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271 lines
7.1 KiB
C++
271 lines
7.1 KiB
C++
/*
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Stream.cpp - adds parsing methods to Stream class
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Copyright (c) 2008 David A. Mellis. All right reserved.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Created July 2011
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parsing functions based on TextFinder library by Michael Margolis
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*/
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#include "Arduino.h"
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#include "Stream.h"
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#define PARSE_TIMEOUT 1000 // default number of milli-seconds to wait
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#define NO_SKIP_CHAR 1 // a magic char not found in a valid ASCII numeric field
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// private method to read stream with timeout
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int Stream::timedRead()
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{
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int c;
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_startMillis = millis();
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do {
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c = read();
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if (c >= 0) return c;
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} while(millis() - _startMillis < _timeout);
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return -1; // -1 indicates timeout
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}
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// private method to peek stream with timeout
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int Stream::timedPeek()
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{
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int c;
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_startMillis = millis();
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do {
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c = peek();
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if (c >= 0) return c;
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} while(millis() - _startMillis < _timeout);
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return -1; // -1 indicates timeout
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}
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// returns peek of the next digit in the stream or -1 if timeout
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// discards non-numeric characters
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int Stream::peekNextDigit()
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{
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int c;
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while (1) {
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c = timedPeek();
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if (c < 0) return c; // timeout
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if (c == '-') return c;
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if (c >= '0' && c <= '9') return c;
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read(); // discard non-numeric
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}
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}
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// Public Methods
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//////////////////////////////////////////////////////////////
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void Stream::setTimeout(unsigned long timeout) // sets the maximum number of milliseconds to wait
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{
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_timeout = timeout;
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}
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// find returns true if the target string is found
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bool Stream::find(char *target)
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{
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return findUntil(target, NULL);
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}
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// reads data from the stream until the target string of given length is found
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// returns true if target string is found, false if timed out
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bool Stream::find(char *target, size_t length)
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{
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return findUntil(target, length, NULL, 0);
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}
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// as find but search ends if the terminator string is found
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bool Stream::findUntil(char *target, char *terminator)
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{
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return findUntil(target, strlen(target), terminator, strlen(terminator));
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}
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// reads data from the stream until the target string of the given length is found
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// search terminated if the terminator string is found
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// returns true if target string is found, false if terminated or timed out
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bool Stream::findUntil(char *target, size_t targetLen, char *terminator, size_t termLen)
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{
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size_t index = 0; // maximum target string length is 64k bytes!
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size_t termIndex = 0;
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int c;
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if( *target == 0)
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return true; // return true if target is a null string
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while( (c = timedRead()) > 0){
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if(c != target[index])
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index = 0; // reset index if any char does not match
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if( c == target[index]){
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//////Serial.print("found "); Serial.write(c); Serial.print("index now"); Serial.println(index+1);
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if(++index >= targetLen){ // return true if all chars in the target match
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return true;
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}
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}
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if(termLen > 0 && c == terminator[termIndex]){
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if(++termIndex >= termLen)
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return false; // return false if terminate string found before target string
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}
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else
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termIndex = 0;
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}
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return false;
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}
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// returns the first valid (long) integer value from the current position.
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// initial characters that are not digits (or the minus sign) are skipped
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// function is terminated by the first character that is not a digit.
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long Stream::parseInt()
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{
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return parseInt(NO_SKIP_CHAR); // terminate on first non-digit character (or timeout)
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}
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// as above but a given skipChar is ignored
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// this allows format characters (typically commas) in values to be ignored
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long Stream::parseInt(char skipChar)
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{
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boolean isNegative = false;
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long value = 0;
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int c;
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c = peekNextDigit();
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// ignore non numeric leading characters
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if(c < 0)
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return 0; // zero returned if timeout
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do{
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if(c == skipChar)
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; // ignore this charactor
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else if(c == '-')
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isNegative = true;
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else if(c >= '0' && c <= '9') // is c a digit?
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value = value * 10 + c - '0';
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read(); // consume the character we got with peek
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c = timedPeek();
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}
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while( (c >= '0' && c <= '9') || c == skipChar );
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if(isNegative)
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value = -value;
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return value;
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}
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// as parseInt but returns a floating point value
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float Stream::parseFloat()
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{
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return parseFloat(NO_SKIP_CHAR);
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}
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// as above but the given skipChar is ignored
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// this allows format characters (typically commas) in values to be ignored
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float Stream::parseFloat(char skipChar){
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boolean isNegative = false;
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boolean isFraction = false;
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long value = 0;
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char c;
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float fraction = 1.0;
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c = peekNextDigit();
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// ignore non numeric leading characters
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if(c < 0)
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return 0; // zero returned if timeout
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do{
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if(c == skipChar)
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; // ignore
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else if(c == '-')
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isNegative = true;
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else if (c == '.')
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isFraction = true;
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else if(c >= '0' && c <= '9') { // is c a digit?
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value = value * 10 + c - '0';
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if(isFraction)
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fraction *= 0.1;
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}
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read(); // consume the character we got with peek
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c = timedPeek();
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}
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while( (c >= '0' && c <= '9') || c == '.' || c == skipChar );
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if(isNegative)
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value = -value;
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if(isFraction)
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return value * fraction;
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else
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return value;
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}
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// read characters from stream into buffer
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// terminates if length characters have been read, or timeout (see setTimeout)
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// returns the number of characters placed in the buffer
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// the buffer is NOT null terminated.
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//
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size_t Stream::readBytes(char *buffer, size_t length)
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{
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size_t count = 0;
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while (count < length) {
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int c = timedRead();
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if (c < 0) break;
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*buffer++ = (char)c;
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count++;
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}
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return count;
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}
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// as readBytes with terminator character
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// terminates if length characters have been read, timeout, or if the terminator character detected
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// returns the number of characters placed in the buffer (0 means no valid data found)
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size_t Stream::readBytesUntil(char terminator, char *buffer, size_t length)
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{
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if (length < 1) return 0;
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size_t index = 0;
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while (index < length) {
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int c = timedRead();
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if (c < 0 || c == terminator) break;
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*buffer++ = (char)c;
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index++;
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}
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return index; // return number of characters, not including null terminator
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}
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String Stream::readString()
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{
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String ret;
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int c = timedRead();
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while (c >= 0)
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{
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ret += (char)c;
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c = timedRead();
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}
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return ret;
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}
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String Stream::readStringUntil(char terminator)
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{
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String ret;
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int c = timedRead();
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while (c >= 0 && c != terminator)
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{
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ret += (char)c;
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c = timedRead();
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}
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return ret;
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}
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