root / arduino-1.0 / hardware / arduino / cores / arduino / Stream.cpp @ 58d82c77
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1 | 58d82c77 | Tom Mullins | /*
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2 | Stream.cpp - adds parsing methods to Stream class
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3 | Copyright (c) 2008 David A. Mellis. All right reserved.
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4 | |||
5 | This library is free software; you can redistribute it and/or
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6 | modify it under the terms of the GNU Lesser General Public
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7 | License as published by the Free Software Foundation; either
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8 | version 2.1 of the License, or (at your option) any later version.
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9 | |||
10 | This library is distributed in the hope that it will be useful,
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 | Lesser General Public License for more details.
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14 | |||
15 | You should have received a copy of the GNU Lesser General Public
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16 | License along with this library; if not, write to the Free Software
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17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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18 | |||
19 | Created July 2011
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20 | parsing functions based on TextFinder library by Michael Margolis
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21 | */
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22 | |||
23 | #include "Arduino.h" |
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24 | #include "Stream.h" |
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25 | |||
26 | #define PARSE_TIMEOUT 1000 // default number of milli-seconds to wait |
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27 | #define NO_SKIP_CHAR 1 // a magic char not found in a valid ASCII numeric field |
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28 | |||
29 | // private method to read stream with timeout
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30 | int Stream::timedRead()
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31 | { |
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32 | int c;
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33 | _startMillis = millis(); |
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34 | do {
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35 | c = read(); |
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36 | if (c >= 0) return c; |
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37 | } while(millis() - _startMillis < _timeout);
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38 | return -1; // -1 indicates timeout |
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39 | } |
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40 | |||
41 | // private method to peek stream with timeout
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42 | int Stream::timedPeek()
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43 | { |
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44 | int c;
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45 | _startMillis = millis(); |
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46 | do {
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47 | c = peek(); |
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48 | if (c >= 0) return c; |
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49 | } while(millis() - _startMillis < _timeout);
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50 | return -1; // -1 indicates timeout |
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51 | } |
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52 | |||
53 | // returns peek of the next digit in the stream or -1 if timeout
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54 | // discards non-numeric characters
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55 | int Stream::peekNextDigit()
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56 | { |
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57 | int c;
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58 | while (1) { |
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59 | c = timedPeek(); |
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60 | if (c < 0) return c; // timeout |
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61 | if (c == '-') return c; |
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62 | if (c >= '0' && c <= '9') return c; |
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63 | read(); // discard non-numeric
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64 | } |
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65 | } |
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66 | |||
67 | // Public Methods
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68 | //////////////////////////////////////////////////////////////
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69 | |||
70 | void Stream::setTimeout(unsigned long timeout) // sets the maximum number of milliseconds to wait |
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71 | { |
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72 | _timeout = timeout; |
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73 | } |
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74 | |||
75 | // find returns true if the target string is found
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76 | bool Stream::find(char *target) |
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77 | { |
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78 | return findUntil(target, NULL); |
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79 | } |
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80 | |||
81 | // reads data from the stream until the target string of given length is found
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82 | // returns true if target string is found, false if timed out
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83 | bool Stream::find(char *target, size_t length) |
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84 | { |
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85 | return findUntil(target, length, NULL, 0); |
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86 | } |
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87 | |||
88 | // as find but search ends if the terminator string is found
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89 | bool Stream::findUntil(char *target, char *terminator) |
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90 | { |
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91 | return findUntil(target, strlen(target), terminator, strlen(terminator));
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92 | } |
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93 | |||
94 | // reads data from the stream until the target string of the given length is found
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95 | // search terminated if the terminator string is found
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96 | // returns true if target string is found, false if terminated or timed out
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97 | bool Stream::findUntil(char *target, size_t targetLen, char *terminator, size_t termLen) |
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98 | { |
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99 | size_t index = 0; // maximum target string length is 64k bytes! |
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100 | size_t termIndex = 0;
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101 | int c;
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102 | |||
103 | if( *target == 0) |
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104 | return true; // return true if target is a null string |
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105 | while( (c = timedRead()) > 0){ |
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106 | if( c == target[index]){
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107 | //////Serial.print("found "); Serial.write(c); Serial.print("index now"); Serial.println(index+1);
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108 | if(++index >= targetLen){ // return true if all chars in the target match |
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109 | return true; |
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110 | } |
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111 | } |
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112 | else{
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113 | index = 0; // reset index if any char does not match |
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114 | } |
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115 | if(termLen > 0 && c == terminator[termIndex]){ |
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116 | if(++termIndex >= termLen)
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117 | return false; // return false if terminate string found before target string |
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118 | } |
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119 | else
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120 | termIndex = 0;
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121 | } |
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122 | return false; |
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123 | } |
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124 | |||
125 | |||
126 | // returns the first valid (long) integer value from the current position.
