[io] IOStream: printf now supports basic %m.nf float formatting.

examples/linux/printf/SConstruct

@@ -0,0 +1,33 @@
+# path to the xpcc root directory
+rootpath = '../../..'
+
+env = Environment(tools = ['xpcc'], toolpath = [rootpath + '/scons/site_tools'])
+
+# find all source files
+files = env.FindFiles('.')
+
+# build the program
+program = env.Program(target = env['XPCC_CONFIG']['general']['name'], source = files.sources)
+
+# build the xpcc library
+env.XpccLibrary()
+
+# build xpcc_git_info.hpp and xpcc_build_info.hpp file
+env.GitInfoHeader()
+env.BuildInfoHeader()
+
+# build xpcc_build_info.hpp file
+env.BuildInfoHeader()
+
+# create a file called 'defines.hpp' with all preprocessor defines if necessary
+env.Defines()
+
+env.Alias('size', env.Size(program))
+env.Alias('symbols', env.Symbols(program))
+env.Alias('defines', env.ShowDefines())
+
+env.Alias('build', program)
+env.Alias('run', env.Run(program))
+env.Alias('all', ['build', 'run'])
+
+env.Default('all')

examples/linux/printf/main.cpp

@@ -0,0 +1,59 @@
+#include <xpcc/architecture.hpp>
+#include <xpcc/debug/logger.hpp>
+
+#include <xpcc_build_info.hpp>
+
+// Set the log level
+#undef	XPCC_LOG_LEVEL
+#define	XPCC_LOG_LEVEL xpcc::log::INFO
+
+int
+main()
+{
+	// Let's print some information that is provided in the xpcc_build_info.hpp
+	XPCC_LOG_INFO << "Machine:  " << XPCC_BUILD_MACHINE  << xpcc::endl;
+	XPCC_LOG_INFO << "User:     " << XPCC_BUILD_USER     << xpcc::endl;
+	XPCC_LOG_INFO << "Os:       " << XPCC_BUILD_OS       << xpcc::endl;
+	XPCC_LOG_INFO << "Compiler: " << XPCC_BUILD_COMPILER << xpcc::endl;
+
+	XPCC_LOG_INFO << "Compare xpcc's printf and xpcc with glibc's printf" << xpcc::endl;
+
+	int32_t ii = -42;
+
+	char format_string[] = ">>%5d<<";
+
+	XPCC_LOG_INFO << "xpcc  ";
+	XPCC_LOG_INFO.printf(format_string, ii);
+	XPCC_LOG_INFO << xpcc::endl;
+
+	char buf[32] = {' '};
+	sprintf(buf, format_string, ii);
+	XPCC_LOG_INFO.printf("glibc %s", buf);
+	XPCC_LOG_INFO << xpcc::endl;
+
+	float ff_testvector[] = {123.556789, -123.4};
+
+	for (size_t ii = 0; ii < XPCC__ARRAY_SIZE(ff_testvector); ++ii) {
+		float ff = ff_testvector[ii];
+
+		for (uint_fast8_t width = 1; width < 10; ++width)
+		{
+			for (uint_fast8_t width_frac = 1; width_frac < 10; ++width_frac)
+			{
+				char fmt_str[10];
+				sprintf(fmt_str, ">>%%%d.%df<<", width, width_frac);
+				XPCC_LOG_INFO << "xpcc  ";
+				XPCC_LOG_INFO.printf(fmt_str, ff);
+				XPCC_LOG_INFO << xpcc::endl;
+
+				char buf[23];
+				sprintf(buf, fmt_str, ff);
+				XPCC_LOG_INFO.printf("glibc %s", buf);
+
+				XPCC_LOG_INFO << xpcc::endl << xpcc::endl;
+			}
+		}
+	}
+
+	return 0;
+}

examples/linux/printf/project.cfg

@@ -0,0 +1,6 @@
+[general]
+name = printf_hosted
+
+[build]
+device = hosted
+buildpath = ${xpccpath}/build/${name}

src/xpcc/io/iostream.hpp

@@ -33,7 +33,7 @@ namespace xpcc
  */
 class IOStream
 {
-public :
+public:
 	/**
 	 * @param	device	device to write the stream to
 	 *
@@ -444,7 +444,7 @@ public :
 	IOStream&
 	vprintf(const char *fmt, va_list vlist);
 
-protected :
+protected:
 	void
 	writeInteger(int16_t value);
 
@@ -486,7 +486,10 @@ protected :
 	writeDouble(const double& value);
 #endif
 
-private :
+	void
+	writeUnsignedInteger(unsigned long unsignedValue, uint_fast8_t base, size_t width, char fill, bool isNegative);
+
+private:
 	enum class
 	Mode
 	{

src/xpcc/io/iostream_printf.cpp

@@ -10,6 +10,7 @@
 #include <stdarg.h>
 #include <stdio.h>		// snprintf()
 #include <stdlib.h>
+#include <xpcc/math/utils/misc.hpp>        // xpcc::pow
 
