60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
|
#include <stdio.h>
|
||
|
|
#include "dbg.h"
|
||
|
|
|
||
|
|
#define MAX_FILENAME 2048
|
||
|
|
|
||
|
|
|
||
|
|
int main(int argc, char *argv[])
|
||
|
|
{
|
||
|
|
int rc = -1;
|
||
|
|
char *filename;
|
||
|
|
int nchars = 0;
|
||
|
|
int nlines = 0;
|
||
|
|
int i;
|
||
|
|
long seekpos;
|
||
|
|
char c;
|
||
|
|
FILE *fp;
|
||
|
|
|
||
|
|
check(argc > 1, "You must provide a filename as arg 1");
|
||
|
|
filename = argv[1];
|
||
|
|
|
||
|
|
fp = fopen(filename, "r");
|
||
|
|
check(fp != NULL, "Failed to open \"%s\".", filename);
|
||
|
|
|
||
|
|
while((c = fgetc(fp)) != EOF) {
|
||
|
|
nchars++;
|
||
|
|
if (c == '\n') {
|
||
|
|
nlines++;
|
||
|
|
if (nlines % 10 == 0) {
|
||
|
|
printf("At line %d of \"%s\"\n", nlines, filename);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
printf("\"%s\" contains %d chars\n", filename, nchars);
|
||
|
|
|
||
|
|
printf("Current position of \"%s\" is %ld\n", filename, ftell(fp));
|
||
|
|
printf("Writing out \"%s\" in reverse:\n", filename);
|
||
|
|
|
||
|
|
for (i = 0; i < nchars; i++) {
|
||
|
|
seekpos = (long)nchars - (i + 1);
|
||
|
|
rc = fseek(fp, seekpos, SEEK_SET);
|
||
|
|
check(rc != -1, "Failed to seek to %ld", seekpos);
|
||
|
|
c = fgetc(fp);
|
||
|
|
check(c != EOF, "Failed to read char at %ld", seekpos);
|
||
|
|
putc(c, stdout);
|
||
|
|
}
|
||
|
|
|
||
|
|
rewind(fp);
|
||
|
|
printf("\n\nRewound \"%s\" to position %ld\n", filename, ftell(fp));
|
||
|
|
|
||
|
|
rc = fclose(fp);
|
||
|
|
check(rc != -1, "Failed to close \"%s\".", filename);
|
||
|
|
|
||
|
|
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
error:
|
||
|
|
return 0;
|
||
|
|
}
|