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Add some single-call buffer-to-buffer coding functions.

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This commit is contained in:
Lasse Collin 2009-01-20 16:37:27 +02:00
parent d8b58d0993
commit 9ec80355a7
9 changed files with 768 additions and 26 deletions
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57
src/liblzma/api/lzma/block.h
View file

@ -55,6 +55,7 @@ typedef struct {
* - lzma_block_total_size()
* - lzma_block_encoder()
* - lzma_block_decoder()
* - lzma_block_buffer_encode()
*
* Written by:
* - lzma_block_header_decode()
@ -76,6 +77,7 @@ typedef struct {
*
* Written by:
* - lzma_block_header_size()
* - lzma_block_buffer_encode()
*/
uint32_t header_size;
# define LZMA_BLOCK_HEADER_SIZE_MIN 8
@ -95,6 +97,7 @@ typedef struct {
* - lzma_block_total_size()
* - lzma_block_encoder()
* - lzma_block_decoder()
* - lzma_block_buffer_encode()
*/
lzma_check check;
@ -147,6 +150,7 @@ typedef struct {
* - lzma_block_compressed_size()
* - lzma_block_encoder()
* - lzma_block_decoder()
* - lzma_block_buffer_encode()
*/
lzma_vli compressed_size;
@ -168,6 +172,7 @@ typedef struct {
* - lzma_block_header_decode()
* - lzma_block_encoder()
* - lzma_block_decoder()
* - lzma_block_buffer_encode()
*/
lzma_vli uncompressed_size;
@ -182,6 +187,7 @@ typedef struct {
* - lzma_block_header_encode()
* - lzma_block_encoder()
* - lzma_block_decoder()
* - lzma_block_buffer_encode()
*
* Written by:
* - lzma_block_header_decode(): Note that this does NOT free()
@ -415,3 +421,54 @@ extern lzma_ret lzma_block_encoder(lzma_stream *strm, lzma_block *block)
*/
extern lzma_ret lzma_block_decoder(lzma_stream *strm, lzma_block *block)
lzma_attr_warn_unused_result;
/**
* \brief Calculate maximum output buffer size for single-call encoding
*
* This is equivalent to lzma_stream_buffer_bound() but for .xz Blocks.
* See the documentation of lzma_stream_buffer_bound().
*/
extern size_t lzma_block_buffer_bound(size_t uncompressed_size);
/**
* \brief Single-call .xz Block encoder
*
* In contrast to the multi-call encoder initialized with
* lzma_block_encoder(), this function encodes also the Block Header. This
* is required to make it possible to write appropriate Block Header also
* in case the data isn't compressible, and different filter chain has to be
* used to encode the data in uncompressed form using uncompressed chunks
* of the LZMA2 filter.
*
* When the data isn't compressible, header_size, compressed_size, and
* uncompressed_size are set just like when the data was compressible, but
* it is possible that header_size is too small to hold the filter chain
* specified in block->filters, because that isn't necessarily the filter
* chain that was actually used to encode the data. lzma_block_unpadded_size()
* still works normally, because it doesn't read the filters array.
*
* \param block Block options: block->version, block->check,
* and block->filters must be initialized.
* \param allocator lzma_allocator for custom allocator functions.
* Set to NULL to use malloc() and free().
* \param in Beginning of the input buffer
* \param in_size Size of the input buffer
* \param out Beginning of the output buffer
* \param out_pos The next byte will be written to out[*out_pos].
* *out_pos is updated only if encoding succeeds.
* \param out_size Size of the out buffer; the first byte into
* which no data is written to is out[out_size].
*
* \return - LZMA_OK: Encoding was successful.
* - LZMA_BUF_ERROR: Not enough output buffer space.
* - LZMA_OPTIONS_ERROR
* - LZMA_MEM_ERROR
* - LZMA_DATA_ERROR
* - LZMA_PROG_ERROR
*/
extern lzma_ret lzma_block_buffer_encode(
lzma_block *block, lzma_allocator *allocator,
const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size);

