/
ascii.go
432 lines (384 loc) · 15.7 KB
/
ascii.go
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package ascii
/*
* Copyright 2020-2023 Aldelo, LP
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import (
"fmt"
"strconv"
"strings"
)
// ascii definition
// use string(...) to convert the const into string value
const (
NUL = 0x00 // '\0' Null
SOH = 0x01 // Start of Header
STX = 0x02 // Start of Text
ETX = 0x03 // End of Text
EOT = 0x04 // End of Transmission
ENQ = 0x05 // Enquiry
ACK = 0x06 // Acknowledgement
BEL = 0x07 // '\a' Bell
BS = 0x08 // '\b' Backspace
HT = 0x09 // '\t' Horizontal Tab
LF = 0x0A // '\n' Line Feed
VT = 0x0B // '\v' Vertical Tab
FF = 0x0C // '\f' Form Feed
CR = 0x0D // '\r' Carriage Return
SO = 0x0E // Shift Out
SI = 0x0F // Shift In
DLE = 0x10 // Device Idle
DC1 = 0x11 // Device Control 1
DC2 = 0x12 // Device Control 2
DC3 = 0x13 // Device Control 3
DC4 = 0x14 // Device Control 4
NAK = 0x15 // Negative Ack
SYN = 0x16 // Synchronize
ETB = 0x17 // End of Transmission Block
CAN = 0x18 // Cancel
EM = 0x19 // End of Medium
SUB = 0x1A // Substitute
ESC = 0x1B // '\e' Escape
FS = 0x1C // Field Separator
GS = 0x1D // Group Separator
RS = 0x1E // Record Separator
US = 0x1F // Unit Separator
SP = 0x20 // Space
DEL = 0x7F // Delete
COMMA = 0x2C // Comma
COLON = 0x3A // Colon
PIPE = 0x7C // Pipe
)
func AsciiToString(i int) string {
return string(rune(i))
}
// GetLRC calculates the LRC value for input string,
// returns blank LRC to indicate error condition (see error for reason)
//
// parameters:
//
// data = includes the STX and ETX but not LRC if exists
//
// returns:
//
// string = LRC string value
func GetLRC(data string) (string, error) {
if len(strings.Trim(data, " ")) <= 1 {
return "", fmt.Errorf("Data is Required for LRC Calculation")
}
// LRC check excludes STX
firstChar := data[:1]
if firstChar == AsciiToString(STX) {
data = data[1:]
}
// excluding STX, must be 2 or more chars
if len(data) < 2 {
return "", fmt.Errorf("Data Must Be 2 Characters or More for LRC Calculation")
}
lrcBytes := []byte(data)
lrc := byte(0)
// loop through each element, XOR product of element and next adjacent element and continue
for i, v := range lrcBytes {
if i == 0 {
lrc = v
} else {
lrc ^= v
}
}
// return lrc value
return string(lrc), nil
}
// IsLRCValid checks if the input data that contains the entire string, including STX ETX and LRC, that its LRC is valid for the content of the data
func IsLRCValid(data string) bool {
if len(data) <= 2 {
return false
}
if calcLrc, err := GetLRC(data[:len(data)-1]); err != nil || len(calcLrc) == 0 {
return false
} else {
return data[len(data)-1:] == calcLrc
}
}
// IsCreditCardMod10Valid performs modulo 10 credit card number validation
func IsCreditCardMod10Valid(cardNumber string) (bool, error) {
cardNumber = strings.Trim(cardNumber, " ")
if len(cardNumber) < 5 {
return false, fmt.Errorf("Card Number Must Be Greater or Equal to 5 Digits")
}
if _, err := strconv.ParseUint(cardNumber, 10, 64); err != nil {