 #include "iostream.hpp"
 
@@ -33,9 +34,11 @@ xpcc::IOStream::vprintf(const char *fmt, va_list ap)
 	// for all chars in format (fmt)
 	while ((c = *fmt++) != 0)
 	{
-		bool isSigned = 0;
-		bool isLong = 0;
-		bool isLongLong = 0;
+		bool isSigned = false;
+		bool isLong = false;
+		bool isLongLong = false;
+		bool isFloat = false;
+		bool isNegative = false;
 
 		if (c != '%')
 		{
@@ -45,6 +48,7 @@ xpcc::IOStream::vprintf(const char *fmt, va_list ap)
 		c = *fmt++;
 
 		size_t width = 0;
+		size_t width_frac = 0;
 		char fill = ' ';
 		if (c == '0')
 		{
@@ -57,6 +61,15 @@ xpcc::IOStream::vprintf(const char *fmt, va_list ap)
 			c = *fmt++;
 		}
 
+		if (c == '.') {
+			c = *fmt++;
+
+			if (c >= '0' && c <= '9') {
+				width_frac = c - '0';
+			}
+			c = *fmt++;
+		}
+
 		if (c == 'l')
 		{
 			isLong = true;
@@ -88,6 +101,10 @@ xpcc::IOStream::vprintf(const char *fmt, va_list ap)
 				}
 				continue;
 
+			case 'f':
+				isFloat = true;
+				break;
+
 			case 'd':
 				isSigned = true;
 				/* no break */
@@ -107,6 +124,44 @@ xpcc::IOStream::vprintf(const char *fmt, va_list ap)
 
 
 		// Number output
+		if (isFloat)
+		{
+			// va_arg(ap, float) not allowed
+			float float_value = va_arg(ap, double);
+
+			if (float_value < 0)
+			{
+				float_value = -float_value; // make it positive
+				isNegative = true;
+			}
+
+			// 1) Print integer part
+			int width_integer = width - width_frac - 1;
+			if (width_integer < 0) {
+				width_integer = 0;
+			}
+
+			writeUnsignedInteger((unsigned int)float_value, base, width_integer, fill, isNegative);
+
+			// 2) Decimal dot
+			this->device->write('.');
+
+			// 3) Fractional part
+			float_value = float_value - ((int) float_value);
+			float_value *= xpcc::pow(10, width_frac);
+
+			// Alternative: Smaller code size but probably less precise
+			// for (uint_fast8_t ii = 0; ii < width_frac; ++ii) {
+			//     float_value = float_value * (10.0);
+			// }
+
+			// Add 1/2 for roundig of last digit
+			float_value += 0.5;
+
+			// Print fractional part
+			writeUnsignedInteger((unsigned int)float_value, base, width_frac, '0', false);
+		}
+		else
 		{
 			unsigned long unsignedValue;
 
@@ -127,50 +182,62 @@ xpcc::IOStream::vprintf(const char *fmt, va_list ap)
 				{
 					if (signedValue < 0)
 					{
+						isNegative = true;
 						signedValue = -signedValue; // make it positive
-						this->device->write('-');
-						if (width) {
-							--width;
-						}
 					}
 				}
 				unsignedValue = (unsigned long) signedValue;
 			}
 
-			{
-				char scratch[26];
+			writeUnsignedInteger(unsignedValue, base, width, fill, isNegative);
+		}
+	}
 
-				ptr = scratch + sizeof(scratch);
-				*--ptr = 0;
-				do
-				{
-					char ch = (unsignedValue % base) + '0';
+	return *this;
+}
 
-					if (ch > '9') {
-						ch += 'A' - '9' - 1;
-					}
+void
+xpcc::IOStream::writeUnsignedInteger(
+	unsigned long unsignedValue, uint_fast8_t base,
+	size_t width, char fill, bool isNegative)
+{
+	char scratch[26];
 
-					*--ptr = ch;
-					unsignedValue /= base;
+	char *ptr = scratch + sizeof(scratch);
+	*--ptr = 0;
+	do
+	{
+		char ch = (unsignedValue % base) + '0';
 
-					if (width) {
-						--width;
-					}
-				} while (unsignedValue);
+		if (ch > '9') {
+			ch += 'A' - '9' - 1;
+		}
 
-				// insert padding chars
-				while (width--) {
-					*--ptr = fill;
-				}
+		*--ptr = ch;
+		unsignedValue /= base;
 
-				// output result
-				while ((c = *ptr++)) {
-					this->device->write(c);
-				}
-			}
+		if (width) {
+			--width;
+		}
+	} while (unsignedValue);
+
+	// Insert minus sign if needed
+	if (isNegative)
+	{
+		*--ptr = '-';
+		if (width) {
+			--width;
 		}
 	}
 
-	return *this;
-}
+	// insert padding chars
+	while (width--) {
+		*--ptr = fill;
+	}
 
+	// output result
+	char ch;
+	while ((ch = *ptr++)) {
+		this->device->write(ch);
+	}
+}