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

xz/src/liblzma/common/alone_decoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       alone_decoder.c
+/// \brief      Decoder for LZMA_Alone files
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "alone_decoder.h"
+#include "lzma_decoder.h"
+#include "lz_decoder.h"
+
+
+struct lzma_coder_s {
+        lzma_next_coder next;
+
+        enum {
+                SEQ_PROPERTIES,
+                SEQ_DICTIONARY_SIZE,
+                SEQ_UNCOMPRESSED_SIZE,
+                SEQ_CODER_INIT,
+                SEQ_CODE,
+        } sequence;
+
+        /// Position in the header fields
+        size_t pos;
+
+        /// Uncompressed size decoded from the header
+        lzma_vli uncompressed_size;
+
+        /// Memory usage limit
+        uint64_t memlimit;
+
+        /// Amount of memory actually needed (only an estimate)
+        uint64_t memusage;
+
+        /// Options decoded from the header needed to initialize
+        /// the LZMA decoder
+        lzma_options_lzma options;
+};
+
+
+static lzma_ret
+alone_decode(lzma_coder *coder,
+                lzma_allocator *allocator lzma_attribute((unused)),
+                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)
+{
+        while (*out_pos < out_size
+                        && (coder->sequence == SEQ_CODE || *in_pos < in_size))
+        switch (coder->sequence) {
+        case SEQ_PROPERTIES:
+                if (lzma_lzma_lclppb_decode(&coder->options, in[*in_pos]))
+                        return LZMA_FORMAT_ERROR;
+
+                coder->sequence = SEQ_DICTIONARY_SIZE;
+                ++*in_pos;
+                break;
+
+        case SEQ_DICTIONARY_SIZE:
+                coder->options.dict_size
+                                |= (size_t)(in[*in_pos]) << (coder->pos * 8);
+
+                if (++coder->pos == 4) {
+                        if (coder->options.dict_size != UINT32_MAX) {
+                                // A hack to ditch tons of false positives:
+                                // We allow only dictionary sizes that are
+                                // 2^n or 2^n + 2^(n-1). LZMA_Alone created
+                                // only files with 2^n, but accepts any
+                                // dictionary size. If someone complains, this
+                                // will be reconsidered.
+                                uint32_t d = coder->options.dict_size - 1;
+                                d |= d >> 2;
+                                d |= d >> 3;
+                                d |= d >> 4;
+                                d |= d >> 8;
+                                d |= d >> 16;
+                                ++d;
+
+                                if (d != coder->options.dict_size)
+                                        return LZMA_FORMAT_ERROR;
+                        }
+
+                        coder->pos = 0;
+                        coder->sequence = SEQ_UNCOMPRESSED_SIZE;
+                }
+
+                ++*in_pos;
+                break;
+
+        case SEQ_UNCOMPRESSED_SIZE:
+                coder->uncompressed_size
+                                |= (lzma_vli)(in[*in_pos]) << (coder->pos * 8);
+                ++*in_pos;
+                if (++coder->pos < 8)
+                        break;
+
+                // Another hack to ditch false positives: Assume that
+                // if the uncompressed size is known, it must be less
+                // than 256 GiB. Again, if someone complains, this
+                // will be reconsidered.
+                if (coder->uncompressed_size != LZMA_VLI_UNKNOWN
+                                && coder->uncompressed_size
+                                        >= (LZMA_VLI_C(1) << 38))
+                        return LZMA_FORMAT_ERROR;
+
+                // Calculate the memory usage so that it is ready
+                // for SEQ_CODER_INIT.
+                coder->memusage = lzma_lzma_decoder_memusage(&coder->options)
+                                + LZMA_MEMUSAGE_BASE;
+
+                coder->pos = 0;
+                coder->sequence = SEQ_CODER_INIT;
+
+        // Fall through
+
+        case SEQ_CODER_INIT: {
+                if (coder->memusage > coder->memlimit)
+                        return LZMA_MEMLIMIT_ERROR;
+
+                lzma_filter_info filters[2] = {
+                        {
+                                .init = &lzma_lzma_decoder_init,
+                                .options = &coder->options,
+                        }, {
+                                .init = NULL,
+                        }
+                };
+
+                const lzma_ret ret = lzma_next_filter_init(&coder->next,
+                                allocator, filters);
+                if (ret != LZMA_OK)
+                        return ret;
+
+                // Use a hack to set the uncompressed size.
+                lzma_lz_decoder_uncompressed(coder->next.coder,
+                                coder->uncompressed_size);
+
+                coder->sequence = SEQ_CODE;
+                break;
+        }
+
+        case SEQ_CODE: {
+                return coder->next.code(coder->next.coder,
+                                allocator, in, in_pos, in_size,
+                                out, out_pos, out_size, action);
+        }
+
+        default:
+                return LZMA_PROG_ERROR;
+        }
+
+        return LZMA_OK;
+}
+
+
+static void
+alone_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+        lzma_next_end(&coder->next, allocator);
+        lzma_free(coder, allocator);
+        return;
+}
+
+
+static lzma_ret
+alone_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
+                uint64_t *old_memlimit, uint64_t new_memlimit)
+{
+        *memusage = coder->memusage;
+        *old_memlimit = coder->memlimit;
+
+        if (new_memlimit != 0) {
+                if (new_memlimit < coder->memusage)
+                        return LZMA_MEMLIMIT_ERROR;
+
+                coder->memlimit = new_memlimit;
+        }
+
+        return LZMA_OK;
+}
+
+
+extern lzma_ret
+lzma_alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+                uint64_t memlimit)
+{
+        lzma_next_coder_init(&lzma_alone_decoder_init, next, allocator);
+
+        if (memlimit == 0)
+                return LZMA_PROG_ERROR;
+
+        if (next->coder == NULL) {
+                next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+                if (next->coder == NULL)
+                        return LZMA_MEM_ERROR;
+
+                next->code = &alone_decode;
+                next->end = &alone_decoder_end;
+                next->memconfig = &alone_decoder_memconfig;
+                next->coder->next = LZMA_NEXT_CODER_INIT;
+        }
+
+        next->coder->sequence = SEQ_PROPERTIES;
+        next->coder->pos = 0;
+        next->coder->options.dict_size = 0;
+        next->coder->options.preset_dict = NULL;
+        next->coder->options.preset_dict_size = 0;
+        next->coder->uncompressed_size = 0;
+        next->coder->memlimit = memlimit;
+        next->coder->memusage = LZMA_MEMUSAGE_BASE;
+
+        return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_alone_decoder(lzma_stream *strm, uint64_t memlimit)
+{
+        lzma_next_strm_init(lzma_alone_decoder_init, strm, memlimit);
+
+        strm->internal->supported_actions[LZMA_RUN] = true;
+        strm->internal->supported_actions[LZMA_FINISH] = true;
+
+        return LZMA_OK;
+}