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127 | // initial characters that are not digits (or the minus sign) are skipped
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128 | // function is terminated by the first character that is not a digit.
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129 | long Stream::parseInt()
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130 | { |
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131 | return parseInt(NO_SKIP_CHAR); // terminate on first non-digit character (or timeout) |
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132 | } |
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133 | |||
134 | // as above but a given skipChar is ignored
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135 | // this allows format characters (typically commas) in values to be ignored
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136 | long Stream::parseInt(char skipChar) |
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137 | { |
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138 | boolean isNegative = false;
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139 | long value = 0; |
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140 | int c;
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141 | |||
142 | c = peekNextDigit(); |
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143 | // ignore non numeric leading characters
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144 | if(c < 0) |
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145 | return 0; // zero returned if timeout |
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146 | |||
147 | do{
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148 | if(c == skipChar)
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149 | ; // ignore this charactor
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150 | else if(c == '-') |
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151 | isNegative = true;
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152 | else if(c >= '0' && c <= '9') // is c a digit? |
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153 | value = value * 10 + c - '0'; |
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154 | read(); // consume the character we got with peek
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155 | c = timedPeek(); |
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156 | } |
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157 | while( (c >= '0' && c <= '9') || c == skipChar ); |
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158 | |||
159 | if(isNegative)
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160 | value = -value; |
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161 | return value;
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162 | } |
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163 | |||
164 | |||
165 | // as parseInt but returns a floating point value
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166 | float Stream::parseFloat()
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167 | { |
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168 | return parseFloat(NO_SKIP_CHAR);
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169 | } |
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170 | |||
171 | // as above but the given skipChar is ignored
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172 | // this allows format characters (typically commas) in values to be ignored
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173 | float Stream::parseFloat(char skipChar){ |
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174 | boolean isNegative = false;
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175 | boolean isFraction = false;
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176 | long value = 0; |
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177 | char c;
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178 | float fraction = 1.0; |
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179 | |||
180 | c = peekNextDigit(); |
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181 | // ignore non numeric leading characters
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182 | if(c < 0) |
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183 | return 0; // zero returned if timeout |
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184 | |||
185 | do{
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186 | if(c == skipChar)
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187 | ; // ignore
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188 | else if(c == '-') |
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189 | isNegative = true;
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190 | else if (c == '.') |
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191 | isFraction = true;
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192 | else if(c >= '0' && c <= '9') { // is c a digit? |
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193 | value = value * 10 + c - '0'; |
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194 | if(isFraction)
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195 | fraction *= 0.1; |
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196 | } |
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197 | read(); // consume the character we got with peek
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198 | c = timedPeek(); |
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199 | } |
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200 | while( (c >= '0' && c <= '9') || c == '.' || c == skipChar ); |
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201 | |||
202 | if(isNegative)
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203 | value = -value; |
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204 | if(isFraction)
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205 | return value * fraction;
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206 | else
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207 | return value;
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208 | } |
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209 | |||
210 | // read characters from stream into buffer
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211 | // terminates if length characters have been read, or timeout (see setTimeout)
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212 | // returns the number of characters placed in the buffer
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213 | // the buffer is NOT null terminated.
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214 | //
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215 | size_t Stream::readBytes(char *buffer, size_t length)
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216 | { |
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217 | size_t count = 0;
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218 | while (count < length) {
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219 | int c = timedRead();
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220 | if (c < 0) break; |
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221 | *buffer++ = (char)c;
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222 | count++; |
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223 | } |
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224 | return count;
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225 | } |
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226 | |||
227 | |||
228 | // as readBytes with terminator character
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229 | // terminates if length characters have been read, timeout, or if the terminator character detected
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230 | // returns the number of characters placed in the buffer (0 means no valid data found)
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231 | |||
232 | size_t Stream::readBytesUntil(char terminator, char *buffer, size_t length) |
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233 | { |
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234 | if (length < 1) return 0; |
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235 | size_t index = 0;
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236 | while (index < length) {
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237 | int c = timedRead();
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238 | if (c < 0 || c == terminator) break; |
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239 | *buffer++ = (char)c;
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240 | index++; |
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241 | } |
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242 | return index; // return number of characters, not including null terminator |
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243 | } |