source: svn/trunk/newcon3bcm2_21bu/BSEAV/lib/bcmplayer/utils/byteswap.c @ 2

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void byteswap_4(char *b, int size) {
        while (size >= 4) {
                char b0 = b[0];
                char b1 = b[1];
                b[0] = b[3];
                b[1] = b[2];
                b[2] = b1;
                b[3] = b0;
                size -= 4;
                b += 4;
        }
}

void byteswap_2(char *b, int size) {
        while (size >= 2) {
                char b0 = b[0];
                b[0] = b[1];
                b[1] = b0;
                size -= 2;
                b += 2;
        }
}

#define BUFSIZE 4096 /* should be multiple of 4 */

int main(int argc, char **argv) {
        FILE *in = stdin;
        FILE *out = stdout;
        char buf[BUFSIZE];
        int mode = 4;

        if (argc >= 2) {
                if (!strcmp(argv[1], "--help")) {
                        printf(
                                "Usage: byteswap [-2] <infile >outfile\n"
                                "\n"
                                "-2 means 16 bit word byteswap.\n"
                                "Otherwise it does 32 bit word byteswap.\n"
                                "Stdin and Stdout are used.\n"
                                );
                        exit(0);
                }
                else if (!strcmp(argv[1], "-2"))
                        mode = 2;
        }

        while (!feof(in)) {
                int n= fread(buf, 1, BUFSIZE, in);
                if (mode == 2)
                        byteswap_2(buf, n);
                else
                        byteswap_4(buf, n);
                fwrite(buf, 1, n, out);
        }

        return 0;
}