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 */
xz_compress(FILE * in_file,FILE * out_file)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 struct */
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
main()120 int main ()
121 {
122 int ret;
123
124 ret = xz_compress (stdin, stdout);
125 return ret;
126 }
127
128