Updated _advance() iter methods. Some have signed offsets.

utf8_peek()/utf8_peek_off() added/changed.

1 files changed, 9 insertions, 3 deletions

diff --git a/include/stc/utf8.h b/include/stc/utf8.h
index c20b80cb..7a4ba921 100644
--- a/include/stc/utf8.h
+++ b/include/stc/utf8.h
@@ -17,13 +17,13 @@ extern uint32_t utf8_toupper(uint32_t c);
 extern bool     utf8_valid_n(const char* s, size_t nbytes);
 extern int      utf8_icmp_sv(csview s1, csview s2);
 extern unsigned utf8_encode(char *out, uint32_t c);
-extern uint32_t utf8_peek(const char *s, int u8pos);
+extern uint32_t utf8_peek_off(const char *s, int offset);
+
+/* following functions uses src/utf8code.c */
 
 STC_INLINE bool utf8_isupper(uint32_t c) { return utf8_tolower(c) != c; }
 STC_INLINE bool utf8_islower(uint32_t c) { return utf8_toupper(c) != c; }
 
-/* following functions uses src/utf8code.c */
-
 /* decode next utf8 codepoint. https://bjoern.hoehrmann.de/utf-8/decoder/dfa */
 typedef struct { uint32_t state, codep; } utf8_decode_t;
 
@@ -35,6 +35,12 @@ STC_INLINE uint32_t utf8_decode(utf8_decode_t* d, const uint32_t byte) {
     return d->state = utf8_dtab[256 + d->state + type];
 }
 
+STC_INLINE uint32_t utf8_peek(const char* s) {
+    utf8_decode_t d = {.state=0};
+    do { utf8_decode(&d, (uint8_t)*s++); } while (d.state);
+    return d.codep;
+}
+
 /* case-insensitive utf8 string comparison */
 STC_INLINE int utf8_icmp(const char* s1, const char* s2) {
     return utf8_icmp_sv(c_sv(s1, ~(size_t)0), c_sv(s2, ~(size_t)0));