AP_HAL: add BetterStream, Stream, and Print interfaces

* BetterStream Means AP_HAL depends on AP_Common, for now, in order to have
  the AVR specific pgm_char_t defined.
  I'll need to factor that out in the future but for now it can stay

libraries/AP_HAL/AP_HAL.h

@@ -16,6 +16,10 @@
 #include "PPMInput.h"
 #include "PWMOutput.h"
 
+#include "utility/Print.h"
+#include "utility/Stream.h"
+#include "utility/BetterStream.h"
+
 /* HAL Class definition */
 #include "HAL.h"
 

libraries/AP_HAL/AP_HAL_Namespace.h

@@ -34,6 +34,11 @@ namespace AP_HAL {
     class APM2PPMInput;
     class APM1PWMOutput;
     class APM2PWMOutput;
+
+    /* Utility Classes */
+    class Print;
+    class Stream;
+    class BetterStream;
 }
 
 

libraries/AP_HAL/HAL.h

@@ -49,11 +49,9 @@ public:
     AP_HAL::UARTDriver* uart1;
     AP_HAL::UARTDriver* uart2;
     AP_HAL::UARTDriver* uart3;
-
     AP_HAL::I2CDriver*  i2c;
     AP_HAL::SPIDriver*  spi;
     AP_HAL::AnalogIn*   analogIn;
-
     AP_HAL::Storage*    storage;
     AP_HAL::Log*        log;
     AP_HAL::Console*    console;

libraries/AP_HAL/UARTDriver.h

@@ -5,15 +5,46 @@
 #include <stdint.h>
 
 #include "AP_HAL_Namespace.h"
+#include "utility/BetterStream.h"
 
 /* Pure virtual UARTDriver class */
-
-class AP_HAL::UARTDriver {
+class AP_HAL::UARTDriver : public AP_HAL::BetterStream {
 public:
     UARTDriver() {}
-    virtual void init(uint16_t baud) = 0;
-    /* XXX stub */
+    virtual void   begin(long baud) = 0;
+    virtual void   begin(long baud,
+                     unsigned int rxSpace,
+                     unsigned int txSpace) = 0;
+    virtual void   end() = 0;
+    virtual void   flush() = 0;
 };
 
+/* Concrete EmptyUARTDriver class provided for convenience */
+class AP_HAL::EmptyUARTDriver : public AP_HAL::UARTDriver {
+public:
+    EmptyUARTDriver() {}
+    /* Empty implementations of UARTDriver virtual methods */
+    void begin(long b) {}
+    void begin(long b, unsigned int rxS, unsigned int txS) {}
+    void end() {}
+    void flush() {}
+
+    /* Empty implementations of BetterStream virtual methods */
+    void print_P(const prog_char_t *pstr) {}
+    void println_P(const prog_char_t *pstr) {}
+    void printf(const char *pstr, ...) {}
+    void _printf_P(const prog_char_t *pstr, ...) {}
+    int txspace() { return 1; }
+
+    /* Empty implementations of Stream virtual methods */
+    int available() { return 0; }
+    int read() { return -1; }
+    int peek() { return -1; }
+
+    /* Empty implementations of Print virtual methods */
+    size_t write(uint8_t c) { return 0; }
+};
+
+
 #endif // __AP_HAL_UART_DRIVER_H__
 

libraries/AP_HAL/utility/BetterStream.h

@@ -10,25 +10,39 @@
 #ifndef __AP_HAL_UTILITY_BETTERSTREAM_H__
 #define __AP_HAL_UTILITY_BETTERSTREAM_H__
 
+#include "../AP_HAL_Namespace.h"
+#include "Stream.h"
+
+/* prog_char_t: */
+#include <AP_Common.h>
+#include <avr/pgmspace.h>
+
+/* AP_HAL::BetterStream is derived from Michael Smith's FastSerial library for
+ * Arduino. Mike's library has an implementation of _vprintf() for AVR.
+ * Please provide your own platform-specic implementation for this library.
+ *
+ * TODO: Segregate prog_char_t dependent functions to be available on AVR
+ * platform only, with default implementations elsewhere.
+ */
 
 class AP_HAL::BetterStream : public AP_HAL::Stream {
 public:
     BetterStream(void) {}
 
     // Stream extensions
-    void    print_P(const prog_char_t *);
-    void    println_P(const prog_char_t *);
-    void    printf(const char *, ...)
-                __attribute__ ((format(__printf__, 2, 3)));
-    void    _printf_P(const prog_char *, ...)
-                __attribute__ ((format(__printf__, 2, 3)));
+    virtual void print_P(const prog_char_t *);
+    virtual void println_P(const prog_char_t *);
+    virtual void printf(const char *, ...)
+                        __attribute__ ((format(__printf__, 2, 3)));
+    virtual void _printf_P(const prog_char *, ...)
+                        __attribute__ ((format(__printf__, 2, 3)));
 
     virtual int txspace(void);
 
 #define printf_P(fmt, ...) _printf_P((const prog_char *)fmt, ## __VA_ARGS__)
 
 private:
-    void    _vprintf(unsigned char, const char *, va_list)
+    virtual void _vprintf(unsigned char, const char *, va_list)
                 __attribute__ ((format(__printf__, 3, 0)));
 
