From 4ebf244d3bbee104ac41c61bf1c50566d7fe2964 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 19 Nov 2022 13:15:13 +0100
Subject: [PATCH] Support printing some integers in output_integer

---
 kernel/src/main.cpp |   2 +
 luna/Format.h       | 147 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 147 insertions(+), 2 deletions(-)

diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index e0c7d376..258e35ee 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -26,6 +26,8 @@ extern "C" [[noreturn]] void _start()
 
     const u64 address = 0xfffffffff8000000;
 
+    Serial::printf("Mapping address 0x%lx\n", address);
+
     u64 physical = MemoryManager::alloc_physical_page().release_value();
 
     auto rc = MMU::map(address, physical, MMU::ReadWrite);
diff --git a/luna/Format.h b/luna/Format.h
index 1be99216..c683d882 100644
--- a/luna/Format.h
+++ b/luna/Format.h
@@ -200,9 +200,152 @@ static bool is_integer_format_specifier(char c)
     return (c == 'd') || (c == 'i') || (c == 'u') || (c == 'x') || (c == 'X') || (c == 'o') || (c == 'b');
 }
 
-static int output_integer(char, const conv_state&, format_state&, va_list)
+template <typename T> static usize to_string(T value, T base, char* buf, usize max, bool uppercase)
 {
-    return -1; // FIXME: Implement this.
+    usize i = 0;
+    if (!value && max)
+    {
+        buf[i] = '0';
+        return 1;
+    }
+    do {
+        int digit = (int)(value % base);
+        char c = (char)(digit < 10 ? '0' + digit : ((uppercase ? 'A' : 'a') + (digit - 10)));
+        buf[i++] = c;
+        value /= base;
+    } while (value && i < max);
+    return i;
+}
+
+static int output_integer(char specifier, const conv_state& vstate, format_state& state, va_list ap)
+{
+    usize base = 10;
+    bool is_signed = false;
+    bool uppercase = false;
+    bool negative = false;
+
+    if (specifier == 'd' || specifier == 'i') is_signed = true;
+    switch (specifier)
+    {
+    case 'x':
+    case 'X': base = 16; break;
+    case 'o': base = 8; break;
+    case 'b': base = 2; break;
+    default: break;
+    }
+    if (specifier == 'X') uppercase = true;
+
+    char buf[1024];
+    usize buflen;
+    if (vstate.flags & FLAG_CHAR)
+    {
+        if (is_signed)
+        {
+            char v = (char)va_arg(ap, int);
+            if (v < 0)
+            {
+                v = -v;
+                negative = true;
+            }
+            buflen = to_string(v, (char)base, buf, sizeof(buf), uppercase);
+        }
+        else
+        {
+            unsigned char v = (unsigned char)va_arg(ap, unsigned int);
+            buflen = to_string(v, (unsigned char)base, buf, sizeof(buf), uppercase);
+        }
+    }
+    else if (vstate.flags & FLAG_SHORT)
+    {
+        if (is_signed)
+        {
+            short v = (short)va_arg(ap, int);
+            if (v < 0)
+            {
+                v = -v;
+                negative = true;
+            }
+            buflen = to_string(v, (short)base, buf, sizeof(buf), uppercase);
+        }
+        else
+        {
+            unsigned short v = (unsigned short)va_arg(ap, unsigned int);
+            buflen = to_string(v, (unsigned short)base, buf, sizeof(buf), uppercase);
+        }
+    }
+    else if (vstate.flags & FLAG_LONG_LONG)
+    {
+        if (is_signed)
+        {
+            long long v = va_arg(ap, long long);
+            if (v < 0)
+            {
+                v = -v;
+                negative = true;
+            }
+            buflen = to_string(v, (long long)base, buf, sizeof(buf), uppercase);
+        }
+        else
+        {
+            unsigned long long v = va_arg(ap, unsigned long long);
+            buflen = to_string(v, (unsigned long long)base, buf, sizeof(buf), uppercase);
+        }
+    }
+    else if (vstate.flags & FLAG_LONG)
+    {
+        if (is_signed)
+        {
+            long v = va_arg(ap, long);
+            if (v < 0)
+            {
+                v = -v;
+                negative = true;
+            }
+            buflen = to_string(v, (long)base, buf, sizeof(buf), uppercase);
+        }
+        else
+        {
+            unsigned long v = va_arg(ap, unsigned long);
+            buflen = to_string(v, (unsigned long)base, buf, sizeof(buf), uppercase);
+        }
+    }
+    else
+    {
+        if (is_signed)
+        {
+            int v = va_arg(ap, int);
+            if (v < 0)
+            {
+                v = -v;
+                negative = true;
+            }
+            buflen = to_string(v, (int)base, buf, sizeof(buf), uppercase);
+        }
+        else
+        {
+            unsigned int v = va_arg(ap, unsigned int);
+            buflen = to_string(v, (unsigned int)base, buf, sizeof(buf), uppercase);
+        }
+    }
+
+    // FIXME: Start padding and alternate forms.
+
+    if (buflen < sizeof(buf))
+    {
+        if (negative) buf[buflen++] = '-';
+        else if (vstate.flags & FLAG_SIGN)
+            buf[buflen++] = '+';
+        else if (vstate.flags & FLAG_BLANK_SIGNED)
+            buf[buflen++] = ' ';
+    }
+
+    usize i = buflen;
+
+    while (i--) TRY_PUTCHAR(buf[i], state);
+
+    TRY_END_PAD(vstate, state, buflen);
+
+    return 0;
 }
 
 #endif