From 2404b22c1ff08168cf5c2f0f83c3d4378ae58f55 Mon Sep 17 00:00:00 2001
From: "Justin C. Miller" <justin@devjustinian.com>
Date: Wed, 25 Apr 2018 19:52:27 -0700
Subject: [PATCH] support widths in printf

---
 src/kernel/console.cpp | 68 ++++++++++++++++++++++++++++--------------
 src/kernel/console.h   | 18 ++++++++---
 2 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/src/kernel/console.cpp b/src/kernel/console.cpp
index eb05df5..e2622df 100644
--- a/src/kernel/console.cpp
+++ b/src/kernel/console.cpp
@@ -244,6 +244,7 @@ console::puts(const char *message)
 	while (message && *message) {
 		char c = *message++;
 		if (m_screen) m_screen->putc(c);
+
 		serial_write(c);
 		if (c == '\n') serial_write('\r');
 	}
@@ -271,37 +272,60 @@ void console::printf(const char *fmt, ...)
 			continue;
 		}
 
+		r++; // chomp the %
 		flush();
 
-		r++; // chomp the %
-		switch (*r++) {
-			case '%': *w = '%'; break;
+		bool done = false;
+		bool right = true;
+		int width = 0;
 
-			case 'x': put_hex<uint32_t>(va_arg(args, uint32_t)); break;
+		while (!done) {
+			char c = *r++;
+			switch (c) {
+				case '%': *w = '%'; done = true; break;
 
-			case 'd':
-			case 'u': put_dec<uint32_t>(va_arg(args, uint32_t)); break;
+				case '0':
+				case '1':
+				case '2':
+				case '3':
+				case '4':
+				case '5':
+				case '6':
+				case '7':
+				case '8':
+				case '9': width = width * 10 + (c - '0'); break;
 
-			case 's': {
-					const char *s = va_arg(args, const char*);
-					if (s) puts(s);
-				}
-				break;
+				case '-': right = !right; break;
 
-			case 'l':
-				switch (*r++) {
-					case 'x': put_hex<uint64_t>(va_arg(args, uint64_t)); break;
+				case 'x': put_hex<uint32_t>(va_arg(args, uint32_t), right ? width : -width); done = true; break;
 
-					case 'd':
-					case 'u': put_dec<uint32_t>(va_arg(args, uint64_t)); break;
+				case 'd':
+				case 'u': put_dec<uint32_t>(va_arg(args, uint32_t), right ? width : -width); done = true; break;
 
-					default:
-						break;
-				}
-				break;
+				case 's': {
+						const char *s = va_arg(args, const char*);
+						if (s) puts(s);
+					}
+					done = true;
+					break;
 
-			default:
-				break;
+				case 'l':
+					switch (*r++) {
+						case 'x': put_hex<uint64_t>(va_arg(args, uint64_t), right ? width : -width); done = true; break;
+
+						case 'd':
+						case 'u': put_dec<uint32_t>(va_arg(args, uint64_t), right ? width : -width); done = true; break;
+
+						default:
+							done = true;
+							break;
+					}
+					break;
+
+				default:
+					done = true;
+					break;
+			}
 		}
 	}
 
diff --git a/src/kernel/console.h b/src/kernel/console.h
index ced19ff..4dccd57 100644
--- a/src/kernel/console.h
+++ b/src/kernel/console.h
@@ -17,10 +17,12 @@ public:
 	void printf(const char *fmt, ...);
 
 	template <typename T>
-	void put_hex(T x);
+	void put_hex(T x, int width = 0);
 
 	template <typename T>
-	void put_dec(T x);
+	void put_dec(T x, int width = 0);
+
+	void set_screen(console_out_screen *out) { m_screen = out; }
 
 	static console * get();
 
@@ -39,7 +41,7 @@ console_out_screen * console_get_screen_out(
 extern const char digits[];
 
 template <typename T>
-void console::put_hex(T x)
+void console::put_hex(T x, int width)
 {
 	static const int chars = sizeof(x) * 2;
 	char message[chars + 1];
@@ -47,19 +49,27 @@ void console::put_hex(T x)
 		message[chars - i - 1] = digits[(x >> (i*4)) & 0xf];
 	}
 	message[chars] = 0;
+
+	if (width > chars) for(int i=0; i<(width-chars); ++i) puts(" ");
 	puts(message);
+	if (-width > chars) for(int i=0; i<(-width-chars); ++i) puts(" ");
 }
 
 template <typename T>
-void console::put_dec(T x)
+void console::put_dec(T x, int width)
 {
 	static const int chars = sizeof(x) * 3;
 	char message[chars + 1];
 	char *p = message + chars;
+	int length = 0;
 	*p-- = 0;
 	do {
 		*p-- = digits[x % 10];
 		x /= 10;
+		length += 1;
 	} while (x != 0);
+
+	if (width > length) for(int i=0; i<(width-length); ++i) puts(" ");
 	puts(++p);
+	if (-width > length) for(int i=0; i<(-width-length); ++i) puts(" ");
 }