Move mg_ncasecmp and sister to common string utils

PUBLISHED_FROM=182c43c3bd82190cb816c8ebaddccc13a94950d0

docs/c-api/util.h/intro.md

@@ -8,7 +8,6 @@ items:
   - { name: mg_base64_decode.md }
   - { name: mg_base64_encode.md }
   - { name: mg_basic_auth_header.md }
-  - { name: mg_casecmp.md }
   - { name: mg_conn_addr_to_str.md }
   - { name: mg_fopen.md }
   - { name: mg_hexdump.md }
@@ -17,7 +16,6 @@ items:
   - { name: mg_match_prefix.md }
   - { name: mg_mbuf_append_base64.md }
   - { name: mg_mbuf_append_base64_putc.md }
-  - { name: mg_ncasecmp.md }
   - { name: mg_next_comma_list_entry.md }
   - { name: mg_open.md }
   - { name: mg_skip.md }

docs/c-api/util.h/mg_casecmp.md

----
-title: "mg_casecmp()"
-decl_name: "mg_casecmp"
-symbol_kind: "func"
-signature: |
-  int mg_casecmp(const char *s1, const char *s2);
----
-
-Cross-platform version of `strcasecmp()`. 
-

docs/c-api/util.h/mg_ncasecmp.md

----
-title: "mg_ncasecmp()"
-decl_name: "mg_ncasecmp"
-symbol_kind: "func"
-signature: |
-  int mg_ncasecmp(const char *s1, const char *s2, size_t len);
----
-
-Cross-platform version of `strncasecmp()`. 
-

mongoose.c

@@ -1794,6 +1794,24 @@ int64_t cs_to64(const char *s) {
 }
 #endif
 
+static int str_util_lowercase(const char *s) {
+  return tolower(*(const unsigned char *) s);
+}
+
+int mg_ncasecmp(const char *s1, const char *s2, size_t len) {
+  int diff = 0;
+
+  if (len > 0) do {
+      diff = str_util_lowercase(s1++) - str_util_lowercase(s2++);
+    } while (diff == 0 && s1[-1] != '\0' && --len > 0);
+
+  return diff;
+}
+
+int mg_casecmp(const char *s1, const char *s2) {
+  return mg_ncasecmp(s1, s2, (size_t) ~0);
+}
+
 #endif /* EXCLUDE_COMMON */
 #ifdef MG_MODULE_LINES
 #line 1 "mongoose/src/tun.h"
@@ -8891,7 +8909,7 @@ struct mg_connection *mg_connect_ws(struct mg_mgr *mgr,
 
 /* For platforms with limited libc */
 #ifndef MAX
-#define MAX(a,b) ((a) > (b)? (a): (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
 #endif
 
 const char *mg_skip(const char *s, const char *end, const char *delims,
@@ -8907,20 +8925,6 @@ static int lowercase(const char *s) {
   return tolower(*(const unsigned char *) s);
 }
 
-int mg_ncasecmp(const char *s1, const char *s2, size_t len) {
-  int diff = 0;
-
-  if (len > 0) do {
-      diff = lowercase(s1++) - lowercase(s2++);
-    } while (diff == 0 && s1[-1] != '\0' && --len > 0);
-
-  return diff;
-}
-
-int mg_casecmp(const char *s1, const char *s2) {
-  return mg_ncasecmp(s1, s2, (size_t) ~0);
-}
-
 #if MG_ENABLE_FILESYSTEM
 int mg_stat(const char *path, cs_stat_t *st) {
 #ifdef _WIN32

mongoose.h

@@ -1859,6 +1859,16 @@ char *strdup(const char *src);
 int64_t cs_to64(const char *s);
 #endif
 
+/*
+ * Cross-platform version of `strncasecmp()`.
+ */
+int mg_ncasecmp(const char *s1, const char *s2, size_t len);
+
+/*
+ * Cross-platform version of `strcasecmp()`.
+ */
+int mg_casecmp(const char *s1, const char *s2);
+
 #ifdef __cplusplus
 }
 #endif
@@ -3640,16 +3650,6 @@ extern "C" {
 const char *mg_skip(const char *s, const char *end_string,
                     const char *delimiters, struct mg_str *v);
 
-/*
- * Cross-platform version of `strncasecmp()`.
- */
-int mg_ncasecmp(const char *s1, const char *s2, size_t len);
-
-/*
- * Cross-platform version of `strcasecmp()`.
- */
-int mg_casecmp(const char *s1, const char *s2);
-
 /*
  * Decodes base64-encoded string `s`, `len` into the destination `dst`.
  * The destination has to have enough space to hold the decoded buffer.