return false, fmt.Errorf("Card Number Must Be Numeric")
}
source := cardNumber[:len(cardNumber)-1]
checkDigit := cardNumber[len(cardNumber)-1:]
result := 0
multiplier := 2
// loop through each element from right to left,
// multiple element by value of 2, and 1 alternating
for i := len(source) - 1; i >= 0; i-- {
if temp, e := strconv.Atoi(string(source[i])); e == nil {
temp *= multiplier
if multiplier == 2 {
multiplier = 1
} else {
multiplier = 2
}
for {
if temp < 10 {
result += temp
break
}
buf := strconv.Itoa(temp)
x, _ := strconv.Atoi(buf[:1])
y, _ := strconv.Atoi(buf[len(buf)-1:])
temp = x + y
}
}
}
// find the next highest multiple of 10
multiplier = result % 10
if multiplier > 0 {
multiplier = result/10 + 1
} else {
multiplier = result / 10
}
// get check digit
result = multiplier*10 - result
if chk, err := strconv.Atoi(checkDigit); err != nil {
return false, fmt.Errorf("Convert Check Digit Failed: %s", err)
} else {
return chk == result, nil
}
}
// EnvelopWithStxEtxLrc will take content data, wrap with STX, ETX, and calculate LRC to append
//
// contentData = do not include STX, ETX, LRC
func EnvelopWithStxEtxLrc(contentData string) string {
if len(contentData) == 0 {
return ""
}
if contentData[:1] != AsciiToString(STX) {
contentData = AsciiToString(STX) + contentData
}
if len(contentData) >= 2 {
removeLast := false
d := contentData[:2]
if d[:1] == AsciiToString(ETX) {
removeLast = true
} else if d[len(d)-1:] != AsciiToString(ETX) {
contentData += AsciiToString(ETX)
}
if removeLast {
contentData = contentData[:len(contentData)-1]
}
} else {
contentData += AsciiToString(ETX)
}
lrc, _ := GetLRC(contentData)
return contentData + lrc
}
// StripStxEtxLrcFromEnvelop removes STX ETX and LRC from envelopment and returns content data.
// this method will validate LRC, if LRC fails, blank is returned.
//
// ignoreValueToLeftOfDelimiterSymbol = if set, any value to left side of this delimiter (along with this delimiter) is excluded from the return result
func StripStxEtxLrcFromEnvelop(envelopData string, ignoreValueToLeftOfDelimiterSymbol ...string) string {
if len(envelopData) == 0 {
return ""
}
if ok := IsLRCValid(envelopData); ok {
// remove lrc
envelopData = envelopData[:len(envelopData)-1]
if len(envelopData) == 0 {
return ""
}
// remove stx
if envelopData[:1] == AsciiToString(STX) {
if len(envelopData) > 1 {
envelopData = envelopData[1:]
} else {
return ""
}
}
// remove etx
if envelopData[len(envelopData)-1:] == AsciiToString(ETX) {
if len(envelopData) > 1 {
envelopData = envelopData[:len(envelopData)-1]
} else {
return ""
}
}
// if value to left of delimiter is to be excluded
if len(ignoreValueToLeftOfDelimiterSymbol) > 0 {
if p := strings.SplitN(envelopData, ignoreValueToLeftOfDelimiterSymbol[0], 2); len(p) == 2 {
envelopData = p[1]
}
}
return envelopData
} else {
return ""
}
}
// ControlCharToWord converts non-printable control char to word
func ControlCharToWord(data string) string {
data = strings.ReplaceAll(data, AsciiToString(STX), "[STX]")
