From 88af7a915b29b484e4673ebff0da46c106650d3f Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 19 Nov 2022 13:59:06 +0100
Subject: [PATCH] Start padding and alternate forms for integers

---
 luna/Format.h | 42 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/luna/Format.h b/luna/Format.h
index b2b47506..f3c38144 100644
--- a/luna/Format.h
+++ b/luna/Format.h
@@ -200,7 +200,7 @@ static bool is_integer_format_specifier(char c)
     return (c == 'd') || (c == 'i') || (c == 'u') || (c == 'x') || (c == 'X') || (c == 'o') || (c == 'b');
 }
 
-template <typename T> static usize to_string(T value, T base, char* buf, usize max, bool uppercase)
+static usize to_string(usize value, usize base, char* buf, usize max, bool uppercase)
 {
     usize i = 0;
     if (!value && max)
@@ -217,8 +217,7 @@ template <typename T> static usize to_string(T value, T base, char* buf, usize m
     return i;
 }
 
-template <typename T>
-static int output_integer(char specifier, const conv_state& vstate, format_state& state, T value, bool negative)
+static int output_integer(char specifier, conv_state& vstate, format_state& state, usize value, bool negative)
 {
     usize base = 10;
     bool uppercase = false;
@@ -233,10 +232,37 @@ static int output_integer(char specifier, const conv_state& vstate, format_state
     }
     if (specifier == 'X') uppercase = true;
 
-    char buf[1024];
-    usize buflen = to_string(value, (T)base, buf, sizeof(buf), uppercase);
+    if (base == 10) vstate.flags &= ~FLAG_ALTERNATE; // decimal doesn't have an alternate form
 
-    // FIXME: Start padding and alternate forms.
+    char buf[1024];
+    usize buflen = to_string(value, base, buf, sizeof(buf), uppercase);
+
+    if (!(vstate.flags & FLAG_LEFT_ALIGN) &&
+        (vstate.flags & FLAG_ZERO_PAD)) // we're padding with zeroes from the beginning
+    {
+        bool extra_char =
+            negative || ((vstate.flags & FLAG_SIGN) ||
+                         (vstate.flags & FLAG_BLANK_SIGNED)); // are we adding an extra character after the buffer?
+        if (vstate.width && extra_char) vstate.width--;
+
+        if (vstate.width && (vstate.flags & FLAG_ALTERNATE)) // fit in the characters we're using for the alternate form
+        {
+            vstate.width--;
+            if (vstate.width && (base == 2 || base == 16)) vstate.width--;
+        }
+
+        while (buflen < vstate.width && buflen < sizeof(buf)) buf[buflen++] = '0';
+    }
+
+    while (buflen < vstate.precision && buflen < sizeof(buf)) buf[buflen++] = '0';
+
+    if (vstate.flags & FLAG_ALTERNATE)
+    {
+        if (base == 16 && !uppercase && buflen < sizeof(buf)) buf[buflen++] = 'x';
+        if (base == 16 && uppercase && buflen < sizeof(buf)) buf[buflen++] = 'X';
+        if (base == 2 && buflen < sizeof(buf)) buf[buflen++] = 'b';
+        if (buflen < sizeof(buf)) buf[buflen++] = '0';
+    }
 
     if (buflen < sizeof(buf))
     {
@@ -247,6 +273,8 @@ static int output_integer(char specifier, const conv_state& vstate, format_state
             buf[buflen++] = ' ';
     }
 
+    if (!(vstate.flags & FLAG_ZERO_PAD)) TRY_START_PAD(vstate, state, buflen);
+
     usize i = buflen;
 
     while (i--) TRY_PUTCHAR(buf[i], state);
@@ -256,7 +284,7 @@ static int output_integer(char specifier, const conv_state& vstate, format_state
     return 0;
 }
 
-static int va_output_integer(char specifier, const conv_state& vstate, format_state& state, va_list ap)
+static int va_output_integer(char specifier, conv_state& vstate, format_state& state, va_list ap)
 {
     bool is_signed = false;
     bool negative = false;