Diff: Arduino_lib/arStream.cpp

Revision:

0:b1ce54272580

Child:

1:da31140f2a1c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Arduino_lib/arStream.cpp	Sat Jan 18 15:06:35 2020 +0000
@@ -0,0 +1,321 @@
+/*
+ arStream.cpp - adds parsing methods to arStream 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
+
+ findMulti/findUntil routines written by Jim Leonard/Xuth
+ */
+
+#include "Arduino.h"
+#include "arStream.h"
+#include "Usb.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
+
+extern Timer USB::arduinoTimer;
+
+// private method to read stream with timeout
+int arStream::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 arStream::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 arStream::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 arStream::setTimeout(unsigned long timeout)  // sets the maximum number of milliseconds to wait
+{
+  _timeout = timeout;
+}
+
+ // find returns true if the target string is found
+bool  arStream::find(char *target)
+{
+  return findUntil(target, strlen(target), NULL, 0);
+}
+
+// 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 arStream::find(char *target, size_t length)
+{
+  return findUntil(target, length, NULL, 0);
+}
+
+// as find but search ends if the terminator string is found
+bool  arStream::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 arStream::findUntil(char *target, size_t targetLen, char *terminator, size_t termLen)
+{
+  if (terminator == NULL) {
+    MultiTarget t[1] = {{target, targetLen, 0}};
+    return findMulti(t, 1) == 0 ? true : false;
+  } else {
+    MultiTarget t[2] = {{target, targetLen, 0}, {terminator, termLen, 0}};
+    return findMulti(t, 2) == 0 ? true : 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 arStream::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 arStream::parseInt(char skipChar)
+{
+  bool 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 arStream::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 arStream::parseFloat(char skipChar){
+  bool isNegative = false;
+  bool 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 arStream::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 arStream::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 arStream::readString()
+{
+  String ret;
+  int c = timedRead();
+  while (c >= 0)
+  {
+    ret += (char)c;
+    c = timedRead();
+  }
+  return ret;
+}
+
+String arStream::readStringUntil(char terminator)
+{
+  String ret;
+  int c = timedRead();
+  while (c >= 0 && c != terminator)
+  {
+    ret += (char)c;
+    c = timedRead();
+  }
+  return ret;
+}
+
+int arStream::findMulti( struct arStream::MultiTarget *targets, int tCount) {
+  // any zero length target string automatically matches and would make
+  // a mess of the rest of the algorithm.
+  for (struct MultiTarget *t = targets; t < targets+tCount; ++t) {
+    if (t->len <= 0)
+      return t - targets;
+  }
+
+  while (1) {
+    int c = timedRead();
+    if (c < 0)
+      return -1;
+
+    for (struct MultiTarget *t = targets; t < targets+tCount; ++t) {
+      // the simple case is if we match, deal with that first.
+      if (c == t->str[t->index]) {
+        if (++t->index == t->len)
+          return t - targets;
+        else
+          continue;
+      }
+
+      // if not we need to walk back and see if we could have matched further
+      // down the stream (ie '1112' doesn't match the first position in '11112'
+      // but it will match the second position so we can't just reset the current
+      // index to 0 when we find a mismatch.
+      if (t->index == 0)
+        continue;
+
+      int origIndex = t->index;
+      do {
+        --t->index;
+        // first check if current char works against the new current index
+        if (c != t->str[t->index])
+          continue;
+
+        // if it's the only char then we're good, nothing more to check
+        if (t->index == 0) {
+          t->index++;
+          break;
+        }
+
+        // otherwise we need to check the rest of the found string
+        int diff = origIndex - t->index;
+        size_t i;
+        for (i = 0; i < t->index; ++i) {
+          if (t->str[i] != t->str[i + diff])
+            break;
+        }
+
+        // if we successfully got through the previous loop then our current
+        // index is good.
+        if (i == t->index) {
+          t->index++;
+          break;
+        }
+
+        // otherwise we just try the next index
+      } while (t->index);
+    }
+  }
+  // unreachable
+  return -1;
+}
+