From fac70421d77519bbdcac1417c62bcb463ef57354 Mon Sep 17 00:00:00 2001
From: Alex Kotov <kotovalexarian@gmail.com>
Date: Sun, 6 Dec 2020 07:42:56 +0500
Subject: [PATCH] Add function "kernaux_console_printf"

---
 README.md                 |  2 +-
 include/kernaux/console.h |  1 +
 src/console.c             | 59 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index edde0de..e4cef39 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ API
 
 * [Simple command line parser](/include/kernaux/cmdline.h) *(work in progress)*
 * [Multiboot 2 (GRUB 2) information parser](/include/kernaux/multiboot2.h)
-* [Serial console](/include/kernaux/console.h)
+* [Serial console](/include/kernaux/console.h) *(work in progress)*
 * [Page Frame Allocator](/include/kernaux/pfa.h) *(work in progress)*
 * ELF utils *(planned)*
 * [Architecture-specific helpers](/include/kernaux/arch/)
diff --git a/include/kernaux/console.h b/include/kernaux/console.h
index 07de3f0..9a27f94 100644
--- a/include/kernaux/console.h
+++ b/include/kernaux/console.h
@@ -6,6 +6,7 @@ extern "C" {
 #endif
 
 void kernaux_console_print(const char *s);
+void kernaux_console_printf(const char *format, ...);
 void kernaux_console_putc(char c);
 void kernaux_console_puts(const char *s);
 void kernaux_console_write(const char *data, unsigned int size);
diff --git a/src/console.c b/src/console.c
index 6264b10..e58da7f 100644
--- a/src/console.c
+++ b/src/console.c
@@ -31,3 +31,62 @@ void kernaux_console_write(const char *const data, const unsigned int size)
         kernaux_console_putc(data[i]);
     }
 }
+
+void kernaux_console_printf(const char *format, ...)
+{
+    char **arg = (char **) &format;
+    int c;
+    char buf[20];
+    arg++;
+
+    while ((c = *format++) != 0)
+    {
+        if (c == '\n') {
+            if (*format != 0) {
+                kernaux_console_putc('\n');
+            }
+        }
+        else if (c != '%') {
+            kernaux_console_putc(c);
+        }
+        else {
+            char *p, *p2;
+            int pad0 = 0, pad = 0;
+            c = *format++;
+            if (c == '0')
+            {
+                pad0 = 1;
+                c = *format++;
+            }
+            if (c >= '0' && c <= '9')
+            {
+                pad = c - '0';
+                c = *format++;
+            }
+            switch (c)
+            {
+                case 'd':
+                case 'u':
+                case 'x':
+                    kernaux_itoa(*((int*)arg++), buf, c);
+                    p = buf;
+                    goto string;
+                    break;
+                case 's':
+                    p = *arg++;
+                    if (! p)
+                        p = "(null)";
+string:
+                    for (p2 = p; *p2; p2++);
+                    for (; p2 < p + pad; p2++)
+                        kernaux_console_putc(pad0 ? '0' : ' ');
+                    while (*p)
+                        kernaux_console_putc(*p++);
+                    break;
+                default:
+                    kernaux_console_putc(*((int *) arg++));
+                    break;
+            }
+        }
+    }
+}