Add daticns utility

Idea from <https://github.com/philipbel/scripts>. Used to extract
icns files from the .dat file in
/System/Library/Keyboard Layouts/AppleKeyboardLayouts.bundle.

1 files changed, 62 insertions, 0 deletions

diff --git a/etc/daticns.c b/etc/daticns.c
new file mode 100644
index 00000000..63f1649d
--- /dev/null
+++ b/etc/daticns.c
@@ -0,0 +1,62 @@
+/* Copyright (C) 2022  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+
+int main(int argc, char *argv[]) {
+	if (argc < 2) return EX_USAGE;
+
+	FILE *file = fopen(argv[1], "r");
+	if (!file) err(EX_NOINPUT, "%s", argv[1]);
+
+	size_t cap = 0x10000;
+	uint8_t *buf = malloc(cap);
+	if (!buf) err(EX_OSERR, "malloc");
+
+	size_t len = 0;
+	for (size_t n; 0 < (n = fread(&buf[len], 1, cap - len, file)); len += n) {
+		buf = realloc(buf, (cap *= 2));
+		if (!buf) err(EX_OSERR, "realloc");
+	}
+
+	unsigned nr = 0;
+	for (
+		uint8_t *ptr = buf;
+		NULL != (ptr = memmem(ptr, &buf[len] - ptr, "icns", 4));
+		ptr += 4
+	) {
+		if (&ptr[8] > &buf[len]) break;
+		size_t len = ptr[4] << 24 | ptr[5] << 16 | ptr[6] << 8 | ptr[7];
+
+		char path[64];
+		snprintf(path, sizeof(path), "icon%04u.icns", ++nr);
+		printf("%s\n", path);
+
+		FILE *icon = fopen(path, "w");
+		if (!icon) err(EX_CANTCREAT, "%s", path);
+
+		size_t n = fwrite(ptr, 8 + len, 1, icon);
+		if (!n) err(EX_IOERR, "%s", path);
+
+		int error = fclose(icon);
+		if (error) err(EX_IOERR, "%s", path);
+	}
+}