PR tree-optimization/86274 - SEGFAULT when logging std::to_string(NAN)

[official-gcc.git] / libgo / go / encoding / binary / binary.go

// 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.

// Package binary implements simple translation between numbers and byte
// sequences and encoding and decoding of varints.
//
// Numbers are translated by reading and writing fixed-size values.
// A fixed-size value is either a fixed-size arithmetic
// type (bool, int8, uint8, int16, float32, complex64, ...)
// or an array or struct containing only fixed-size values.
//
// The varint functions encode and decode single integer values using
// a variable-length encoding; smaller values require fewer bytes.
// For a specification, see
// https://developers.google.com/protocol-buffers/docs/encoding.
//
// This package favors simplicity over efficiency. Clients that require
// high-performance serialization, especially for large data structures,
// should look at more advanced solutions such as the encoding/gob
// package or protocol buffers.
package binary

import (
        "errors"
        "io"
        "math"
        "reflect"
)

// A ByteOrder specifies how to convert byte sequences into
// 16-, 32-, or 64-bit unsigned integers.
type ByteOrder interface {
        Uint16([]byte) uint16
        Uint32([]byte) uint32
        Uint64([]byte) uint64
        PutUint16([]byte, uint16)
        PutUint32([]byte, uint32)
        PutUint64([]byte, uint64)
        String() string
}

// LittleEndian is the little-endian implementation of ByteOrder.
var LittleEndian littleEndian

// BigEndian is the big-endian implementation of ByteOrder.
var BigEndian bigEndian

type littleEndian struct{}

func (littleEndian) Uint16(b []byte) uint16 {
        _ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
        return uint16(b[0]) | uint16(b[1])<<8
}

func (littleEndian) PutUint16(b []byte, v uint16) {
        _ = b[1] // early bounds check to guarantee safety of writes below
        b[0] = byte(v)
        b[1] = byte(v >> 8)
}

func (littleEndian) Uint32(b []byte) uint32 {
        _ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
        return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}

func (littleEndian) PutUint32(b []byte, v uint32) {
        _ = b[3] // early bounds check to guarantee safety of writes below
        b[0] = byte(v)
        b[1] = byte(v >> 8)
        b[2] = byte(v >> 16)
        b[3] = byte(v >> 24)
}

func (littleEndian) Uint64(b []byte) uint64 {
        _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
        return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
                uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}

func (littleEndian) PutUint64(b []byte, v uint64) {
        _ = b[7] // early bounds check to guarantee safety of writes below
        b[0] = byte(v)
        b[1] = byte(v >> 8)
        b[2] = byte(v >> 16)
        b[3] = byte(v >> 24)
        b[4] = byte(v >> 32)
        b[5] = byte(v >> 40)
        b[6] = byte(v >> 48)
        b[7] = byte(v >> 56)
}

func (littleEndian) String() string { return "LittleEndian" }

func (littleEndian) GoString() string { return "binary.LittleEndian" }

type bigEndian struct{}

func (bigEndian) Uint16(b []byte) uint16 {
        _ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
        return uint16(b[1]) | uint16(b[0])<<8
}

func (bigEndian) PutUint16(b []byte, v uint16) {
        _ = b[1] // early bounds check to guarantee safety of writes below
        b[0] = byte(v >> 8)
        b[1] = byte(v)
}

func (bigEndian) Uint32(b []byte) uint32 {
        _ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
        return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
}

func (bigEndian) PutUint32(b []byte, v uint32) {
        _ = b[3] // early bounds check to guarantee safety of writes below
        b[0] = byte(v >> 24)
        b[1] = byte(v >> 16)
        b[2] = byte(v >> 8)
        b[3] = byte(v)
}

func (bigEndian) Uint64(b []byte) uint64 {
        _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
        return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
                uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
}

