1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file stream_buffer_decoder.c
4 /// \brief Single-call .xz Stream 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 "stream_decoder.h"
14
15
16 extern LZMA_API(lzma_ret)
lzma_stream_buffer_decode(uint64_t * memlimit,uint32_t flags,const lzma_allocator * allocator,const uint8_t * in,size_t * in_pos,size_t in_size,uint8_t * out,size_t * out_pos,size_t out_size)17 lzma_stream_buffer_decode(uint64_t *memlimit, uint32_t flags,
18 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 // Sanity checks
23 if (in_pos == NULL || (in == NULL && *in_pos != in_size)
24 || *in_pos > in_size || out_pos == NULL
25 || (out == NULL && *out_pos != out_size)
26 || *out_pos > out_size)
27 return LZMA_PROG_ERROR;
28
29 // Catch flags that are not allowed in buffer-to-buffer decoding.
30 if (flags & LZMA_TELL_ANY_CHECK)
31 return LZMA_PROG_ERROR;
32
33 // Initialize the Stream decoder.
34 // TODO: We need something to tell the decoder that it can use the
35 // output buffer as workspace, and thus save significant amount of RAM.
36 lzma_next_coder stream_decoder = LZMA_NEXT_CODER_INIT;
37 lzma_ret ret = lzma_stream_decoder_init(
38 &stream_decoder, allocator, *memlimit, flags);
39
40 if (ret == LZMA_OK) {
41 // Save the positions so that we can restore them in case
42 // an error occurs.
43 const size_t in_start = *in_pos;
44 const size_t out_start = *out_pos;
45
46 // Do the actual decoding.
47 ret = stream_decoder.code(stream_decoder.coder, allocator,
48 in, in_pos, in_size, out, out_pos, out_size,
49 LZMA_FINISH);
50
51 if (ret == LZMA_STREAM_END) {
52 ret = LZMA_OK;
53 } else {
54 // Something went wrong, restore the positions.
55 *in_pos = in_start;
56 *out_pos = out_start;
57
58 if (ret == LZMA_OK) {
59 // Either the input was truncated or the
60 // output buffer was too small.
61 assert(*in_pos == in_size
62 || *out_pos == out_size);
63
64 // If all the input was consumed, then the
65 // input is truncated, even if the output
66 // buffer is also full. This is because
67 // processing the last byte of the Stream
68 // never produces output.
69 if (*in_pos == in_size)
70 ret = LZMA_DATA_ERROR;
71 else
72 ret = LZMA_BUF_ERROR;
73
74 } else if (ret == LZMA_MEMLIMIT_ERROR) {
75 // Let the caller know how much memory would
76 // have been needed.
77 uint64_t memusage;
78 (void)stream_decoder.memconfig(
79 stream_decoder.coder,
80 memlimit, &memusage, 0);
81 }
82 }
83 }
84
85 // Free the decoder memory. This needs to be done even if
86 // initialization fails, because the internal API doesn't
87 // require the initialization function to free its memory on error.
88 lzma_next_end(&stream_decoder, allocator);
89
90 return ret;
91 }
92