-#define _FILE_OFFSET_BITS 64
+#include "reverse_lib.h"
-#define BUFFER_SIZE 4096
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <unistd.h>
#include <err.h>
+#include <stdio.h>
+#include <string.h>
#include <sysexits.h>
-void write_all(int fd, const void *buf, size_t count) {
- const char* cbuf = buf;
- size_t written = 0;
- while (written < count) {
- int ret = write(fd, &cbuf[written], count - written);
- if (ret == -1) {
- err(EX_IOERR, "Could not write");
- }
- written += ret;
- }
-}
-
-
int main(int argc, char** argv) {
- if (argc != 2) {
+ if (argc == 1 || (argc == 2 && strcmp(argv[1], "-") == 0)) {
+ reverse_stream(stdin, stdout);
+ } else if (argc == 2) {
+ reverse_file(argv[1], stdout);
+ } else {
errx(EX_USAGE, "Usage: reverse filename");
}
-
- int fd = open(argv[1], O_RDONLY);
- if (fd == -1) {
- err(EX_NOINPUT, "Could not open specified file");
- }
-
- struct stat stats;
- if (fstat(fd, &stats) == -1) {
- err(EX_NOINPUT, "Could not stat input");
- }
-
- long page_size = sysconf(_SC_PAGE_SIZE);
- off_t pages = (stats.st_size - 1) / page_size + 1;
- long map_size = pages * page_size;
- char *m = mmap(NULL, map_size, PROT_READ, MAP_SHARED, fd, 0);
- if (m == MAP_FAILED) {
- err(EX_NOINPUT, "Could not mmap input");
- }
-
- char buf[BUFFER_SIZE];
- off_t buf_offset = 0;
- for (off_t p = stats.st_size - 1; p >= 0; p--) {
- buf[buf_offset++] = m[p];
- if (buf_offset >= BUFFER_SIZE) {
- write_all(1, buf, buf_offset);
- buf_offset = 0;
- }
- }
- if (buf_offset) {
- write_all(1, buf, buf_offset);
- }
-
- if (munmap(m, map_size) == -1) {
- err(EX_IOERR, "Could not unmap input");
- }
- if (close(fd) == -1) {
- err(EX_IOERR, "Could not close input");
- }
-
return 0;
}