block_buffer_decoder.c revision 292588 
1///////////////////////////////////////////////////////////////////////////////
2//
3/// \file       block_buffer_decoder.c
4/// \brief      Single-call .xz Block decoder
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 "block_decoder.h"
14
15
16extern LZMA_API(lzma_ret)
17lzma_block_buffer_decode(lzma_block *block, const lzma_allocator *allocator,
18		const uint8_t *in, size_t *in_pos, size_t in_size,
19		uint8_t *out, size_t *out_pos, size_t out_size)
20{
21	if (in_pos == NULL || (in == NULL && *in_pos != in_size)
22			|| *in_pos > in_size || out_pos == NULL
23			|| (out == NULL && *out_pos != out_size)
24			|| *out_pos > out_size)
25		return LZMA_PROG_ERROR;
26
27	// Initialize the Block decoder.
28	lzma_next_coder block_decoder = LZMA_NEXT_CODER_INIT;
29	lzma_ret ret = lzma_block_decoder_init(
30			&block_decoder, allocator, block);
31
32	if (ret == LZMA_OK) {
33		// Save the positions so that we can restore them in case
34		// an error occurs.
35		const size_t in_start = *in_pos;
36		const size_t out_start = *out_pos;
37
38		// Do the actual decoding.
39		ret = block_decoder.code(block_decoder.coder, allocator,
40				in, in_pos, in_size, out, out_pos, out_size,
41				LZMA_FINISH);
42
43		if (ret == LZMA_STREAM_END) {
44			ret = LZMA_OK;
45		} else {
46			if (ret == LZMA_OK) {
47				// Either the input was truncated or the
48				// output buffer was too small.
49				assert(*in_pos == in_size
50						|| *out_pos == out_size);
51
52				// If all the input was consumed, then the
53				// input is truncated, even if the output
54				// buffer is also full. This is because
55				// processing the last byte of the Block
56				// never produces output.
57				//
58				// NOTE: This assumption may break when new
59				// filters are added, if the end marker of
60				// the filter doesn't consume at least one
61				// complete byte.
62				if (*in_pos == in_size)
63					ret = LZMA_DATA_ERROR;
64				else
65					ret = LZMA_BUF_ERROR;
66			}
67
68			// Restore the positions.
69			*in_pos = in_start;
70			*out_pos = out_start;
71		}
72	}
73
74	// Free the decoder memory. This needs to be done even if
75	// initialization fails, because the internal API doesn't
76	// require the initialization function to free its memory on error.
77	lzma_next_end(&block_decoder, allocator);
78
79	return ret;
80}
81