Stream.h

/*
  Stream.h - base class for character-based streams.
  Copyright (c) 2010 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
 
  parsing functions based on TextFinder library by Michael Margolis
*/
 
#ifndef Stream_h
#define Stream_h
 
#include <inttypes.h>
#include "Print.h"
 
// compatibility macros for testing
/*
#define   getInt()            parseInt()
#define   getInt(ignore)    parseInt(ignore)
#define   getFloat()          parseFloat()
#define   getFloat(ignore)  parseFloat(ignore)
#define   getString( pre_string, post_string, buffer, length)
readBytesBetween( pre_string, terminator, buffer, length)
*/
 
// This enumeration provides the lookahead options for parseInt(), parseFloat()
// The rules set out here are used until either the first valid character is found
// or a time out occurs due to lack of input.
enum LookaheadMode {
  SKIP_ALL,       // All invalid characters are ignored.
  SKIP_NONE,      // Nothing is skipped, and the stream is not touched unless the first waiting character is valid.
  SKIP_WHITESPACE // Only tabs, spaces, line feeds & carriage returns are skipped.
};
 
#define NO_IGNORE_CHAR  '\x01' // a char not found in a valid ASCII numeric field
 
class Stream : public Print {
  protected:
    unsigned long _timeout;      // number of milliseconds to wait for the next char before aborting timed read
    unsigned long _startMillis;  // used for timeout measurement
    int timedRead();    // private method to read stream with timeout
    int timedPeek();    // private method to peek stream with timeout
    int peekNextDigit(LookaheadMode lookahead, bool detectDecimal); // returns the next numeric digit in the stream or -1 if timeout
 
  public:
    virtual int available() = 0;
    virtual int read() = 0;
    virtual int peek() = 0;
 
    Stream()
    {
      _timeout = 1000;
    }
 
    // parsing methods
 
    void setTimeout(unsigned long timeout);  // sets maximum milliseconds to wait for stream data, default is 1 second
    unsigned long getTimeout(void)
    {
      return _timeout;
    }
 
    bool find(const char *target);   // reads data from the stream until the target string is found
    bool find(const uint8_t *target)
    {
      return find((const char *)target);
    }
    // returns true if target string is found, false if timed out (see setTimeout)
 
    bool find(const char *target, size_t length);   // reads data from the stream until the target string of given length is found
    bool find(const uint8_t *target, size_t length)
    {
      return find((const char *)target, length);
    }
    // returns true if target string is found, false if timed out
 
    bool find(char target)
    {
      return find(&target, 1);
    }
 
    bool findUntil(const char *target, const char *terminator);   // as find but search ends if the terminator string is found
    bool findUntil(const uint8_t *target, const char *terminator)
    {
      return findUntil((const char *)target, terminator);
    }
 
    bool findUntil(const char *target, size_t targetLen, const char *terminate, size_t termLen);   // as above but search ends if the terminate string is found
    bool findUntil(const uint8_t *target, size_t targetLen, const char *terminate, size_t termLen)
    {
      return findUntil((const char *)target, targetLen, terminate, termLen);
    }
 
    long parseInt(LookaheadMode lookahead = SKIP_ALL, char ignore = NO_IGNORE_CHAR);
    // returns the first valid (long) integer value from the current position.
    // lookahead determines how parseInt looks ahead in the stream.
    // See LookaheadMode enumeration at the top of the file.
    // Lookahead is terminated by the first character that is not a valid part of an integer.
    // Once parsing commences, 'ignore' will be skipped in the stream.
 
    float parseFloat(LookaheadMode lookahead = SKIP_ALL, char ignore = NO_IGNORE_CHAR);
    // float version of parseInt
 
    virtual size_t readBytes(char *buffer, size_t length);  // read chars from stream into buffer
    size_t readBytes(uint8_t *buffer, size_t length)
    {
      return readBytes((char *)buffer, length);
    }
    // terminates if length characters have been read or timeout (see setTimeout)
    // returns the number of characters placed in the buffer (0 means no valid data found)
 
    virtual size_t readBytesUntil(char terminator, char *buffer, size_t length);  // as readBytes with terminator character
    size_t readBytesUntil(char terminator, uint8_t *buffer, size_t length)
    {
      return readBytesUntil(terminator, (char *)buffer, length);
    }
    // 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)
 
    // Arduino String functions to be added here
    String readString();
    String readStringUntil(char terminator);
 
  protected:
    long parseInt(char ignore)
    {
      return parseInt(SKIP_ALL, ignore);
    }
    float parseFloat(char ignore)
    {
      return parseFloat(SKIP_ALL, ignore);
    }
    // These overload exists for compatibility with any class that has derived
    // Stream and used parseFloat/Int with a custom ignore character. To keep
    // the public API simple, these overload remains protected.
 
    struct MultiTarget {
      const char *str;  // string you're searching for
      size_t len;       // length of string you're searching for
      size_t index;     // index used by the search routine.
    };
 
    // This allows you to search for an arbitrary number of strings.
    // Returns index of the target that is found first or -1 if timeout occurs.
    int findMulti(struct MultiTarget *targets, int tCount);
};
 
#undef NO_IGNORE_CHAR
#endif