ulogo/primitive.go at main · 05sec/ulogo · GitHub

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package ulogo

import (
	"encoding/binary"
	"fmt"
	"math"
)

type primitiveType struct {
	size int
}

var primitiveTypes = map[string]primitiveType{
	"int8_t":   {size: 1},
	"uint8_t":  {size: 1},
	"int16_t":  {size: 2},
	"uint16_t": {size: 2},
	"int32_t":  {size: 4},
	"uint32_t": {size: 4},
	"int64_t":  {size: 8},
	"uint64_t": {size: 8},
	"float":    {size: 4},
	"double":   {size: 8},
	"bool":     {size: 1},
	"char":     {size: 1},
}

// FieldSize returns the byte width of a primitive ULog type.
func FieldSize(typeName string) (int, bool) {
	info, ok := primitiveTypes[typeName]
	return info.size, ok
}

func isPrimitive(typeName string) bool {
	_, ok := primitiveTypes[typeName]
	return ok
}

func decodePrimitive(typeName string, data []byte) (Value, error) {
	size, ok := FieldSize(typeName)
	if !ok {
		return Value{}, fmt.Errorf("unknown ULog primitive type %q", typeName)
	}
	if len(data) < size {
		return Value{}, fmt.Errorf("not enough bytes for %s: have %d need %d", typeName, len(data), size)
	}

	switch typeName {
	case "int8_t":
		return Value{Type: typeName, Any: int8(data[0])}, nil
	case "uint8_t":
		return Value{Type: typeName, Any: uint8(data[0])}, nil
	case "int16_t":
		return Value{Type: typeName, Any: int16(binary.LittleEndian.Uint16(data[:2]))}, nil
	case "uint16_t":
		return Value{Type: typeName, Any: binary.LittleEndian.Uint16(data[:2])}, nil
	case "int32_t":
		return Value{Type: typeName, Any: int32(binary.LittleEndian.Uint32(data[:4]))}, nil
	case "uint32_t":
		return Value{Type: typeName, Any: binary.LittleEndian.Uint32(data[:4])}, nil
	case "int64_t":
		return Value{Type: typeName, Any: int64(binary.LittleEndian.Uint64(data[:8]))}, nil
	case "uint64_t":
		return Value{Type: typeName, Any: binary.LittleEndian.Uint64(data[:8])}, nil
	case "float":
		return Value{Type: typeName, Any: math.Float32frombits(binary.LittleEndian.Uint32(data[:4]))}, nil
	case "double":
		return Value{Type: typeName, Any: math.Float64frombits(binary.LittleEndian.Uint64(data[:8]))}, nil
	case "bool":
		return Value{Type: typeName, Any: data[0] != 0}, nil
	case "char":
		return Value{Type: typeName, Any: data[0]}, nil
	default:
		return Value{}, fmt.Errorf("unknown ULog primitive type %q", typeName)
	}
}