AK: Support fixed point formatting to print real numbers

2 files changed, 33 insertions, 12 deletions

diff --git a/AK/Format.cpp b/AK/Format.cpp
index 0f52a50dde..9fa6f9e429 100644
--- a/AK/Format.cpp
+++ b/AK/Format.cpp
@@ -367,7 +367,8 @@ ErrorOr<void> FormatBuilder::put_fixed_point(
     size_t min_width,
     size_t precision,
     char fill,
-    SignMode sign_mode)
+    SignMode sign_mode,
+    RealNumberDisplayMode display_mode)
 {
     StringBuilder string_builder;
     FormatBuilder format_builder { string_builder };
@@ -395,7 +396,7 @@ ErrorOr<void> FormatBuilder::put_fixed_point(
         {
             auto fraction_tmp = fraction;
             for (; visible_precision < precision; ++visible_precision) {
-                if (fraction_tmp == 0)
+                if (fraction_tmp == 0 && display_mode != RealNumberDisplayMode::FixedPoint)
                     break;
                 fraction_tmp /= 10;
             }
@@ -425,7 +426,8 @@ ErrorOr<void> FormatBuilder::put_f64(
     size_t min_width,
     size_t precision,
     char fill,
-    SignMode sign_mode)
+    SignMode sign_mode,
+    RealNumberDisplayMode display_mode)
 {
     StringBuilder string_builder;
     FormatBuilder format_builder { string_builder };
@@ -464,7 +466,7 @@ ErrorOr<void> FormatBuilder::put_f64(
 
         size_t visible_precision = 0;
         for (; visible_precision < precision; ++visible_precision) {
-            if (value - static_cast<i64>(value) < epsilon)
+            if (value - static_cast<i64>(value) < epsilon && display_mode != RealNumberDisplayMode::FixedPoint)
                 break;
             value *= 10.0;
             epsilon *= 10.0;
@@ -492,7 +494,8 @@ ErrorOr<void> FormatBuilder::put_f80(
     size_t min_width,
     size_t precision,
     char fill,
-    SignMode sign_mode)
+    SignMode sign_mode,
+    RealNumberDisplayMode display_mode)
 {
     StringBuilder string_builder;
     FormatBuilder format_builder { string_builder };
@@ -531,7 +534,7 @@ ErrorOr<void> FormatBuilder::put_f80(
 
         size_t visible_precision = 0;
         for (; visible_precision < precision; ++visible_precision) {
-            if (value - static_cast<i64>(value) < epsilon)
+            if (value - static_cast<i64>(value) < epsilon && display_mode != RealNumberDisplayMode::FixedPoint)
                 break;
             value *= 10.0l;
             epsilon *= 10.0l;
@@ -794,9 +797,12 @@ ErrorOr<void> Formatter<long double>::format(FormatBuilder& builder, long double
 {
     u8 base;
     bool upper_case;
+    FormatBuilder::RealNumberDisplayMode real_number_display_mode = FormatBuilder::RealNumberDisplayMode::General;
     if (m_mode == Mode::Default || m_mode == Mode::FixedPoint) {
         base = 10;
         upper_case = false;
+        if (m_mode == Mode::FixedPoint)
+            real_number_display_mode = FormatBuilder::RealNumberDisplayMode::FixedPoint;
     } else if (m_mode == Mode::Hexfloat) {
         base = 16;
         upper_case = false;
@@ -810,16 +816,19 @@ ErrorOr<void> Formatter<long double>::format(FormatBuilder& builder, long double
     m_width = m_width.value_or(0);
     m_precision = m_precision.value_or(6);
 
-    return builder.put_f80(value, base, upper_case, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode);
+    return builder.put_f80(value, base, upper_case, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode, real_number_display_mode);
 }
 
