vsprintf.h is gPXE-specific; move it to include/gpxe

src/include/gpxe/vsprintf.h

@@ -0,0 +1,67 @@
+#ifndef _GPXE_VSPRINTF_H
+#define _GPXE_VSPRINTF_H
+
+/** @file
+ *
+ * printf() and friends
+ *
+ * Etherboot's printf() functions understand the following subset of
+ * the standard C printf()'s format specifiers:
+ *
+ *	- Flag characters
+ *		- '#'		- Alternate form (i.e. "0x" prefix)
+ *		- '0'		- Zero-pad
+ *	- Field widths
+ *	- Length modifiers
+ *		- 'hh'		- Signed / unsigned char
+ *		- 'h'		- Signed / unsigned short
+ *		- 'l'		- Signed / unsigned long
+ *		- 'll'		- Signed / unsigned long long
+ *		- 'z'		- Signed / unsigned size_t
+ *	- Conversion specifiers
+ *		- 'd'		- Signed decimal
+ *		- 'x','X'	- Unsigned hexadecimal
+ *		- 'c'		- Character
+ *		- 's'		- String
+ *		- 'p'		- Pointer
+ *
+ * Hexadecimal numbers are always zero-padded to the specified field
+ * width (if any); decimal numbers are always space-padded.  Decimal
+ * long longs are not supported.
+ *
+ */
+
+#include <stdint.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+/**
+ * A printf context
+ *
+ * Contexts are used in order to be able to share code between
+ * vprintf() and vsnprintf(), without requiring the allocation of a
+ * buffer for vprintf().
+ */
+struct printf_context {
+	/**
+	 * Character handler
+	 *
+	 * @v ctx	Context
+	 * @v c		Character
+	 *
+	 * This method is called for each character written to the
+	 * formatted string.
+	 */
+	void ( * handler ) ( struct printf_context *ctx, unsigned int c );
+	/** Length of formatted string
+	 *
+	 * When handler() is called, @len will be set to the number of
+	 * characters written so far (i.e. zero for the first call to
+	 * handler()).
+	 */
+	size_t len;
+};
+
+extern size_t vcprintf ( struct printf_context *ctx, const char *fmt,
+			 va_list args );
+#endif /* _GPXE_VSPRINTF_H */