The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/xpcom/ds/StringBuilder.h	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,84 @@
     1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
     1.5 +/* vim:set ts=4 sw=4 sts=4 et cindent: */
     1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
     1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
     1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
     1.9 +
    1.10 +/* We would use std::max but MS makes it painful
    1.11 +// windef.h defines min and max macros that we don't want
    1.12 +// http://support.microsoft.com/kb/143208
    1.13 +#ifdef _WIN32
    1.14 +#define NOMINMAX
    1.15 +#endif
    1.16 +*/
    1.17 +
    1.18 +#include <stdlib.h>
    1.19 +#include <string.h>
    1.20 +#include "nsAlgorithm.h"
    1.21 +
    1.22 +/* This is a standard string builder like ones in Java
    1.23 +   or C#. It uses a doubling allocation strategy
    1.24 +   to grow when out of capacity.
    1.25 +
    1.26 +   This does not use nsTArray because nsTArray starts
    1.27 +   growing by multiples of page size after it is the
    1.28 +   size of one page. We want to keep doubling in size
    1.29 +   so that we can continue to append at high speed even
    1.30 +   for large strings.
    1.31 +
    1.32 +   Eventually, this should be templated for wide characters.
    1.33 +
    1.34 + */
    1.35 +
    1.36 +namespace mozilla {
    1.37 +
    1.38 +class StringBuilder
    1.39 +{
    1.40 +public:
    1.41 +    StringBuilder() {
    1.42 +        mCapacity = 16;
    1.43 +        mLength = 0;
    1.44 +        mBuffer = static_cast<char*>(malloc(sizeof(char)*mCapacity));
    1.45 +        mBuffer[0] = '\0';
    1.46 +    }
    1.47 +
    1.48 +    void Append(const char *s) {
    1.49 +        size_t newLength = strlen(s);
    1.50 +
    1.51 +        EnsureCapacity(mLength + newLength+1);
    1.52 +
    1.53 +        // copy the entire string including the null terminator
    1.54 +        memcpy(&mBuffer[mLength], s, newLength+1);
    1.55 +        mLength += newLength;
    1.56 +    }
    1.57 +
    1.58 +    char *Buffer() {
    1.59 +        return mBuffer;
    1.60 +    }
    1.61 +
    1.62 +    size_t Length() {
    1.63 +        return mLength;
    1.64 +    }
    1.65 +
    1.66 +    size_t EnsureCapacity(size_t capacity) {
    1.67 +        if (capacity > mCapacity) {
    1.68 +            // make sure we at least double in size
    1.69 +            mCapacity = XPCOM_MAX(capacity, mCapacity*2);
    1.70 +            mBuffer = static_cast<char*>(realloc(mBuffer, mCapacity));
    1.71 +            mCapacity = moz_malloc_usable_size(mBuffer);
    1.72 +        }
    1.73 +        return mCapacity;
    1.74 +    }
    1.75 +
    1.76 +    ~StringBuilder()
    1.77 +    {
    1.78 +        free(mBuffer);
    1.79 +    }
    1.80 +
    1.81 +private:
    1.82 +    char *mBuffer;
    1.83 +    size_t mLength; // the length of the contained string not including the null terminator
    1.84 +    size_t mCapacity; // the total size of mBuffer
    1.85 +};
    1.86 +
    1.87 +}