Added sparse file support

src/compiler/Write.go

@@ -1,7 +1,6 @@
 package compiler
 
 import (
-	"bufio"
 	"io"
 
 	"git.urbach.dev/cli/q/src/config"
@@ -13,24 +12,20 @@ import (
 )
 
 // Write writes the executable to the given writer.
-func (r *Result) Write(writer io.Writer) error {
+func (r *Result) Write(writer io.WriteSeeker) {
-	return write(writer, r.Code, r.Data, r.DLLs)
+	write(writer, r.Code, r.Data, r.DLLs)
 }
 
 // write writes an executable file to the given writer.
-func write(writer io.Writer, code []byte, data []byte, dlls dll.List) error {
+func write(writer io.WriteSeeker, code []byte, data []byte, dlls dll.List) {
-	buffer := bufio.NewWriter(writer)
-
 	switch config.TargetOS {
 	case config.Linux:
-		elf.Write(buffer, code, data)
+		elf.Write(writer, code, data)
 	case config.Mac:
-		macho.Write(buffer, code, data)
+		macho.Write(writer, code, data)
 	case config.Web:
-		wasm.Write(buffer, code, data)
+		wasm.Write(writer, code, data)
 	case config.Windows:
-		pe.Write(buffer, code, data, dlls)
+		pe.Write(writer, code, data, dlls)
 	}
-
-	return buffer.Flush()
 }

src/compiler/WriteFile.go

@@ -10,13 +10,7 @@ func (r *Result) WriteFile(path string) error {
 		return err
 	}
 
-	err = r.Write(file)
+	r.Write(file)
-
-	if err != nil {
-		file.Close()
-		return err
-	}
-
 	err = file.Close()
 
 	if err != nil {

src/elf/ELF.go

@@ -1,7 +1,6 @@
 package elf
 
 import (
-	"bytes"
 	"encoding/binary"
 	"io"
 
@@ -21,7 +20,7 @@ type ELF struct {
 }
 
 // Write writes the ELF64 format to the given writer.
-func Write(writer io.Writer, codeBytes []byte, dataBytes []byte) {
+func Write(writer io.WriteSeeker, codeBytes []byte, dataBytes []byte) {
 	sections := exe.MakeSections(HeaderEnd, codeBytes, dataBytes)
 	code := sections[0]
 	data := sections[1]
@@ -76,9 +75,9 @@ func Write(writer io.Writer, codeBytes []byte, dataBytes []byte) {
 	binary.Write(writer, binary.LittleEndian, &elf.Header)
 	binary.Write(writer, binary.LittleEndian, &elf.CodeHeader)
 	binary.Write(writer, binary.LittleEndian, &elf.DataHeader)
-	writer.Write(bytes.Repeat([]byte{0x00}, code.Padding))
+	writer.Seek(int64(code.Padding), io.SeekCurrent)
 	writer.Write(code.Bytes)
-	writer.Write(bytes.Repeat([]byte{0x00}, data.Padding))
+	writer.Seek(int64(data.Padding), io.SeekCurrent)
 	writer.Write(data.Bytes)
 
 	if config.Sections {

src/elf/ELF_test.go

@@ -1,12 +1,12 @@
 package elf_test
 
 import (
-	"io"
 	"testing"
 
 	"git.urbach.dev/cli/q/src/elf"
+	"git.urbach.dev/cli/q/src/test"
 )
 
 func TestWrite(t *testing.T) {
-	elf.Write(io.Discard, nil, nil)
+	elf.Write(&test.Discard{}, nil, nil)
 }

src/macho/MachO.go

@@ -1,7 +1,6 @@
 package macho
 
 import (
-	"bytes"
 	"encoding/binary"
 	"io"
 
@@ -24,7 +23,7 @@ type MachO struct {
 }
 
 // Write writes the Mach-O format to the given writer.
-func Write(writer io.Writer, codeBytes []byte, dataBytes []byte) {
+func Write(writer io.WriteSeeker, codeBytes []byte, dataBytes []byte) {
 	sections := exe.MakeSections(HeaderEnd, codeBytes, dataBytes)
 	code := sections[0]
 	data := sections[1]
@@ -116,8 +115,8 @@ func Write(writer io.Writer, codeBytes []byte, dataBytes []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}, code.Padding))
+	writer.Seek(int64(code.Padding), io.SeekCurrent)
 	writer.Write(code.Bytes)
-	writer.Write(bytes.Repeat([]byte{0x00}, data.Padding))
+	writer.Seek(int64(data.Padding), io.SeekCurrent)
 	writer.Write(data.Bytes)
 }

src/macho/MachO_test.go

@@ -1,12 +1,12 @@
 package macho_test
 
 import (
-	"io"
 	"testing"
 
 	"git.urbach.dev/cli/q/src/macho"
+	"git.urbach.dev/cli/q/src/test"
 )
 
 func TestWrite(t *testing.T) {
-	macho.Write(io.Discard, nil, nil)
+	macho.Write(&test.Discard{}, nil, nil)
 }

src/pe/EXE.go

@@ -24,7 +24,7 @@ type EXE struct {
 }
 
 // Write writes the EXE file to the given writer.
-func Write(writer io.Writer, codeBytes []byte, dataBytes []byte, dlls dll.List) {
+func Write(writer io.WriteSeeker, codeBytes []byte, dataBytes []byte, dlls dll.List) {
 	var (
 		sections  = exe.MakeSections(HeaderEnd, codeBytes, dataBytes, nil)
 		code      = sections[0]
@@ -144,10 +144,10 @@ func Write(writer io.Writer, codeBytes []byte, dataBytes []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}, code.Padding))
+	writer.Seek(int64(code.Padding), io.SeekCurrent)
 	writer.Write(code.Bytes)
-	writer.Write(bytes.Repeat([]byte{0x00}, data.Padding))
+	writer.Seek(int64(data.Padding), io.SeekCurrent)
 	writer.Write(data.Bytes)
-	writer.Write(bytes.Repeat([]byte{0x00}, imports.Padding))
+	writer.Seek(int64(imports.Padding), io.SeekCurrent)
 	writer.Write(imports.Bytes)
 }

src/pe/EXE_test.go

@@ -1,12 +1,12 @@
 package pe_test
 
 import (
-	"io"
 	"testing"
 
 	"git.urbach.dev/cli/q/src/pe"
+	"git.urbach.dev/cli/q/src/test"
 )
 
 func TestWrite(t *testing.T) {
-	pe.Write(io.Discard, nil, nil, nil)
+	pe.Write(&test.Discard{}, nil, nil, nil)
 }

src/readme.md

@@ -26,6 +26,7 @@
 - [scope](scope) - Defines a `Scope` used for code blocks
 - [set](set) - Generic set implementation
 - [sizeof](sizeof) - Calculates the byte size of numbers
+- [test](test) - Testing utilities
 - [token](token) - Converts a file to tokens with the `Tokenize` function
 - [types](types) - Type system
 - [x86](x86) - x86-64 implementation

src/test/Discard.go

@@ -0,0 +1,7 @@
+package test
+
+// Discard implements a no-op WriteSeeker.
+type Discard struct{}
+
+func (w *Discard) Write(_ []byte) (int, error)        { return 0, nil }
+func (w *Discard) Seek(_ int64, _ int) (int64, error) { return 0, nil }