cws2fws.c
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1 /*
2  * cws2fws by Alex Beregszaszi
3  * This file is placed in the public domain.
4  * Use the program however you see fit.
5  *
6  * This utility converts compressed Macromedia Flash files to uncompressed ones.
7  */
8 
9 #include <sys/stat.h>
10 #include <fcntl.h>
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <unistd.h>
14 #include <zlib.h>
15 
16 #ifdef DEBUG
17 #define dbgprintf printf
18 #else
19 #define dbgprintf(...)
20 #endif
21 
22 int main(int argc, char *argv[])
23 {
24  int fd_in, fd_out, comp_len, uncomp_len, i, last_out;
25  char buf_in[1024], buf_out[65536];
26  z_stream zstream;
27  struct stat statbuf;
28 
29  if (argc < 3)
30  {
31  printf("Usage: %s <infile.swf> <outfile.swf>\n", argv[0]);
32  return 1;
33  }
34 
35  fd_in = open(argv[1], O_RDONLY);
36  if (fd_in < 0)
37  {
38  perror("Error opening input file");
39  return 1;
40  }
41 
42  fd_out = open(argv[2], O_WRONLY|O_CREAT, 00644);
43  if (fd_out < 0)
44  {
45  perror("Error opening output file");
46  close(fd_in);
47  return 1;
48  }
49 
50  if (read(fd_in, &buf_in, 8) != 8)
51  {
52  printf("Header error\n");
53  close(fd_in);
54  close(fd_out);
55  return 1;
56  }
57 
58  if (buf_in[0] != 'C' || buf_in[1] != 'W' || buf_in[2] != 'S')
59  {
60  printf("Not a compressed flash file\n");
61  return 1;
62  }
63 
64  fstat(fd_in, &statbuf);
65  comp_len = statbuf.st_size;
66  uncomp_len = buf_in[4] | (buf_in[5] << 8) | (buf_in[6] << 16) | (buf_in[7] << 24);
67 
68  printf("Compressed size: %d Uncompressed size: %d\n", comp_len-4, uncomp_len-4);
69 
70  // write out modified header
71  buf_in[0] = 'F';
72  if (write(fd_out, &buf_in, 8) < 8) {
73  perror("Error writing output file");
74  return 1;
75  }
76 
77  zstream.zalloc = NULL;
78  zstream.zfree = NULL;
79  zstream.opaque = NULL;
80  inflateInit(&zstream);
81 
82  for (i = 0; i < comp_len-8;)
83  {
84  int ret, len = read(fd_in, &buf_in, 1024);
85 
86  dbgprintf("read %d bytes\n", len);
87 
88  last_out = zstream.total_out;
89 
90  zstream.next_in = &buf_in[0];
91  zstream.avail_in = len;
92  zstream.next_out = &buf_out[0];
93  zstream.avail_out = 65536;
94 
95  ret = inflate(&zstream, Z_SYNC_FLUSH);
96  if (ret != Z_STREAM_END && ret != Z_OK)
97  {
98  printf("Error while decompressing: %d\n", ret);
99  inflateEnd(&zstream);
100  return 1;
101  }
102 
103  dbgprintf("a_in: %d t_in: %lu a_out: %d t_out: %lu -- %lu out\n",
104  zstream.avail_in, zstream.total_in, zstream.avail_out, zstream.total_out,
105  zstream.total_out-last_out);
106 
107  if (write(fd_out, &buf_out, zstream.total_out - last_out) < zstream.total_out - last_out) {
108  perror("Error writing output file");
109  return 1;
110  }
111 
112  i += len;
113 
114  if (ret == Z_STREAM_END || ret == Z_BUF_ERROR)
115  break;
116  }
117 
118  if (zstream.total_out != uncomp_len-8)
119  {
120  printf("Size mismatch (%lu != %d), updating header...\n",
121  zstream.total_out, uncomp_len-8);
122 
123  buf_in[0] = (zstream.total_out+8) & 0xff;
124  buf_in[1] = ((zstream.total_out+8) >> 8) & 0xff;
125  buf_in[2] = ((zstream.total_out+8) >> 16) & 0xff;
126  buf_in[3] = ((zstream.total_out+8) >> 24) & 0xff;
127 
128  lseek(fd_out, 4, SEEK_SET);
129  if (write(fd_out, &buf_in, 4) < 4) {
130  perror("Error writing output file");
131  return 1;
132  }
133  }
134 
135  inflateEnd(&zstream);
136  close(fd_in);
137  close(fd_out);
138  return 0;
139 }