kat: don't read whole file in memory

1 files changed, 17 insertions, 8 deletions

diff --git a/src/kat.c b/src/kat.c
index a8f8360..a80015e 100644
--- a/src/kat.c
+++ b/src/kat.c
@@ -4,7 +4,7 @@
 #include <unistd.h>
 
 #include "util/versie.h"
-#include "util/loop_files.h"
+#include "util/loop_args.h"
 #include "io/read_file.h"
 
 static void usage(FILE *f) {
@@ -40,16 +40,25 @@ static char** parse_options(int argc, char **argv) {
   return argv + optind;
 }
 
-static int process(struct filebuf *fb, char*, bool) {
-  fwrite(fb->buf, 1, fb->sz, stdout);
-  free_filebuf(fb);
+static int process(char *fname, bool isstdin) {
+#define BUF_SIZE 4096
+
+  static char buf[BUF_SIZE];
+
+  FILE *stream = isstdin ? stdin : fopen(fname, "rb");
+
+  while (!feof(stream)) {
+    const size_t n = fread(buf, 1, BUF_SIZE, stream);
+    fwrite(buf, 1, n, stdout);
+  }
+
+  if (!isstdin) fclose(stream);
   return 0;
-}
 
-// TODO: be smarter, kat doesn't have to read the whole file in memory (for
-// unmappable files)
+#undef BUF_SIZE
+}
 
 int entry_kat(int argc, char **argv) {
   char **args = parse_options(argc, argv);
-  return loop_files(args, process);
+  return loop_args(args, process);
 }