56
src/liblzma/api/lzma/container.h
View file

@ -169,6 +169,62 @@ extern lzma_ret lzma_alone_encoder(
lzma_attr_warn_unused_result;
/**
* \brief Calculate output buffer size for single-call Stream encoder
*
* When trying to compress uncompressible data, the encoded size will be
* slightly bigger than the input data. This function calculates how much
* output buffer space is required to be sure that lzma_stream_buffer_encode()
* doesn't return LZMA_BUF_ERROR.
*
* The calculated value is not exact, but it is guaranteed to be big enough.
* The actual maximum output space required may be slightly smaller (up to
* about 100 bytes). This should not be a problem in practice.
*
* If the calculated maximum size doesn't fit into size_t or would make the
* Stream grow past LZMA_VLI_MAX (which should never happen in practice),
* zero is returned to indicate the error.
*
* \note The limit calculated by this function applies only to
* single-call encoding. Multi-call encoding may (and probably
* will) have larger maximum expansion when encoding
* uncompressible data. Currently there is no function to
* calculate the maximum expansion of multi-call encoding.
*/
extern size_t lzma_stream_buffer_bound(size_t uncompressed_size);
/**
* \brief Single-call Stream encoder
*
* \param filters Array of filters. This must be terminated with
* filters[n].id = LZMA_VLI_UNKNOWN. See filter.h
* for more information.
* \param check Type of the integrity check to calculate from
* uncompressed data.
* \param allocator lzma_allocator for custom allocator functions.
* Set to NULL to use malloc() and free().
* \param in Beginning of the input buffer
* \param in_size Size of the input buffer
* \param out Beginning of the output buffer
* \param out_pos The next byte will be written to out[*out_pos].
* *out_pos is updated only if encoding succeeds.
* \param out_size Size of the out buffer; the first byte into
* which no data is written to is out[out_size].
*
* \return - LZMA_OK: Encoding was successful.
* - LZMA_BUF_ERROR: Not enough output buffer space.
* - LZMA_OPTIONS_ERROR
* - LZMA_MEM_ERROR
* - LZMA_DATA_ERROR
* - LZMA_PROG_ERROR
*/
extern lzma_ret lzma_stream_buffer_encode(
lzma_filter *filters, lzma_check check,
lzma_allocator *allocator, const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size);
/************
* Decoding *
************/

70
src/liblzma/api/lzma/index.h
View file

@ -255,7 +255,7 @@ extern lzma_ret lzma_index_cat(lzma_index *lzma_restrict dest,
/**
* \brief Duplicates an Index list
* \brief Duplicate an Index list
*
* Makes an identical copy of the Index. Also the read position is copied.
*
@ -267,7 +267,7 @@ extern lzma_index *lzma_index_dup(
/**
* \brief Compares if two Index lists are identical
* \brief Compare if two Index lists are identical
*
* \return True if *a and *b are equal, false otherwise.
*/
@ -276,7 +276,7 @@ extern lzma_bool lzma_index_equal(const lzma_index *a, const lzma_index *b)
/**
* \brief Initializes Index encoder
* \brief Initialize Index encoder
*
