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Diffstat (limited to '')
| -rw-r--r-- | src/liblzma/common/raw_common.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/liblzma/common/raw_common.c b/src/liblzma/common/raw_common.c new file mode 100644 index 00000000..394903bc --- /dev/null +++ b/src/liblzma/common/raw_common.c @@ -0,0 +1,175 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file raw_common.c +/// \brief Stuff shared between raw encoder and raw decoder +// +// Copyright (C) 2007 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 "raw_common.h" + + +/// \brief Prepares the filter chain +/// +/// Prepares the filter chain by setting uncompressed sizes for each filter, +/// and adding implicit Subblock filter when needed. +/// +/// \return true if error occurred, false on success. +/// +static bool +prepare(lzma_vli *id, lzma_vli *uncompressed_size, bool implicit) +{ + bool needs_end_of_input = false; + + switch (id[0]) { + case LZMA_FILTER_COPY: + case LZMA_FILTER_X86: + case LZMA_FILTER_POWERPC: + case LZMA_FILTER_IA64: + case LZMA_FILTER_ARM: + case LZMA_FILTER_ARMTHUMB: + case LZMA_FILTER_SPARC: + case LZMA_FILTER_DELTA: + uncompressed_size[1] = uncompressed_size[0]; + needs_end_of_input = true; + break; + + case LZMA_FILTER_SUBBLOCK: + case LZMA_FILTER_LZMA: + // These change the size of the data unpredictably. + uncompressed_size[1] = LZMA_VLI_VALUE_UNKNOWN; + break; + + case LZMA_FILTER_SUBBLOCK_HELPER: + uncompressed_size[1] = uncompressed_size[0]; + break; + + default: + // Unknown filter. + return true; + } + + // Is this the last filter in the chain? + if (id[1] == LZMA_VLI_VALUE_UNKNOWN) { + if (!needs_end_of_input || !implicit || uncompressed_size[0] + != LZMA_VLI_VALUE_UNKNOWN) + return false; + + // Add implicit Subblock filter. + id[1] = LZMA_FILTER_SUBBLOCK; + uncompressed_size[1] = LZMA_VLI_VALUE_UNKNOWN; + id[2] = LZMA_VLI_VALUE_UNKNOWN; + } + + return prepare(id + 1, uncompressed_size + 1, implicit); +} + + +extern lzma_ret +lzma_raw_coder_init(lzma_next_coder *next, lzma_allocator *allocator, + const lzma_options_filter *options, lzma_vli uncompressed_size, + lzma_init_function (*get_function)(lzma_vli id), + bool allow_implicit, bool is_encoder) +{ + if (options == NULL || !lzma_vli_is_valid(uncompressed_size)) + return LZMA_PROG_ERROR; + + // Count the number of filters in the chain. + size_t count = 0; + while (options[count].id != LZMA_VLI_VALUE_UNKNOWN) + ++count; + + // Allocate enough space from the stack for IDs and uncompressed + // sizes. We need two extra: possible implicit Subblock and end + // of array indicator. + lzma_vli ids[count + 2]; + lzma_vli uncompressed_sizes[count + 2]; + bool using_implicit = false; + + uncompressed_sizes[0] = uncompressed_size; + + if (count == 0) { + if (!allow_implicit) + return LZMA_PROG_ERROR; + + count = 1; + using_implicit = true; + + // Special case: no filters were specified, so an implicit + // Copy or Subblock filter is used. + if (uncompressed_size == LZMA_VLI_VALUE_UNKNOWN) + ids[0] = LZMA_FILTER_SUBBLOCK; + else + ids[0] = LZMA_FILTER_COPY; + + ids[1] = LZMA_VLI_VALUE_UNKNOWN; + + } else { + // Prepare the ids[] and uncompressed_sizes[]. + for (size_t i = 0; i < count; ++i) + ids[i] = options[i].id; + + ids[count] = LZMA_VLI_VALUE_UNKNOWN; + + if (prepare(ids, uncompressed_sizes, allow_implicit)) + return LZMA_HEADER_ERROR; + + // Check if implicit Subblock filter was added. + if (ids[count] != LZMA_VLI_VALUE_UNKNOWN) { + assert(ids[count] == LZMA_FILTER_SUBBLOCK); + ++count; + using_implicit = true; + } + } + + // Set the filter functions, and copy uncompressed sizes and options. + lzma_filter_info filters[count + 1]; + if (is_encoder) { + for (size_t i = 0; i < count; ++i) { + // The order of the filters is reversed in the + // encoder. It allows more efficient handling + // of the uncompressed data. + const size_t j = count - i - 1; + + filters[j].init = get_function(ids[i]); + if (filters[j].init == NULL) + return LZMA_HEADER_ERROR; + + filters[j].options = options[i].options; + filters[j].uncompressed_size = uncompressed_sizes[i]; + } + + if (using_implicit) + filters[0].options = NULL; + + } else { + for (size_t i = 0; i < count; ++i) { + filters[i].init = get_function(ids[i]); + if (filters[i].init == NULL) + return LZMA_HEADER_ERROR; + + filters[i].options = options[i].options; + filters[i].uncompressed_size = uncompressed_sizes[i]; + } + + if (using_implicit) + filters[count - 1].options = NULL; + } + + // Terminate the array. + filters[count].init = NULL; + + // Initialize the filters. + return lzma_next_filter_init(next, allocator, filters); +} |