From 2688277a4efe011ffd35f0e3ce859bb110207d8e Mon Sep 17 00:00:00 2001
From: Tyge Lovset <tylovset@gmail.com>
Date: Mon, 30 May 2022 23:15:53 +0200
Subject: Added utf8_icmp_n() case insensitive comparison.

---
 include/stc/ccommon.h |  8 ++++----
 include/stc/utf8.h    |  6 ++++++
 src/utf8code.c        | 13 +++++++++++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/include/stc/ccommon.h b/include/stc/ccommon.h
index 9c8ba414..2ebcf7c1 100644
--- a/include/stc/ccommon.h
+++ b/include/stc/ccommon.h
@@ -120,7 +120,7 @@ typedef const char* crawstr;
 #define _c_ROTL(x, k) (x << (k) | x >> (8*sizeof(x) - (k)))
 
 STC_INLINE uint64_t c_fasthash(const void* key, size_t len) {
-    const uint8_t *x = (const uint8_t*) key; 
+    const uint8_t *x = (const uint8_t*) key;
     uint64_t u8, h = 1; size_t n = len >> 3;
     uint32_t u4;
     while (n--) {
@@ -137,16 +137,16 @@ STC_INLINE uint64_t c_fasthash(const void* key, size_t len) {
     return _c_ROTL(h, 26) ^ h;
 }
 
-STC_INLINE uint64_t c_strhash(const char *str) 
+STC_INLINE uint64_t c_strhash(const char *str)
     { return c_fasthash(str, strlen(str)); }
 
-STC_INLINE char* c_strnstrn(const char *s, const char *needle, 
+STC_INLINE char* c_strnstrn(const char *s, const char *needle,
                             size_t slen, const size_t nlen) {
     if (!nlen) return (char *)s;
     if (nlen > slen) return NULL;
     slen -= nlen;
     do {
-        if (*s == *needle && !memcmp(s, needle, nlen)) 
+        if (*s == *needle && !memcmp(s, needle, nlen))
             return (char *)s;
         ++s;
     } while (slen--);
diff --git a/include/stc/utf8.h b/include/stc/utf8.h
index 67722345..333a0f92 100644
--- a/include/stc/utf8.h
+++ b/include/stc/utf8.h
@@ -35,8 +35,10 @@ bool        utf8_isalpha(uint32_t c);
 bool        utf8_isalnum(uint32_t c);
 uint32_t    utf8_tolower(uint32_t c);
 uint32_t    utf8_toupper(uint32_t c);
+
 bool        utf8_valid(const char* s);
 bool        utf8_valid_n(const char* s, size_t n);
+int         utf8_icmp_n(const char* s1, const char* s2, size_t u8max);
 
 /* encode/decode next utf8 codepoint. */
 enum { UTF8_OK = 0, UTF8_ERROR = 4 };
@@ -46,6 +48,10 @@ void        utf8_peek(utf8_decode_t* d, const char *s);
 unsigned    utf8_encode(char *out, uint32_t c);
 void        utf8_decode(utf8_decode_t *d, const uint8_t b);
 
+/* case-insensitive utf8 string comparison */
+STC_INLINE int utf8_icmp(const char* s1, const char* s2)
+    { return utf8_icmp_n(s1, s2, (size_t)(-1)); }
+
 /* number of characters in the utf8 codepoint from s */
 STC_INLINE unsigned utf8_codep_size(const char *s) {
     unsigned b = (uint8_t)*s;
diff --git a/src/utf8code.c b/src/utf8code.c
index c58f78b6..cef3efca 100644
--- a/src/utf8code.c
+++ b/src/utf8code.c
@@ -100,6 +100,19 @@ uint32_t utf8_toupper(uint32_t c) {
     return c;
 }
 
+int utf8_icmp_n(const char* s1, const char* s2, size_t u8max) {
+    int ret = 0;
+    utf8_decode_t d1 = {UTF8_OK}, d2 = {UTF8_OK};
+    for (; u8max--; s1 += d1.size, s2 += d2.size) {
+        utf8_peek(&d1, s1);
+        utf8_peek(&d2, s2);
+        ret = utf8_tolower(d1.codep) - utf8_tolower(d2.codep);
+        if (ret || !*s2)
+            break;
+    }
+    return ret;
+}
+
 bool utf8_isupper(uint32_t c) {
     return utf8_tolower(c) != c;
 }
-- 
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