Simplified the functions that generate executables

src/macho/MachO.go

@@ -116,7 +116,6 @@ func Write(writer io.Writer, code []byte, data []byte) {
 	binary.Write(writer, binary.LittleEndian, &m.CodeHeader)
 	binary.Write(writer, binary.LittleEndian, &m.DataHeader)
 	binary.Write(writer, binary.LittleEndian, &m.UnixThread)
-
 	writer.Write(bytes.Repeat([]byte{0x00}, codePadding))
 	writer.Write(code)
 	writer.Write(bytes.Repeat([]byte{0x00}, dataPadding))

src/pe/EXE.go

@@ -25,73 +25,22 @@ type EXE struct {
 
 // Write writes the EXE file to the given writer.
 func Write(writer io.Writer, code []byte, data []byte, dlls dll.List) {
-	codeStart, codePadding := fs.Align(HeaderEnd, config.Align)
+	var (
-	dataStart, dataPadding := fs.Align(codeStart+len(code), config.Align)
+		codeStart, codePadding                     = fs.Align(HeaderEnd, config.Align)
-	importsStart, importsPadding := fs.Align(dataStart+len(data), config.Align)
+		dataStart, dataPadding                     = fs.Align(codeStart+len(code), config.Align)
-
+		importsStart, importsPadding               = fs.Align(dataStart+len(data), config.Align)
-	subSystem := IMAGE_SUBSYSTEM_WINDOWS_CUI
+		subSystem                                  = IMAGE_SUBSYSTEM_WINDOWS_CUI
+		imports, dllData, dllImports, dllDataStart = importLibraries(dlls, importsStart)
+		importDirectoryStart                       = dllDataStart + len(dllData)
+		importDirectorySize                        = DLLImportSize * len(dllImports)
+		importSectionSize                          = len(imports)*8 + len(dllData) + importDirectorySize
+		imageSize, _                               = fs.Align(importsStart+importSectionSize, config.Align)
+	)
 
 	if dlls.Contains("user32") {
 		subSystem = IMAGE_SUBSYSTEM_WINDOWS_GUI
 	}
 
-	imports := make([]uint64, 0)
-	dllData := make([]byte, 0)
-	dllImports := []DLLImport{}
-
-	for _, library := range dlls {
-		functionsStart := len(imports) * 8
-		dllNamePos := len(dllData)
-		dllData = append(dllData, library.Name...)
-		dllData = append(dllData, ".dll"...)
-		dllData = append(dllData, 0x00)
-
-		dllImports = append(dllImports, DLLImport{
-			RvaFunctionNameList:    uint32(importsStart + functionsStart),
-			TimeDateStamp:          0,
-			ForwarderChain:         0,
-			RvaModuleName:          uint32(dllNamePos),
-			RvaFunctionAddressList: uint32(importsStart + functionsStart),
-		})
-
-		for _, fn := range library.Functions {
-			if len(dllData)&1 != 0 {
-				dllData = append(dllData, 0x00) // align the next entry on an even boundary
-			}
-
-			offset := len(dllData)
-			dllData = append(dllData, 0x00, 0x00)
-			dllData = append(dllData, fn...)
-			dllData = append(dllData, 0x00)
-
-			imports = append(imports, uint64(offset))
-		}
-
-		imports = append(imports, 0)
-	}
-
-	dllDataStart := importsStart + len(imports)*8
-
-	for i := range imports {
-		if imports[i] == 0 {
-			continue
-		}
-
-		imports[i] += uint64(dllDataStart)
-	}
-
-	for i := range dllImports {
-		dllImports[i].RvaModuleName += uint32(dllDataStart)
-	}
-
-	dllImports = append(dllImports, DLLImport{}) // a zeroed structure marks the end of the list
-	importDirectoryStart := dllDataStart + len(dllData)
-	importDirectorySize := DLLImportSize * len(dllImports)
-
-	importSectionSize := len(imports)*8 + len(dllData) + importDirectorySize
-	imageSize := importsStart + importSectionSize
-	imageSize, _ = fs.Align(imageSize, config.Align)
-
 	pe := &EXE{
 		DOSHeader: DOSHeader{
 			Magic:          [4]byte{'M', 'Z', 0, 0},
@@ -188,7 +137,6 @@ func Write(writer io.Writer, code []byte, data []byte, dlls dll.List) {
 	binary.Write(writer, binary.LittleEndian, &pe.NTHeader)
 	binary.Write(writer, binary.LittleEndian, &pe.OptionalHeader64)
 	binary.Write(writer, binary.LittleEndian, &pe.Sections)
-
 	writer.Write(bytes.Repeat([]byte{0x00}, codePadding))
 	writer.Write(code)
 	writer.Write(bytes.Repeat([]byte{0x00}, dataPadding))

src/pe/importLibraries.go

@@ -0,0 +1,60 @@
+package pe
+
+import "git.akyoto.dev/cli/q/src/dll"
+
+// importLibraries generates the import address table which contains the addresses of functions imported from DLLs.
+func importLibraries(dlls dll.List, importsStart int) ([]uint64, []byte, []DLLImport, int) {
+	imports := make([]uint64, 0)
+	dllData := make([]byte, 0)
+	dllImports := []DLLImport{}
+
+	for _, library := range dlls {
+		functionsStart := len(imports) * 8
+		dllNamePos := len(dllData)
+		dllData = append(dllData, library.Name...)
+		dllData = append(dllData, ".dll"...)
+		dllData = append(dllData, 0x00)
+
+		dllImports = append(dllImports, DLLImport{
+			RvaFunctionNameList:    uint32(importsStart + functionsStart),
+			TimeDateStamp:          0,
+			ForwarderChain:         0,
+			RvaModuleName:          uint32(dllNamePos),
+			RvaFunctionAddressList: uint32(importsStart + functionsStart),
+		})
+
+		for _, fn := range library.Functions {
+			if len(dllData)&1 != 0 {
+				dllData = append(dllData, 0x00) // align the next entry on an even boundary
+			}
+
+			offset := len(dllData)
+			dllData = append(dllData, 0x00, 0x00)
+			dllData = append(dllData, fn...)
+			dllData = append(dllData, 0x00)
+
+			imports = append(imports, uint64(offset))
+		}
+
+		imports = append(imports, 0)
+	}
+
+	dllDataStart := importsStart + len(imports)*8
+
+	for i := range imports {
+		if imports[i] == 0 {
+			continue
+		}
+
+		imports[i] += uint64(dllDataStart)
+	}
+
+	for i := range dllImports {
+		dllImports[i].RvaModuleName += uint32(dllDataStart)
+	}
+
+	// a zeroed structure marks the end of the list
+	dllImports = append(dllImports, DLLImport{})
+
+	return imports, dllData, dllImports, dllDataStart
+}