1 | /* |
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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3 | * contributor license agreements. See the NOTICE file distributed with |
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4 | * this work for additional information regarding copyright ownership. |
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5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
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6 | * (the "License"); you may not use this file except in compliance with |
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7 | * the License. You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
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16 | */ |
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17 | |
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18 | /* |
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19 | * $Id: XMLBuffer.hpp 568078 2007-08-21 11:43:25Z amassari $ |
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20 | */ |
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21 | |
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22 | |
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23 | #if !defined(XMLBUFFER_HPP) |
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24 | #define XMLBUFFER_HPP |
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25 | |
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26 | #include <xercesc/util/XMemory.hpp> |
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27 | #include <xercesc/util/PlatformUtils.hpp> |
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28 | #include <xercesc/framework/MemoryManager.hpp> |
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29 | #include <string.h> |
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30 | |
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31 | XERCES_CPP_NAMESPACE_BEGIN |
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32 | |
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33 | class XMLBufferFullHandler; |
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34 | |
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35 | /** |
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36 | * XMLBuffer is a lightweight, expandable Unicode text buffer. Since XML is |
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37 | * inherently theoretically unbounded in terms of the sizes of things, we |
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38 | * very often need to have expandable buffers. The primary concern here is |
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39 | * that appends of characters and other buffers or strings be very fast, so |
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40 | * it always maintains the current buffer size. |
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41 | * |
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42 | * The buffer is not null terminated until some asks to see the raw buffer |
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43 | * contents. This also avoids overhead during append operations. |
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44 | */ |
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45 | class XMLPARSER_EXPORT XMLBuffer : public XMemory |
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46 | { |
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47 | public : |
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48 | // ----------------------------------------------------------------------- |
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49 | // Constructors and Destructor |
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50 | // ----------------------------------------------------------------------- |
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51 | |
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52 | /** @name Constructor */ |
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53 | //@{ |
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54 | XMLBuffer(const unsigned int capacity = 1023 |
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55 | , MemoryManager* const manager = XMLPlatformUtils::fgMemoryManager) : |
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56 | |
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57 | fIndex(0) |
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58 | , fCapacity(capacity) |
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59 | , fFullSize(0) |
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60 | , fUsed(false) |
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61 | , fMemoryManager(manager) |
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62 | , fFullHandler(0) |
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63 | , fBuffer(0) |
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64 | { |
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65 | // Buffer is one larger than capacity, to allow for zero term |
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66 | fBuffer = (XMLCh*) manager->allocate((capacity+1) * sizeof(XMLCh)); //new XMLCh[fCapacity+1]; |
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67 | |
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68 | // Keep it null terminated |
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69 | fBuffer[0] = XMLCh(0); |
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70 | } |
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71 | //@} |
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72 | |
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73 | /** @name Destructor */ |
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74 | //@{ |
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75 | ~XMLBuffer() |
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76 | { |
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77 | fMemoryManager->deallocate(fBuffer); //delete [] fBuffer; |
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78 | } |
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79 | //@} |
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80 | |
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81 | // ----------------------------------------------------------------------- |
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82 | // Buffer Full Handler Management |
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83 | // ----------------------------------------------------------------------- |
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84 | void setFullHandler(XMLBufferFullHandler* handler, const unsigned int fullSize) |
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85 | { |
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86 | if (handler && fullSize) { |
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87 | fFullHandler = handler; |
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88 | fFullSize = fullSize; |
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89 | |
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90 | // Need to consider the case that the fullsize is less than the current capacity. |
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91 | // For example, say fullSize = 100 and fCapacity is 1023 (the default). |
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92 | // If the fIndex is less than the fullSize, then no problem. We can just carry |
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93 | // on by resetting fCapacity to fullsize and proceed business as usual. |
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94 | // If the fIndex is already bigger than the fullSize then we call insureCapacity |
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95 | // to see if it can handle emptying the current buffer (it will throw an |
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96 | // exception if it can't). |
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97 | if (fullSize < fCapacity) { |
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98 | fCapacity = fullSize; |
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99 | if (fIndex >= fullSize) { |
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100 | insureCapacity(0); |
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101 | } |
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102 | } |
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103 | } |
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104 | else { |
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105 | // reset fFullHandler to zero because setFullHandler had bad input |
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106 | fFullHandler = 0; |
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107 | } |
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108 | } |
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109 | |
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110 | // ----------------------------------------------------------------------- |
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111 | // Buffer Management |
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112 | // ----------------------------------------------------------------------- |
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113 | void append(const XMLCh toAppend) |
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114 | { |
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115 | // Put in char and bump the index |
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116 | if (fIndex == fCapacity) |
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117 | insureCapacity(1); |
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118 | fBuffer[fIndex++] = toAppend; |
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119 | } |
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120 | |
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121 | void append (const XMLCh* const chars, const unsigned int count) |
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122 | { |
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123 | if (count) { |
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124 | if (fIndex + count >= fCapacity) { |
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125 | insureCapacity(count); |
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126 | } |
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127 | memcpy(&fBuffer[fIndex], chars, count * sizeof(XMLCh)); |
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128 | fIndex += count; |
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129 | } |
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130 | else { |
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131 | append(chars); |
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132 | } |
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133 | } |
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134 | |
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135 | void append (const XMLCh* const chars) |
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136 | { |
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137 | if (chars != 0 && *chars != 0) { |
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138 | // get length of chars |
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139 | unsigned int count = 0; |
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140 | for (; *(chars+count); count++ ); |
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141 | |
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142 | if (fIndex + count >= fCapacity) { |
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143 | insureCapacity(count); |
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144 | } |
