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1 /* | |
2 * xz_pipe_comp.c | |
3 * A simple example of pipe-only xz compressor 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_comp.c -o xz_pipe_comp | |
10 * | |
11 * Usage example: | |
12 * $ cat some_file | ./xz_pipe_comp > some_file.xz | |
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 /* COMPRESSION SETTINGS */ | |
23 | |
24 /* analogous to xz CLI options: -0 to -9 */ | |
25 #define COMPRESSION_LEVEL 6 | |
26 | |
27 /* boolean setting, analogous to xz CLI option: -e */ | |
28 #define COMPRESSION_EXTREME true | |
29 | |
30 /* see: /usr/include/lzma/check.h LZMA_CHECK_* */ | |
31 #define INTEGRITY_CHECK LZMA_CHECK_CRC64 | |
32 | |
33 | |
34 /* read/write buffer sizes */ | |
35 #define IN_BUF_MAX 4096 | |
36 #define OUT_BUF_MAX 4096 | |
37 | |
38 /* error codes */ | |
39 #define RET_OK 0 | |
40 #define RET_ERROR_INIT 1 | |
41 #define RET_ERROR_INPUT 2 | |
42 #define RET_ERROR_OUTPUT 3 | |
43 #define RET_ERROR_COMPRESSION 4 | |
44 | |
45 | |
46 /* note: in_file and out_file must be open already */ | |
47 int xz_compress (FILE *in_file, FILE *out_file) | |
48 { | |
49 uint32_t preset = COMPRESSION_LEVEL | (COMPRESSION_EXTREME ? LZMA_PRESET
_EXTREME : 0); | |
50 lzma_check check = INTEGRITY_CHECK; | |
51 lzma_stream strm = LZMA_STREAM_INIT; /* alloc and init lzma_stream struc
t */ | |
52 uint8_t in_buf [IN_BUF_MAX]; | |
53 uint8_t out_buf [OUT_BUF_MAX]; | |
54 size_t in_len; /* length of useful data in in_buf */ | |
55 size_t out_len; /* length of useful data in out_buf */ | |
56 bool in_finished = false; | |
57 bool out_finished = false; | |
58 lzma_action action; | |
59 lzma_ret ret_xz; | |
60 int ret; | |
61 | |
62 ret = RET_OK; | |
63 | |
64 /* initialize xz encoder */ | |
65 ret_xz = lzma_easy_encoder (&strm, preset, check); | |
66 if (ret_xz != LZMA_OK) { | |
67 fprintf (stderr, "lzma_easy_encoder error: %d\n", (int) ret_xz); | |
68 return RET_ERROR_INIT; | |
69 } | |
70 | |
71 while ((! in_finished) && (! out_finished)) { | |
72 /* read incoming data */ | |
73 in_len = fread (in_buf, 1, IN_BUF_MAX, in_file); | |
74 | |
75 if (feof (in_file)) { | |
76 in_finished = true; | |
77 } | |
78 if (ferror (in_file)) { | |
79 in_finished = true; | |
80 ret = RET_ERROR_INPUT; | |
81 } | |
82 | |
83 strm.next_in = in_buf; | |
84 strm.avail_in = in_len; | |
85 | |
86 /* if no more data from in_buf, flushes the | |
87 internal xz buffers and closes the xz data | |
88 with LZMA_FINISH */ | |
89 action = in_finished ? LZMA_FINISH : LZMA_RUN; | |
90 | |
91 /* loop until there's no pending compressed output */ | |
92 do { | |
93 /* out_buf is clean at this point */ | |
94 strm.next_out = out_buf; | |
95 strm.avail_out = OUT_BUF_MAX; | |
96 | |
97 /* compress data */ | |
98 ret_xz = lzma_code (&strm, action); | |
99 | |
100 if ((ret_xz != LZMA_OK) && (ret_xz != LZMA_STREAM_END))
{ | |
101 fprintf (stderr, "lzma_code error: %d\n", (int)
ret_xz); | |
102 out_finished = true; | |
103 ret = RET_ERROR_COMPRESSION; | |
104 } else { | |
105 /* write compressed data */ | |
106 out_len = OUT_BUF_MAX - strm.avail_out; | |
107 fwrite (out_buf, 1, out_len, out_file); | |
108 if (ferror (out_file)) { | |
109 out_finished = true; | |
110 ret = RET_ERROR_OUTPUT; | |
111 } | |
112 } | |
113 } while (strm.avail_out == 0); | |
114 } | |
115 | |
116 lzma_end (&strm); | |
117 return ret; | |
118 } | |
119 | |
120 int main () | |
121 { | |
122 int ret; | |
123 | |
124 ret = xz_compress (stdin, stdout); | |
125 return ret; | |
126 } | |
127 | |
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