|
| 1 | +/* |
| 2 | + Stream.cpp - adds parsing methods to Stream class |
| 3 | + Copyright (c) 2008 David A. Mellis. All right reserved. |
| 4 | +
|
| 5 | + This library is free software; you can redistribute it and/or |
| 6 | + modify it under the terms of the GNU Lesser General Public |
| 7 | + License as published by the Free Software Foundation; either |
| 8 | + version 2.1 of the License, or (at your option) any later version. |
| 9 | +
|
| 10 | + This library is distributed in the hope that it will be useful, |
| 11 | + but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | + Lesser General Public License for more details. |
| 14 | +
|
| 15 | + You should have received a copy of the GNU Lesser General Public |
| 16 | + License along with this library; if not, write to the Free Software |
| 17 | + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | +
|
| 19 | + Created July 2011 |
| 20 | + parsing functions based on TextFinder library by Michael Margolis |
| 21 | +
|
| 22 | + findMulti/findUntil routines written by Jim Leonard/Xuth |
| 23 | +*/ |
| 24 | + |
| 25 | +#include"Arduino.h" |
| 26 | +#include"Stream.h" |
| 27 | + |
| 28 | +#definePARSE_TIMEOUT1000// default number of milli-seconds to wait |
| 29 | + |
| 30 | +// private method to read stream with timeout |
| 31 | +intStream::timedRead() |
| 32 | +{ |
| 33 | +int c; |
| 34 | + _startMillis =millis(); |
| 35 | +do { |
| 36 | + c =read(); |
| 37 | +if (c >=0)return c; |
| 38 | + }while(millis() - _startMillis < _timeout); |
| 39 | +return -1;// -1 indicates timeout |
| 40 | +} |
| 41 | + |
| 42 | +// private method to peek stream with timeout |
| 43 | +intStream::timedPeek() |
| 44 | +{ |
| 45 | +int c; |
| 46 | + _startMillis =millis(); |
| 47 | +do { |
| 48 | + c =peek(); |
| 49 | +if (c >=0)return c; |
| 50 | + }while(millis() - _startMillis < _timeout); |
| 51 | +return -1;// -1 indicates timeout |
| 52 | +} |
| 53 | + |
| 54 | +// returns peek of the next digit in the stream or -1 if timeout |
| 55 | +// discards non-numeric characters |
| 56 | +intStream::peekNextDigit(LookaheadMode lookahead,bool detectDecimal) |
| 57 | +{ |
| 58 | +int c; |
| 59 | +while (1) { |
| 60 | + c =timedPeek(); |
| 61 | + |
| 62 | +if( c <0 || |
| 63 | + c =='-' || |
| 64 | + (c >='0' && c <='9') || |
| 65 | + (detectDecimal && c =='.'))return c; |
| 66 | + |
| 67 | +switch( lookahead ){ |
| 68 | +case SKIP_NONE:return -1;// Fail code. |
| 69 | +case SKIP_WHITESPACE: |
| 70 | +switch( c ){ |
| 71 | +case'': |
| 72 | +case'\t': |
| 73 | +case'\r': |
| 74 | +case'\n':break; |
| 75 | +default:return -1;// Fail code. |
| 76 | + } |
| 77 | +case SKIP_ALL: |
| 78 | +break; |
| 79 | + } |
| 80 | +read();// discard non-numeric |
| 81 | + } |
| 82 | +} |
| 83 | + |
| 84 | +// Public Methods |
| 85 | +////////////////////////////////////////////////////////////// |
| 86 | + |
| 87 | +voidStream::setTimeout(unsignedlong timeout)// sets the maximum number of milliseconds to wait |
| 88 | +{ |
| 89 | + _timeout = timeout; |
| 90 | +} |
| 91 | + |
| 92 | +// find returns true if the target string is found |
| 93 | +boolStream::find(char *target) |
| 94 | +{ |
| 95 | +returnfindUntil(target,strlen(target),NULL,0); |
| 96 | +} |
| 97 | + |
| 98 | +// reads data from the stream until the target string of given length is found |
| 99 | +// returns true if target string is found, false if timed out |
| 100 | +boolStream::find(char *target,size_t length) |
| 101 | +{ |
| 102 | +returnfindUntil(target, length,NULL,0); |
| 103 | +} |
| 104 | + |
| 105 | +// as find but search ends if the terminator string is found |
| 106 | +boolStream::findUntil(char *target,char *terminator) |
| 107 | +{ |
