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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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