added snprintf and a test for it

4 files changed, 131 insertions, 2 deletions

diff --git a/src/libc/stdio.c b/src/libc/stdio.c
index 9fdf510..e0b87a8 100644
--- a/src/libc/stdio.c
+++ b/src/libc/stdio.c
@@ -150,6 +150,107 @@ int vprintf( const char *format, va_list args )
 	return n;
 }
 
+int snprintf( char *buf, size_t n, const char *format, ... )
+{
+	va_list args;
+	
+	va_start( args, format );
+	int res = vsnprintf( buf, n, format, args );
+	va_end( args );
+	
+	return res;
+}
+
+#define EMIT( x ) if( len < n ) { *buf = ( x ); buf++; *buf = '\0'; len++; }
+
+#define APPEND_STRING( s, s2 ) \
+	strlcat( s, s2, n - len ); \
+	s += strlen( s2 ); \
+	len += strlen( s2 ); \
+	if( len < n ) { \
+		*s = '\0'; \
+	}
+
+int vsnprintf( char *buf, size_t n, const char *format, va_list args )
+{
+	const char *s = format;
+	int len = 0;
+
+	*buf = '\0';	
+	while( *s != '\0' && len < n ) {
+		switch( *s ) {
+			case '\n':
+				EMIT( '\n' );
+				break;
+			
+			case '%':
+				s++;
+				if( *s == '\0' ) {
+					strlcpy( buf, "<truncated % found at end of format string>", n - len );
+					strlcat( buf, "\n", n - len - 1 );
+					return -1;
+				}
+				
+				switch( *s ) {
+					case '%':
+						EMIT( '%' );
+						break;
+						
+					case 'X': {
+						char buf2[19];
+						itoa( va_arg( args, int ), (char *)buf2, 16 );
+						APPEND_STRING( buf, buf2 );
+						}
+						break;
+					
+					case 'd': {
+						char buf2[19];
+						itoa( va_arg( args, int ), (char *)buf2, 10 );
+						APPEND_STRING( buf, buf2 );
+						}
+						break;
+
+					case 'c': {
+						char buf2[2];
+						buf2[0] = (char)va_arg( args, int );
+						buf2[1] = '\0';
+						APPEND_STRING( buf, buf2 );
+						}
+						break;
+						
+					case 's': {
+						const char *s = va_arg( args, const char * );
+						APPEND_STRING( buf, s );
+						}
+						break;
+
+					default: {
+						APPEND_STRING( buf, "<illegal format string %" );
+						char buf2[2];
+						buf2[0] = (char)( *s );
+						buf2[1] = '\0';
+						APPEND_STRING( buf, buf2 );
+						buf2[0] = '\n';
+						APPEND_STRING( buf, buf2 );
+						}
+				}
+				
+				break;				
+			
+			default: {
+				char buf2[2];
+				buf2[0] = (char)( *s );
+				buf2[1] = '\0';
+				APPEND_STRING( buf, buf2 );
+				}
+		}
+		s++;
+	}
+	
+	return len;
+}
+
+
 #ifdef OS_ABAOS
 void __stdio_set_console( console_t *console )
 {
diff --git a/src/libc/stdio.h b/src/libc/stdio.h
index 58c80b1..e32683f 100644
--- a/src/libc/stdio.h
+++ b/src/libc/stdio.h
@@ -18,6 +18,8 @@
 int puts( const char *s );
 int printf( const char *format, ... );
 int vprintf( const char *format, va_list args );
+int snprintf( char *buf, size_t n, const char *format, ... );
+int vsnprintf( char *buf, size_t n, const char *format, va_list args );
 
 #ifdef OS_ABAOS
 void __stdio_set_console( console_t *console );
diff --git a/tests/libc/Makefile b/tests/libc/Makefile
index 37c383a..c21263d 100644
--- a/tests/libc/Makefile
+++ b/tests/libc/Makefile
@@ -37,9 +37,15 @@ test_malloc.o: test_malloc.c ../../src/libc/stdlib.h
 test_printf: test_printf.o ../../src/libc/stdlib.o ../../src/libc/stdio.o ../../src/libc/string.o ../../src/kernel/memorymanagement.o kernel_stub.o kernel_stub_asm.o
 	$(LD) $(LDFLAGS) -o test_printf test_printf.o ../../src/libc/stdio.o ../../src/libc/stdlib.o ../../src/libc/string.o ../../src/kernel/memorymanagement.o kernel_stub.o kernel_stub_asm.o
 
+test_sprintf: test_sprintf.o ../../src/libc/stdlib.o ../../src/libc/stdio.o ../../src/libc/string.o ../../src/kernel/memorymanagement.o kernel_stub.o kernel_stub_asm.o
+	$(LD) $(LDFLAGS) -o test_sprintf test_sprintf.o ../../src/libc/stdio.o ../../src/libc/stdlib.o ../../src/libc/string.o ../../src/kernel/memorymanagement.o kernel_stub.o kernel_stub_asm.o
+
 test_printf.o: test_printf.c ../../src/libc/stdlib.h
 	$(CC) $(CFLAGS) -c -o test_printf.o test_printf.c
 
+test_sprintf.o: test_sprintf.c ../../src/libc/stdlib.h
+	$(CC) $(CFLAGS) -c -o test_sprintf.o test_sprintf.c
+
 test_exit: test_exit.o ../../src/libc/stdlib.o ../../src/libc/stdio.o ../../src/libc/string.o ../../src/kernel/memorymanagement.o kernel_stub.o kernel_stub_asm.o
 	$(LD) $(LDFLAGS) -o test_exit test_exit.o ../../src/libc/stdio.o ../../src/libc/stdlib.o ../../src/libc/string.o ../../src/kernel/memorymanagement.o kernel_stub.o kernel_stub_asm.o
 
@@ -64,15 +70,16 @@ kernel_stub.o: kernel_stub.c
 kernel_stub_asm.o: kernel_stub.asm
 	$(NASM) kernel_stub.asm $(NASMFLAGS) -o kernel_stub_asm.o
 	
-test: test_strlcpy test_strlcat test_itoa test_malloc test_exit test_printf
+test: test_strlcpy test_strlcat test_itoa test_malloc test_exit test_printf test_sprintf
 	./test_strlcpy
 	./test_strlcat
 	./test_itoa
 	./test_malloc
 	./test_printf
+	./test_sprintf
 	./test_exit
 	
 clean:
-	-rm -f test_strlcpy test_strlcat test_itoa test_malloc test_printf test_exit
+	-rm -f test_strlcpy test_strlcat test_itoa test_malloc test_printf test_sprintf test_exit
 	-rm -f ../../src/libc/stdlib.o ../../src/libc/string.o ../../src/libc/stdio.o ../../src/kernel/memorymanagement.o
 	-rm -f *.o
diff --git a/tests/libc/test_sprintf.c b/tests/libc/test_sprintf.c
new file mode 100644
index 0000000..b1f25c7
--- /dev/null
+++ b/tests/libc/test_sprintf.c
@@ -0,0 +1,19 @@
+#include "string.h"
+#include "stdlib.h"
+#include "stdio.h"
+#include "string.h"
+
+int main( void )
+{
+	char *s = "test_string";
+	int i = 47;
+	char c = 'X';
+	char buf[100];
+	const char *must = "string 'test_string', decimal 47, hex 0x2F, character 'X'\n";
+
+	snprintf( buf, 100, "string '%s', decimal %d, hex 0x%X, character '%c'\n",
+		s, i, i, c );
+	if( strncmp( buf, must, strlen( must ) ) != 0 ) exit( 1 );
+
+	exit( 0 );
+}