X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=lzma%2Fcommon%2Fblock_encoder.c;fp=lzma%2Fcommon%2Fblock_encoder.c;h=def586410d287e53ccfeeacbeceef6e9d8ab0dd1;hb=32b8a6b26ed8843828e03e505d2256960bda0980;hp=0000000000000000000000000000000000000000;hpb=d48fc23a4bcf8ca3c406d6e8c8a6f8c6b0fa2f1e;p=zpackage diff --git a/lzma/common/block_encoder.c b/lzma/common/block_encoder.c new file mode 100644 index 0000000..def5864 --- /dev/null +++ b/lzma/common/block_encoder.c @@ -0,0 +1,217 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \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" + + +struct lzma_coder_s { + /// 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; +}; + + +static lzma_ret +block_encode(lzma_coder *coder, 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) +{ + // 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; + + 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(lzma_coder *coder, const lzma_allocator *allocator) +{ + lzma_next_end(&coder->next, allocator); + lzma_free(coder, allocator); + return; +} + + +static lzma_ret +block_encoder_update(lzma_coder *coder, const lzma_allocator *allocator, + const lzma_filter *filters lzma_attribute((__unused__)), + const lzma_filter *reversed_filters) +{ + 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. + if (next->coder == NULL) { + next->coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (next->coder == NULL) + return LZMA_MEM_ERROR; + + next->code = &block_encode; + next->end = &block_encoder_end; + next->update = &block_encoder_update; + next->coder->next = LZMA_NEXT_CODER_INIT; + } + + // Basic initializations + next->coder->sequence = SEQ_CODE; + next->coder->block = block; + next->coder->compressed_size = 0; + next->coder->uncompressed_size = 0; + next->coder->pos = 0; + + // Initialize the check + lzma_check_init(&next->coder->check, block->check); + + // Initialize the requested filters. + return lzma_raw_encoder_init(&next->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_FINISH] = true; + + return LZMA_OK; +}