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auto-plow / bccaf55

A wheelchair motor-propelled battery-powered ESP32-driven remote control snow plow.

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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#define PARSE_TIMEOUT 1000 // default number of milli-seconds to wait
29
30// protected method to read stream with timeout
31int Stream::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// protected method to peek stream with timeout
43int Stream::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
56int Stream::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
87void Stream::setTimeout(unsigned long 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
93bool Stream::find(char *target)
94{
95 return findUntil(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
100bool Stream::find(char *target, size_t length)
101{
102 return findUntil(target, length, NULL, 0);
103}
104
105// as find but search ends if the terminator string is found
106bool Stream::findUntil(char *target, char *terminator)
107{
108 return findUntil(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
114bool Stream::findUntil(char *target, size_t targetLen, char *terminator, size_t termLen)
115{
116 if (terminator == NULL) {
117 MultiTarget t[1] = {{target, targetLen, 0}};
118 return findMulti(t, 1) == 0 ? true : false;
119 } else {
120 MultiTarget t[2] = {{target, targetLen, 0}, {terminator, termLen, 0}};
121 return findMulti(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.
130long Stream::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 return 0; // zero returned if timeout
140
141 do{
142 if(c == ignore)
143 ; // ignore this character
144 else if(c == '-')
145 isNegative = true;
146 else if(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
159float Stream::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 return 0; // zero returned if timeout
171
172 do{
173 if(c == ignore)
174 ; // ignore
175 else if(c == '-')
176 isNegative = true;
177 else if (c == '.')
178 isFraction = true;
179 else if(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//
202size_t Stream::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
219size_t Stream::readBytesUntil(char terminator, char *buffer, size_t length)
220{
221 if (length < 1) return 0;
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
232String Stream::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
244String Stream::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
256int Stream::findMulti( struct Stream::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 (struct MultiTarget *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 (struct MultiTarget *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}
320