name : xz_pipe_decomp.c /* * xz_pipe_decomp.c * A simple example of pipe-only xz decompressor implementation. * version: 2012-06-14 - by Daniel Mealha Cabrita * Not copyrighted -- provided to the public domain. * * Compiling: * Link with liblzma. GCC example: * $ gcc -llzma xz_pipe_decomp.c -o xz_pipe_decomp * * Usage example: * $ cat some_file.xz | ./xz_pipe_decomp > some_file */ #include <stdio.h> #include <stdint.h> #include <inttypes.h> #include <stdbool.h> #include <lzma.h> /* read/write buffer sizes */ #define IN_BUF_MAX 4096 #define OUT_BUF_MAX 4096 /* error codes */ #define RET_OK 0 #define RET_ERROR_INIT 1 #define RET_ERROR_INPUT 2 #define RET_ERROR_OUTPUT 3 #define RET_ERROR_DECOMPRESSION 4 /* note: in_file and out_file must be open already */ int xz_decompress (FILE *in_file, FILE *out_file) { lzma_stream strm = LZMA_STREAM_INIT; /* alloc and init lzma_stream struct */ const uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK | LZMA_CONCATENATED; const uint64_t memory_limit = UINT64_MAX; /* no memory limit */ uint8_t in_buf [IN_BUF_MAX]; uint8_t out_buf [OUT_BUF_MAX]; size_t in_len; /* length of useful data in in_buf */ size_t out_len; /* length of useful data in out_buf */ bool in_finished = false; bool out_finished = false; lzma_action action; lzma_ret ret_xz; int ret; ret = RET_OK; /* initialize xz decoder */ ret_xz = lzma_stream_decoder (&strm, memory_limit, flags); if (ret_xz != LZMA_OK) { fprintf (stderr, "lzma_stream_decoder error: %d\n", (int) ret_xz); return RET_ERROR_INIT; } while ((! in_finished) && (! out_finished)) { /* read incoming data */ in_len = fread (in_buf, 1, IN_BUF_MAX, in_file); if (feof (in_file)) { in_finished = true; } if (ferror (in_file)) { in_finished = true; ret = RET_ERROR_INPUT; } strm.next_in = in_buf; strm.avail_in = in_len; /* if no more data from in_buf, flushes the internal xz buffers and closes the decompressed data with LZMA_FINISH */ action = in_finished ? LZMA_FINISH : LZMA_RUN; /* loop until there's no pending decompressed output */ do { /* out_buf is clean at this point */ strm.next_out = out_buf; strm.avail_out = OUT_BUF_MAX; /* decompress data */ ret_xz = lzma_code (&strm, action); if ((ret_xz != LZMA_OK) && (ret_xz != LZMA_STREAM_END)) { fprintf (stderr, "lzma_code error: %d\n", (int) ret_xz); out_finished = true; ret = RET_ERROR_DECOMPRESSION; } else { /* write decompressed data */ out_len = OUT_BUF_MAX - strm.avail_out; fwrite (out_buf, 1, out_len, out_file); if (ferror (out_file)) { out_finished = true; ret = RET_ERROR_OUTPUT; } } } while (strm.avail_out == 0); } /* Bug fix (2012-06-14): If no errors were detected, check that the last lzma_code() call returned LZMA_STREAM_END. If not, the file is probably truncated. */ if ((ret == RET_OK) && (ret_xz != LZMA_STREAM_END)) { fprintf (stderr, "Input truncated or corrupt\n"); ret = RET_ERROR_DECOMPRESSION; } lzma_end (&strm); return ret; } int main () { int ret; ret = xz_decompress (stdin, stdout); return ret; }