xref: /freebsd/contrib/xz/src/liblzma/simple/simple_decoder.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file       simple_decoder.c
4 /// \brief      Properties decoder for simple filters
5 //
6 //  Author:     Lasse Collin
7 //
8 //  This file has been put into the public domain.
9 //  You can do whatever you want with this file.
10 //
11 ///////////////////////////////////////////////////////////////////////////////
12 
13 #include "simple_decoder.h"
14 
15 
16 extern lzma_ret
17 lzma_simple_props_decode(void **options, const lzma_allocator *allocator,
18 		const uint8_t *props, size_t props_size)
19 {
20 	if (props_size == 0)
21 		return LZMA_OK;
22 
23 	if (props_size != 4)
24 		return LZMA_OPTIONS_ERROR;
25 
26 	lzma_options_bcj *opt = lzma_alloc(
27 			sizeof(lzma_options_bcj), allocator);
28 	if (opt == NULL)
29 		return LZMA_MEM_ERROR;
30 
31 	opt->start_offset = unaligned_read32le(props);
32 
33 	// Don't leave an options structure allocated if start_offset is zero.
34 	if (opt->start_offset == 0)
35 		lzma_free(opt, allocator);
36 	else
37 		*options = opt;
38 
39 	return LZMA_OK;
40 }
41