1 | /*
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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 |
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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 |
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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 |
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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 |
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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 |
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23 | #include "Arduino.h"
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24 | #include "Stream.h"
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25 |
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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 |
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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 |
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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 |
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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 |
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67 | // Public Methods
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68 | //////////////////////////////////////////////////////////////
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69 |
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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 |
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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, "");
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79 | }
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80 |
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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 |
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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 |
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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 |
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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 |
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107 | if(c != target[index])
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108 | index = 0; // reset index if any char does not match
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109 |
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110 | if( c == target[index]){
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111 | if(++index >= targetLen){ // return true if all chars in the target match
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112 | return true;
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113 | }
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114 | }
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115 |
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116 | if(termLen > 0 && c == terminator[termIndex]){
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117 | if(++termIndex >= termLen)
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118 | return false; // return false if terminate string found before target string
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119 | }
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120 | else
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121 | termIndex = 0;
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122 | }
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123 | return false;
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124 | }
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125 |
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126 |
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127 | // returns the first valid (long) integer value from the current position.
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128 | // initial characters that are not digits (or the minus sign) are skipped
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129 | // function is terminated by the first character that is not a digit.
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130 | long Stream::parseInt()
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131 | {
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132 | return parseInt(NO_SKIP_CHAR); // terminate on first non-digit character (or timeout)
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133 | }
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134 |
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135 | // as above but a given skipChar is ignored
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136 | // this allows format characters (typically commas) in values to be ignored
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137 | long Stream::parseInt(char skipChar)
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138 | {
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139 | boolean isNegative = false;
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140 | long value = 0;
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141 | int c;
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142 |
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143 | c = peekNextDigit();
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144 | // ignore non numeric leading characters
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145 | if(c < 0)
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146 | return 0; // zero returned if timeout
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147 |
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148 | do{
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149 | if(c == skipChar)
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150 | ; // ignore this charactor
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151 | else if(c == '-')
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152 | isNegative = true;
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153 | else if(c >= '0' && c <= '9') // is c a digit?
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154 | value = value * 10 + c - '0';
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155 | read(); // consume the character we got with peek
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156 | c = timedPeek();
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157 | }
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158 | while( (c >= '0' && c <= '9') || c == skipChar );
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159 |
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160 | if(isNegative)
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161 | value = -value;
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162 | return value;
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163 | }
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164 |
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165 |
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166 | // as parseInt but returns a floating point value
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167 | float Stream::parseFloat()
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168 | {
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169 | return parseFloat(NO_SKIP_CHAR);
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170 | }
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171 |
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172 | // as above but the given skipChar is ignored
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173 | // this allows format characters (typically commas) in values to be ignored
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174 | float Stream::parseFloat(char skipChar){
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175 | boolean isNegative = false;
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176 | boolean isFraction = false;
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177 | long value = 0;
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178 | int c;
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179 | float fraction = 1.0;
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180 |
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181 | c = peekNextDigit();
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182 | // ignore non numeric leading characters
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183 | if(c < 0)
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184 | return 0; // zero returned if timeout
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185 |
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186 | do{
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187 | if(c == skipChar)
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188 | ; // ignore
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189 | else if(c == '-')
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190 | isNegative = true;
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191 | else if (c == '.')
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192 | isFraction = true;
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193 | else if(c >= '0' && c <= '9') { // is c a digit?
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194 | value = value * 10 + c - '0';
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195 | if(isFraction)
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196 | fraction *= 0.1;
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197 | }
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198 | read(); // consume the character we got with peek
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199 | c = timedPeek();
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200 | }
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201 | while( (c >= '0' && c <= '9') || c == '.' || c == skipChar );
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202 |
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203 | if(isNegative)
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204 | value = -value;
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205 | if(isFraction)
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206 | return value * fraction;
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207 | else
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208 | return value;
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209 | }
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210 |
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211 | // read characters from stream into buffer
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212 | // terminates if length characters have been read, or timeout (see setTimeout)
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213 | // returns the number of characters placed in the buffer
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214 | // the buffer is NOT null terminated.
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215 | //
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216 | size_t Stream::readBytes(char *buffer, size_t length)
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217 | {
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218 | size_t count = 0;
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219 | while (count < length) {
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220 | int c = timedRead();
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221 | if (c < 0) break;
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222 | *buffer++ = (char)c;
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223 | count++;
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224 | }
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225 | return count;
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226 | }
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227 |
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228 |
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229 | // as readBytes with terminator character
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230 | // terminates if length characters have been read, timeout, or if the terminator character detected
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231 | // returns the number of characters placed in the buffer (0 means no valid data found)
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232 |
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233 | size_t Stream::readBytesUntil(char terminator, char *buffer, size_t length)
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234 | {
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235 | if (length < 1) return 0;
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236 | size_t index = 0;
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237 | while (index < length) {
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238 | int c = timedRead();
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239 | if (c < 0 || c == terminator) break;
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240 | *buffer++ = (char)c;
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241 | index++;
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242 | }
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243 | return index; // return number of characters, not including null terminator
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244 | }
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245 |
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246 | String Stream::readString()
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247 | {
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248 | String ret;
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249 | int c = timedRead();
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250 | while (c >= 0)
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251 | {
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252 | ret += (char)c;
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253 | c = timedRead();
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254 | }
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255 | return ret;
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256 | }
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257 |
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258 | String Stream::readStringUntil(char terminator)
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259 | {
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260 | String ret;
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261 | int c = timedRead();
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262 | while (c >= 0 && c != terminator)
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263 | {
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264 | ret += (char)c;
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265 | c = timedRead();
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266 | }
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267 | return ret;
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268 | }
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269 |
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