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DEFINITIONS
This source file includes following definitions.
- block_encoder_init
- stream_encode
- stream_encoder_end
- stream_encoder_update
- lzma_stream_encoder_init
- LZMA_API
///////////////////////////////////////////////////////////////////////////////
//
/// \file stream_encoder.c
/// \brief Encodes .xz Streams
//
// Author: Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include "stream_encoder.h"
#include "block_encoder.h"
#include "index_encoder.h"
struct lzma_coder_s {
enum {
SEQ_STREAM_HEADER,
SEQ_BLOCK_INIT,
SEQ_BLOCK_HEADER,
SEQ_BLOCK_ENCODE,
SEQ_INDEX_ENCODE,
SEQ_STREAM_FOOTER,
} sequence;
/// True if Block encoder has been initialized by
/// lzma_stream_encoder_init() or stream_encoder_update()
/// and thus doesn't need to be initialized in stream_encode().
bool block_encoder_is_initialized;
/// Block
lzma_next_coder block_encoder;
/// Options for the Block encoder
lzma_block block_options;
/// The filter chain currently in use
lzma_filter filters[LZMA_FILTERS_MAX + 1];
/// Index encoder. This is separate from Block encoder, because this
/// doesn't take much memory, and when encoding multiple Streams
/// with the same encoding options we avoid reallocating memory.
lzma_next_coder index_encoder;
/// Index to hold sizes of the Blocks
lzma_index *index;
/// Read position in buffer[]
size_t buffer_pos;
/// Total number of bytes in buffer[]
size_t buffer_size;
/// Buffer to hold Stream Header, Block Header, and Stream Footer.
/// Block Header has biggest maximum size.
uint8_t buffer[LZMA_BLOCK_HEADER_SIZE_MAX];
};
static lzma_ret
block_encoder_init(lzma_coder *coder, lzma_allocator *allocator)
{
// Prepare the Block options. Even though Block encoder doesn't need
// compressed_size, uncompressed_size, and header_size to be
// initialized, it is a good idea to do it here, because this way
// we catch if someone gave us Filter ID that cannot be used in
// Blocks/Streams.
coder->block_options.compressed_size = LZMA_VLI_UNKNOWN;
coder->block_options.uncompressed_size = LZMA_VLI_UNKNOWN;
return_if_error(lzma_block_header_size(&coder->block_options));
// Initialize the actual Block encoder.
return lzma_block_encoder_init(&coder->block_encoder, allocator,
&coder->block_options);
}
static lzma_ret
stream_encode(lzma_coder *coder, 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)
{
// Main loop
while (*out_pos < out_size)
switch (coder->sequence) {
case SEQ_STREAM_HEADER:
case SEQ_BLOCK_HEADER:
case SEQ_STREAM_FOOTER:
lzma_bufcpy(coder->buffer, &coder->buffer_pos,
coder->buffer_size, out, out_pos, out_size);
if (coder->buffer_pos < coder->buffer_size)
return LZMA_OK;
if (coder->sequence == SEQ_STREAM_FOOTER)
return LZMA_STREAM_END;
coder->buffer_pos = 0;
++coder->sequence;
break;
case SEQ_BLOCK_INIT: {
if (*in_pos == in_size) {
// If we are requested to flush or finish the current
// Block, return LZMA_STREAM_END immediately since
// there's nothing to do.
if (action != LZMA_FINISH)
return action == LZMA_RUN
? LZMA_OK : LZMA_STREAM_END;
// The application had used LZMA_FULL_FLUSH to finish
// the previous Block, but now wants to finish without
// encoding new data, or it is simply creating an
// empty Stream with no Blocks.
//
// Initialize the Index encoder, and continue to
// actually encoding the Index.
return_if_error(lzma_index_encoder_init(
&coder->index_encoder, allocator,
coder->index));
coder->sequence = SEQ_INDEX_ENCODE;
break;
}
// Initialize the Block encoder unless it was already
// initialized by lzma_stream_encoder_init() or
// stream_encoder_update().
if (!coder->block_encoder_is_initialized)
return_if_error(block_encoder_init(coder, allocator));
// Make it false so that we don't skip the initialization
// with the next Block.
coder->block_encoder_is_initialized = false;
// Encode the Block Header. This shouldn't fail since we have
// already initialized the Block encoder.
if (lzma_block_header_encode(&coder->block_options,
coder->buffer) != LZMA_OK)
return LZMA_PROG_ERROR;
coder->buffer_size = coder->block_options.header_size;
coder->sequence = SEQ_BLOCK_HEADER;
break;
}
case SEQ_BLOCK_ENCODE: {
static const lzma_action convert[4] = {
LZMA_RUN,
LZMA_SYNC_FLUSH,
LZMA_FINISH,
LZMA_FINISH,
};
const lzma_ret ret = coder->block_encoder.code(
coder->block_encoder.coder, allocator,
in, in_pos, in_size,
out, out_pos, out_size, convert[action]);
if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
return ret;
// Add a new Index Record.
