godot/core/string_builder.cpp
Karroffel 95a0886f93 added StringBuilder class
When doing large string concatenations the default push_back on the
String class can slow down things quite a bit. This is because it
has to constantly reallocate the memory and copy the contents. This
StringBuilder class delays the concatenation until the size of the
resulting string is known.
2017-09-01 19:52:32 +02:00

95 lines
3.4 KiB
C++

/*************************************************************************/
/* string_builder.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "string_builder.h"
#include <string.h>
StringBuilder &StringBuilder::append(const String &p_string) {
strings.push_back(p_string);
appended_strings.push_back(-1);
string_length += p_string.length();
return *this;
}
StringBuilder &StringBuilder::append(const char *p_cstring) {
int32_t len = strlen(p_cstring);
c_strings.push_back(p_cstring);
appended_strings.push_back(len);
string_length += len;
return *this;
}
String StringBuilder::as_string() const {
CharType *buffer = memnew_arr(CharType, string_length);
int current_position = 0;
int godot_string_elem = 0;
int c_string_elem = 0;
for (int i = 0; i < appended_strings.size(); i++) {
if (appended_strings[i] == -1) {
// Godot string
const String &s = strings[godot_string_elem];
memcpy(buffer + current_position, s.ptr(), s.length() * sizeof(CharType));
current_position += s.length();
godot_string_elem++;
} else {
const char *s = c_strings[c_string_elem];
for (int32_t j = 0; j < appended_strings[i]; j++) {
buffer[current_position + j] = s[j];
}
current_position += appended_strings[i];
c_string_elem++;
}
}
String final_string = String(buffer, string_length);
memdelete_arr(buffer);
return final_string;
}