* \param strm Pointer to properly prepared lzma_stream
* \param i Pointer to lzma_index which should be encoded.
@ -294,14 +294,15 @@ extern lzma_ret lzma_index_encoder(lzma_stream *strm, lzma_index *i)
/**
* \brief Initializes Index decoder
* \brief Initialize Index decoder
*
* \param strm Pointer to properly prepared lzma_stream
* \param i Pointer to a pointer that will be made to point
* to the final decoded Index once lzma_code() has
* returned LZMA_STREAM_END. That is,
* lzma_index_decoder() takes care of allocating
* a new lzma_index structure.
* lzma_index_decoder() always takes care of
* allocating a new lzma_index structure, and *i
* doesn't need to be initialized by the caller.
* \param memlimit How much memory the resulting Index is allowed
* to require.
*
@ -321,3 +322,60 @@ extern lzma_ret lzma_index_encoder(lzma_stream *strm, lzma_index *i)
extern lzma_ret lzma_index_decoder(
lzma_stream *strm, lzma_index **i, uint64_t memlimit)
lzma_attr_warn_unused_result;
/**
* \brief Single-call Index encoder
*
* \param i Index to be encoded. The read position will be at
* the end of the Index if encoding succeeds, or at
* unspecified position in case an error occurs.
* \param out Beginning of the output buffer
* \param out_pos The next byte will be written to out[*out_pos].
* *out_pos is updated only if encoding succeeds.
* \param out_size Size of the out buffer; the first byte into
* which no data is written to is out[out_size].
*
* \return - LZMA_OK: Encoding was successful.
* - LZMA_BUF_ERROR: Output buffer is too small. Use
* lzma_index_size() to find out how much output
* space is needed.
* - LZMA_PROG_ERROR
*
* \note This function doesn't take allocator argument since all
* the internal data is allocated on stack.
*/
extern lzma_ret lzma_index_buffer_encode(lzma_index *i,
uint8_t *out, size_t *out_pos, size_t out_size);
/**
* \brief Single-call Index decoder
*
* \param i Pointer to a pointer that will be made to point
* to the final decoded Index if decoding is
* successful. That is, lzma_index_buffer_decode()
* always takes care of allocating a new
* lzma_index structure, and *i doesn't need to be
* initialized by the caller.
* \param memlimit Pointer to how much memory the resulting Index
* is allowed to require. The value pointed by
* this pointer is modified if and only if
* LZMA_MEMLIMIT_ERROR is returned.
* \param allocator Pointer to lzma_allocator, or NULL to use malloc()
* \param in Beginning of the input buffer
* \param in_pos The next byte will be read from in[*in_pos].
* *in_pos is updated only if decoding succeeds.
* \param in_size Size of the input buffer; the first byte that
* won't be read is in[in_size].
*
* \return - LZMA_OK: Decoding was successful.
* - LZMA_MEM_ERROR
* - LZMA_MEMLIMIT_ERROR: Memory usage limit was reached.
* The minimum required memlimit value was stored to *memlimit.
* - LZMA_DATA_ERROR
* - LZMA_PROG_ERROR
*/
extern lzma_ret lzma_index_buffer_decode(
lzma_index **i, uint64_t *memlimit, lzma_allocator *allocator,
const uint8_t *in, size_t *in_pos, size_t in_size);