data = strings.ReplaceAll(data, AsciiToString(ETX), "[ETX]")
data = strings.ReplaceAll(data, AsciiToString(ETB), "[ETB]")
data = strings.ReplaceAll(data, AsciiToString(ACK), "[ACK]")
data = strings.ReplaceAll(data, AsciiToString(NAK), "[NAK]")
data = strings.ReplaceAll(data, AsciiToString(ENQ), "[ENQ]")
data = strings.ReplaceAll(data, AsciiToString(DLE), "[DLE]")
data = strings.ReplaceAll(data, AsciiToString(DC1), "[DC1]")
data = strings.ReplaceAll(data, AsciiToString(DC2), "[DC2]")
data = strings.ReplaceAll(data, AsciiToString(DC3), "[DC3]")
data = strings.ReplaceAll(data, AsciiToString(DC4), "[DC4]")
data = strings.ReplaceAll(data, AsciiToString(FS), "[FS]")
data = strings.ReplaceAll(data, AsciiToString(US), "[US]")
data = strings.ReplaceAll(data, AsciiToString(GS), "[GS]")
data = strings.ReplaceAll(data, AsciiToString(RS), "[RS]")
data = strings.ReplaceAll(data, AsciiToString(BS), "[BS]")
data = strings.ReplaceAll(data, AsciiToString(BEL), "[BEL]")
data = strings.ReplaceAll(data, AsciiToString(DEL), "[DEL]")
data = strings.ReplaceAll(data, AsciiToString(EOT), "[EOT]")
data = strings.ReplaceAll(data, AsciiToString(COMMA), "[COMMA]")
data = strings.ReplaceAll(data, AsciiToString(COLON), "[COLON]")
data = strings.ReplaceAll(data, AsciiToString(PIPE), "[PIPE]")
data = strings.ReplaceAll(data, AsciiToString(NUL), "[NULL]")
data = strings.ReplaceAll(data, AsciiToString(SOH), "[SOH]")
data = strings.ReplaceAll(data, AsciiToString(HT), "[HT]")
data = strings.ReplaceAll(data, AsciiToString(LF), "[LF]")
data = strings.ReplaceAll(data, AsciiToString(VT), "[VT]")
data = strings.ReplaceAll(data, AsciiToString(FF), "[FF]")
data = strings.ReplaceAll(data, AsciiToString(CR), "[CR]")
data = strings.ReplaceAll(data, AsciiToString(SO), "[SO]")
data = strings.ReplaceAll(data, AsciiToString(SI), "[SI]")
data = strings.ReplaceAll(data, AsciiToString(SP), "[SP]")
data = strings.ReplaceAll(data, AsciiToString(SYN), "[SYN]")
data = strings.ReplaceAll(data, AsciiToString(CAN), "[CAN]")
data = strings.ReplaceAll(data, AsciiToString(EM), "[EM]")
data = strings.ReplaceAll(data, AsciiToString(SUB), "[SUB]")
data = strings.ReplaceAll(data, AsciiToString(ESC), "[ESC]")
return data
}
// ControlCharToASCII converts non-printable control char represented in word to ascii non-printable form
func ControlCharToASCII(data string) string {
data = strings.ReplaceAll(data, "[STX]", AsciiToString(STX))
data = strings.ReplaceAll(data, "[ETX]", AsciiToString(ETX))
data = strings.ReplaceAll(data, "[ETB]", AsciiToString(ETB))
data = strings.ReplaceAll(data, "[ACK]", AsciiToString(ACK))
data = strings.ReplaceAll(data, "[NAK]", AsciiToString(NAK))
data = strings.ReplaceAll(data, "[ENQ]", AsciiToString(ENQ))
data = strings.ReplaceAll(data, "[DLE]", AsciiToString(DLE))
data = strings.ReplaceAll(data, "[DC1]", AsciiToString(DC1))
data = strings.ReplaceAll(data, "[DC2]", AsciiToString(DC2))
data = strings.ReplaceAll(data, "[DC3]", AsciiToString(DC3))
data = strings.ReplaceAll(data, "[DC4]", AsciiToString(DC4))
