1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file       filter_buffer_decoder.c
4 /// \brief      Single-call raw decoding
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 "filter_decoder.h"
14 
15 
16 extern LZMA_API(lzma_ret)
17 lzma_raw_buffer_decode(
18 		const lzma_filter *filters, const lzma_allocator *allocator,
19 		const uint8_t *in, size_t *in_pos, size_t in_size,
20 		uint8_t *out, size_t *out_pos, size_t out_size)
21 {
22 	// Validate what isn't validated later in filter_common.c.
23 	if (in == NULL || in_pos == NULL || *in_pos > in_size || out == NULL
24 			|| out_pos == NULL || *out_pos > out_size)
25 		return LZMA_PROG_ERROR;
26 
27 	// Initialize the decoer.
28 	lzma_next_coder next = LZMA_NEXT_CODER_INIT;
29 	return_if_error(lzma_raw_decoder_init(&next, allocator, filters));
30 
31 	// Store the positions so that we can restore them if something
32 	// goes wrong.
33 	const size_t in_start = *in_pos;
34 	const size_t out_start = *out_pos;
35 
36 	// Do the actual decoding and free decoder's memory.
37 	lzma_ret ret = next.code(next.coder, allocator, in, in_pos, in_size,
38 			out, out_pos, out_size, LZMA_FINISH);
39 
40 	if (ret == LZMA_STREAM_END) {
41 		ret = LZMA_OK;
42 	} else {
43 		if (ret == LZMA_OK) {
44 			// Either the input was truncated or the
45 			// output buffer was too small.
46 			assert(*in_pos == in_size || *out_pos == out_size);
47 
48 			if (*in_pos != in_size) {
49 				// Since input wasn't consumed completely,
50 				// the output buffer became full and is
51 				// too small.
52 				ret = LZMA_BUF_ERROR;
53 
54 			} else if (*out_pos != out_size) {
55 				// Since output didn't became full, the input
56 				// has to be truncated.
57 				ret = LZMA_DATA_ERROR;
58 
59 			} else {
60 				// All the input was consumed and output
61 				// buffer is full. Now we don't immediately
62 				// know the reason for the error. Try
63 				// decoding one more byte. If it succeeds,
64 				// then the output buffer was too small. If
65 				// we cannot get a new output byte, the input
66 				// is truncated.
67 				uint8_t tmp[1];
68 				size_t tmp_pos = 0;
69 				(void)next.code(next.coder, allocator,
70 						in, in_pos, in_size,
71 						tmp, &tmp_pos, 1, LZMA_FINISH);
72 
73 				if (tmp_pos == 1)
74 					ret = LZMA_BUF_ERROR;
75 				else
76 					ret = LZMA_DATA_ERROR;
77 			}
78 		}
79 
80 		// Restore the positions.
81 		*in_pos = in_start;
82 		*out_pos = out_start;
83 	}
84 
85 	lzma_next_end(&next, allocator);
86 
87 	return ret;
88 }
89