2
src/liblzma/common/Makefile.am
View file

@ -39,6 +39,7 @@ libcommon_la_SOURCES = \
if COND_MAIN_ENCODER
libcommon_la_SOURCES += \
alone_encoder.c \
block_buffer_encoder.c \
block_encoder.c \
block_encoder.h \
block_header_encoder.c \
@ -48,6 +49,7 @@ libcommon_la_SOURCES += \
filter_flags_encoder.c \
index_encoder.c \
index_encoder.h \
stream_buffer_encoder.c \
stream_encoder.c \
stream_encoder.h \
stream_flags_encoder.c \

305
src/liblzma/common/block_buffer_encoder.c Normal file
View file

@ -0,0 +1,305 @@
///////////////////////////////////////////////////////////////////////////////
//
/// \file block_buffer_encoder.c
/// \brief Single-call .xz Block encoder
//
// Copyright (C) 2009 Lasse Collin
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#include "block_encoder.h"
#include "filter_encoder.h"
#include "lzma2_encoder.h"
#include "check.h"
/// Estimate the maximum size of the Block Header and Check fields for
/// a Block that uses LZMA2 uncompressed chunks. We could use
/// lzma_block_header_size() but this is simpler.
///
/// Block Header Size + Block Flags + Compressed Size
/// + Uncompressed Size + Filter Flags for LZMA2 + CRC32 + Check
/// and round up to the next multiple of four to take Header Padding
/// into account.
#define HEADERS_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 3 + 4 \
+ LZMA_CHECK_SIZE_MAX + 3) & ~3)
static lzma_vli
lzma2_bound(lzma_vli uncompressed_size)
{
// Prevent integer overflow in overhead calculation.
if (uncompressed_size > COMPRESSED_SIZE_MAX)
return 0;
// Calculate the exact overhead of the LZMA2 headers: Round
// uncompressed_size up to the next multiple of LZMA2_CHUNK_MAX,
// multiply by the size of per-chunk header, and add one byte for
// the end marker.
const lzma_vli overhead = ((uncompressed_size + LZMA2_CHUNK_MAX - 1)
/ LZMA2_CHUNK_MAX)
* LZMA2_HEADER_UNCOMPRESSED + 1;
// Catch the possible integer overflow.
if (COMPRESSED_SIZE_MAX - overhead < uncompressed_size)
return 0;
return uncompressed_size + overhead;
}
extern LZMA_API size_t
lzma_block_buffer_bound(size_t uncompressed_size)
{
// For now, if the data doesn't compress, we always use uncompressed
// chunks of LZMA2. In future we may use Subblock filter too, but
// but for simplicity we probably will still use the same bound
// calculation even though Subblock filter would have slightly less
// overhead.
lzma_vli lzma2_size = lzma2_bound(uncompressed_size);
if (lzma2_size == 0)
return 0;
// Take Block Padding into account.
lzma2_size = (lzma2_size + 3) & ~LZMA_VLI_C(3);
#if SIZE_MAX < LZMA_VLI_MAX
// Catch the possible integer overflow on 32-bit systems. There's no
// overflow on 64-bit systems, because lzma2_bound() already takes
// into account the size of the headers in the Block.
if (SIZE_MAX - HEADERS_BOUND < lzma2_size)
return 0;
#endif
return HEADERS_BOUND + lzma2_size;
}
static lzma_ret
block_encode_uncompressed(lzma_block *block, const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size)
{
// TODO: Figure out if the last filter is LZMA2 or Subblock and use
// that filter to encode the uncompressed chunks.
// Use LZMA2 uncompressed chunks. We wouldn't need a dictionary at
// all, but LZMA2 always requires a dictionary, so use the minimum
// value to minimize memory usage of the decoder.
lzma_options_lzma lzma2 = {
.dict_size = LZMA_DICT_SIZE_MIN,
};
lzma_filter filters[2];
filters[0].id = LZMA_FILTER_LZMA2;
filters[0].options = &lzma2;
filters[1].id = LZMA_VLI_UNKNOWN;
// Set the above filter options to *block temporarily so that we can
// encode the Block Header.
lzma_filter *filters_orig = block->filters;
block->filters = filters;
if (lzma_block_header_size(block) != LZMA_OK) {
block->filters = filters_orig;
return LZMA_PROG_ERROR;
}
// Check that there's enough output space. The caller has already
// set block->compressed_size to what lzma2_bound() has returned,
// so we can reuse that value. We know that compressed_size is a
// known valid VLI and header_size is a small value so their sum
// will never overflow.
assert(block->compressed_size == lzma2_bound(in_size));
if (out_size - *out_pos
< block->header_size + block->compressed_size) {
block->filters = filters_orig;
return LZMA_BUF_ERROR;
}
if (lzma_block_header_encode(block, out + *out_pos) != LZMA_OK) {
block->filters = filters_orig;
return LZMA_PROG_ERROR;
}
block->filters = filters_orig;
*out_pos += block->header_size;
// Encode the data using LZMA2 uncompressed chunks.
size_t in_pos = 0;
uint8_t control = 0x01; // Dictionary reset
while (in_pos < in_size) {
// Control byte: Indicate uncompressed chunk, of which
