From 37669147781468a0908c1240b26055898ca1e431 Mon Sep 17 00:00:00 2001
From: Lieuwe Rooijakkers <lieuwerooijakkers@gmail.com>
Date: Tue, 6 Aug 2024 16:41:29 +0200
Subject: hoofd: don't read whole file in memory

---
 src/hoofd.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 48 insertions(+), 13 deletions(-)

diff --git a/src/hoofd.c b/src/hoofd.c
index ffb5563..596461a 100644
--- a/src/hoofd.c
+++ b/src/hoofd.c
@@ -1,3 +1,5 @@
+#include <assert.h>
+#include <errno.h>
 #include <getopt.h>
 #include <pwd.h>
 #include <stdlib.h>
@@ -7,7 +9,7 @@
 
 #include "util/debug.h"
 #include "util/error.h"
-#include "util/loop_files.h"
+#include "util/loop_args.h"
 #include "util/versie.h"
 
 #include "io/read_file.h"
@@ -59,28 +61,61 @@ static char** parse_options(int argc, char **argv, int *n, int *c) {
   return argv + optind;
 }
 
-// TODO: be smarter, hoofd doesn't have to read the whole file in memory (for
-// unmappable files)
+static int process(char *fname, bool isstdin) {
+  FILE *stream = NULL;
+  if (isstdin) {
+    stream = stdin;
+  } else {
+    stream = fopen(fname, "rb");
+  }
+
+  if (gc != -1) {
+    char *buf = calloc(gc, 1);
 
-static int process(struct filebuf *fb, char*, bool) {
-  int n = gn, c = gc;
+    if (fread(buf, 1, gc, stream) != (unsigned int)gc) {
+      printf("hoofd: fout bij lezen uit bestand '%s'\n", fname);
+      exit(1);
+    }
 
-  size_t i;
-  for (i = 0; i < fb->sz && (n > 0 || n == -1) && (c > 0 || c == -1); i++) {
-    if (fb->buf[i] == '\n') {
-      if (n != -1) n--;
+    if (fwrite(buf, 1, gc, stdout) != (unsigned int)gc) {
+      printf("hoofd: fout bij schrijven naar stanaard uitvoer\n");
+      exit(1);
     }
-    if (c != -1) c--;
+
+    free(buf);
+    goto done;
+  }
+
+  assert(gn >= 0);
+  int n = gn;
+
+  char *line = NULL;
+  size_t linen = 0;
+
+  ssize_t nread = 0;
+  while ((errno = 0, nread = getline(&line, &linen, stream)) != -1) {
+    if (n == 0) break;
+    printf("%s", line);
+    n--;
   }
-  fwrite(fb->buf, 1, i, stdout);
 
-  free_filebuf(fb);
+  free(line);
+
+  if (errno != 0) {
+    printf("hoofd: fout bij lezen uit bestand '%s'\n", fname);
+    exit(1);
+  }
 
+done:
+  if (!isstdin) {
+    fclose(stream);
+  }
   return 0;
 }
 
 int entry_hoofd(int argc, char **argv) {
   gn = 10, gc = -1;
   char **args = parse_options(argc, argv, &gn, &gc);
-  return loop_files(args, process);
+
+  return loop_args(args, process);
 }
-- 
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