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 /*  Stream.cpp - adds parsing methods to Stream class  Copyright (c) 2008 David A. Mellis.  All right reserved.   This library is free softw...”

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/*
Stream.cpp - adds parsing methods to Stream class
Copyright (c) 2008 David A. Mellis. All right reserved.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Created July 2011
parsing functions based on TextFinder library by Michael Margolis
*/

#include "Arduino.h"
#include "Stream.h"

#define PARSE_TIMEOUT 1000 // default number of milli-seconds to wait
#define NO_SKIP_CHAR 1 // a magic char not found in a valid ASCII numeric field

// private method to read stream with timeout
int Stream::timedRead()
{
int c;
_startMillis = millis();
do {
c = read();
if (c >= 0) return c;
} while(millis() - _startMillis < _timeout);
return -1; // -1 indicates timeout
}

// private method to peek stream with timeout
int Stream::timedPeek()
{
int c;
_startMillis = millis();
do {
c = peek();
if (c >= 0) return c;
} while(millis() - _startMillis < _timeout);
return -1; // -1 indicates timeout
}

// returns peek of the next digit in the stream or -1 if timeout
// discards non-numeric characters
int Stream::peekNextDigit()
{
int c;
while (1) {
c = timedPeek();
if (c < 0) return c; // timeout
if (c == '-') return c;
if (c >= '0' && c <= '9') return c;
read(); // discard non-numeric
}
}

// Public Methods
//////////////////////////////////////////////////////////////

void Stream::setTimeout(unsigned long timeout) // sets the maximum number of milliseconds to wait
{
_timeout = timeout;
}

// find returns true if the target string is found
bool Stream::find(char *target)
{
return findUntil(target, NULL);
}

// reads data from the stream until the target string of given length is found
// returns true if target string is found, false if timed out
bool Stream::find(char *target, size_t length)
{
return findUntil(target, length, NULL, 0);
}

// as find but search ends if the terminator string is found
bool Stream::findUntil(char *target, char *terminator)
{
return findUntil(target, strlen(target), terminator, strlen(terminator));
}

// reads data from the stream until the target string of the given length is found
// search terminated if the terminator string is found
// returns true if target string is found, false if terminated or timed out
bool Stream::findUntil(char *target, size_t targetLen, char *terminator, size_t termLen)
{
size_t index = 0; // maximum target string length is 64k bytes!
size_t termIndex = 0;
int c;

if( *target == 0)
return true; // return true if target is a null string
while( (c = timedRead()) > 0){

if(c != target[index])
index = 0; // reset index if any char does not match

if( c == target[index]){
//////Serial.print("found "); Serial.write(c); Serial.print("index now"); Serial.println(index+1);
if(++index >= targetLen){ // return true if all chars in the target match
return true;
}
}

if(termLen > 0 && c == terminator[termIndex]){
if(++termIndex >= termLen)
return false; // return false if terminate string found before target string
}
else
termIndex = 0;
}
return false;
}

// returns the first valid (long) integer value from the current position.
// initial characters that are not digits (or the minus sign) are skipped
// function is terminated by the first character that is not a digit.
long Stream::parseInt()
{
return parseInt(NO_SKIP_CHAR); // terminate on first non-digit character (or timeout)
}

// as above but a given skipChar is ignored
// this allows format characters (typically commas) in values to be ignored
long Stream::parseInt(char skipChar)
{
boolean isNegative = false;
long value = 0;
int c;

c = peekNextDigit();
// ignore non numeric leading characters
if(c < 0)
return 0; // zero returned if timeout

do{
if(c == skipChar)
; // ignore this charactor
else if(c == '-')
isNegative = true;
else if(c >= '0' && c <= '9') // is c a digit?
value = value * 10 + c - '0';
read(); // consume the character we got with peek
c = timedPeek();
}
while( (c >= '0' && c <= '9') || c == skipChar );

if(isNegative)
value = -value;
return value;
}

// as parseInt but returns a floating point value
float Stream::parseFloat()
{
return parseFloat(NO_SKIP_CHAR);
}

// as above but the given skipChar is ignored
// this allows format characters (typically commas) in values to be ignored
float Stream::parseFloat(char skipChar){
boolean isNegative = false;
boolean isFraction = false;
long value = 0;
char c;
float fraction = 1.0;

c = peekNextDigit();
// ignore non numeric leading characters
if(c < 0)
return 0; // zero returned if timeout

do{
if(c == skipChar)
; // ignore
else if(c == '-')
isNegative = true;
else if (c == '.')
isFraction = true;
else if(c >= '0' && c <= '9') { // is c a digit?
value = value * 10 + c - '0';
if(isFraction)
fraction *= 0.1;
}
read(); // consume the character we got with peek
c = timedPeek();
}
while( (c >= '0' && c <= '9') || c == '.' || c == skipChar );

if(isNegative)
value = -value;
if(isFraction)
return value * fraction;
else
return value;
}

// read characters from stream into buffer
// terminates if length characters have been read, or timeout (see setTimeout)
// returns the number of characters placed in the buffer
// the buffer is NOT null terminated.
//
size_t Stream::readBytes(char *buffer, size_t length)
{
size_t count = 0;
while (count < length) {
int c = timedRead();
if (c < 0) break;
*buffer++ = (char)c;
count++;
}
return count;
}

// as readBytes with terminator character
// terminates if length characters have been read, timeout, or if the terminator character detected
// returns the number of characters placed in the buffer (0 means no valid data found)

size_t Stream::readBytesUntil(char terminator, char *buffer, size_t length)
{
if (length < 1) return 0;
size_t index = 0;
while (index < length) {
int c = timedRead();
if (c < 0 || c == terminator) break;
*buffer++ = (char)c;
index++;
}
return index; // return number of characters, not including null terminator
}

String Stream::readString()
{
String ret;
int c = timedRead();
while (c >= 0)
{
ret += (char)c;
c = timedRead();
}
return ret;
}

String Stream::readStringUntil(char terminator)
{
String ret;
int c = timedRead();
while (c >= 0 && c != terminator)
{
ret += (char)c;
c = timedRead();
}
return ret;
}

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Stream.cpp - 版本历史

YWrobot CYB：创建页面，内容为“
/* Stream.cpp - adds parsing methods to Stream class Copyright (c) 2008 David A. Mellis. All right reserved. This library is free softw...”