Accept streams as input. Use a temp file

[overonion] / reverse.c

diff --git a/reverse.c b/reverse.c
index ac55a102c1fc2f8fd4d6513a99f182aade5aa8a7..02a349fc33009860caa43dea115fbc27fdc86b19 100644 (file)
--- a/reverse.c
+++ b/reverse.c
@@ -1,70 +1,17 @@
-#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;
 }