The Tor Browser: xpcom/ds/StringBuilder.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

     2 /* vim:set ts=4 sw=4 sts=4 et cindent: */

     3 /* This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 /* We would use std::max but MS makes it painful

     8 // windef.h defines min and max macros that we don't want

     9 // http://support.microsoft.com/kb/143208

    10 #ifdef _WIN32

    11 #define NOMINMAX

    12 #endif

    13 */

    15 #include <stdlib.h>

    16 #include <string.h>

    17 #include "nsAlgorithm.h"

    19 /* This is a standard string builder like ones in Java

    20    or C#. It uses a doubling allocation strategy

    21    to grow when out of capacity.

    23    This does not use nsTArray because nsTArray starts

    24    growing by multiples of page size after it is the

    25    size of one page. We want to keep doubling in size

    26    so that we can continue to append at high speed even

    27    for large strings.

    29    Eventually, this should be templated for wide characters.

    31  */

    33 namespace mozilla {

    35 class StringBuilder

    36 {

    37 public:

    38     StringBuilder() {

    39         mCapacity = 16;

    40         mLength = 0;

    41         mBuffer = static_cast<char*>(malloc(sizeof(char)*mCapacity));

    42         mBuffer[0] = '\0';

    43     }

    45     void Append(const char *s) {

    46         size_t newLength = strlen(s);

    48         EnsureCapacity(mLength + newLength+1);

    50         // copy the entire string including the null terminator

    51         memcpy(&mBuffer[mLength], s, newLength+1);

    52         mLength += newLength;

    53     }

    55     char *Buffer() {

    56         return mBuffer;

    57     }

    59     size_t Length() {

    60         return mLength;

    61     }

    63     size_t EnsureCapacity(size_t capacity) {

    64         if (capacity > mCapacity) {

    65             // make sure we at least double in size

    66             mCapacity = XPCOM_MAX(capacity, mCapacity*2);

    67             mBuffer = static_cast<char*>(realloc(mBuffer, mCapacity));

    68             mCapacity = moz_malloc_usable_size(mBuffer);

    69         }

    70         return mCapacity;

    71     }

    73     ~StringBuilder()

    74     {

    75         free(mBuffer);

    76     }

    78 private:

    79     char *mBuffer;

    80     size_t mLength; // the length of the contained string not including the null terminator

    81     size_t mCapacity; // the total size of mBuffer

    82 };

    84 }

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