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// SPDX-License-Identifier: 0BSD
///////////////////////////////////////////////////////////////////////////////
//
/// \file known_sizes.c
/// \brief 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.
//
// Author: Lasse Collin
//
///////////////////////////////////////////////////////////////////////////////
#include "sysdefs.h"
#include "lzma.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/unistd.h>
#include <stdio.h>
// Support file sizes up to 1 MiB. We use this for output space too, so files
// close to 1 MiB had better compress at least a little or we have a buffer
// overflow.
#define BUFFER_SIZE (1U << 20)
int
main(void)
{
// 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;
}
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