const lzma_vli unpadded_size = lzma_block_unpadded_size(
&coder->block_options);
assert(unpadded_size != 0);
return_if_error(lzma_index_append(coder->index, allocator,
unpadded_size,
coder->block_options.uncompressed_size));
coder->sequence = SEQ_BLOCK_INIT;
break;
}
case SEQ_INDEX_ENCODE: {
// Call the Index encoder. It doesn't take any input, so
// those pointers can be NULL.
const lzma_ret ret = coder->index_encoder.code(
coder->index_encoder.coder, allocator,
NULL, NULL, 0,
out, out_pos, out_size, LZMA_RUN);
if (ret != LZMA_STREAM_END)
return ret;
// Encode the Stream Footer into coder->buffer.
const lzma_stream_flags stream_flags = {
.version = 0,
.backward_size = lzma_index_size(coder->index),
.check = coder->block_options.check,
};
if (lzma_stream_footer_encode(&stream_flags, coder->buffer)
!= LZMA_OK)
return LZMA_PROG_ERROR;
coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
coder->sequence = SEQ_STREAM_FOOTER;
break;
}
default:
assert(0);
return LZMA_PROG_ERROR;
}
return LZMA_OK;
}
static void
stream_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
{
lzma_next_end(&coder->block_encoder, allocator);
lzma_next_end(&coder->index_encoder, allocator);
lzma_index_end(coder->index, allocator);
for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
lzma_free(coder->filters[i].options, allocator);
lzma_free(coder, allocator);
return;
}
static lzma_ret
stream_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
const lzma_filter *filters,
const lzma_filter *reversed_filters)
{
if (coder->sequence <= SEQ_BLOCK_INIT) {
// There is no incomplete Block waiting to be finished,
// thus we can change the whole filter chain. Start by
// trying to initialize the Block encoder with the new
// chain. This way we detect if the chain is valid.
coder->block_encoder_is_initialized = false;
coder->block_options.filters = (lzma_filter *)(filters);
const lzma_ret ret = block_encoder_init(coder, allocator);
coder->block_options.filters = coder->filters;
if (ret != LZMA_OK)
return ret;
coder->block_encoder_is_initialized = true;
} else if (coder->sequence <= SEQ_BLOCK_ENCODE) {
// We are in the middle of a Block. Try to update only
// the filter-specific options.
return_if_error(coder->block_encoder.update(
coder->block_encoder.coder, allocator,
filters, reversed_filters));
} else {
// Trying to update the filter chain when we are already
// encoding Index or Stream Footer.
return LZMA_PROG_ERROR;
}
// Free the copy of the old chain and make a copy of the new chain.
for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
lzma_free(coder->filters[i].options, allocator);
return lzma_filters_copy(filters, coder->filters, allocator);
}
extern lzma_ret
lzma_stream_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
const lzma_filter *filters, lzma_check check)
{
lzma_next_coder_init(&lzma_stream_encoder_init, next, allocator);
if (filters == NULL)
return LZMA_PROG_ERROR;
if (next->coder == NULL) {
next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
if (next->coder == NULL)
return LZMA_MEM_ERROR;
next->code = &stream_encode;
next->end = &stream_encoder_end;
next->update = &stream_encoder_update;
next->coder->filters[0].id = LZMA_VLI_UNKNOWN;
next->coder->block_encoder = LZMA_NEXT_CODER_INIT;
next->coder->index_encoder = LZMA_NEXT_CODER_INIT;
next->coder->index = NULL;
}
// Basic initializations
next->coder->sequence = SEQ_STREAM_HEADER;
next->coder->block_options.version = 0;
next->coder->block_options.check = check;
// Initialize the Index
lzma_index_end(next->coder->index, allocator);
next->coder->index = lzma_index_init(allocator);
if (next->coder->index == NULL)
return LZMA_MEM_ERROR;
// Encode the Stream Header
lzma_stream_flags stream_flags = {
.version = 0,
.check = check,
};
return_if_error(lzma_stream_header_encode(
&stream_flags, next->coder->buffer));
next->coder->buffer_pos = 0;
next->coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
// Initialize the Block encoder. This way we detect unsupported
// filter chains when initializing the Stream encoder instead of
// giving an error after Stream Header has already written out.
return stream_encoder_update(
next->coder, allocator, filters, NULL);
}
extern LZMA_API(lzma_ret)
lzma_stream_encoder(lzma_stream *strm,
const lzma_filter *filters, lzma_check check)
{
lzma_next_strm_init(lzma_stream_encoder_init, strm, filters, check);
strm->internal->supported_actions[LZMA_RUN] = true;
strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
strm->internal->supported_actions[LZMA_FULL_FLUSH] = true;
strm->internal->supported_actions[LZMA_FINISH] = true;
return LZMA_OK;
}