pe(optional header): support writing PE32 header

Well, PE32 should be something of the past, but, corkami tests PE are mostly PE32,
so for testing reason, it helps to support that usecase.

src/pe/optional_header.rs

@@ -239,6 +239,36 @@ impl From<WindowsFields32> for WindowsFields {
     }
 }
 
+impl TryFrom<WindowsFields64> for WindowsFields32 {
+    type Error = crate::error::Error;
+
+    fn try_from(value: WindowsFields64) -> Result<Self, Self::Error> {
+        Ok(WindowsFields32 {
+            image_base: value.image_base.try_into()?,
+            section_alignment: value.section_alignment,
+            file_alignment: value.file_alignment,
+            major_operating_system_version: value.major_operating_system_version,
+            minor_operating_system_version: value.minor_operating_system_version,
+            major_image_version: value.major_image_version,
+            minor_image_version: value.minor_image_version,
+            major_subsystem_version: value.major_subsystem_version,
+            minor_subsystem_version: value.minor_subsystem_version,
+            win32_version_value: value.win32_version_value,
+            size_of_image: value.size_of_image,
+            size_of_headers: value.size_of_headers,
+            check_sum: value.check_sum,
+            subsystem: value.subsystem,
+            dll_characteristics: value.dll_characteristics,
+            size_of_stack_reserve: value.size_of_stack_reserve.try_into()?,
+            size_of_stack_commit: value.size_of_stack_commit.try_into()?,
+            size_of_heap_reserve: value.size_of_heap_reserve.try_into()?,
+            size_of_heap_commit: value.size_of_heap_commit.try_into()?,
+            loader_flags: value.loader_flags,
+            number_of_rva_and_sizes: value.number_of_rva_and_sizes
+        })
+    }
+}
+
 // impl From<WindowsFields32> for WindowsFields {
 //     fn from(windows: WindowsFields32) -> Self {
 //         WindowsFields {
@@ -328,8 +358,12 @@ impl ctx::TryIntoCtx<scroll::Endian> for OptionalHeader {
         match self.standard_fields.magic {
             MAGIC_32 => {
                 bytes.gwrite_with::<StandardFields32>(self.standard_fields.into(), offset, ctx)?;
-                // TODO: windowsfields64 -> windowsfields32
-                todo!();
+                bytes.gwrite_with(
+                    WindowsFields32::try_from(self.windows_fields)?,
+                    offset,
+                    ctx
+                )?;
+                bytes.gwrite_with(self.data_directories, offset, ctx)?;
             },
             MAGIC_64 => {
                 bytes.gwrite_with::<StandardFields64>(self.standard_fields.into(), offset, ctx)?;