Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/common/block_decoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       block_decoder.c
+/// \brief      Decodes .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_decoder.h"
+#include "filter_decoder.h"
+#include "check.h"
+
+
+struct lzma_coder_s {
+        enum {
+                SEQ_CODE,
+                SEQ_PADDING,
+                SEQ_CHECK,
+        } sequence;
+
+        /// The filters in the chain; initialized with lzma_raw_decoder_init().
+        lzma_next_coder next;
+
+        /// Decoding options; we also write Compressed Size and Uncompressed
+        /// Size back to this structure when the decoding has been finished.
+        lzma_block *block;
+
+        /// Compressed Size calculated while decoding
+        lzma_vli compressed_size;
+
+        /// Uncompressed Size calculated while decoding
+        lzma_vli uncompressed_size;
+
+        /// Maximum allowed Compressed Size; this takes into account the
+        /// size of the Block Header and Check fields when Compressed Size
+        /// is unknown.
+        lzma_vli compressed_limit;
+
+        /// Position when reading the Check field
+        size_t check_pos;
+
+        /// Check of the uncompressed data
+        lzma_check_state check;
+};
+
+
+static inline bool
+update_size(lzma_vli *size, lzma_vli add, lzma_vli limit)
+{
+        if (limit > LZMA_VLI_MAX)
+                limit = LZMA_VLI_MAX;
+
+        if (limit < *size || limit - *size < add)
+                return true;
+
+        *size += add;
+
+        return false;
+}
+
+
+static inline bool
+is_size_valid(lzma_vli size, lzma_vli reference)
+{
+        return reference == LZMA_VLI_UNKNOWN || reference == size;
+}
+
+
+static lzma_ret
+block_decode(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)
+{
+        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;
+
+                // NOTE: We compare to compressed_limit here, which prevents
+                // the total size of the Block growing past LZMA_VLI_MAX.
+                if (update_size(&coder->compressed_size, in_used,
+                                        coder->compressed_limit)
+                                || update_size(&coder->uncompressed_size,
+                                        out_used,
+                                        coder->block->uncompressed_size))
+                        return LZMA_DATA_ERROR;
+
+                lzma_check_update(&coder->check, coder->block->check,
+                                out + out_start, out_used);
+
+                if (ret != LZMA_STREAM_END)
+                        return ret;
+
+                // Compressed and Uncompressed Sizes are now at their final
+                // values. Verify that they match the values given to us.
+                if (!is_size_valid(coder->compressed_size,
+                                        coder->block->compressed_size)
+                                || !is_size_valid(coder->uncompressed_size,
+                                        coder->block->uncompressed_size))
+                        return LZMA_DATA_ERROR;
+
+                // 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:
+                // Compressed Data is padded to a multiple of four bytes.
+                while (coder->compressed_size & 3) {
+                        if (*in_pos >= in_size)
+                                return LZMA_OK;
+
+                        // We use compressed_size here just get the Padding
+                        // right. The actual Compressed Size was stored to
+                        // coder->block already, and won't be modified by
+                        // us anymore.
+                        ++coder->compressed_size;
+
+                        if (in[(*in_pos)++] != 0x00)
+                                return LZMA_DATA_ERROR;
+                }
+
+                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(in, in_pos, in_size, coder->block->raw_check,
+                                &coder->check_pos, check_size);
+                if (coder->check_pos < check_size)
+                        return LZMA_OK;
+
+                // Validate the Check only if we support it.
+                // coder->check.buffer may be uninitialized
+                // when the Check ID is not supported.
+                if (lzma_check_is_supported(coder->block->check)
+                                && memcmp(coder->block->raw_check,
+                                        coder->check.buffer.u8,
+                                        check_size) != 0)
+                        return LZMA_DATA_ERROR;
+
+                return LZMA_STREAM_END;
+        }
+        }
+
+        return LZMA_PROG_ERROR;
+}
+
+
+static void
+block_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+        lzma_next_end(&coder->next, allocator);
+        lzma_free(coder, allocator);
+        return;
+}
+
+
+extern lzma_ret
+lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+                lzma_block *block)
+{
+        lzma_next_coder_init(&lzma_block_decoder_init, next, allocator);
+
+        // Validate the options. lzma_block_unpadded_size() does that for us
+        // except for Uncompressed Size and filters. Filters are validated
+        // by the raw decoder.
+        if (lzma_block_unpadded_size(block) == 0
+                        || !lzma_vli_is_valid(block->uncompressed_size))
+                return LZMA_PROG_ERROR;
+
+        // 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_decode;
+                next->end = &block_decoder_end;
+                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;
+
+        // If Compressed Size is not known, we calculate the maximum allowed
+        // value so that encoded size of the Block (including Block Padding)
+        // is still a valid VLI and a multiple of four.
+        next->coder->compressed_limit
+                        = block->compressed_size == LZMA_VLI_UNKNOWN
+                                ? (LZMA_VLI_MAX & ~LZMA_VLI_C(3))
+                                        - block->header_size
+                                        - lzma_check_size(block->check)
+                                : block->compressed_size;
+
+        // Initialize the check. It's caller's problem if the Check ID is not
+        // supported, and the Block decoder cannot verify the Check field.
+        // Caller can test lzma_check_is_supported(block->check).
+        next->coder->check_pos = 0;
+        lzma_check_init(&next->coder->check, block->check);
+
+        // Initialize the filter chain.
+        return lzma_raw_decoder_init(&next->coder->next, allocator,
+                        block->filters);
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_block_decoder(lzma_stream *strm, lzma_block *block)
+{
+        lzma_next_strm_init(lzma_block_decoder_init, strm, block);
+
+        strm->internal->supported_actions[LZMA_RUN] = true;
+        strm->internal->supported_actions[LZMA_FINISH] = true;
+
+        return LZMA_OK;
+}