func (bigEndian) PutUint64(b []byte, v uint64) {
        _ = b[7] // early bounds check to guarantee safety of writes below
        b[0] = byte(v >> 56)
        b[1] = byte(v >> 48)
        b[2] = byte(v >> 40)
        b[3] = byte(v >> 32)
        b[4] = byte(v >> 24)
        b[5] = byte(v >> 16)
        b[6] = byte(v >> 8)
        b[7] = byte(v)
}

func (bigEndian) String() string { return "BigEndian" }

func (bigEndian) GoString() string { return "binary.BigEndian" }

// Read reads structured binary data from r into data.
// Data must be a pointer to a fixed-size value or a slice
// of fixed-size values.
// Bytes read from r are decoded using the specified byte order
// and written to successive fields of the data.
// When decoding boolean values, a zero byte is decoded as false, and
// any other non-zero byte is decoded as true.
// When reading into structs, the field data for fields with
// blank (_) field names is skipped; i.e., blank field names
// may be used for padding.
// When reading into a struct, all non-blank fields must be exported
// or Read may panic.
//
// The error is EOF only if no bytes were read.
// If an EOF happens after reading some but not all the bytes,
// Read returns ErrUnexpectedEOF.
func Read(r io.Reader, order ByteOrder, data interface{}) error {
        // Fast path for basic types and slices.
        if n := intDataSize(data); n != 0 {
                var b [8]byte
                var bs []byte
                if n > len(b) {
                        bs = make([]byte, n)
                } else {
                        bs = b[:n]
                }
                if _, err := io.ReadFull(r, bs); err != nil {
                        return err
                }
                switch data := data.(type) {
                case *bool:
                        *data = b[0] != 0
                case *int8:
                        *data = int8(b[0])
                case *uint8:
                        *data = b[0]
                case *int16:
                        *data = int16(order.Uint16(bs))
                case *uint16:
                        *data = order.Uint16(bs)
                case *int32:
                        *data = int32(order.Uint32(bs))
                case *uint32:
                        *data = order.Uint32(bs)
                case *int64:
                        *data = int64(order.Uint64(bs))
                case *uint64:
                        *data = order.Uint64(bs)
                case []bool:
                        for i, x := range bs { // Easier to loop over the input for 8-bit values.
                                data[i] = x != 0
                        }
                case []int8:
                        for i, x := range bs {
                                data[i] = int8(x)
                        }
                case []uint8:
                        copy(data, bs)
                case []int16:
                        for i := range data {
                                data[i] = int16(order.Uint16(bs[2*i:]))
                        }
                case []uint16:
                        for i := range data {
                                data[i] = order.Uint16(bs[2*i:])
                        }
                case []int32:
                        for i := range data {
                                data[i] = int32(order.Uint32(bs[4*i:]))
                        }
                case []uint32:
                        for i := range data {
                                data[i] = order.Uint32(bs[4*i:])
                        }
                case []int64:
                        for i := range data {
                                data[i] = int64(order.Uint64(bs[8*i:]))
                        }
                case []uint64:
                        for i := range data {
                                data[i] = order.Uint64(bs[8*i:])
                        }
                }
                return nil
        }

        // Fallback to reflect-based decoding.
        v := reflect.ValueOf(data)
        size := -1
        switch v.Kind() {
        case reflect.Ptr:
                v = v.Elem()
                size = dataSize(v)
        case reflect.Slice:
                size = dataSize(v)
        }
        if size < 0 {
                return errors.New("binary.Read: invalid type " + reflect.TypeOf(data).String())
        }
        d := &decoder{order: order, buf: make([]byte, size)}
        if _, err := io.ReadFull(r, d.buf); err != nil {
                return err
        }
        d.value(v)
        return nil
}

