src/shared/utf8.c: follow upstream adding utf8_encode_unichar()

This is part of upstream's e7eebcfc42f00aa481ef31abc8e7e243c16f5b2c
in which they add a minimal JSON tokenizer.  We don't add that but
update utf8 stuff from that commit to follow upstream more closely.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

2 files changed, 23 insertions, 24 deletions

diff --git a/src/shared/utf8.c b/src/shared/utf8.c
index 75ed7caee3..4420a45b36 100644
--- a/src/shared/utf8.c
+++ b/src/shared/utf8.c
@@ -177,39 +177,37 @@ char *ascii_is_valid(const char *str) {
         return (char*) str;
 }
 
+int utf8_encode_unichar(uint16_t c, char *p) {
+        uint8_t *t = (uint8_t*) p;
+        int d;
+
+        if (c < 0x80) {
+                t[0] = (uint8_t) c;
+                return 1;
+        } else if (c < 0x800) {
+                t[0] = (uint8_t) (0xc0 | (c >> 6));
+                t[1] = (uint8_t) (0x80 | (c & 0x3f));
+                return 2;
+        } else {
+                t[0] = (uint8_t) (0xe0 | (c >> 12));
+                t[1] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
+                t[2] = (uint8_t) (0x80 | (c & 0x3f));
+                return 3;
+        }
+}
+
 char *utf16_to_utf8(const void *s, size_t length) {
-        char *r;
         const uint8_t *f;
-        uint8_t *t;
+        char *r, *t;
 
         r = new(char, (length*3+1)/2 + 1);
         if (!r)
                 return NULL;
 
-        t = (uint8_t*) r;
-
-        for (f = s; f < (const uint8_t*) s + length; f += 2) {
-                uint16_t c;
-
-                c = (f[1] << 8) | f[0];
-
-                if (c == 0) {
-                        *t = 0;
-                        return r;
-                } else if (c < 0x80) {
-                        *(t++) = (uint8_t) c;
-                } else if (c < 0x800) {
-                        *(t++) = (uint8_t) (0xc0 | (c >> 6));
-                        *(t++) = (uint8_t) (0x80 | (c & 0x3f));
-                } else {
-                        *(t++) = (uint8_t) (0xe0 | (c >> 12));
-                        *(t++) = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
-                        *(t++) = (uint8_t) (0x80 | (c & 0x3f));
-                }
-        }
+        for (f = s, t = r; f < (const uint8_t*) s + length; f += 2)
+                t += utf8_encode_unichar((f[1] << 8) | f[0], t);
 
         *t = 0;
-
         return r;
 }
 
diff --git a/src/shared/utf8.h b/src/shared/utf8.h
index 24232247f5..6112332a4e 100644
--- a/src/shared/utf8.h
+++ b/src/shared/utf8.h
@@ -30,6 +30,7 @@ _pure_ static inline bool utf8_is_printable(const char* str, size_t length) {
         return utf8_is_printable_newline(str, length, true);
 }
 
+int utf8_encode_unichar(uint16_t c, char *p);
 char *utf16_to_utf8(const void *s, size_t length);
 
 int utf8_encoded_valid_unichar(const char *str);