+/**
+ * utf8_encode_unichar() - Encode single UCS-4 character as UTF-8
+ * @out_utf8: output buffer of at least 4 bytes or NULL
+ * @g: UCS-4 character to encode
+ *
+ * This encodes a single UCS-4 character as UTF-8 and writes it into @out_utf8.
+ * The length of the character is returned. It is not zero-terminated! If the
+ * output buffer is NULL, only the length is returned.
+ *
+ * Returns: The length in bytes that the UTF-8 representation does or would
+ * occupy.
+ */
+size_t utf8_encode_unichar(char *out_utf8, uint32_t g) {
+ if (g < (1 << 7)) {
+ if (out_utf8)
+ out_utf8[0] = g & 0x7f;
+ return 1;
+ } else if (g < (1 << 11)) {
+ if (out_utf8) {
+ out_utf8[0] = 0xc0 | ((g >> 6) & 0x1f);
+ out_utf8[1] = 0x80 | (g & 0x3f);
+ }
+ return 2;
+ } else if (g < (1 << 16)) {
+ if (out_utf8) {
+ out_utf8[0] = 0xe0 | ((g >> 12) & 0x0f);
+ out_utf8[1] = 0x80 | ((g >> 6) & 0x3f);
+ out_utf8[2] = 0x80 | (g & 0x3f);
+ }
+ return 3;
+ } else if (g < (1 << 21)) {
+ if (out_utf8) {
+ out_utf8[0] = 0xf0 | ((g >> 18) & 0x07);
+ out_utf8[1] = 0x80 | ((g >> 12) & 0x3f);
+ out_utf8[2] = 0x80 | ((g >> 6) & 0x3f);
+ out_utf8[3] = 0x80 | (g & 0x3f);
+ }
+ return 4;
+ } else {
+ return 0;
+ }
+}
+