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package gohex
import (
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
"io"
"strings"
)
func calcSum(bytes []byte) byte {
sum := 0
for _, b := range bytes {
sum += int(b)
}
sum %= 256
sum = 256 - sum
return byte(sum)
}
func checkSum(bytes []byte) error {
sum := calcSum(bytes[:len(bytes)-1])
last := bytes[len(bytes)-1]
if sum != last {
return errors.New("incorrect checksum (sum = " + fmt.Sprintf("%02X != %02X", sum, last) + ")")
}
return nil
}
func checkRecordSize(bytes []byte) error {
if (int(bytes[0]) + 5) != len(bytes) {
return errors.New("incorrect data length")
}
return nil
}
func checkEOF(bytes []byte) error {
if bytes[0] != 0 {
return errors.New("incorrect data length field in eof line")
}
if binary.BigEndian.Uint16(bytes[1:3]) != 0 {
return errors.New("incorrect address field in eof line")
}
return nil
}
func getExtendedAddress(bytes []byte) (adr uint32, err error) {
if bytes[0] != 2 {
return 0, errors.New("incorrect data length field in extended linear address line")
}
if binary.BigEndian.Uint16(bytes[1:3]) != 0 {
return 0, errors.New("incorrect address field in extended linear address line")
}
adr = uint32(binary.BigEndian.Uint16(bytes[4:6])) << (1 << bytes[3])
return adr, nil
}
func getDataLine(bytes []byte) (adr uint16, data []byte) {
size := bytes[0]
adr = binary.BigEndian.Uint16(bytes[1:3])
data = bytes[4 : size+4]
return adr, data
}
func getStartAddress(bytes []byte) (adr uint32, err error) {
if bytes[0] != 4 {
return 0, errors.New("incorrect data length field in start address line")
}
if binary.BigEndian.Uint16(bytes[1:3]) != 0 {
return 0, errors.New("incorrect address field in start address line")
}
adr = binary.BigEndian.Uint32(bytes[4:8])
return adr, nil
}
func makeDataLine(adr uint16, recordType byte, data []byte) []byte {
line := make([]byte, 5+len(data))
line[0] = byte(len(data))
binary.BigEndian.PutUint16(line[1:3], adr)
line[3] = recordType
copy(line[4:], data)
line[len(line)-1] = calcSum(line[:len(line)-1])
return line
}
func writeDataLine(writer io.Writer, lineAdr *uint32, byteAdr uint32, lineData *[]byte) error {
s := strings.ToUpper(hex.EncodeToString(makeDataLine(uint16(*lineAdr&0x0000FFFF), _DATA_RECORD, *lineData)))
_, err := fmt.Fprintf(writer, ":%s\n", s)
*lineAdr = byteAdr
*lineData = []byte{}
return err
}
func writeStartAddressLine(writer io.Writer, startAdr uint32) error {
a := make([]byte, 4)
binary.BigEndian.PutUint32(a, startAdr)
s := strings.ToUpper(hex.EncodeToString(makeDataLine(0, _START_RECORD, a)))
_, err := fmt.Fprintf(writer, ":%s\n", s)
return err
}
func writeExtendedAddressLine(writer io.Writer, extAdr uint32) {
a := make([]byte, 2)
binary.BigEndian.PutUint16(a, uint16(extAdr>>16))
s := strings.ToUpper(hex.EncodeToString(makeDataLine(0, _ADR_32_RECORD, a)))
fmt.Fprintf(writer, ":%s\n", s)
}
func writeEofLine(writer io.Writer) error {
s := strings.ToUpper(hex.EncodeToString(makeDataLine(0, _EOF_RECORD, []byte{})))
_, err := fmt.Fprintf(writer, ":%s\n", s)
return err
}
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