// Write writes the binary representation of data into w.
// Data must be a fixed-size value or a slice of fixed-size
// values, or a pointer to such data.
// Boolean values encode as one byte: 1 for true, and 0 for false.
// Bytes written to w are encoded using the specified byte order
// and read from successive fields of the data.
// When writing structs, zero values are written for fields
// with blank (_) field names.
func Write(w io.Writer, order ByteOrder, data interface{}) error {
        // Fast path for basic types and slices.
        if n := intDataSize(data); n != 0 {
                var b [8]byte
                var bs []byte
                if n > len(b) {
                        bs = make([]byte, n)
                } else {
                        bs = b[:n]
                }
                switch v := data.(type) {
                case *bool:
                        if *v {
                                b[0] = 1
                        } else {
                                b[0] = 0
                        }
                case bool:
                        if v {
                                b[0] = 1
                        } else {
                                b[0] = 0
                        }
                case []bool:
                        for i, x := range v {
                                if x {
                                        bs[i] = 1
                                } else {
                                        bs[i] = 0
                                }
                        }
                case *int8:
                        b[0] = byte(*v)
                case int8:
                        b[0] = byte(v)
                case []int8:
                        for i, x := range v {
                                bs[i] = byte(x)
                        }
                case *uint8:
                        b[0] = *v
                case uint8:
                        b[0] = v
                case []uint8:
                        bs = v
                case *int16:
                        order.PutUint16(bs, uint16(*v))
                case int16:
                        order.PutUint16(bs, uint16(v))
                case []int16:
                        for i, x := range v {
                                order.PutUint16(bs[2*i:], uint16(x))
                        }
                case *uint16:
                        order.PutUint16(bs, *v)
                case uint16:
                        order.PutUint16(bs, v)
                case []uint16:
                        for i, x := range v {
                                order.PutUint16(bs[2*i:], x)
                        }
                case *int32:
                        order.PutUint32(bs, uint32(*v))
                case int32:
                        order.PutUint32(bs, uint32(v))
                case []int32:
                        for i, x := range v {
                                order.PutUint32(bs[4*i:], uint32(x))
                        }
                case *uint32:
                        order.PutUint32(bs, *v)
                case uint32:
                        order.PutUint32(bs, v)
                case []uint32:
                        for i, x := range v {
                                order.PutUint32(bs[4*i:], x)
                        }
                case *int64:
                        order.PutUint64(bs, uint64(*v))
                case int64:
                        order.PutUint64(bs, uint64(v))
                case []int64:
                        for i, x := range v {
                                order.PutUint64(bs[8*i:], uint64(x))
                        }
                case *uint64:
                        order.PutUint64(bs, *v)
                case uint64:
                        order.PutUint64(bs, v)
                case []uint64:
                        for i, x := range v {
                                order.PutUint64(bs[8*i:], x)
                        }
                }
                _, err := w.Write(bs)
                return err
        }

        // Fallback to reflect-based encoding.
        v := reflect.Indirect(reflect.ValueOf(data))
        size := dataSize(v)
        if size < 0 {
                return errors.New("binary.Write: invalid type " + reflect.TypeOf(data).String())
        }
        buf := make([]byte, size)
        e := &encoder{order: order, buf: buf}
        e.value(v)
        _, err := w.Write(buf)
        return err
}

// Size returns how many bytes Write would generate to encode the value v, which
// must be a fixed-size value or a slice of fixed-size values, or a pointer to such data.
// If v is neither of these, Size returns -1.
func Size(v interface{}) int {
        return dataSize(reflect.Indirect(reflect.ValueOf(v)))
}

// dataSize returns the number of bytes the actual data represented by v occupies in memory.
// For compound structures, it sums the sizes of the elements. Thus, for instance, for a slice
// it returns the length of the slice times the element size and does not count the memory
// occupied by the header. If the type of v is not acceptable, dataSize returns -1.
func dataSize(v reflect.Value) int {
        if v.Kind() == reflect.Slice {
                if s := sizeof(v.Type().Elem()); s >= 0 {
                        return s * v.Len()
                }
                return -1
        }
        return sizeof(v.Type())
}

