50 lines
1.3 KiB
Go
50 lines
1.3 KiB
Go
package csgo
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import (
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"encoding/binary"
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"fmt"
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"math/big"
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"regexp"
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"strings"
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)
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//goland:noinspection SpellCheckingInspection
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var DICT = "ABCDEFGHJKLMNOPQRSTUVWXYZabcdefhijkmnopqrstuvwxyz23456789"
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var sharecodeRexEx = regexp.MustCompile("^CSGO(?:-?[\\w]{5}){5}$")
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func DecodeSharecode(code string) (uint64, uint64, uint16, error) {
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if !sharecodeRexEx.MatchString(code) {
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return 0, 0, 0, fmt.Errorf("not a CSGO sharecode: %s", code)
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}
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cleanCode := strings.ReplaceAll(strings.ReplaceAll(code, "CSGO", ""), "-", "")
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chars := ReverseString(strings.Split(cleanCode, ""))
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bigInt := new(big.Int)
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dictLenBig := big.NewInt(int64(len(DICT)))
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for _, c := range chars {
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bigInt.Mul(bigInt, dictLenBig)
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bigInt.Add(bigInt, big.NewInt(int64(strings.Index(DICT, c))))
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}
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if bigInt.BitLen() > 144 {
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return 0, 0, 0, fmt.Errorf("invalid sharecode")
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}
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bytes := make([]byte, 18)
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bigInt.FillBytes(bytes)
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matchId := binary.LittleEndian.Uint64(bytes[0:8])
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outcomeId := binary.LittleEndian.Uint64(bytes[8:16])
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tokenId := binary.LittleEndian.Uint16(bytes[16:18])
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return matchId, outcomeId, tokenId, nil
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}
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func ReverseString(numbers []string) []string {
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for i, j := 0, len(numbers)-1; i < j; i, j = i+1, j-1 {
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numbers[i], numbers[j] = numbers[j], numbers[i]
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}
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return numbers
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}
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