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85 lines
2.1 KiB
85 lines
2.1 KiB
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package mysql
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import (
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"encoding/hex"
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"fmt"
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"strconv"
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"strings"
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"github.com/juju/errors"
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)
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// Hex is for mysql hexadecimal literal type.
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type Hex struct {
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// Value holds numeric value for hexadecimal literal.
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Value int64
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}
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// String implements fmt.Stringer interface.
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func (h Hex) String() string {
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s := fmt.Sprintf("%X", h.Value)
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if len(s)%2 != 0 {
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return "0x0" + s
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}
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return "0x" + s
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}
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// ToNumber changes hexadecimal type to float64 for numeric operation.
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// MySQL treats hexadecimal literal as double type.
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func (h Hex) ToNumber() float64 {
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return float64(h.Value)
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}
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// ToString returns the string representation for hexadecimal literal.
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func (h Hex) ToString() string {
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s := fmt.Sprintf("%x", h.Value)
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if len(s)%2 != 0 {
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s = "0" + s
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}
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// should never error.
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b, _ := hex.DecodeString(s)
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return string(b)
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}
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// ParseHex parses hexadecimal literal string.
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// The string format can be X'val', x'val' or 0xval.
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// val must in (0...9, a...z, A...Z).
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func ParseHex(s string) (Hex, error) {
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if len(s) == 0 {
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return Hex{}, errors.Errorf("invalid empty string for parsing hexadecimal literal")
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}
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if s[0] == 'x' || s[0] == 'X' {
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// format is x'val' or X'val'
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s = strings.Trim(s[1:], "'")
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if len(s)%2 != 0 {
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return Hex{}, errors.Errorf("invalid hexadecimal format, must even numbers, but %d", len(s))
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}
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s = "0x" + s
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} else if !strings.HasPrefix(s, "0x") {
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// here means format is not x'val', X'val' or 0xval.
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return Hex{}, errors.Errorf("invalid hexadecimal format %s", s)
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}
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n, err := strconv.ParseInt(s, 0, 64)
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if err != nil {
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return Hex{}, errors.Trace(err)
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}
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return Hex{Value: n}, nil
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}
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