// sizeof returns the size >= 0 of variables for the given type or -1 if the type is not acceptable.
func sizeof(t reflect.Type) int {
        switch t.Kind() {
        case reflect.Array:
                if s := sizeof(t.Elem()); s >= 0 {
                        return s * t.Len()
                }

        case reflect.Struct:
                sum := 0
                for i, n := 0, t.NumField(); i < n; i++ {
                        s := sizeof(t.Field(i).Type)
                        if s < 0 {
                                return -1
                        }
                        sum += s
                }
                return sum

        case reflect.Bool,
                reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
                reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
                reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
                return int(t.Size())
        }

        return -1
}

type coder struct {
        order ByteOrder
        buf   []byte
}

type decoder coder
type encoder coder

func (d *decoder) bool() bool {
        x := d.buf[0]
        d.buf = d.buf[1:]
        return x != 0
}

func (e *encoder) bool(x bool) {
        if x {
                e.buf[0] = 1
        } else {
                e.buf[0] = 0
        }
        e.buf = e.buf[1:]
}

func (d *decoder) uint8() uint8 {
        x := d.buf[0]
        d.buf = d.buf[1:]
        return x
}

func (e *encoder) uint8(x uint8) {
        e.buf[0] = x
        e.buf = e.buf[1:]
}

func (d *decoder) uint16() uint16 {
        x := d.order.Uint16(d.buf[0:2])
        d.buf = d.buf[2:]
        return x
}

func (e *encoder) uint16(x uint16) {
        e.order.PutUint16(e.buf[0:2], x)
        e.buf = e.buf[2:]
}

func (d *decoder) uint32() uint32 {
        x := d.order.Uint32(d.buf[0:4])
        d.buf = d.buf[4:]
        return x
}

func (e *encoder) uint32(x uint32) {
        e.order.PutUint32(e.buf[0:4], x)
        e.buf = e.buf[4:]
}

func (d *decoder) uint64() uint64 {
        x := d.order.Uint64(d.buf[0:8])
        d.buf = d.buf[8:]
        return x
}

func (e *encoder) uint64(x uint64) {
        e.order.PutUint64(e.buf[0:8], x)
        e.buf = e.buf[8:]
}

func (d *decoder) int8() int8 { return int8(d.uint8()) }

func (e *encoder) int8(x int8) { e.uint8(uint8(x)) }

func (d *decoder) int16() int16 { return int16(d.uint16()) }

func (e *encoder) int16(x int16) { e.uint16(uint16(x)) }

func (d *decoder) int32() int32 { return int32(d.uint32()) }

func (e *encoder) int32(x int32) { e.uint32(uint32(x)) }

func (d *decoder) int64() int64 { return int64(d.uint64()) }

func (e *encoder) int64(x int64) { e.uint64(uint64(x)) }

func (d *decoder) value(v reflect.Value) {
        switch v.Kind() {
        case reflect.Array:
                l := v.Len()
                for i := 0; i < l; i++ {
                        d.value(v.Index(i))
                }

        case reflect.Struct:
                t := v.Type()
                l := v.NumField()
                for i := 0; i < l; i++ {
                        // Note: Calling v.CanSet() below is an optimization.
                        // It would be sufficient to check the field name,
                        // but creating the StructField info for each field is
                        // costly (run "go test -bench=ReadStruct" and compare
                        // results when making changes to this code).
                        if v := v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
                                d.value(v)
                        } else {
                                d.skip(v)
                        }
                }

        case reflect.Slice:
                l := v.Len()
                for i := 0; i < l; i++ {
                        d.value(v.Index(i))
                }

        case reflect.Bool:
                v.SetBool(d.bool())

        case reflect.Int8:
                v.SetInt(int64(d.int8()))
        case reflect.Int16:
                v.SetInt(int64(d.int16()))
        case reflect.Int32:
                v.SetInt(int64(d.int32()))
        case reflect.Int64:
                v.SetInt(d.int64())

        case reflect.Uint8:
                v.SetUint(uint64(d.uint8()))
        case reflect.Uint16:
                v.SetUint(uint64(d.uint16()))
        case reflect.Uint32:
                v.SetUint(uint64(d.uint32()))
        case reflect.Uint64:
                v.SetUint(d.uint64())