data = strings.ReplaceAll(data, "[FS]", AsciiToString(FS))
data = strings.ReplaceAll(data, "[US]", AsciiToString(US))
data = strings.ReplaceAll(data, "[GS]", AsciiToString(GS))
data = strings.ReplaceAll(data, "[RS]", AsciiToString(RS))
data = strings.ReplaceAll(data, "[BS]", AsciiToString(BS))
data = strings.ReplaceAll(data, "[BEL]", AsciiToString(BEL))
data = strings.ReplaceAll(data, "[DEL]", AsciiToString(DEL))
data = strings.ReplaceAll(data, "[EOT]", AsciiToString(EOT))
data = strings.ReplaceAll(data, "[COMMA]", AsciiToString(COMMA))
data = strings.ReplaceAll(data, "[COLON]", AsciiToString(COLON))
data = strings.ReplaceAll(data, "[PIPE]", AsciiToString(PIPE))
data = strings.ReplaceAll(data, "[NULL]", AsciiToString(NUL))
data = strings.ReplaceAll(data, "[SOH]", AsciiToString(SOH))
data = strings.ReplaceAll(data, "[HT]", AsciiToString(HT))
data = strings.ReplaceAll(data, "[LF]", AsciiToString(LF))
data = strings.ReplaceAll(data, "[VT]", AsciiToString(VT))
data = strings.ReplaceAll(data, "[FF]", AsciiToString(FF))
data = strings.ReplaceAll(data, "[CR]", AsciiToString(CR))
data = strings.ReplaceAll(data, "[SO]", AsciiToString(SO))
data = strings.ReplaceAll(data, "[SI]", AsciiToString(SI))
data = strings.ReplaceAll(data, "[SP]", AsciiToString(SP))
data = strings.ReplaceAll(data, "[SYN]", AsciiToString(SYN))
data = strings.ReplaceAll(data, "[CAN]", AsciiToString(CAN))
data = strings.ReplaceAll(data, "[EM]", AsciiToString(EM))
data = strings.ReplaceAll(data, "[SUB]", AsciiToString(SUB))
data = strings.ReplaceAll(data, "[ESC]", AsciiToString(ESC))
return data
}
// EscapeNonPrintable converts non printable \x00 - \x1f to pseudo escaped format
func EscapeNonPrintable(data string) string {
data = strings.Replace(data, AsciiToString(NUL), "[NUL_00]", -1)
data = strings.Replace(data, AsciiToString(SOH), "[SOH_01]", -1)
data = strings.Replace(data, AsciiToString(STX), "[STX_02]", -1)
data = strings.Replace(data, AsciiToString(ETX), "[ETX_03]", -1)
data = strings.Replace(data, AsciiToString(EOT), "[EOT_04]", -1)
data = strings.Replace(data, AsciiToString(ENQ), "[ENQ_05]", -1)
data = strings.Replace(data, AsciiToString(ACK), "[ACK_06]", -1)
data = strings.Replace(data, AsciiToString(BEL), "[BEL_07]", -1)
data = strings.Replace(data, AsciiToString(BS), "[BS_08]", -1)
data = strings.Replace(data, AsciiToString(HT), "[HT_09]", -1)
data = strings.Replace(data, AsciiToString(LF), "[LF_0A]", -1)
data = strings.Replace(data, AsciiToString(VT), "[VT_0B]", -1)
data = strings.Replace(data, AsciiToString(FF), "[FF_0C]", -1)
data = strings.Replace(data, AsciiToString(CR), "[CR_0D]", -1)
data = strings.Replace(data, AsciiToString(SO), "[SO_0E]", -1)
data = strings.Replace(data, AsciiToString(SI), "[SI_0F]", -1)
data = strings.Replace(data, AsciiToString(DLE), "[DLE_10]", -1)
data = strings.Replace(data, AsciiToString(DC1), "[DC1_11]", -1)
data = strings.Replace(data, AsciiToString(DC2), "[DC2_12]", -1)
data = strings.Replace(data, AsciiToString(DC3), "[DC3_13]", -1)