// the first resets the dictionary.
out[(*out_pos)++] = control;
control = 0x02; // No dictionary reset
// Size of the uncompressed chunk
const size_t copy_size
= MIN(in_size - in_pos, LZMA2_CHUNK_MAX);
out[(*out_pos)++] = (copy_size - 1) >> 8;
out[(*out_pos)++] = (copy_size - 1) & 0xFF;
// The actual data
assert(*out_pos + copy_size <= out_size);
memcpy(out + *out_pos, in + in_pos, copy_size);
in_pos += copy_size;
*out_pos += copy_size;
}
// End marker
out[(*out_pos)++] = 0x00;
assert(*out_pos <= out_size);
return LZMA_OK;
}
static lzma_ret
block_encode_normal(lzma_block *block, lzma_allocator *allocator,
const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size)
{
// Find out the size of the Block Header.
block->compressed_size = lzma2_bound(in_size);
if (block->compressed_size == 0)
return LZMA_DATA_ERROR;
block->uncompressed_size = in_size;
return_if_error(lzma_block_header_size(block));
// Reserve space for the Block Header and skip it for now.
if (out_size - *out_pos <= block->header_size)
return LZMA_BUF_ERROR;
const size_t out_start = *out_pos;
*out_pos += block->header_size;
// Limit out_size so that we stop encoding if the output would grow
// bigger than what uncompressed Block would be.
if (out_size - *out_pos > block->compressed_size)
out_size = *out_pos + block->compressed_size;
// TODO: In many common cases this could be optimized to use
// significantly less memory.
lzma_next_coder raw_encoder = LZMA_NEXT_CODER_INIT;
lzma_ret ret = lzma_raw_encoder_init(
&raw_encoder, allocator, block->filters);
if (ret == LZMA_OK) {
size_t in_pos = 0;
ret = raw_encoder.code(raw_encoder.coder, allocator,
in, &in_pos, in_size, out, out_pos, out_size,
LZMA_FINISH);
}
// NOTE: This needs to be run even if lzma_raw_encoder_init() failed.
lzma_next_end(&raw_encoder, allocator);
if (ret == LZMA_STREAM_END) {
// Compression was successful. Write the Block Header.
block->compressed_size
= *out_pos - (out_start + block->header_size);
ret = lzma_block_header_encode(block, out + out_start);
if (ret != LZMA_OK)
ret = LZMA_PROG_ERROR;
} else if (ret == LZMA_OK) {
// Output buffer became full.
ret = LZMA_BUF_ERROR;
}
// Reset *out_pos if something went wrong.
if (ret != LZMA_OK)
*out_pos = out_start;
return ret;
}
extern LZMA_API lzma_ret
lzma_block_buffer_encode(lzma_block *block, lzma_allocator *allocator,
const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size)
{
// Sanity checks
if (block == NULL || block->filters == NULL
|| (in == NULL && in_size != 0) || out == NULL
|| out_pos == NULL || *out_pos > out_size)
return LZMA_PROG_ERROR;
// Check the version field.
if (block->version != 0)
return LZMA_OPTIONS_ERROR;
// Size of a Block has to be a multiple of four, so limit the size
// here already. This way we don't need to check it again when adding
// Block Padding.
out_size -= (out_size - *out_pos) & 3;
// Get the size of the Check field.
const size_t check_size = lzma_check_size(block->check);
if (check_size == UINT32_MAX)
return LZMA_PROG_ERROR;
// Reserve space for the Check field.
if (out_size - *out_pos <= check_size)
return LZMA_BUF_ERROR;
out_size -= check_size;
// Do the actual compression.
const lzma_ret ret = block_encode_normal(block, allocator,
in, in_size, out, out_pos, out_size);
if (ret != LZMA_OK) {
// If the error was something else than output buffer
// becoming full, return the error now.
if (ret != LZMA_BUF_ERROR)
return ret;
// The data was uncompressible (at least with the options
// given to us) or the output buffer was too small. Use the
// uncompressed chunks of LZMA2 to wrap the data into a valid
// Block. If we haven't been given enough output space, even
// this may fail.
return_if_error(block_encode_uncompressed(block, in, in_size,
out, out_pos, out_size));
}
assert(*out_pos <= out_size);
// Block Padding. No buffer overflow here, because we already adjusted
// out_size so that (out_size - out_start) is a multiple of four.
// Thus, if the buffer is full, the loop body can never run.
for (size_t i = (size_t)(block->compressed_size); i & 3; ++i) {
assert(*out_pos < out_size);
out[(*out_pos)++] = 0x00;
}
// If there's no Check field, we are done now.
if (check_size > 0) {
// Calculate the integrity check. We reserved space for
// the Check field earlier so we don't need to check for
// available output space here.
lzma_check_state check;
lzma_check_init(&check, block->check);
lzma_check_update(&check, block->check, in, in_size);
lzma_check_finish(&check, block->check);
memcpy(out + *out_pos, check.buffer.u8, check_size);
*out_pos += check_size;
}
return LZMA_OK;
}

