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

xz/src/liblzma/common/auto_decoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       auto_decoder.c
+/// \brief      Autodetect between .xz Stream and .lzma (LZMA_Alone) formats
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "stream_decoder.h"
+#include "alone_decoder.h"
+
+
+struct lzma_coder_s {
+        /// Stream decoder or LZMA_Alone decoder
+        lzma_next_coder next;
+
+        uint64_t memlimit;
+        uint32_t flags;
+
+        enum {
+                SEQ_INIT,
+                SEQ_CODE,
+                SEQ_FINISH,
+        } sequence;
+};
+
+
+static lzma_ret
+auto_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_INIT:
+                if (*in_pos >= in_size)
+                        return LZMA_OK;
+
+                // Update the sequence now, because we want to continue from
+                // SEQ_CODE even if we return some LZMA_*_CHECK.
+                coder->sequence = SEQ_CODE;
+
+                // Detect the file format. For now this is simple, since if
+                // it doesn't start with 0xFD (the first magic byte of the
+                // new format), it has to be LZMA_Alone, or something that
+                // we don't support at all.
+                if (in[*in_pos] == 0xFD) {
+                        return_if_error(lzma_stream_decoder_init(
+                                        &coder->next, allocator,
+                                        coder->memlimit, coder->flags));
+                } else {
+                        return_if_error(lzma_alone_decoder_init(&coder->next,
+                                        allocator, coder->memlimit));
+
+                        // If the application wants to know about missing
+                        // integrity check or about the check in general, we
+                        // need to handle it here, because LZMA_Alone decoder
+                        // doesn't accept any flags.
+                        if (coder->flags & LZMA_TELL_NO_CHECK)
+                                return LZMA_NO_CHECK;
+
+                        if (coder->flags & LZMA_TELL_ANY_CHECK)
+                                return LZMA_GET_CHECK;
+                }
+
+        // Fall through
+
+        case SEQ_CODE: {
+                const lzma_ret ret = coder->next.code(
+                                coder->next.coder, allocator,
+                                in, in_pos, in_size,
+                                out, out_pos, out_size, action);
+                if (ret != LZMA_STREAM_END
+                                || (coder->flags & LZMA_CONCATENATED) == 0)
+                        return ret;
+
+                coder->sequence = SEQ_FINISH;
+        }
+
+        // Fall through
+
+        case SEQ_FINISH:
+                // When LZMA_DECODE_CONCATENATED was used and we were decoding
+                // LZMA_Alone file, we need to check check that there is no
+                // trailing garbage and wait for LZMA_FINISH.
+                if (*in_pos < in_size)
+                        return LZMA_DATA_ERROR;
+
+                return action == LZMA_FINISH ? LZMA_STREAM_END : LZMA_OK;
+
+        default:
+                assert(0);
+                return LZMA_PROG_ERROR;
+        }
+}
+
+
+static void
+auto_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+        lzma_next_end(&coder->next, allocator);
+        lzma_free(coder, allocator);
+        return;
+}
+
+
+static lzma_check
+auto_decoder_get_check(const lzma_coder *coder)
+{
+        // It is LZMA_Alone if get_check is NULL.
+        return coder->next.get_check == NULL ? LZMA_CHECK_NONE
+                        : coder->next.get_check(coder->next.coder);
+}
+
+
+static lzma_ret
+auto_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
+                uint64_t *old_memlimit, uint64_t new_memlimit)
+{
+        lzma_ret ret;
+
+        if (coder->next.memconfig != NULL) {
+                ret = coder->next.memconfig(coder->next.coder,
+                                memusage, old_memlimit, new_memlimit);
+                assert(*old_memlimit == coder->memlimit);
+        } else {
+                // No coder is configured yet. Use the base value as
+                // the current memory usage.
+                *memusage = LZMA_MEMUSAGE_BASE;
+                *old_memlimit = coder->memlimit;
+                ret = LZMA_OK;
+        }
+
+        if (ret == LZMA_OK && new_memlimit != 0)
+                coder->memlimit = new_memlimit;
+
+        return ret;
+}
+
+
+static lzma_ret
+auto_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+                uint64_t memlimit, uint32_t flags)
+{
+        lzma_next_coder_init(&auto_decoder_init, next, allocator);
+
+        if (memlimit == 0)
+                return LZMA_PROG_ERROR;
+
+        if (flags & ~LZMA_SUPPORTED_FLAGS)
+                return LZMA_OPTIONS_ERROR;
+
+        if (next->coder == NULL) {
+                next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+                if (next->coder == NULL)
+                        return LZMA_MEM_ERROR;
+
+                next->code = &auto_decode;
+                next->end = &auto_decoder_end;
+                next->get_check = &auto_decoder_get_check;
+                next->memconfig = &auto_decoder_memconfig;
+                next->coder->next = LZMA_NEXT_CODER_INIT;
+        }
+
+        next->coder->memlimit = memlimit;
+        next->coder->flags = flags;
+        next->coder->sequence = SEQ_INIT;
+
+        return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_auto_decoder(lzma_stream *strm, uint64_t memlimit, uint32_t flags)
+{
+        lzma_next_strm_init(auto_decoder_init, strm, memlimit, flags);
+
+        strm->internal->supported_actions[LZMA_RUN] = true;
+        strm->internal->supported_actions[LZMA_FINISH] = true;
+
+        return LZMA_OK;
+}