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145 | memcpy(&fBuffer[fIndex], chars, count * sizeof(XMLCh)); |
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146 | fIndex += count; |
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147 | } |
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148 | } |
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149 | |
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150 | void set (const XMLCh* const chars, const unsigned int count) |
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151 | { |
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152 | fIndex = 0; |
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153 | append(chars, count); |
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154 | } |
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155 | |
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156 | void set (const XMLCh* const chars) |
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157 | { |
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158 | fIndex = 0; |
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159 | append(chars); |
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160 | } |
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161 | |
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162 | const XMLCh* getRawBuffer() const |
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163 | { |
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164 | fBuffer[fIndex] = 0; |
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165 | return fBuffer; |
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166 | } |
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167 | |
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168 | XMLCh* getRawBuffer() |
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169 | { |
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170 | fBuffer[fIndex] = 0; |
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171 | return fBuffer; |
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172 | } |
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173 | |
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174 | void reset() |
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175 | { |
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176 | fIndex = 0; |
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177 | fBuffer[0] = 0; |
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178 | } |
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179 | |
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180 | // ----------------------------------------------------------------------- |
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181 | // Getters |
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182 | // ----------------------------------------------------------------------- |
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183 | bool getInUse() const |
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184 | { |
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185 | return fUsed; |
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186 | } |
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187 | |
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188 | unsigned int getLen() const |
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189 | { |
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190 | return fIndex; |
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191 | } |
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192 | |
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193 | bool isEmpty() const |
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194 | { |
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195 | return (fIndex == 0); |
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196 | } |
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197 | |
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198 | // ----------------------------------------------------------------------- |
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199 | // Setters |
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200 | // ----------------------------------------------------------------------- |
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201 | void setInUse(const bool newValue) |
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202 | { |
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203 | fUsed = newValue; |
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204 | } |
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205 | |
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206 | private : |
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207 | // ----------------------------------------------------------------------- |
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208 | // Unimplemented constructors and operators |
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209 | // ----------------------------------------------------------------------- |
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210 | XMLBuffer(const XMLBuffer&); |
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211 | XMLBuffer& operator=(const XMLBuffer&); |
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212 | |
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213 | // ----------------------------------------------------------------------- |
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214 | // Declare our friends |
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215 | // ----------------------------------------------------------------------- |
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216 | friend class XMLBufBid; |
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217 | |
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218 | // ----------------------------------------------------------------------- |
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219 | // Private helpers |
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220 | // ----------------------------------------------------------------------- |
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221 | void insureCapacity(const unsigned int extraNeeded); |
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222 | |
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223 | |
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224 | // ----------------------------------------------------------------------- |
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225 | // Private data members |
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226 | // |
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227 | // fBuffer |
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228 | // The pointer to the buffer data. Its grown as needed. Its always |
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229 | // one larger than fCapacity, to leave room for the null terminator. |
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230 | // |
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231 | // fIndex |
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232 | // The current index into the buffer, as characters are appended |
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233 | // to it. If its zero, then the buffer is empty. |
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234 | // |
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235 | // fCapacity |
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236 | // The current capacity of the buffer. Its actually always one |
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237 | // larger, to leave room for the null terminator. |
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238 | // |
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239 | // fUsed |
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240 | // Indicates whether this buffer is in use or not. |
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241 | // |
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242 | // fFullHandler, fFullSize |
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243 | // If fFullHandler is non-null, the buffer has a maximum size |
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244 | // indicated by fFullSize. If writing to the buffer would exceed the |
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245 | // buffer's maximum size, fFullHandler's bufferFull callback is |
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246 | // invoked, to empty the buffer. |
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247 | // ----------------------------------------------------------------------- |
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248 | unsigned int fIndex; |
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249 | unsigned int fCapacity; |
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250 | unsigned int fFullSize; |
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251 | bool fUsed; |
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252 | MemoryManager* const fMemoryManager; |
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253 | XMLBufferFullHandler* fFullHandler; |
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254 | XMLCh* fBuffer; |
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255 | }; |
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256 | |
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257 | /** |
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258 | * XMLBufferFullHandler is a callback interface for clients of |
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259 | * XMLBuffers that impose a size restriction (e.g. XMLScanner). |
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260 | * Note that this is intended solely as a mix-in for internal |
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261 | * use, and therefore does not derive from XMemory (to avoid |
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262 | * the ambiguous base class problem). |
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263 | */ |
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264 | class XMLPARSER_EXPORT XMLBufferFullHandler |
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265 | { |
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266 | public : |
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267 | |
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268 | virtual ~XMLBufferFullHandler() {} |
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269 | |
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270 | /** |
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271 | * Callback method, intended to allow clients of an XMLBuffer which has |
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272 | * become full to empty it appropriately. |
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273 | * @return true if the handler was able to empty the buffer (either |
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274 | * partially or completely), otherwise false to indicate an error. |
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275 | */ |
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276 | virtual bool bufferFull(XMLBuffer&) = 0; |
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277 | |
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278 | }; |
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279 | |
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280 | XERCES_CPP_NAMESPACE_END |
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281 | |
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282 | #endif |
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