| 108 | +returnfindUntil(target,strlen(target), terminator,strlen(terminator)); |
| 109 | +} |
| 110 | + |
| 111 | +// reads data from the stream until the target string of the given length is found |
| 112 | +// search terminated if the terminator string is found |
| 113 | +// returns true if target string is found, false if terminated or timed out |
| 114 | +boolStream::findUntil(char *target,size_t targetLen,char *terminator,size_t termLen) |
| 115 | +{ |
| 116 | +if (terminator ==NULL) { |
| 117 | + MultiTarget t[1] = {{target, targetLen,0}}; |
| 118 | +returnfindMulti(t,1) ==0 ?true :false; |
| 119 | + }else { |
| 120 | + MultiTarget t[2] = {{target, targetLen,0}, {terminator, termLen,0}}; |
| 121 | +returnfindMulti(t,2) ==0 ?true :false; |
| 122 | + } |
| 123 | +} |
| 124 | + |
| 125 | +// returns the first valid (long) integer value from the current position. |
| 126 | +// lookahead determines how parseInt looks ahead in the stream. |
| 127 | +// See LookaheadMode enumeration at the top of the file. |
| 128 | +// Lookahead is terminated by the first character that is not a valid part of an integer. |
| 129 | +// Once parsing commences, 'ignore' will be skipped in the stream. |
| 130 | +longStream::parseInt(LookaheadMode lookahead,char ignore) |
| 131 | +{ |
| 132 | +bool isNegative =false; |
| 133 | +long value =0; |
| 134 | +int c; |
| 135 | + |
| 136 | + c =peekNextDigit(lookahead,false); |
| 137 | +// ignore non numeric leading characters |
| 138 | +if(c <0) |
| 139 | +return0;// zero returned if timeout |
| 140 | + |
| 141 | +do{ |
| 142 | +if(c == ignore) |
| 143 | + ;// ignore this character |
| 144 | +elseif(c =='-') |
| 145 | + isNegative =true; |
| 146 | +elseif(c >='0' && c <='9')// is c a digit? |
| 147 | + value = value *10 + c -'0'; |
| 148 | +read();// consume the character we got with peek |
| 149 | + c =timedPeek(); |
| 150 | + } |
| 151 | +while( (c >='0' && c <='9') || c == ignore ); |
| 152 | + |
| 153 | +if(isNegative) |
| 154 | + value = -value; |
| 155 | +return value; |
| 156 | +} |
| 157 | + |
| 158 | +// as parseInt but returns a floating point value |
| 159 | +floatStream::parseFloat(LookaheadMode lookahead,char ignore) |
| 160 | +{ |
| 161 | +bool isNegative =false; |
| 162 | +bool isFraction =false; |
| 163 | +long value =0; |
| 164 | +int c; |
| 165 | +float fraction =1.0; |
| 166 | + |
| 167 | + c =peekNextDigit(lookahead,true); |
| 168 | +// ignore non numeric leading characters |
| 169 | +if(c <0) |
| 170 | +return0;// zero returned if timeout |
| 171 | + |
| 172 | +do{ |
| 173 | +if(c == ignore) |
| 174 | + ;// ignore |
| 175 | +elseif(c =='-') |
| 176 | + isNegative =true; |
| 177 | +elseif (c =='.') |
| 178 | + isFraction =true; |
| 179 | +elseif(c >='0' && c <='9') {// is c a digit? |
| 180 | + value = value *10 + c -'0'; |
| 181 | +if(isFraction) |
| 182 | + fraction *=0.1; |
| 183 | + } |
| 184 | +read();// consume the character we got with peek |
| 185 | + c =timedPeek(); |
| 186 | + } |
| 187 | +while( (c >='0' && c <='9') || (c =='.' && !isFraction) || c == ignore ); |
| 188 | + |
| 189 | +if(isNegative) |
| 190 | + value = -value; |
| 191 | +if(isFraction) |
| 192 | +return value * fraction; |
| 193 | +else |
| 194 | +return value; |
| 195 | +} |
| 196 | + |
| 197 | +// read characters from stream into buffer |
| 198 | +// terminates if length characters have been read, or timeout (see setTimeout) |
| 199 | +// returns the number of characters placed in the buffer |
| 200 | +// the buffer is NOT null terminated. |
| 201 | +// |
| 202 | +size_tStream::readBytes(char *buffer,size_t length) |
| 203 | +{ |
| 204 | +size_t count =0; |
| 205 | +while (count < length) { |
