mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-08 05:54:40 +00:00
241 lines
4.7 KiB
Go
241 lines
4.7 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build ignore
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// encgen writes the helper functions for encoding. Intended to be
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// used with go generate; see the invocation in encode.go.
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// TODO: We could do more by being unsafe. Add a -unsafe flag?
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package main
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import (
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"bytes"
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"flag"
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"fmt"
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"go/format"
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"log"
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"os"
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)
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var output = flag.String("output", "dec_helpers.go", "file name to write")
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type Type struct {
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lower string
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upper string
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decoder string
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}
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var types = []Type{
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{
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"bool",
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"Bool",
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`slice[i] = state.decodeUint() != 0`,
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},
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{
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"complex64",
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"Complex64",
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`real := float32FromBits(state.decodeUint(), ovfl)
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imag := float32FromBits(state.decodeUint(), ovfl)
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slice[i] = complex(float32(real), float32(imag))`,
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},
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{
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"complex128",
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"Complex128",
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`real := float64FromBits(state.decodeUint())
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imag := float64FromBits(state.decodeUint())
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slice[i] = complex(real, imag)`,
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},
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{
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"float32",
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"Float32",
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`slice[i] = float32(float32FromBits(state.decodeUint(), ovfl))`,
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},
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{
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"float64",
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"Float64",
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`slice[i] = float64FromBits(state.decodeUint())`,
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},
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{
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"int",
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"Int",
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`x := state.decodeInt()
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// MinInt and MaxInt
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if x < ^int64(^uint(0)>>1) || int64(^uint(0)>>1) < x {
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error_(ovfl)
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}
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slice[i] = int(x)`,
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},
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{
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"int16",
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"Int16",
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`x := state.decodeInt()
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if x < math.MinInt16 || math.MaxInt16 < x {
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error_(ovfl)
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}
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slice[i] = int16(x)`,
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},
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{
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"int32",
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"Int32",
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`x := state.decodeInt()
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if x < math.MinInt32 || math.MaxInt32 < x {
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error_(ovfl)
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}
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slice[i] = int32(x)`,
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},
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{
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"int64",
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"Int64",
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`slice[i] = state.decodeInt()`,
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},
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{
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"int8",
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"Int8",
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`x := state.decodeInt()
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if x < math.MinInt8 || math.MaxInt8 < x {
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error_(ovfl)
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}
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slice[i] = int8(x)`,
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},
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{
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"string",
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"String",
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`u := state.decodeUint()
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n := int(u)
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if n < 0 || uint64(n) != u || n > state.b.Len() {
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errorf("length of string exceeds input size (%d bytes)", u)
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}
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if n > state.b.Len() {
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errorf("string data too long for buffer: %d", n)
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}
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// Read the data.
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data := make([]byte, n)
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if _, err := state.b.Read(data); err != nil {
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errorf("error decoding string: %s", err)
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}
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slice[i] = string(data)`,
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},
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{
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"uint",
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"Uint",
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`x := state.decodeUint()
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/*TODO if math.MaxUint32 < x {
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error_(ovfl)
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}*/
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slice[i] = uint(x)`,
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},
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{
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"uint16",
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"Uint16",
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`x := state.decodeUint()
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if math.MaxUint16 < x {
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error_(ovfl)
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}
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slice[i] = uint16(x)`,
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},
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{
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"uint32",
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"Uint32",
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`x := state.decodeUint()
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if math.MaxUint32 < x {
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error_(ovfl)
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}
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slice[i] = uint32(x)`,
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},
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{
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"uint64",
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"Uint64",
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`slice[i] = state.decodeUint()`,
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},
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{
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"uintptr",
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"Uintptr",
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`x := state.decodeUint()
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if uint64(^uintptr(0)) < x {
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error_(ovfl)
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}
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slice[i] = uintptr(x)`,
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},
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// uint8 Handled separately.
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}
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func main() {
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log.SetFlags(0)
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log.SetPrefix("decgen: ")
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flag.Parse()
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if flag.NArg() != 0 {
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log.Fatal("usage: decgen [--output filename]")
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}
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var b bytes.Buffer
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fmt.Fprintf(&b, "// Created by decgen --output %s; DO NOT EDIT\n", *output)
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fmt.Fprint(&b, header)
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printMaps(&b, "Array")
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fmt.Fprint(&b, "\n")
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printMaps(&b, "Slice")
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for _, t := range types {
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fmt.Fprintf(&b, arrayHelper, t.lower, t.upper)
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fmt.Fprintf(&b, sliceHelper, t.lower, t.upper, t.decoder)
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}
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source, err := format.Source(b.Bytes())
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if err != nil {
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log.Fatal("source format error:", err)
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}
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fd, err := os.Create(*output)
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_, err = fd.Write(source)
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if err != nil {
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log.Fatal(err)
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}
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}
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func printMaps(b *bytes.Buffer, upperClass string) {
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fmt.Fprintf(b, "var dec%sHelper = map[reflect.Kind]decHelper{\n", upperClass)
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for _, t := range types {
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fmt.Fprintf(b, "reflect.%s: dec%s%s,\n", t.upper, t.upper, upperClass)
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}
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fmt.Fprintf(b, "}\n")
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}
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const header = `
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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package gob
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import (
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"math"
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"reflect"
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)
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`
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const arrayHelper = `
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func dec%[2]sArray(state *decoderState, v reflect.Value, length int, ovfl error) bool {
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// Can only slice if it is addressable.
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if !v.CanAddr() {
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return false
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}
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return dec%[2]sSlice(state, v.Slice(0, v.Len()), length, ovfl)
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}
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`
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const sliceHelper = `
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func dec%[2]sSlice(state *decoderState, v reflect.Value, length int, ovfl error) bool {
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slice, ok := v.Interface().([]%[1]s)
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if !ok {
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// It is kind %[1]s but not type %[1]s. TODO: We can handle this unsafely.
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return false
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}
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for i := 0; i < length; i++ {
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if state.b.Len() == 0 {
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errorf("decoding %[1]s array or slice: length exceeds input size (%%d elements)", length)
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}
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%[3]s
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}
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return true
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}
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`
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