83
src/liblzma/common/index_decoder.c
View file

@ -225,6 +225,27 @@ index_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
}
static lzma_ret
index_decoder_reset(lzma_coder *coder, lzma_allocator *allocator,
lzma_index **i, uint64_t memlimit)
{
// We always allocate a new lzma_index.
*i = lzma_index_init(NULL, allocator);
if (*i == NULL)
return LZMA_MEM_ERROR;
// Initialize the rest.
coder->sequence = SEQ_INDICATOR;
coder->memlimit = memlimit;
coder->index = *i;
coder->count = 0; // Needs to be initialized due to _memconfig().
coder->pos = 0;
coder->crc32 = 0;
return LZMA_OK;
}
static lzma_ret
index_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
lzma_index **i, uint64_t memlimit)
@ -247,20 +268,7 @@ index_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
lzma_index_end(next->coder->index, allocator);
}
// We always allocate a new lzma_index.
*i = lzma_index_init(NULL, allocator);
if (*i == NULL)
return LZMA_MEM_ERROR;
// Initialize the rest.
next->coder->sequence = SEQ_INDICATOR;
next->coder->memlimit = memlimit;
next->coder->index = *i;
next->coder->count = 0; // Needs to be initialized due to _memconfig().
next->coder->pos = 0;
next->coder->crc32 = 0;
return LZMA_OK;
return index_decoder_reset(next->coder, allocator, i, memlimit);
}
@ -273,3 +281,50 @@ lzma_index_decoder(lzma_stream *strm, lzma_index **i, uint64_t memlimit)
return LZMA_OK;
}
extern LZMA_API lzma_ret
lzma_index_buffer_decode(
lzma_index **i, uint64_t *memlimit, lzma_allocator *allocator,
const uint8_t *in, size_t *in_pos, size_t in_size)
{
// Sanity checks
if (i == NULL || in == NULL || in_pos == NULL || *in_pos > in_size)
return LZMA_PROG_ERROR;
// Initialize the decoder.
lzma_coder coder;
return_if_error(index_decoder_reset(&coder, allocator, i, *memlimit));
// Store the input start position so that we can restore it in case
// of an error.
const size_t in_start = *in_pos;
// Do the actual decoding.
lzma_ret ret = index_decode(&coder, allocator, in, in_pos, in_size,
NULL, NULL, 0, LZMA_RUN);
if (ret == LZMA_STREAM_END) {
ret = LZMA_OK;
} else {
// Something went wrong, free the Index structure and restore
// the input position.
lzma_index_end(*i, allocator);
*i = NULL;
*in_pos = in_start;
if (ret == LZMA_OK) {
// The input is truncated or otherwise corrupt.
// Use LZMA_DATA_ERROR instead of LZMA_BUF_ERROR
// like lzma_vli_decode() does in single-call mode.
ret = LZMA_DATA_ERROR;
} else if (ret == LZMA_MEMLIMIT_ERROR) {
// Tell the caller how much memory would have
// been needed.
*memlimit = lzma_index_memusage(coder.count);
}
}
return ret;
}

59
src/liblzma/common/index_encoder.c
View file

@ -178,6 +178,20 @@ index_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
}
static void
index_encoder_reset(lzma_coder *coder, lzma_index *i)
{
lzma_index_rewind(i);
coder->sequence = SEQ_INDICATOR;
coder->index = i;
coder->pos = 0;
coder->crc32 = 0;
return;
}
extern lzma_ret
lzma_index_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
lzma_index *i)
@ -196,12 +210,7 @@ lzma_index_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
next->end = &index_encoder_end;
}
lzma_index_rewind(i);
next->coder->sequence = SEQ_INDICATOR;
next->coder->index = i;
next->coder->pos = 0;
next->coder->crc32 = 0;
index_encoder_reset(next->coder, i);
return LZMA_OK;
}
@ -216,3 +225,41 @@ lzma_index_encoder(lzma_stream *strm, lzma_index *i)
return LZMA_OK;
}
extern LZMA_API lzma_ret
lzma_index_buffer_encode(lzma_index *i,
uint8_t *out, size_t *out_pos, size_t out_size)
{
// Validate the arugments.
if (i == NULL || out == NULL || out_pos == NULL || *out_pos > out_size)
return LZMA_PROG_ERROR;
// Don't try to encode if there's not enough output space.
if (out_size - *out_pos < lzma_index_size(i))
return LZMA_BUF_ERROR;
// The Index encoder needs just one small data structure so we can
// allocate it on stack.
lzma_coder coder;
index_encoder_reset(&coder, i);
// Do the actual encoding. This should never fail, but store
// the original *out_pos just in case.
const size_t out_start = *out_pos;
lzma_ret ret = index_encode(&coder, NULL, NULL, NULL, 0,
out, out_pos, out_size, LZMA_RUN);
if (ret == LZMA_STREAM_END) {
ret = LZMA_OK;
} else {
// We should never get here, but just in case, restore the
// output position and set the error accordingly if something
// goes wrong and debugging isn't enabled.
assert(0);
*out_pos = out_start;
ret = LZMA_PROG_ERROR;
}
return ret;
}