        case reflect.Float32:
                v.SetFloat(float64(math.Float32frombits(d.uint32())))
        case reflect.Float64:
                v.SetFloat(math.Float64frombits(d.uint64()))

        case reflect.Complex64:
                v.SetComplex(complex(
                        float64(math.Float32frombits(d.uint32())),
                        float64(math.Float32frombits(d.uint32())),
                ))
        case reflect.Complex128:
                v.SetComplex(complex(
                        math.Float64frombits(d.uint64()),
                        math.Float64frombits(d.uint64()),
                ))
        }
}

func (e *encoder) value(v reflect.Value) {
        switch v.Kind() {
        case reflect.Array:
                l := v.Len()
                for i := 0; i < l; i++ {
                        e.value(v.Index(i))
                }

        case reflect.Struct:
                t := v.Type()
                l := v.NumField()
                for i := 0; i < l; i++ {
                        // see comment for corresponding code in decoder.value()
                        if v := v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
                                e.value(v)
                        } else {
                                e.skip(v)
                        }
                }

        case reflect.Slice:
                l := v.Len()
                for i := 0; i < l; i++ {
                        e.value(v.Index(i))
                }

        case reflect.Bool:
                e.bool(v.Bool())

        case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
                switch v.Type().Kind() {
                case reflect.Int8:
                        e.int8(int8(v.Int()))
                case reflect.Int16:
                        e.int16(int16(v.Int()))
                case reflect.Int32:
                        e.int32(int32(v.Int()))
                case reflect.Int64:
                        e.int64(v.Int())
                }

        case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
                switch v.Type().Kind() {
                case reflect.Uint8:
                        e.uint8(uint8(v.Uint()))
                case reflect.Uint16:
                        e.uint16(uint16(v.Uint()))
                case reflect.Uint32:
                        e.uint32(uint32(v.Uint()))
                case reflect.Uint64:
                        e.uint64(v.Uint())
                }

        case reflect.Float32, reflect.Float64:
                switch v.Type().Kind() {
                case reflect.Float32:
                        e.uint32(math.Float32bits(float32(v.Float())))
                case reflect.Float64:
                        e.uint64(math.Float64bits(v.Float()))
                }

        case reflect.Complex64, reflect.Complex128:
                switch v.Type().Kind() {
                case reflect.Complex64:
                        x := v.Complex()
                        e.uint32(math.Float32bits(float32(real(x))))
                        e.uint32(math.Float32bits(float32(imag(x))))
                case reflect.Complex128:
                        x := v.Complex()
                        e.uint64(math.Float64bits(real(x)))
                        e.uint64(math.Float64bits(imag(x)))
                }
        }
}

func (d *decoder) skip(v reflect.Value) {
        d.buf = d.buf[dataSize(v):]
}

func (e *encoder) skip(v reflect.Value) {
        n := dataSize(v)
        for i := range e.buf[0:n] {
                e.buf[i] = 0
        }
        e.buf = e.buf[n:]
}

// intDataSize returns the size of the data required to represent the data when encoded.
// It returns zero if the type cannot be implemented by the fast path in Read or Write.
func intDataSize(data interface{}) int {
        switch data := data.(type) {
        case bool, int8, uint8, *bool, *int8, *uint8:
                return 1
        case []int8:
                return len(data)
        case []uint8:
                return len(data)
        case int16, uint16, *int16, *uint16:
                return 2
        case []int16:
                return 2 * len(data)
        case []uint16:
                return 2 * len(data)
        case int32, uint32, *int32, *uint32:
                return 4
        case []int32:
                return 4 * len(data)
        case []uint32:
                return 4 * len(data)
        case int64, uint64, *int64, *uint64:
                return 8
        case []int64:
                return 8 * len(data)
        case []uint64:
                return 8 * len(data)
        }
        return 0
}