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|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build ignore
// encgen writes the helper functions for encoding. Intended to be
// used with go generate; see the invocation in encode.go.
// TODO: We could do more by being unsafe. Add a -unsafe flag?
package main
import (
"bytes"
"flag"
"fmt"
"go/format"
"log"
"os"
)
var output = flag.String("output", "enc_helpers.go", "file name to write")
type Type struct {
lower string
upper string
zero string
encoder string
}
var types = []Type{
{
"bool",
"Bool",
"false",
`if x {
state.encodeUint(1)
} else {
state.encodeUint(0)
}`,
},
{
"complex64",
"Complex64",
"0+0i",
`rpart := floatBits(float64(real(x)))
ipart := floatBits(float64(imag(x)))
state.encodeUint(rpart)
state.encodeUint(ipart)`,
},
{
"complex128",
"Complex128",
"0+0i",
`rpart := floatBits(real(x))
ipart := floatBits(imag(x))
state.encodeUint(rpart)
state.encodeUint(ipart)`,
},
{
"float32",
"Float32",
"0",
`bits := floatBits(float64(x))
state.encodeUint(bits)`,
},
{
"float64",
"Float64",
"0",
`bits := floatBits(x)
state.encodeUint(bits)`,
},
{
"int",
"Int",
"0",
`state.encodeInt(int64(x))`,
},
{
"int16",
"Int16",
"0",
`state.encodeInt(int64(x))`,
},
{
"int32",
"Int32",
"0",
`state.encodeInt(int64(x))`,
},
{
"int64",
"Int64",
"0",
`state.encodeInt(x)`,
},
{
"int8",
"Int8",
"0",
`state.encodeInt(int64(x))`,
},
{
"string",
"String",
`""`,
`state.encodeUint(uint64(len(x)))
state.b.WriteString(x)`,
},
{
"uint",
"Uint",
"0",
`state.encodeUint(uint64(x))`,
},
{
"uint16",
"Uint16",
"0",
`state.encodeUint(uint64(x))`,
},
{
"uint32",
"Uint32",
"0",
`state.encodeUint(uint64(x))`,
},
{
"uint64",
"Uint64",
"0",
`state.encodeUint(x)`,
},
{
"uintptr",
"Uintptr",
"0",
`state.encodeUint(uint64(x))`,
},
// uint8 Handled separately.
}
func main() {
log.SetFlags(0)
log.SetPrefix("encgen: ")
flag.Parse()
if flag.NArg() != 0 {
log.Fatal("usage: encgen [--output filename]")
}
var b bytes.Buffer
fmt.Fprintf(&b, "// Created by encgen --output %s; DO NOT EDIT\n", *output)
fmt.Fprint(&b, header)
printMaps(&b, "Array")
fmt.Fprint(&b, "\n")
printMaps(&b, "Slice")
for _, t := range types {
fmt.Fprintf(&b, arrayHelper, t.lower, t.upper)
fmt.Fprintf(&b, sliceHelper, t.lower, t.upper, t.zero, t.encoder)
}
source, err := format.Source(b.Bytes())
if err != nil {
log.Fatal("source format error:", err)
}
fd, err := os.Create(*output)
_, err = fd.Write(source)
if err != nil {
log.Fatal(err)
}
}
func printMaps(b *bytes.Buffer, upperClass string) {
fmt.Fprintf(b, "var enc%sHelper = map[reflect.Kind]encHelper{\n", upperClass)
for _, t := range types {
fmt.Fprintf(b, "reflect.%s: enc%s%s,\n", t.upper, t.upper, upperClass)
}
fmt.Fprintf(b, "}\n")
}
const header = `
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gob
import (
"reflect"
)
`
const arrayHelper = `
func enc%[2]sArray(state *encoderState, v reflect.Value) bool {
// Can only slice if it is addressable.
if !v.CanAddr() {
return false
}
return enc%[2]sSlice(state, v.Slice(0, v.Len()))
}
`
const sliceHelper = `
func enc%[2]sSlice(state *encoderState, v reflect.Value) bool {
slice, ok := v.Interface().([]%[1]s)
if !ok {
// It is kind %[1]s but not type %[1]s. TODO: We can handle this unsafely.
return false
}
for _, x := range slice {
if x != %[3]s || state.sendZero {
%[4]s
}
}
return true
}
`
|
