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Diffstat (limited to '')
| -rw-r--r-- | src/encoding/gob/decgen.go | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/encoding/gob/decgen.go b/src/encoding/gob/decgen.go new file mode 100644 index 0000000..1c31e66 --- /dev/null +++ b/src/encoding/gob/decgen.go @@ -0,0 +1,243 @@ +// 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", "dec_helpers.go", "file name to write") + +type Type struct { + lower string + upper string + decoder string +} + +var types = []Type{ + { + "bool", + "Bool", + `slice[i] = state.decodeUint() != 0`, + }, + { + "complex64", + "Complex64", + `real := float32FromBits(state.decodeUint(), ovfl) + imag := float32FromBits(state.decodeUint(), ovfl) + slice[i] = complex(float32(real), float32(imag))`, + }, + { + "complex128", + "Complex128", + `real := float64FromBits(state.decodeUint()) + imag := float64FromBits(state.decodeUint()) + slice[i] = complex(real, imag)`, + }, + { + "float32", + "Float32", + `slice[i] = float32(float32FromBits(state.decodeUint(), ovfl))`, + }, + { + "float64", + "Float64", + `slice[i] = float64FromBits(state.decodeUint())`, + }, + { + "int", + "Int", + `x := state.decodeInt() + // MinInt and MaxInt + if x < ^int64(^uint(0)>>1) || int64(^uint(0)>>1) < x { + error_(ovfl) + } + slice[i] = int(x)`, + }, + { + "int16", + "Int16", + `x := state.decodeInt() + if x < math.MinInt16 || math.MaxInt16 < x { + error_(ovfl) + } + slice[i] = int16(x)`, + }, + { + "int32", + "Int32", + `x := state.decodeInt() + if x < math.MinInt32 || math.MaxInt32 < x { + error_(ovfl) + } + slice[i] = int32(x)`, + }, + { + "int64", + "Int64", + `slice[i] = state.decodeInt()`, + }, + { + "int8", + "Int8", + `x := state.decodeInt() + if x < math.MinInt8 || math.MaxInt8 < x { + error_(ovfl) + } + slice[i] = int8(x)`, + }, + { + "string", + "String", + `u := state.decodeUint() + n := int(u) + if n < 0 || uint64(n) != u || n > state.b.Len() { + errorf("length of string exceeds input size (%d bytes)", u) + } + if n > state.b.Len() { + errorf("string data too long for buffer: %d", n) + } + // Read the data. + data := state.b.Bytes() + if len(data) < n { + errorf("invalid string length %d: exceeds input size %d", n, len(data)) + } + slice[i] = string(data[:n]) + state.b.Drop(n)`, + }, + { + "uint", + "Uint", + `x := state.decodeUint() + /*TODO if math.MaxUint32 < x { + error_(ovfl) + }*/ + slice[i] = uint(x)`, + }, + { + "uint16", + "Uint16", + `x := state.decodeUint() + if math.MaxUint16 < x { + error_(ovfl) + } + slice[i] = uint16(x)`, + }, + { + "uint32", + "Uint32", + `x := state.decodeUint() + if math.MaxUint32 < x { + error_(ovfl) + } + slice[i] = uint32(x)`, + }, + { + "uint64", + "Uint64", + `slice[i] = state.decodeUint()`, + }, + { + "uintptr", + "Uintptr", + `x := state.decodeUint() + if uint64(^uintptr(0)) < x { + error_(ovfl) + } + slice[i] = uintptr(x)`, + }, + // uint8 Handled separately. +} + +func main() { + log.SetFlags(0) + log.SetPrefix("decgen: ") + flag.Parse() + if flag.NArg() != 0 { + log.Fatal("usage: decgen [--output filename]") + } + var b bytes.Buffer + fmt.Fprintf(&b, "// Code generated by go run decgen.go -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.decoder) + } + source, err := format.Source(b.Bytes()) + if err != nil { + log.Fatal("source format error:", err) + } + fd, err := os.Create(*output) + if err != nil { + log.Fatal(err) + } + if _, err := fd.Write(source); err != nil { + log.Fatal(err) + } +} + +func printMaps(b *bytes.Buffer, upperClass string) { + fmt.Fprintf(b, "var dec%sHelper = map[reflect.Kind]decHelper{\n", upperClass) + for _, t := range types { + fmt.Fprintf(b, "reflect.%s: dec%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 ( + "math" + "reflect" +) + +` + +const arrayHelper = ` +func dec%[2]sArray(state *decoderState, v reflect.Value, length int, ovfl error) bool { + // Can only slice if it is addressable. + if !v.CanAddr() { + return false + } + return dec%[2]sSlice(state, v.Slice(0, v.Len()), length, ovfl) +} +` + +const sliceHelper = ` +func dec%[2]sSlice(state *decoderState, v reflect.Value, length int, ovfl error) 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 i := 0; i < length; i++ { + if state.b.Len() == 0 { + errorf("decoding %[1]s array or slice: length exceeds input size (%%d elements)", length) + } + %[3]s + } + return true +} +` |