Linux_Matters_Speccy_Demo/ttttt.c
2024-11-11 18:38:56 +00:00

96 lines
2.1 KiB
C

/* McPhail's Tip-Top TAP Top-Tailer
* Takes a raw code file as input
* Prepends data length and appends xor checksum
* Outputs to new file with .block suffix */
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <linux/limits.h>
#include <string.h>
int main(int argc, char *argv[])
{
int fdin, fdout;
char outfilename[PATH_MAX];
unsigned int count = 0;
unsigned char flagopt = 0;
unsigned char tally = 0;
unsigned char next = 0;
if ((argc<2) || (argc>3)) {
printf("Please specify file to read.\n");
return -1;
}
if (3==argc) {
if (!strcmp(argv[2], "header")) flagopt = 1;
if (!strcmp(argv[2], "data")) flagopt = 2;
if (!flagopt) {
printf("Optional flags are \"header\" or \"data\"\n");
return -1;
}
}
if (! flagopt) {
printf("*** WARNING ***\n");
printf("*** ttttt is running in RAW mode.\n");
printf("*** Have you manually included the format flag as the first byte of the block?\n");
printf("*** If not, run again passing 'header' or 'data' as the second parameter.\n");
printf("*** WARNING ***\n\n");
}
fdin = open(argv[1], O_RDONLY);
if (fdin<0) {
printf("Couldn't open %s. for reading\n", argv[1]);
return -1;
}
snprintf(outfilename, PATH_MAX, "%s.block", argv[1]);
outfilename[PATH_MAX - 1] = '\0';
if (! strcmp(argv[1], outfilename)) {
printf("Filename too long - would clobber existing.\n");
close(fdin);
return -1;
}
fdout = open(outfilename, O_CREAT|O_WRONLY|O_TRUNC, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH);
if (fdout<0) {
printf("Couldn't open %s for writing.\n", outfilename);
close(fdin);
return -1;
}
while (read(fdin, &next, 1)) {
tally ^= next;
count ++;
};
lseek(fdin, 0, SEEK_SET);
if (flagopt) count++;
char lsb = (count+1)&255;
char msb = ((count+1)>>8)&255;
write(fdout, &lsb, 1);
write(fdout, &msb, 1);
next = 0;
if (flagopt == 2) next = 255;
if (flagopt) {
write(fdout, &next, 1);
tally ^= next;
}
while (read(fdin, &next, 1)) {
write(fdout, &next, 1);
}
write(fdout, &tally, 1);
close(fdout);
close(fdin);
printf("File %s written.\n", outfilename);
count--;
printf("Code length is %d (0x%.4X).\n", count, count);
return 0;
}