Add mg_http_var

src/http.c

@@ -87,32 +87,32 @@ void mg_http_bauth(struct mg_connection *c, const char *user,
   }
 }
 
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name) {
+  struct mg_str k, v, result = mg_str_n(NULL, 0);
+  while (mg_split(&buf, &k, &v, '&')) {
+    if (name.len == k.len && mg_ncasecmp(name.ptr, k.ptr, k.len) == 0) {
+      result = v;
+      break;
+    }
+  }
+  return result;
+}
+
 int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
                     size_t dst_len) {
-  const char *p, *e, *s;
-  size_t name_len;
   int len;
-
   if (dst == NULL || dst_len == 0) {
     len = -2;  // Bad destination
   } else if (buf->ptr == NULL || name == NULL || buf->len == 0) {
     len = -1;  // Bad source
     dst[0] = '\0';
   } else {
-    name_len = strlen(name);
-    e = buf->ptr + buf->len;
-    len = -4;  // Name does not exist
-    dst[0] = '\0';
-    for (p = buf->ptr; p + name_len < e; p++) {
-      if ((p == buf->ptr || p[-1] == '&') && p[name_len] == '=' &&
-          !mg_ncasecmp(name, p, name_len)) {
-        p += name_len + 1;
-        s = (const char *) memchr(p, '&', (size_t) (e - p));
-        if (s == NULL) s = e;
-        len = mg_url_decode(p, (size_t) (s - p), dst, dst_len, 1);
-        if (len < 0) len = -3;  // Failed to decode
-        break;
-      }
+    struct mg_str v = mg_http_var(*buf, mg_str(name));
+    if (v.ptr == NULL) {
+      len = -4;  // Name does not exist
+    } else {
+      len = mg_url_decode(v.ptr, v.len, dst, dst_len, 1);
+      if (len < 0) len = -3;  // Failed to decode
     }
   }
   return len;