data = strings.Replace(data, AsciiToString(DC4), "[DC4_14]", -1)
data = strings.Replace(data, AsciiToString(NAK), "[NAK_15]", -1)
data = strings.Replace(data, AsciiToString(SYN), "[SYN_16]", -1)
data = strings.Replace(data, AsciiToString(ETB), "[ETB_17]", -1)
data = strings.Replace(data, AsciiToString(CAN), "[CAN_18]", -1)
data = strings.Replace(data, AsciiToString(EM), "[EM_19]", -1)
data = strings.Replace(data, AsciiToString(SUB), "[SUB_1A]", -1)
data = strings.Replace(data, AsciiToString(ESC), "[ESC_1B]", -1)
data = strings.Replace(data, AsciiToString(CR), "[CR_1C]", -1)
data = strings.Replace(data, AsciiToString(FS), "[FS_1D]", -1)
data = strings.Replace(data, AsciiToString(RS), "[RS_1E]", -1)
data = strings.Replace(data, AsciiToString(US), "[US_1F]", -1)
return data
}
// UnescapeNonPrintable converts pseudo escaped back to non printable form
func UnescapeNonPrintable(data string) string {
data = strings.Replace(data, "[NUL_00]", AsciiToString(NUL), -1)
data = strings.Replace(data, "[SOH_01]", AsciiToString(SOH), -1)
data = strings.Replace(data, "[STX_02]", AsciiToString(STX), -1)
data = strings.Replace(data, "[ETX_03]", AsciiToString(ETX), -1)
data = strings.Replace(data, "[EOT_04]", AsciiToString(EOT), -1)
data = strings.Replace(data, "[ENQ_05]", AsciiToString(ENQ), -1)
data = strings.Replace(data, "[ACK_06]", AsciiToString(ACK), -1)
data = strings.Replace(data, "[BEL_07]", AsciiToString(BEL), -1)
data = strings.Replace(data, "[BS_08]", AsciiToString(BS), -1)
data = strings.Replace(data, "[HT_09]", AsciiToString(HT), -1)
data = strings.Replace(data, "[LF_0A]", AsciiToString(LF), -1)
data = strings.Replace(data, "[VT_0B]", AsciiToString(VT), -1)
data = strings.Replace(data, "[FF_0C]", AsciiToString(FF), -1)
data = strings.Replace(data, "[CR_0D]", AsciiToString(CR), -1)
data = strings.Replace(data, "[SO_0E]", AsciiToString(SO), -1)
data = strings.Replace(data, "[SI_0F]", AsciiToString(SI), -1)
data = strings.Replace(data, "[DLE_10]", AsciiToString(DLE), -1)
data = strings.Replace(data, "[DC1_11]", AsciiToString(DC1), -1)
data = strings.Replace(data, "[DC2_12]", AsciiToString(DC2), -1)
data = strings.Replace(data, "[DC3_13]", AsciiToString(DC3), -1)
data = strings.Replace(data, "[DC4_14]", AsciiToString(DC4), -1)
data = strings.Replace(data, "[NAK_15]", AsciiToString(NAK), -1)
data = strings.Replace(data, "[SYN_16]", AsciiToString(SYN), -1)
data = strings.Replace(data, "[ETB_17]", AsciiToString(ETB), -1)
data = strings.Replace(data, "[CAN_18]", AsciiToString(CAN), -1)
data = strings.Replace(data, "[EM_19]", AsciiToString(EM), -1)
data = strings.Replace(data, "[SUB_1A]", AsciiToString(SUB), -1)
data = strings.Replace(data, "[ESC_1B]", AsciiToString(ESC), -1)
data = strings.Replace(data, "[CR_1C]", AsciiToString(CR), -1)
data = strings.Replace(data, "[FS_1D]", AsciiToString(FS), -1)
data = strings.Replace(data, "[RS_1E]", AsciiToString(RS), -1)
data = strings.Replace(data, "[US_1F]", AsciiToString(US), -1)
return data
}