minix/commands/simple/split.c

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2005-04-21 16:53:53 +02:00
/* split - split a file Author: Michiel Huisjes */
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <minix/minlib.h>
#define CHUNK_SIZE 1024
int cut_line = 1000;
int infile;
char out_file[100];
char *suffix;
_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void split, (void));
_PROTOTYPE(int newfile, (void));
_PROTOTYPE(void usage, (void));
_PROTOTYPE(void quit, (void));
int main(argc, argv)
int argc;
char **argv;
{
unsigned short i;
out_file[0] = 'x';
infile = -1;
if (argc > 4) usage();
for (i = 1; i < argc; i++) {
if (argv[i][0] == '-') {
if (argv[i][1] >= '0' && argv[i][1] <= '9'
&& cut_line == 1000)
cut_line = atoi(argv[i]);
else if (argv[i][1] == '\0' && infile == -1)
infile = 0;
else
usage();
} else if (infile == -1) {
if ((infile = open(argv[i], O_RDONLY)) < 0) {
std_err("Cannot open input file.\n");
exit(1);
}
} else
strcpy(out_file, argv[i]);
}
if (infile == -1) infile = 0;
strcat(out_file, "aa");
for (suffix = out_file; *suffix; suffix++);
suffix--;
/* Appendix now points to last `a' of "aa". We have to decrement it by one */
*suffix = 'a' - 1;
split();
return(0);
}
void split()
{
char buf[CHUNK_SIZE];
register char *index, *base;
register int n;
int fd;
long lines = 0L;
fd = -1;
while ((n = read(infile, buf, CHUNK_SIZE)) > 0) {
base = index = buf;
while (--n >= 0) {
if (*index++ == '\n')
if (++lines % cut_line == 0) {
if (fd == -1) fd = newfile();
if (write(fd, base, (int) (index - base)) != (int) (index - base))
quit();
base = index;
close(fd);
fd = -1;
}
}
if (index == base) continue;
if (fd == -1) fd = newfile();
if (write(fd, base, (int) (index - base)) != (int) (index - base))
quit();
}
}
int newfile()
{
int fd;
if (++*suffix > 'z') { /* Increment letter */
*suffix = 'a'; /* Reset last letter */
++*(suffix - 1); /* Previous letter must be incremented */
/* E.g. was `filename.az' */
/* Now `filename.ba' */
}
if ((fd = creat(out_file, 0644)) < 0) {
std_err("Cannot create new file.\n");
exit(2);
}
return fd;
}
void usage()
{
std_err("Usage: split [-n] [file [name]].\n");
exit(1);
}
void quit()
{
std_err("split: write error\n");
exit(1);
}