUFFER_SIZE, lzma_block::check, filters, lzma_block::header_size, lzma_filter::id, setup::idx, in, in_size, LZMA_CHECK_CRC32, LZMA_FILTER_LZMA2, LZMA_FINISH, LZMA_OK, LZMA_RUN, LZMA_STREAM_END, LZMA_STREAM_HEADER_SIZE, LZMA_STREAM_INIT, LZMA_VLI_UNKNOWN, malloc(), lzma_stream::next_in, lzma_stream::next_out, NULL, opt_lzma, out, strm, lzma_stream::total_in, and lzma_stream::total_out.