pd.if.org Git - zpackage/blob - lib/uncompress.c

   1 #include <stdio.h>
   2 #include <sys/types.h>
   3 #include <sys/stat.h>
   4 #include <fcntl.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <stdlib.h>
   9 #include <assert.h>
  10
  11 #include <sys/mman.h>
  12
  13 #include "lzma.h"
  14
  15 void uncompresslzma(void *buf, size_t bufsize, FILE *out) {
  16         lzma_stream s = LZMA_STREAM_INIT;
  17         lzma_stream *strm;
  18
  19         uint8_t outbuf[BUFSIZ];
  20
  21         int ret;
  22
  23         strm = &s;
  24
  25         ret = lzma_stream_decoder(strm, UINT64_MAX, 0);
  26         /* The only reasonable error here is LZMA_MEM_ERROR. */
  27         if (ret != LZMA_OK) {
  28                 fprintf(stderr, "%s", ret == LZMA_MEM_ERROR ? strerror(ENOMEM)
  29                                 : "Internal error (bug)");
  30                 exit(EXIT_FAILURE);
  31         }
  32
  33         strm->avail_in = bufsize;
  34         strm->next_in = buf;
  35         strm->avail_out = BUFSIZ;
  36         strm->next_out = outbuf;
  37
  38         lzma_action action = LZMA_RUN;
  39
  40         while (1) {
  41                 ret = lzma_code(strm, action);
  42
  43                 // Write and check write error before checking decoder error.
  44                 // This way as much data as possible gets written to output
  45                 // even if decoder detected an error.
  46                 if (strm->avail_out == 0 || ret != LZMA_OK) {
  47                         const size_t write_size = BUFSIZ - strm->avail_out;
  48
  49                         if (fwrite(outbuf, 1, write_size, out) != write_size) {
  50                                 // Wouldn't be a surprise if writing to stderr
  51                                 // would fail too but at least try to show an
  52                                 // error message.
  53                                 fprintf(stderr, "Cannot write to output file stream: "
  54                                                 "%s", strerror(errno));
  55                                 exit(EXIT_FAILURE);
  56                         }
  57
  58                         strm->next_out = outbuf;
  59                         strm->avail_out = BUFSIZ;
  60                 }
  61
  62                 if (ret != LZMA_OK) {
  63                         if (ret == LZMA_STREAM_END) {
  64                                 // lzma_stream_decoder() already guarantees
  65                                 // that there's no trailing garbage.
  66                                 assert(strm->avail_in == 0);
  67                                 //assert(action == LZMA_FINISH);
  68                                 return;
  69                         }
  70
  71                         const char *msg;
  72                         switch (ret) {
  73                                 case LZMA_MEM_ERROR:
  74                                         msg = strerror(ENOMEM);
  75                                         break;
  76
  77                                 case LZMA_FORMAT_ERROR:
  78                                         msg = "File format not recognized";
  79                                         break;
  80
  81                                 case LZMA_OPTIONS_ERROR:
  82                                         // FIXME: Better message?
  83                                         msg = "Unsupported compression options";
  84                                         break;
  85
  86                                 case LZMA_DATA_ERROR:
  87                                         msg = "File is corrupt";
  88                                         break;
  89
  90                                 case LZMA_BUF_ERROR:
  91                                         msg = "Unexpected end of input";
  92                                         break;
  93
  94                                 default:
  95                                         msg = "Internal error (bug)";
  96                                         break;
  97                         }
  98
  99                         fprintf(stderr, "xz: %s\n", msg);
 100                         exit(EXIT_FAILURE);
 101                 }
 102         }
 103 }