--- /dev/null
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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, 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)
+{
+ 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, true));
+
+ // 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, const 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, const 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;
+}
projects / zpackage / blobdiff