src/kits/network/libnetapi/DynamicBuffer.cpp

   1 /*
   2  * Copyright 2009, Haiku, Inc. All Rights Reserved.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Authors:
   6  *              Bruno Albuquerque, bga@bug-br.org.br
   7  */
   8
   9 #include "DynamicBuffer.h"
  10
  11 #include <stdio.h>
  12 #include <string.h>
  13
  14 #include <algorithm>
  15
  16 #include <Errors.h>
  17 #include <SupportDefs.h>
  18
  19 #include <new>
  20
  21 DynamicBuffer::DynamicBuffer(size_t initialSize) :
  22         fBuffer(NULL),
  23         fBufferSize(0),
  24         fDataStart(0),
  25         fDataEnd(0),
  26         fInit(B_NO_INIT)
  27 {
  28         fBuffer = new (std::nothrow) unsigned char[initialSize];
  29         if (fBuffer != NULL) {
  30                 fBufferSize = initialSize;
  31                 fInit = B_OK;
  32         }
  33 }
  34
  35
  36 DynamicBuffer::~DynamicBuffer()
  37 {
  38         delete[] fBuffer;
  39         fBufferSize = 0;
  40         fDataStart = 0;
  41         fDataEnd = 0;
  42 }
  43
  44
  45 DynamicBuffer::DynamicBuffer(const DynamicBuffer& buffer) :
  46         fBuffer(NULL),
  47         fBufferSize(0),
  48         fDataStart(0),
  49         fDataEnd(0),
  50         fInit(B_NO_INIT)
  51 {
  52         fInit = buffer.fInit;
  53         if (fInit == B_OK) {
  54                 status_t result = _GrowToFit(buffer.fBufferSize, true);
  55                 if (result == B_OK) {
  56                         memcpy(fBuffer, buffer.fBuffer, fBufferSize);
  57                         fDataStart = buffer.fDataStart;
  58                         fDataEnd = buffer.fDataEnd;
  59                 } else
  60                         fInit = result;
  61         }
  62 }
  63
  64
  65 status_t
  66 DynamicBuffer::InitCheck() const
  67 {
  68         return fInit;
  69 }
  70
  71
  72 ssize_t
  73 DynamicBuffer::Write(const void* data, size_t size)
  74 {
  75         if (fInit != B_OK)
  76                 return fInit;
  77
  78         status_t result = _GrowToFit(size);
  79         if (result != B_OK)
  80                 return result;
  81
  82         memcpy(fBuffer + fDataEnd, data, size);
  83         fDataEnd += size;
  84
  85         return (ssize_t)size;
  86 }
  87
  88
  89 ssize_t
  90 DynamicBuffer::Read(void* data, size_t size)
  91 {
  92         if (fInit != B_OK)
  93                 return fInit;
  94
  95         size = std::min(size, Size());
  96         if (size == 0)
  97                 return 0;
  98
  99         memcpy(data, fBuffer + fDataStart, size);
 100         fDataStart += size;
 101
 102         if (fDataStart == fDataEnd)
 103                 fDataStart = fDataEnd = 0;
 104
 105         return size;
 106 }
 107
 108
 109 unsigned char*
 110 DynamicBuffer::Data() const
 111 {
 112         return fBuffer + fDataStart;
 113 }
 114
 115
 116 size_t
 117 DynamicBuffer::Size() const
 118 {
 119         return fDataEnd - fDataStart;
 120 }
 121
 122
 123 size_t
 124 DynamicBuffer::BytesRemaining() const
 125 {
 126         return fBufferSize - fDataEnd;
 127 }
 128
 129
 130 void
 131 DynamicBuffer::PrintToStream()
 132 {
 133         printf("Current buffer size : %ld\n", fBufferSize);
 134         printf("Data start position : %ld\n", fDataStart);
 135         printf("Data end position   : %ld\n", fDataEnd);
 136         printf("Bytes wasted        : %ld\n", fDataStart);
 137         printf("Bytes available     : %ld\n", fBufferSize - fDataEnd);
 138 }
 139
 140
 141 status_t
 142 DynamicBuffer::_GrowToFit(size_t size, bool exact)
 143 {
 144         if (size <= fBufferSize - fDataEnd)
 145                 return B_OK;
 146
 147         size_t newSize;
 148         if (!exact)
 149                 newSize = (fBufferSize + size) * 2;
 150         else
 151                 newSize = size;
 152
 153         unsigned char* newBuffer = new (std::nothrow) unsigned char[newSize];
 154         if (newBuffer == NULL)
 155                 return B_NO_MEMORY;
 156
 157         if (fDataStart != fDataEnd)
 158                 memcpy(newBuffer, fBuffer + fDataStart, fDataEnd - fDataStart);
 159
 160         delete[] fBuffer;
 161         fBuffer = newBuffer;
 162         fDataEnd -= fDataStart;
 163         fDataStart = 0;
 164         fBufferSize = newSize;
 165
 166         return B_OK;
 167 }