 ErrorOr<void> Formatter<double>::format(FormatBuilder& builder, double value)
 {
     u8 base;
     bool upper_case;
+    FormatBuilder::RealNumberDisplayMode real_number_display_mode = FormatBuilder::RealNumberDisplayMode::General;
     if (m_mode == Mode::Default || m_mode == Mode::FixedPoint) {
         base = 10;
         upper_case = false;
+        if (m_mode == Mode::FixedPoint)
+            real_number_display_mode = FormatBuilder::RealNumberDisplayMode::FixedPoint;
     } else if (m_mode == Mode::Hexfloat) {
         base = 16;
         upper_case = false;
@@ -833,7 +842,7 @@ ErrorOr<void> Formatter<double>::format(FormatBuilder& builder, double value)
     m_width = m_width.value_or(0);
     m_precision = m_precision.value_or(6);
 
-    return builder.put_f64(value, base, upper_case, m_zero_pad, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode);
+    return builder.put_f64(value, base, upper_case, m_zero_pad, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode, real_number_display_mode);
 }
 
 ErrorOr<void> Formatter<float>::format(FormatBuilder& builder, float value)
diff --git a/AK/Format.h b/AK/Format.h
index 6dfc1437cd..cb35323e60 100644
--- a/AK/Format.h
+++ b/AK/Format.h
@@ -150,6 +150,12 @@ public:
         Default = OnlyIfNeeded,
     };
 
+    enum class RealNumberDisplayMode {
+        FixedPoint,
+        General,
+        Default = General,
+    };
+
     explicit FormatBuilder(StringBuilder& builder)
         : m_builder(builder)
     {
@@ -200,7 +206,8 @@ public:
         size_t min_width = 0,
         size_t precision = 6,
         char fill = ' ',
-        SignMode sign_mode = SignMode::OnlyIfNeeded);
+        SignMode sign_mode = SignMode::OnlyIfNeeded,
+        RealNumberDisplayMode = RealNumberDisplayMode::Default);
 
 #ifndef KERNEL
     ErrorOr<void> put_f80(
@@ -211,7 +218,8 @@ public:
         size_t min_width = 0,
         size_t precision = 6,
         char fill = ' ',
-        SignMode sign_mode = SignMode::OnlyIfNeeded);
+        SignMode sign_mode = SignMode::OnlyIfNeeded,
+        RealNumberDisplayMode = RealNumberDisplayMode::Default);
 
     ErrorOr<void> put_f64(
         double value,
@@ -222,7 +230,8 @@ public:
         size_t min_width = 0,
         size_t precision = 6,
         char fill = ' ',
-        SignMode sign_mode = SignMode::OnlyIfNeeded);
+        SignMode sign_mode = SignMode::OnlyIfNeeded,
+        RealNumberDisplayMode = RealNumberDisplayMode::Default);
 #endif
 
     ErrorOr<void> put_hexdump(
@@ -520,9 +529,12 @@ struct Formatter<FixedPoint<precision, Underlying>> : StandardFormatter {
     {
         u8 base;
         bool upper_case;
+        FormatBuilder::RealNumberDisplayMode real_number_display_mode = FormatBuilder::RealNumberDisplayMode::General;
         if (m_mode == Mode::Default || m_mode == Mode::FixedPoint) {
             base = 10;
             upper_case = false;
+            if (m_mode == Mode::FixedPoint)
+                real_number_display_mode = FormatBuilder::RealNumberDisplayMode::FixedPoint;
         } else if (m_mode == Mode::Hexfloat) {
             base = 16;
             upper_case = false;
@@ -539,7 +551,7 @@ struct Formatter<FixedPoint<precision, Underlying>> : StandardFormatter {
         i64 integer = value.ltrunk();
         constexpr u64 one = static_cast<Underlying>(1) << precision;
         u64 fraction_raw = value.raw() & (one - 1);
-        return builder.put_fixed_point(integer, fraction_raw, one, base, upper_case, m_zero_pad, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode);
+        return builder.put_fixed_point(integer, fraction_raw, one, base, upper_case, m_zero_pad, m_align, m_width.value(), m_precision.value(), m_fill, m_sign_mode, real_number_display_mode);
     }
 };