mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-12-13 10:25:01 +00:00
85 lines
2.2 KiB
C++
85 lines
2.2 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
|
|
/* vim:set ts=4 sw=4 sts=4 et cindent: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
/* We would use std::max but MS makes it painful
|
|
// windef.h defines min and max macros that we don't want
|
|
// http://support.microsoft.com/kb/143208
|
|
#ifdef _WIN32
|
|
#define NOMINMAX
|
|
#endif
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include "nsAlgorithm.h"
|
|
|
|
/* This is a standard string builder like ones in Java
|
|
or C#. It uses a doubling allocation strategy
|
|
to grow when out of capacity.
|
|
|
|
This does not use nsTArray because nsTArray starts
|
|
growing by multiples of page size after it is the
|
|
size of one page. We want to keep doubling in size
|
|
so that we can continue to append at high speed even
|
|
for large strings.
|
|
|
|
Eventually, this should be templated for wide characters.
|
|
|
|
*/
|
|
|
|
namespace mozilla {
|
|
|
|
class StringBuilder
|
|
{
|
|
public:
|
|
StringBuilder() {
|
|
mCapacity = 16;
|
|
mLength = 0;
|
|
mBuffer = static_cast<char*>(malloc(sizeof(char)*mCapacity));
|
|
mBuffer[0] = '\0';
|
|
}
|
|
|
|
void Append(const char *s) {
|
|
size_t newLength = strlen(s);
|
|
|
|
EnsureCapacity(mLength + newLength+1);
|
|
|
|
// copy the entire string including the null terminator
|
|
memcpy(&mBuffer[mLength], s, newLength+1);
|
|
mLength += newLength;
|
|
}
|
|
|
|
char *Buffer() {
|
|
return mBuffer;
|
|
}
|
|
|
|
size_t Length() {
|
|
return mLength;
|
|
}
|
|
|
|
size_t EnsureCapacity(size_t capacity) {
|
|
if (capacity > mCapacity) {
|
|
// make sure we at least double in size
|
|
mCapacity = XPCOM_MAX(capacity, mCapacity*2);
|
|
mBuffer = static_cast<char*>(realloc(mBuffer, mCapacity));
|
|
mCapacity = moz_malloc_usable_size(mBuffer);
|
|
}
|
|
return mCapacity;
|
|
}
|
|
|
|
~StringBuilder()
|
|
{
|
|
free(mBuffer);
|
|
}
|
|
|
|
private:
|
|
char *mBuffer;
|
|
size_t mLength; // the length of the contained string not including the null terminator
|
|
size_t mCapacity; // the total size of mBuffer
|
|
};
|
|
|
|
}
|