| 206 | +int c =timedRead(); |
| 207 | +if (c <0)break; |
| 208 | + *buffer++ = (char)c; |
| 209 | + count++; |
| 210 | + } |
| 211 | +return count; |
| 212 | +} |
| 213 | + |
| 214 | + |
| 215 | +// as readBytes with terminator character |
| 216 | +// terminates if length characters have been read, timeout, or if the terminator character detected |
| 217 | +// returns the number of characters placed in the buffer (0 means no valid data found) |
| 218 | + |
| 219 | +size_tStream::readBytesUntil(char terminator,char *buffer,size_t length) |
| 220 | +{ |
| 221 | +if (length <1)return0; |
| 222 | +size_t index =0; |
| 223 | +while (index < length) { |
| 224 | +int c =timedRead(); |
| 225 | +if (c <0 || c == terminator)break; |
| 226 | + *buffer++ = (char)c; |
| 227 | + index++; |
| 228 | + } |
| 229 | +return index;// return number of characters, not including null terminator |
| 230 | +} |
| 231 | + |
| 232 | +StringStream::readString() |
| 233 | +{ |
| 234 | + String ret; |
| 235 | +int c =timedRead(); |
| 236 | +while (c >=0) |
| 237 | + { |
| 238 | + ret += (char)c; |
| 239 | + c =timedRead(); |
| 240 | + } |
| 241 | +return ret; |
| 242 | +} |
| 243 | + |
| 244 | +StringStream::readStringUntil(char terminator) |
| 245 | +{ |
| 246 | + String ret; |
| 247 | +int c =timedRead(); |
| 248 | +while (c >=0 && c != terminator) |
| 249 | + { |
| 250 | + ret += (char)c; |
| 251 | + c =timedRead(); |
| 252 | + } |
| 253 | +return ret; |
| 254 | +} |
| 255 | + |
| 256 | +intStream::findMulti(structStream::MultiTarget *targets,int tCount) { |
| 257 | +// any zero length target string automatically matches and would make |
| 258 | +// a mess of the rest of the algorithm. |
| 259 | +for (structMultiTarget *t = targets; t < targets+tCount; ++t) { |
| 260 | +if (t->len <=0) |
| 261 | +return t - targets; |
| 262 | + } |
| 263 | + |
| 264 | +while (1) { |
| 265 | +int c =timedRead(); |
| 266 | +if (c <0) |
| 267 | +return -1; |
| 268 | + |
| 269 | +for (structMultiTarget *t = targets; t < targets+tCount; ++t) { |
| 270 | +// the simple case is if we match, deal with that first. |
| 271 | +if (c == t->str[t->index]) { |
| 272 | +if (++t->index == t->len) |
| 273 | +return t - targets; |
| 274 | +else |
| 275 | +continue; |
| 276 | + } |
| 277 | + |
| 278 | +// if not we need to walk back and see if we could have matched further |
| 279 | +// down the stream (ie '1112' doesn't match the first position in '11112' |
| 280 | +// but it will match the second position so we can't just reset the current |
| 281 | +// index to 0 when we find a mismatch. |
| 282 | +if (t->index ==0) |
| 283 | +continue; |
| 284 | + |
| 285 | +int origIndex = t->index; |
| 286 | +do { |
| 287 | + --t->index; |
| 288 | +// first check if current char works against the new current index |
| 289 | +if (c != t->str[t->index]) |
| 290 | +continue; |
| 291 | + |
| 292 | +// if it's the only char then we're good, nothing more to check |
| 293 | +if (t->index ==0) { |
| 294 | + t->index++; |
| 295 | +break; |
| 296 | + } |
| 297 | + |
| 298 | +// otherwise we need to check the rest of the found string |
| 299 | +int diff = origIndex - t->index; |
| 300 | +size_t i; |
| 301 | +for (i =0; i < t->index; ++i) { |
| 302 | +if (t->str[i] != t->str[i + diff]) |
| 303 | +break; |
| 304 | + } |
| 305 | + |
| 306 | +// if we successfully got through the previous loop then our current |
| 307 | +// index is good. |
| 308 | +if (i == t->index) { |
| 309 | + t->index++; |
| 310 | +break; |
| 311 | + } |
| 312 | + |
| 313 | +// otherwise we just try the next index |
| 314 | + }while (t->index); |
| 315 | + } |
| 316 | + } |
| 317 | +// unreachable |
| 318 | +return -1; |
| 319 | +} |