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131 lines
3.7 KiB
C
131 lines
3.7 KiB
C
///////////////////////////////////////////////////////////////////////////////
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//
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/// \file stream_buffer_encoder.c
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/// \brief Single-call .xz Stream encoder
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "index.h"
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/// Maximum size of Index that has exactly one Record.
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/// Index Indicator + Number of Records + Record + CRC32 rounded up to
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/// the next multiple of four.
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#define INDEX_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 4 + 3) & ~3)
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/// Stream Header, Stream Footer, and Index
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#define HEADERS_BOUND (2 * LZMA_STREAM_HEADER_SIZE + INDEX_BOUND)
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extern LZMA_API(size_t)
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lzma_stream_buffer_bound(size_t uncompressed_size)
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{
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// Get the maximum possible size of a Block.
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const size_t block_bound = lzma_block_buffer_bound(uncompressed_size);
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if (block_bound == 0)
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return 0;
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// Catch the possible integer overflow and also prevent the size of
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// the Stream exceeding LZMA_VLI_MAX (theoretically possible on
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// 64-bit systems).
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if (MIN(SIZE_MAX, LZMA_VLI_MAX) - block_bound < HEADERS_BOUND)
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return 0;
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return block_bound + HEADERS_BOUND;
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}
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extern LZMA_API(lzma_ret)
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lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check,
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lzma_allocator *allocator, const uint8_t *in, size_t in_size,
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uint8_t *out, size_t *out_pos_ptr, size_t out_size)
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{
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// Sanity checks
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if (filters == NULL || (unsigned int)(check) > LZMA_CHECK_ID_MAX
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|| (in == NULL && in_size != 0) || out == NULL
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|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
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return LZMA_PROG_ERROR;
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// Note for the paranoids: Index encoder prevents the Stream from
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// getting too big and still being accepted with LZMA_OK, and Block
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// encoder catches if the input is too big. So we don't need to
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// separately check if the buffers are too big.
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// Use a local copy. We update *out_pos_ptr only if everything
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// succeeds.
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size_t out_pos = *out_pos_ptr;
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// Check that there's enough space for both Stream Header and
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// Stream Footer.
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if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE)
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return LZMA_BUF_ERROR;
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// Reserve space for Stream Footer so we don't need to check for
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// available space again before encoding Stream Footer.
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out_size -= LZMA_STREAM_HEADER_SIZE;
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// Encode the Stream Header.
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lzma_stream_flags stream_flags = {
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.version = 0,
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.check = check,
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};
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if (lzma_stream_header_encode(&stream_flags, out + out_pos)
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!= LZMA_OK)
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return LZMA_PROG_ERROR;
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out_pos += LZMA_STREAM_HEADER_SIZE;
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// Block
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lzma_block block = {
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.version = 0,
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.check = check,
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.filters = filters,
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};
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return_if_error(lzma_block_buffer_encode(&block, allocator,
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in, in_size, out, &out_pos, out_size));
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// Index
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{
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// Create an Index with one Record.
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lzma_index *i = lzma_index_init(NULL, NULL);
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if (i == NULL)
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return LZMA_MEM_ERROR;
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lzma_ret ret = lzma_index_append(i, NULL,
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lzma_block_unpadded_size(&block),
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block.uncompressed_size);
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// If adding the Record was successful, encode the Index
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// and get its size which will be stored into Stream Footer.
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if (ret == LZMA_OK) {
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ret = lzma_index_buffer_encode(
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i, out, &out_pos, out_size);
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stream_flags.backward_size = lzma_index_size(i);
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}
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lzma_index_end(i, NULL);
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if (ret != LZMA_OK)
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return ret;
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}
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// Stream Footer. We have already reserved space for this.
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if (lzma_stream_footer_encode(&stream_flags, out + out_pos)
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!= LZMA_OK)
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return LZMA_PROG_ERROR;
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out_pos += LZMA_STREAM_HEADER_SIZE;
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// Everything went fine, make the new output position available
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// to the application.
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*out_pos_ptr = out_pos;
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return LZMA_OK;
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}
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