Implement UTF-8-clean window titles

src/util.c

@@ -17,6 +17,7 @@
 #include <sys/wait.h>
 #include <stdarg.h>
 #include <assert.h>
+#include <iconv.h>
 
 #include "i3.h"
 #include "data.h"
@@ -25,6 +26,8 @@
 #include "util.h"
 #include "xcb.h"
 
+static iconv_t conversion_descriptor = 0;
+
 int min(int a, int b) {
         return (a < b ? a : b);
 }
@@ -135,6 +138,49 @@ void check_error(xcb_connection_t *conn, xcb_void_cookie_t cookie, char *err_mes
         }
 }
 
+/*
+ * Converts the given string to UCS-2 big endian for use with
+ * xcb_image_text_16(). The amount of real glyphs is stored in real_strlen,
+ * a buffer containing the UCS-2 encoded string (16 bit per glyph) is
+ * returned. It has to be freed when done.
+ *
+ */
+char *convert_utf8_to_ucs2(char *input, int *real_strlen) {
+	size_t input_size = strlen(input) + 1;
+	/* UCS-2 consumes exactly two bytes for each glyph */
+	int buffer_size = input_size * 2;
+	printf("reserving %d bytes\n", buffer_size);
+
+	char *buffer = smalloc(buffer_size);
+	size_t output_size = buffer_size;
+	/* We need to use an additional pointer, because iconv() modifies it */
+	char *output = buffer;
+
+	/* We convert the input into UCS-2 big endian */
+        if (conversion_descriptor == 0) {
+                conversion_descriptor = iconv_open("UCS-2BE", "UTF-8");
+                if (conversion_descriptor == 0) {
+                        fprintf(stderr, "error opening the conversion context\n");
+                        exit(1);
+                }
+        }
+
+	/* Get the conversion descriptor back to original state */
+	iconv(conversion_descriptor, NULL, NULL, NULL, NULL);
+
+	/* Convert our text */
+	int rc = iconv(conversion_descriptor, &input, &input_size, &output, &output_size);
+        if (rc == (size_t)-1) {
+		fprintf(stderr, "Converting to UCS-2 failed\n");
+                perror("erron\n");
+		exit(1);
+	}
+
+	*real_strlen = ((buffer_size - output_size) / 2) - 1;
+
+	return buffer;
+}
+
 /*
  * Removes the given client from the container, either because it will be inserted into another
  * one or because it was unmapped