Clean up String::find to remove duplicate code, and speed up comparis…

…on slightly.

core/string/ustring.cpp

@@ -3135,11 +3135,10 @@ int String::find(const String &p_str, int p_from) const {
 	}
 
 	const int src_len = p_str.length();
-
 	const int len = length();
 
-	if (src_len == 0 || len == 0) {
-		return -1; // won't find anything!
+	if (src_len == 0 || len == 0 || src_len > len - p_from) {
+		return -1; // Won't find anything!
 	}
 
 	if (src_len == 1) {
@@ -3152,14 +3151,7 @@ int String::find(const String &p_str, int p_from) const {
 	for (int i = p_from; i <= (len - src_len); i++) {
 		bool found = true;
 		for (int j = 0; j < src_len; j++) {
-			int read_pos = i + j;
-
-			if (read_pos >= len) {
-				ERR_PRINT("read_pos>=len");
-				return -1;
-			}
-
-			if (src[read_pos] != str[j]) {
+			if (src[i + j] != str[j]) {
 				found = false;
 				break;
 			}
@@ -3179,11 +3171,10 @@ int String::find(const char *p_str, int p_from) const {
 	}
 
 	const int src_len = strlen(p_str);
-
 	const int len = length();
 
-	if (len == 0 || src_len == 0) {
-		return -1; // won't find anything!
+	if (len == 0 || src_len == 0 || src_len > len - p_from) {
+		return -1; // Won't find anything!
 	}
 
 	if (src_len == 1) {
@@ -3192,35 +3183,17 @@ int String::find(const char *p_str, int p_from) const {
 
 	const char32_t *src = get_data();
 
-	if (src_len == 1) {
-		const char32_t needle = p_str[0];
-
-		for (int i = p_from; i < len; i++) {
-			if (src[i] == needle) {
-				return i;
+	for (int i = p_from; i <= (len - src_len); i++) {
+		bool found = true;
+		for (int j = 0; j < src_len; j++) {
+			if (src[i + j] != (char32_t)p_str[j]) {
+				found = false;
+				break;
 			}
 		}
 
-	} else {
-		for (int i = p_from; i <= (len - src_len); i++) {
-			bool found = true;
-			for (int j = 0; j < src_len; j++) {
-				int read_pos = i + j;
-
-				if (read_pos >= len) {
-					ERR_PRINT("read_pos>=len");
-					return -1;
-				}
-
-				if (src[read_pos] != (char32_t)p_str[j]) {
-					found = false;
-					break;
-				}
-			}
-
-			if (found) {
-				return i;
-			}
+		if (found) {
+			return i;
 		}
 	}