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authorLasse Collin <lasse.collin@tukaani.org>2008-08-28 22:53:15 +0300
committerLasse Collin <lasse.collin@tukaani.org>2008-08-28 22:53:15 +0300
commit3b34851de1eaf358cf9268922fa0eeed8278d680 (patch)
tree7bab212af647541df64227a8d350d17a2e789f6b /src/liblzma/delta/delta_decoder.c
parentFix test_filter_flags to match the new restriction of lc+lp. (diff)
downloadxz-3b34851de1eaf358cf9268922fa0eeed8278d680.tar.xz
Sort of garbage collection commit. :-| Many things are still
broken. API has changed a lot and it will still change a little more here and there. The command line tool doesn't have all the required changes to reflect the API changes, so it's easy to get "internal error" or trigger assertions.
Diffstat (limited to 'src/liblzma/delta/delta_decoder.c')
-rw-r--r--src/liblzma/delta/delta_decoder.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/src/liblzma/delta/delta_decoder.c b/src/liblzma/delta/delta_decoder.c
new file mode 100644
index 00000000..ee22ba02
--- /dev/null
+++ b/src/liblzma/delta/delta_decoder.c
@@ -0,0 +1,82 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file delta_decoder.c
+/// \brief Delta filter decoder
+//
+// Copyright (C) 2007, 2008 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 "delta_decoder.h"
+#include "delta_common.h"
+
+
+static void
+decode_buffer(lzma_coder *coder, uint8_t *buffer, size_t size)
+{
+ const size_t distance = coder->distance;
+
+ for (size_t i = 0; i < size; ++i) {
+ buffer[i] += coder->history[(distance + coder->pos) & 0xFF];
+ coder->history[coder->pos-- & 0xFF] = buffer[i];
+ }
+}
+
+
+static lzma_ret
+delta_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)
+{
+ assert(coder->next.code != NULL);
+
+ 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);
+
+ decode_buffer(coder, out + out_start, *out_pos - out_start);
+
+ return ret;
+}
+
+
+extern lzma_ret
+lzma_delta_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+ const lzma_filter_info *filters)
+{
+ return lzma_delta_coder_init(next, allocator, filters, &delta_decode);
+}
+
+
+extern lzma_ret
+lzma_delta_props_decode(void **options, lzma_allocator *allocator,
+ const uint8_t *props, size_t props_size)
+{
+ if (props_size != 1)
+ return LZMA_HEADER_ERROR;
+
+ lzma_options_delta *opt
+ = lzma_alloc(sizeof(lzma_options_delta), allocator);
+ if (opt == NULL)
+ return LZMA_MEM_ERROR;
+
+ opt->type = LZMA_DELTA_TYPE_BYTE;
+ opt->distance = props[0] + 1;
+
+ *options = opt;
+
+ return LZMA_OK;
+}