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///////////////////////////////////////////////////////////////////////////////
//
/// \file block_encoder.c
/// \brief Encodes .xz Blocks
//
// Author: Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include "block_encoder.h"
#include "filter_encoder.h"
#include "check.h"
typedef struct {
/// The filters in the chain; initialized with lzma_raw_decoder_init().
lzma_next_coder next;
/// Encoding options; we also write Unpadded Size, Compressed Size,
/// and Uncompressed Size back to this structure when the encoding
/// has been finished.
lzma_block *block;
enum {
SEQ_CODE,
SEQ_PADDING,
SEQ_CHECK,
} sequence;
/// Compressed Size calculated while encoding
lzma_vli compressed_size;
/// Uncompressed Size calculated while encoding
lzma_vli uncompressed_size;
/// Position in the Check field
size_t pos;
/// Check of the uncompressed data
lzma_check_state check;
} lzma_block_coder;
static lzma_ret
block_encode(void *coder_ptr, const lzma_allocator *allocator,
const uint8_t *restrict in, size_t *restrict in_pos,
size_t in_size, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size, lzma_action action)
{
lzma_block_coder *coder = coder_ptr;
// Check that our amount of input stays in proper limits.
if (LZMA_VLI_MAX - coder->uncompressed_size < in_size - *in_pos)
return LZMA_DATA_ERROR;
switch (coder->sequence) {
case SEQ_CODE: {
const size_t in_start = *in_pos;
const size_t out_start = *out_pos;
const lzma_ret ret = coder->next.code(coder->next.coder,
allocator, in, in_pos, in_size,
out, out_pos, out_size, action);
const size_t in_used = *in_pos - in_start;
const size_t out_used = *out_pos - out_start;
if (COMPRESSED_SIZE_MAX - coder->compressed_size < out_used)
return LZMA_DATA_ERROR;
coder->compressed_size += out_used;
// No need to check for overflow because we have already
// checked it at the beginning of this function.
coder->uncompressed_size += in_used;
// Call lzma_check_update() only if input was consumed. This
// avoids null pointer + 0 (undefined behavior) when in == 0.
if (in_used > 0)
lzma_check_update(&coder->check, coder->block->check,
in + in_start, in_used);
if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
return ret;
assert(*in_pos == in_size);
assert(action == LZMA_FINISH);
// Copy the values into coder->block. The caller
// may use this information to construct Index.
coder->block->compressed_size = coder->compressed_size;
coder->block->uncompressed_size = coder->uncompressed_size;
coder->sequence = SEQ_PADDING;
}
// Fall through
case SEQ_PADDING:
// Pad Compressed Data to a multiple of four bytes. We can
// use coder->compressed_size for this since we don't need
// it for anything else anymore.
while (coder->compressed_size & 3) {
if (*out_pos >= out_size)
return LZMA_OK;
out[*out_pos] = 0x00;
++*out_pos;
++coder->compressed_size;
}
if (coder->block->check == LZMA_CHECK_NONE)
return LZMA_STREAM_END;
lzma_check_finish(&coder->check, coder->block->check);
coder->sequence = SEQ_CHECK;
// Fall through
case SEQ_CHECK: {
const size_t check_size = lzma_check_size(coder->block->check);
lzma_bufcpy(coder->check.buffer.u8, &coder->pos, check_size,
out, out_pos, out_size);
if (coder->pos < check_size)
return LZMA_OK;
memcpy(coder->block->raw_check, coder->check.buffer.u8,
check_size);
return LZMA_STREAM_END;
}
}
return LZMA_PROG_ERROR;
}
static void
block_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
{
lzma_block_coder *coder = coder_ptr;
lzma_next_end(&coder->next, allocator);
lzma_free(coder, allocator);
return;
}
static lzma_ret
block_encoder_update(void *coder_ptr, const lzma_allocator *allocator,
const lzma_filter *filters lzma_attribute((__unused__)),
const lzma_filter *reversed_filters)
{
lzma_block_coder *coder = coder_ptr;
if (coder->sequence != SEQ_CODE)
return LZMA_PROG_ERROR;
return lzma_next_filter_update(
&coder->next, allocator, reversed_filters);
}
extern lzma_ret
lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
lzma_block *block)
{
lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
if (block == NULL)
return LZMA_PROG_ERROR;
// The contents of the structure may depend on the version so
// check the version first.
if (block->version > 1)
return LZMA_OPTIONS_ERROR;
// If the Check ID is not supported, we cannot calculate the check and
// thus not create a proper Block.
if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
return LZMA_PROG_ERROR;
if (!lzma_check_is_supported(block->check))
return LZMA_UNSUPPORTED_CHECK;
// Allocate and initialize *next->coder if needed.
lzma_block_coder *coder = next->coder;
if (coder == NULL) {
coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
if (coder == NULL)
return LZMA_MEM_ERROR;
next->coder = coder;
next->code = &block_encode;
next->end = &block_encoder_end;
next->update = &block_encoder_update;
coder->next = LZMA_NEXT_CODER_INIT;
}
// Basic initializations
coder->sequence = SEQ_CODE;
coder->block = block;
coder->compressed_size = 0;
coder->uncompressed_size = 0;
coder->pos = 0;
// Initialize the check
lzma_check_init(&coder->check, block->check);
// Initialize the requested filters.
return lzma_raw_encoder_init(&coder->next, allocator, block->filters);
}
extern LZMA_API(lzma_ret)
lzma_block_encoder(lzma_stream *strm, lzma_block *block)
{
lzma_next_strm_init(lzma_block_encoder_init, strm, block);
strm->internal->supported_actions[LZMA_RUN] = true;
strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
strm->internal->supported_actions[LZMA_FINISH] = true;
return LZMA_OK;
}
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