cws2fws.c 3.38 KB
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/*
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 * cws2fws by Alex Beregszaszi
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 * This file is placed in the public domain.
 * Use the program however you see fit.
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 *
 * This utility converts compressed Macromedia Flash files to uncompressed ones.
 */

#include <sys/stat.h>
#include <fcntl.h>
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#include <stdio.h>
#include <stdlib.h>
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#include <unistd.h>
#include <zlib.h>

#ifdef DEBUG
#define dbgprintf printf
#else
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#define dbgprintf(...)
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#endif

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int main(int argc, char *argv[])
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{
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    int fd_in, fd_out, comp_len, uncomp_len, i, last_out;
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    char buf_in[1024], buf_out[65536];
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    z_stream zstream;
    struct stat statbuf;

    if (argc < 3)
    {
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        printf("Usage: %s <infile.swf> <outfile.swf>\n", argv[0]);
        exit(1);
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    }
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    fd_in = open(argv[1], O_RDONLY);
    if (fd_in < 0)
    {
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        perror("Error opening input file");
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        exit(1);
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    }

    fd_out = open(argv[2], O_WRONLY|O_CREAT, 00644);
    if (fd_out < 0)
    {
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        perror("Error opening output file");
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        close(fd_in);
        exit(1);
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    }
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    if (read(fd_in, &buf_in, 8) != 8)
    {
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        printf("Header error\n");
        close(fd_in);
        close(fd_out);
        exit(1);
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    }
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    if (buf_in[0] != 'C' || buf_in[1] != 'W' || buf_in[2] != 'S')
    {
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        printf("Not a compressed flash file\n");
        exit(1);
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    }

    fstat(fd_in, &statbuf);
    comp_len = statbuf.st_size;
    uncomp_len = buf_in[4] | (buf_in[5] << 8) | (buf_in[6] << 16) | (buf_in[7] << 24);
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    printf("Compressed size: %d Uncompressed size: %d\n", comp_len-4, uncomp_len-4);

    // write out modified header
    buf_in[0] = 'F';
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    if (write(fd_out, &buf_in, 8) < 8) {
        perror("Error writing output file");
        exit(1);
    }
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    zstream.zalloc = NULL;
    zstream.zfree = NULL;
    zstream.opaque = NULL;
    inflateInit(&zstream);
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    for (i = 0; i < comp_len-8;)
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    {
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        int ret, len = read(fd_in, &buf_in, 1024);
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        dbgprintf("read %d bytes\n", len);
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        last_out = zstream.total_out;
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        zstream.next_in = &buf_in[0];
        zstream.avail_in = len;
        zstream.next_out = &buf_out[0];
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        zstream.avail_out = 65536;
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        ret = inflate(&zstream, Z_SYNC_FLUSH);
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        if (ret != Z_STREAM_END && ret != Z_OK)
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        {
            printf("Error while decompressing: %d\n", ret);
            inflateEnd(&zstream);
            exit(1);
        }
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        dbgprintf("a_in: %d t_in: %lu a_out: %d t_out: %lu -- %lu out\n",
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            zstream.avail_in, zstream.total_in, zstream.avail_out, zstream.total_out,
            zstream.total_out-last_out);
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        if (write(fd_out, &buf_out, zstream.total_out - last_out) < zstream.total_out - last_out) {
            perror("Error writing output file");
            exit(1);
        }
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        i += len;
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        if (ret == Z_STREAM_END || ret == Z_BUF_ERROR)
            break;
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    }
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    if (zstream.total_out != uncomp_len-8)
    {
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        printf("Size mismatch (%lu != %d), updating header...\n",
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            zstream.total_out, uncomp_len-8);
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        buf_in[0] = (zstream.total_out+8) & 0xff;
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        buf_in[1] = ((zstream.total_out+8) >> 8) & 0xff;
        buf_in[2] = ((zstream.total_out+8) >> 16) & 0xff;
        buf_in[3] = ((zstream.total_out+8) >> 24) & 0xff;
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        lseek(fd_out, 4, SEEK_SET);
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        if (write(fd_out, &buf_in, 4) < 4) {
            perror("Error writing output file");
            exit(1);
        }
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    }
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    inflateEnd(&zstream);
    close(fd_in);
    close(fd_out);
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    return 0;
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}