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1 /* | |
2 * xz_pipe_decomp.c | |
3 * A simple example of pipe-only xz decompressor implementation. | |
4 * version: 2010-07-12 - by Daniel Mealha Cabrita | |
5 * Not copyrighted -- provided to the public domain. | |
6 * | |
7 * Compiling: | |
8 * Link with liblzma. GCC example: | |
9 * $ gcc -llzma xz_pipe_decomp.c -o xz_pipe_decomp | |
10 * | |
11 * Usage example: | |
12 * $ cat some_file.xz | ./xz_pipe_decomp > some_file | |
13 */ | |
14 | |
15 #include <stdio.h> | |
16 #include <stdint.h> | |
17 #include <inttypes.h> | |
18 #include <stdbool.h> | |
19 #include <lzma.h> | |
20 | |
21 | |
22 /* read/write buffer sizes */ | |
23 #define IN_BUF_MAX 4096 | |
24 #define OUT_BUF_MAX 4096 | |
25 | |
26 /* error codes */ | |
27 #define RET_OK 0 | |
28 #define RET_ERROR_INIT 1 | |
29 #define RET_ERROR_INPUT 2 | |
30 #define RET_ERROR_OUTPUT 3 | |
31 #define RET_ERROR_DECOMPRESSION 4 | |
32 | |
33 | |
34 /* note: in_file and out_file must be open already */ | |
35 int xz_decompress (FILE *in_file, FILE *out_file) | |
36 { | |
37 lzma_stream strm = LZMA_STREAM_INIT; /* alloc and init lzma_stream struc
t */ | |
38 const uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK | LZMA_CONCATENATED; | |
39 const uint64_t memory_limit = UINT64_MAX; /* no memory limit */ | |
40 uint8_t in_buf [IN_BUF_MAX]; | |
41 uint8_t out_buf [OUT_BUF_MAX]; | |
42 size_t in_len; /* length of useful data in in_buf */ | |
43 size_t out_len; /* length of useful data in out_buf */ | |
44 bool in_finished = false; | |
45 bool out_finished = false; | |
46 lzma_action action; | |
47 lzma_ret ret_xz; | |
48 int ret; | |
49 | |
50 ret = RET_OK; | |
51 | |
52 /* initialize xz decoder */ | |
53 ret_xz = lzma_stream_decoder (&strm, memory_limit, flags); | |
54 if (ret_xz != LZMA_OK) { | |
55 fprintf (stderr, "lzma_stream_decoder error: %d\n", (int) ret_xz
); | |
56 return RET_ERROR_INIT; | |
57 } | |
58 | |
59 while ((! in_finished) && (! out_finished)) { | |
60 /* read incoming data */ | |
61 in_len = fread (in_buf, 1, IN_BUF_MAX, in_file); | |
62 | |
63 if (feof (in_file)) { | |
64 in_finished = true; | |
65 } | |
66 if (ferror (in_file)) { | |
67 in_finished = true; | |
68 ret = RET_ERROR_INPUT; | |
69 } | |
70 | |
71 strm.next_in = in_buf; | |
72 strm.avail_in = in_len; | |
73 | |
74 /* if no more data from in_buf, flushes the | |
75 internal xz buffers and closes the decompressed data | |
76 with LZMA_FINISH */ | |
77 action = in_finished ? LZMA_FINISH : LZMA_RUN; | |
78 | |
79 /* loop until there's no pending decompressed output */ | |
80 do { | |
81 /* out_buf is clean at this point */ | |
82 strm.next_out = out_buf; | |
83 strm.avail_out = OUT_BUF_MAX; | |
84 | |
85 /* decompress data */ | |
86 ret_xz = lzma_code (&strm, action); | |
87 | |
88 if ((ret_xz != LZMA_OK) && (ret_xz != LZMA_STREAM_END))
{ | |
89 fprintf (stderr, "lzma_code error: %d\n", (int)
ret_xz); | |
90 out_finished = true; | |
91 ret = RET_ERROR_DECOMPRESSION; | |
92 } else { | |
93 /* write decompressed data */ | |
94 out_len = OUT_BUF_MAX - strm.avail_out; | |
95 fwrite (out_buf, 1, out_len, out_file); | |
96 if (ferror (out_file)) { | |
97 out_finished = true; | |
98 ret = RET_ERROR_OUTPUT; | |
99 } | |
100 } | |
101 } while (strm.avail_out == 0); | |
102 } | |
103 | |
104 lzma_end (&strm); | |
105 return ret; | |
106 } | |
107 | |
108 int main () | |
109 { | |
110 int ret; | |
111 | |
112 ret = xz_decompress (stdin, stdout); | |
113 return ret; | |
114 } | |
115 | |
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