 

libraries/AP_HAL/utility/Print.cpp

@@ -0,0 +1,216 @@
+/*
+ Print.cpp - Base class that provides print() and println()
+ 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
+ 
+ Modified 23 November 2006 by David A. Mellis
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+
+#include "../AP_HAL_Namespace.h"
+#include "Print.h"
+using namespace AP_HAL;
+
+/* default implementation: may be overridden */
+size_t Print::write(const uint8_t *buffer, size_t size)
+{
+  size_t n = 0;
+  while (size--) {
+    n += write(*buffer++);
+  }
+  return n;
+}
+
+size_t Print::print(const char str[])
+{
+  return write(str);
+}
+
+size_t Print::print(char c)
+{
+  return write(c);
+}
+
+size_t Print::print(unsigned char b, int base)
+{
+  return print((unsigned long) b, base);
+}
+
+size_t Print::print(int n, int base)
+{
+  return print((long) n, base);
+}
+
+size_t Print::print(unsigned int n, int base)
+{
+  return print((unsigned long) n, base);
+}
+
+size_t Print::print(long n, int base)
+{
+  if (base == 0) {
+    return write(n);
+  } else if (base == 10) {
+    if (n < 0) {
+      int t = print('-');
+      n = -n;
+      return printNumber(n, 10) + t;
+    }
+    return printNumber(n, 10);
+  } else {
+    return printNumber(n, base);
+  }
+}
+
+size_t Print::print(unsigned long n, int base)
+{
+  if (base == 0) return write(n);
+  else return printNumber(n, base);
+}
+
+size_t Print::print(float n, int digits)
+{
+  return printFloat(n, digits);
+}
+
+size_t Print::println(void)
+{
+  size_t n = print('\r');
+  n += print('\n');
+  return n;
+}
+
+size_t Print::println(const char c[])
+{
+  size_t n = print(c);
+  n += println();
+  return n;
+}
+
+size_t Print::println(char c)
+{
+  size_t n = print(c);
+  n += println();
+  return n;
+}
+
+size_t Print::println(unsigned char b, int base)
+{
+  size_t n = print(b, base);
+  n += println();
+  return n;
+}
+
+size_t Print::println(int num, int base)
+{
+  size_t n = print(num, base);
+  n += println();
+  return n;
+}
+
+size_t Print::println(unsigned int num, int base)
+{
+  size_t n = print(num, base);
+  n += println();
+  return n;
+}
+
+size_t Print::println(long num, int base)
+{
+  size_t n = print(num, base);
+  n += println();
+  return n;
+}
+
+size_t Print::println(unsigned long num, int base)
+{
+  size_t n = print(num, base);
+  n += println();
+  return n;
+}
+
+size_t Print::println(float num, int digits)
+{
+  size_t n = print(num, digits);
+  n += println();
+  return n;
+}
+
+// Private Methods /////////////////////////////////////////////////////////////
+
+size_t Print::printNumber(unsigned long n, uint8_t base) {
+  char buf[8 * sizeof(long) + 1]; // Assumes 8-bit chars plus zero byte.
+  char *str = &buf[sizeof(buf) - 1];
+
+  *str = '\0';
+
+  // prevent crash if called with base == 1
+  if (base < 2) base = 10;
+
+  do {
+    unsigned long m = n;
+    n /= base;
+    char c = m - base * n;
+    *--str = c < 10 ? c + '0' : c + 'A' - 10;
+  } while(n);
+
+  return write(str);
+}
+
+size_t Print::printFloat(float number, uint8_t digits) 
+{ 
+  size_t n = 0;
+  
+  // Handle negative numbers
+  if (number < 0.0)
+  {
+     n += print('-');
+     number = -number;
+  }
+
+  // Round correctly so that print(1.999, 2) prints as "2.00"
+  float rounding = 0.5;
+  for (uint8_t i=0; i<digits; ++i)
+    rounding /= 10.0;
+  
+  number += rounding;
+
+  // Extract the integer part of the number and print it
+  unsigned long int_part = (unsigned long)number;
+  float remainder = number - (float )int_part;
+  n += print(int_part);
+
+  // Print the decimal point, but only if there are digits beyond
+  if (digits > 0) {
+    n += print("."); 
+  }
+
+  // Extract digits from the remainder one at a time
+  while (digits-- > 0)
+  {
+    remainder *= 10.0;
+    int toPrint = int(remainder);
+    n += print(toPrint);
+    remainder -= toPrint; 
+  } 
+  
+  return n;
+}

libraries/AP_HAL/utility/Print.h

@@ -20,6 +20,8 @@
 #ifndef __AP_HAL_UTILITY_PRINT_H__
 #define __AP_HAL_UTILITY_PRINT_H__
 
+#include "../AP_HAL_Namespace.h"
+
 #include <inttypes.h>
 #include <string.h>
 
@@ -28,7 +30,6 @@
  * - Removed methods for class String or _FlashStringHelper
  * - printFloat takes a float, not a double. (double === float on AVR, but
  *   not on other platforms)
- * - Integers use stdint names
  */
 
 #define DEC 10
@@ -55,7 +56,7 @@ class AP_HAL::Print {
     size_t print(unsigned int, int = DEC);
     size_t print(long, int = DEC);
     size_t print(unsigned long, int = DEC);
-    size_t print(double, int = 2);
+    size_t print(float , int = 2);
 
     size_t println(const char[]);
     size_t println(char);
@@ -64,7 +65,7 @@ class AP_HAL::Print {
     size_t println(unsigned int, int = DEC);
     size_t println(long, int = DEC);
     size_t println(unsigned long, int = DEC);
-    size_t println(double, int = 2);
+    size_t println(float , int = 2);
     size_t println(void);
 
 };

libraries/AP_HAL/utility/Stream.h

@@ -2,6 +2,7 @@
 #ifndef __AP_HAL_UTILITY_STREAM_H__
 #define __AP_HAL_UTILITY_STREAM_H__
 
+#include "../AP_HAL_Namespace.h"
 #include "Print.h"
 
 /* A simple Stream library modeled after the bits we actually use

libraries/AP_HAL_AVR/examples/APM1/APM1.pde

@@ -1,4 +1,5 @@
 
+#include <AP_Common.h>
 #include <AP_HAL.h>
 #include <AP_HAL_AVR.h>