From 48510fb45403de8920448f9b73ceb8ca7c23d160 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristoffer=20Gr=C3=B6nlund?= <krig@koru.se>
Date: Tue, 23 May 2017 22:46:16 +0200
Subject: [PATCH] Customize format for I32/U32 (#1920)

Fixes formatting of I32.min_value().

TODO: the u32 and u64 funs in
_format_int.pony could probably be
largely re-unified.

Update formatting to follow style
guide proposal (#1894).

Fixes: #1920
---
 packages/format/_format_int.pony | 70 ++++++++++++++++++++++++++++----
 packages/format/_test.pony       |  2 +
 packages/format/format.pony      |  4 +-
 3 files changed, 68 insertions(+), 8 deletions(-)

diff --git a/packages/format/_format_int.pony b/packages/format/_format_int.pony
index 0b2fc2aeaae..ce75066854b 100644
--- a/packages/format/_format_int.pony
+++ b/packages/format/_format_int.pony
@@ -65,9 +65,59 @@ primitive _FormatInt
       s.reverse_in_place()
     end
 
-  fun u64(x: U64, neg: Bool, fmt: FormatInt, prefix: PrefixNumber,
-    prec: USize, width: USize, align: Align, fill: U32
-  ): String iso^ =>
+  fun u32(
+    x: U32,
+    neg: Bool,
+    fmt: FormatInt,
+    prefix: PrefixNumber,
+    prec: USize,
+    width: USize,
+    align: Align,
+    fill: U32)
+    : String iso^
+  =>
+    match fmt
+    | FormatUTF32 => return recover String.from_utf32(x.u32()) end
+    end
+
+    (var base', var typestring, var table) = _fmt_int(fmt)
+    var prestring = _prefix(neg, prefix)
+    var prec' = if prec == -1 then 0 else prec end
+    let base = base'.u32()
+
+    recover
+      var s = String((prec + 1).max(width.max(31)))
+      var value = x
+
+      try
+        if value == 0 then
+          s.push(table(0))
+        else
+          while value != 0 do
+            let index = ((value = value / base) - (value * base))
+            s.push(table(index.usize()))
+          end
+        end
+      end
+
+      _extend_digits(s, prec')
+      s.append(typestring)
+      s.append(prestring)
+      _pad(s, width, align, fill)
+      s
+    end
+
+  fun u64(
+    x: U64,
+    neg: Bool,
+    fmt: FormatInt,
+    prefix: PrefixNumber,
+    prec: USize,
+    width: USize,
+    align: Align,
+    fill: U32)
+    : String iso^
+  =>
     match fmt
     | FormatUTF32 => return recover String.from_utf32(x.u32()) end
     end
@@ -99,10 +149,16 @@ primitive _FormatInt
       s
     end
 
-  fun u128(x: U128, neg: Bool, fmt: FormatInt = FormatDefault,
-    prefix: PrefixNumber = PrefixDefault, prec: USize = -1, width: USize = 0,
-    align: Align = AlignLeft, fill: U32 = ' '
-  ): String iso^ =>
+  fun u128(x: U128,
+    neg: Bool,
+    fmt: FormatInt = FormatDefault,
+    prefix: PrefixNumber = PrefixDefault,
+    prec: USize = -1,
+    width: USize = 0,
+    align: Align = AlignLeft,
+    fill: U32 = ' ')
+    : String iso^
+  =>
     match fmt
     | FormatUTF32 => return recover String.from_utf32(x.u32()) end
     end
diff --git a/packages/format/_test.pony b/packages/format/_test.pony
index 9f5f47b7f19..9a6bf24310d 100644
--- a/packages/format/_test.pony
+++ b/packages/format/_test.pony
@@ -24,6 +24,8 @@ class iso _TestInt is UnitTest
   fun name(): String => "format/int"
 
   fun apply(h: TestHelper) =>
+    h.assert_eq[String]("-2147483648",
+      Format.int[I32](I32.min_value()))
     h.assert_eq[String]("00010",
       Format.int[U64](10, FormatDefault, PrefixDefault, 5))
     h.assert_eq[String]("0x0000A",
diff --git a/packages/format/format.pony b/packages/format/format.pony
index f56aad56708..23868777e07 100644
--- a/packages/format/format.pony
+++ b/packages/format/format.pony
@@ -96,8 +96,10 @@ primitive Format
       _FormatInt.u128(x.u128(), false, fmt, prefix, prec, width, align, fill)
     elseif x is I128 then
       _FormatInt.u128(abs.u128(), neg, fmt, prefix, prec, width, align, fill)
-    else
+    elseif (x is U64) or (x is I64) then
       _FormatInt.u64(abs.u64(), neg, fmt, prefix, prec, width, align, fill)
+    else
+      _FormatInt.u32(abs.u32(), neg, fmt, prefix, prec, width, align, fill)
     end
 
   fun float[A: (Float & FloatingPoint[A])](x: A,