138
src/liblzma/common/stream_buffer_encoder.c Normal file
View file

@ -0,0 +1,138 @@
///////////////////////////////////////////////////////////////////////////////
//
/// \file stream_buffer_encoder.c
/// \brief Single-call .xz Stream encoder
//
// Copyright (C) 2009 Lasse Collin
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#include "index.h"
/// Maximum size of Index that has exactly one Record.
/// Index Indicator + Number of Records + Record + CRC32 rounded up to
/// the next multiple of four.
#define INDEX_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 4 + 3) & ~3)
/// Stream Header, Stream Footer, and Index
#define HEADERS_BOUND (2 * LZMA_STREAM_HEADER_SIZE + INDEX_BOUND)
extern LZMA_API size_t
lzma_stream_buffer_bound(size_t uncompressed_size)
{
// Get the maximum possible size of a Block.
const size_t block_bound = lzma_block_buffer_bound(uncompressed_size);
if (block_bound == 0)
return 0;
// Catch the possible integer overflow and also prevent the size of
// the Stream exceeding LZMA_VLI_MAX (theoretically possible on
// 64-bit systems).
if (MIN(SIZE_MAX, LZMA_VLI_MAX) - block_bound < HEADERS_BOUND)
return 0;
return block_bound + HEADERS_BOUND;
}
extern LZMA_API lzma_ret
lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check,
lzma_allocator *allocator, const uint8_t *in, size_t in_size,
uint8_t *out, size_t *out_pos_ptr, size_t out_size)
{
// Sanity checks
if (filters == NULL || (unsigned int)(check) > LZMA_CHECK_ID_MAX
|| (in == NULL && in_size != 0) || out == NULL
|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
return LZMA_PROG_ERROR;
// Note for the paranoids: Index encoder prevents the Stream from
// getting too big and still being accepted with LZMA_OK, and Block
// encoder catches if the input is too big. So we don't need to
// separately check if the buffers are too big.
// Use a local copy. We update *out_pos_ptr only if everything
// succeeds.
size_t out_pos = *out_pos_ptr;
// Check that there's enough space for both Stream Header and
// Stream Footer.
if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE)
return LZMA_BUF_ERROR;
// Reserve space for Stream Footer so we don't need to check for
// available space again before encoding Stream Footer.
out_size -= LZMA_STREAM_HEADER_SIZE;
// Encode the Stream Header.
lzma_stream_flags stream_flags = {
.version = 0,
.check = check,
};
if (lzma_stream_header_encode(&stream_flags, out + out_pos)
!= LZMA_OK)
return LZMA_PROG_ERROR;
out_pos += LZMA_STREAM_HEADER_SIZE;
// Block
lzma_block block = {
.version = 0,
.check = check,
.filters = filters,
};
return_if_error(lzma_block_buffer_encode(&block, allocator,
in, in_size, out, &out_pos, out_size));
// Index
{
// Create an Index with one Record.
lzma_index *i = lzma_index_init(NULL, NULL);
if (i == NULL)
return LZMA_MEM_ERROR;
lzma_ret ret = lzma_index_append(i, NULL,
lzma_block_unpadded_size(&block),
block.uncompressed_size);
// If adding the Record was successful, encode the Index
// and get its size which will be stored into Stream Footer.
if (ret == LZMA_OK) {
ret = lzma_index_buffer_encode(
i, out, &out_pos, out_size);
stream_flags.backward_size = lzma_index_size(i);
}
lzma_index_end(i, NULL);
if (ret != LZMA_OK)
return ret;
}
// Stream Footer. We have already reserved space for this.
if (lzma_stream_footer_encode(&stream_flags, out + out_pos)
!= LZMA_OK)
return LZMA_PROG_ERROR;
out_pos += LZMA_STREAM_HEADER_SIZE;
// Everything went fine, make the new output position available
// to the application.
*out_pos_ptr = out_pos;
return LZMA_OK;
}

24
tests/test_index.c
View file

@ -197,6 +197,30 @@ test_code(lzma_index *i)
lzma_index_hash_end(h, NULL);
// Encode buffer
size_t buf_pos = 1;
expect(lzma_index_buffer_encode(i, buf, &buf_pos, index_size)
== LZMA_BUF_ERROR);
expect(buf_pos == 1);
succeed(lzma_index_buffer_encode(i, buf, &buf_pos, index_size + 1));
expect(buf_pos == index_size + 1);
// Decode buffer
buf_pos = 1;
uint64_t memlimit = MEMLIMIT;
expect(lzma_index_buffer_decode(&d, &memlimit, NULL, buf, &buf_pos,
index_size) == LZMA_DATA_ERROR);
expect(buf_pos == 1);
expect(d == NULL);
succeed(lzma_index_buffer_decode(&d, &memlimit, NULL, buf, &buf_pos,
index_size + 1));
expect(buf_pos == index_size + 1);
expect(lzma_index_equal(i, d));
lzma_index_end(d, NULL);
free(buf);
}