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75c149bc80
It is good to keep these around to so that if someone has copied the decompressor bug from xz_pipe_decomp.c he has an example how to easily fix it.
123 lines
3.1 KiB
C
123 lines
3.1 KiB
C
/*
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* xz_pipe_decomp.c
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* A simple example of pipe-only xz decompressor implementation.
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* version: 2012-06-14 - by Daniel Mealha Cabrita
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* Not copyrighted -- provided to the public domain.
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*
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* Compiling:
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* Link with liblzma. GCC example:
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* $ gcc -llzma xz_pipe_decomp.c -o xz_pipe_decomp
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*
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* Usage example:
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* $ cat some_file.xz | ./xz_pipe_decomp > some_file
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <inttypes.h>
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#include <stdbool.h>
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#include <lzma.h>
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/* read/write buffer sizes */
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#define IN_BUF_MAX 4096
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#define OUT_BUF_MAX 4096
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/* error codes */
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#define RET_OK 0
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#define RET_ERROR_INIT 1
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#define RET_ERROR_INPUT 2
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#define RET_ERROR_OUTPUT 3
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#define RET_ERROR_DECOMPRESSION 4
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/* note: in_file and out_file must be open already */
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int xz_decompress (FILE *in_file, FILE *out_file)
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{
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lzma_stream strm = LZMA_STREAM_INIT; /* alloc and init lzma_stream struct */
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const uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK | LZMA_CONCATENATED;
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const uint64_t memory_limit = UINT64_MAX; /* no memory limit */
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uint8_t in_buf [IN_BUF_MAX];
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uint8_t out_buf [OUT_BUF_MAX];
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size_t in_len; /* length of useful data in in_buf */
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size_t out_len; /* length of useful data in out_buf */
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bool in_finished = false;
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bool out_finished = false;
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lzma_action action;
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lzma_ret ret_xz;
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int ret;
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ret = RET_OK;
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/* initialize xz decoder */
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ret_xz = lzma_stream_decoder (&strm, memory_limit, flags);
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if (ret_xz != LZMA_OK) {
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fprintf (stderr, "lzma_stream_decoder error: %d\n", (int) ret_xz);
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return RET_ERROR_INIT;
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}
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while ((! in_finished) && (! out_finished)) {
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/* read incoming data */
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in_len = fread (in_buf, 1, IN_BUF_MAX, in_file);
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if (feof (in_file)) {
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in_finished = true;
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}
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if (ferror (in_file)) {
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in_finished = true;
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ret = RET_ERROR_INPUT;
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}
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strm.next_in = in_buf;
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strm.avail_in = in_len;
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/* if no more data from in_buf, flushes the
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internal xz buffers and closes the decompressed data
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with LZMA_FINISH */
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action = in_finished ? LZMA_FINISH : LZMA_RUN;
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/* loop until there's no pending decompressed output */
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do {
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/* out_buf is clean at this point */
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strm.next_out = out_buf;
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strm.avail_out = OUT_BUF_MAX;
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/* decompress data */
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ret_xz = lzma_code (&strm, action);
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if ((ret_xz != LZMA_OK) && (ret_xz != LZMA_STREAM_END)) {
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fprintf (stderr, "lzma_code error: %d\n", (int) ret_xz);
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out_finished = true;
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ret = RET_ERROR_DECOMPRESSION;
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} else {
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/* write decompressed data */
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out_len = OUT_BUF_MAX - strm.avail_out;
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fwrite (out_buf, 1, out_len, out_file);
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if (ferror (out_file)) {
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out_finished = true;
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ret = RET_ERROR_OUTPUT;
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}
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}
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} while (strm.avail_out == 0);
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}
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/* Bug fix (2012-06-14): If no errors were detected, check
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that the last lzma_code() call returned LZMA_STREAM_END.
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If not, the file is probably truncated. */
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if ((ret == RET_OK) && (ret_xz != LZMA_STREAM_END)) {
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fprintf (stderr, "Input truncated or corrupt\n");
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ret = RET_ERROR_DECOMPRESSION;
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}
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lzma_end (&strm);
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return ret;
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}
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int main ()
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{
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int ret;
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ret = xz_decompress (stdin, stdout);
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return ret;
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}
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