125 lines
2.5 KiB
Go
125 lines
2.5 KiB
Go
// 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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"strings"
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"unicode"
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)
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// GetDefaultFieldLength is used for Interger Types, Flen is the display length.
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// Call this when no Flen assigned in ddl.
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// or column value is calculated from an expression.
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// For example: "select count(*) from t;", the column type is int64 and Flen in ResultField will be 21.
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// See https://dev.mysql.com/doc/refman/5.7/en/storage-requirements.html
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func GetDefaultFieldLength(tp byte) int {
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switch tp {
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case TypeTiny:
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return 4
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case TypeShort:
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return 6
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case TypeInt24:
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return 9
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case TypeLong:
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return 11
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case TypeLonglong:
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return 21
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case TypeDecimal, TypeNewDecimal:
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// See https://dev.mysql.com/doc/refman/5.7/en/fixed-point-types.html
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return 10
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case TypeBit, TypeBlob:
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return -1
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default:
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//TODO: Add more types.
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return -1
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}
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}
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// GetDefaultDecimal returns the default decimal length for column.
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func GetDefaultDecimal(tp byte) int {
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switch tp {
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case TypeDecimal, TypeNewDecimal:
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// See https://dev.mysql.com/doc/refman/5.7/en/fixed-point-types.html
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return 0
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default:
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//TODO: Add more types.
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return -1
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}
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}
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func isSpace(c byte) bool {
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return c == ' ' || c == '\t'
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}
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func isDigit(c byte) bool {
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return c >= '0' && c <= '9'
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}
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func myMax(a, b int) int {
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if a > b {
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return a
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}
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return b
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}
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func myMaxInt8(a, b int8) int8 {
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if a > b {
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return a
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}
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return b
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}
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func myMin(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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func myMinInt8(a, b int8) int8 {
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if a < b {
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return a
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}
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return b
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}
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// strToInt converts a string to an integer in best effort.
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// TODO: Handle overflow and add unittest.
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func strToInt(str string) (int64, error) {
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str = strings.TrimSpace(str)
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if len(str) == 0 {
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return 0, nil
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}
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negative := false
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i := 0
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if str[i] == '-' {
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negative = true
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i++
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} else if str[i] == '+' {
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i++
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}
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r := int64(0)
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for ; i < len(str); i++ {
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if !unicode.IsDigit(rune(str[i])) {
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break
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}
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r = r*10 + int64(str[i]-'0')
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}
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if negative {
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r = -r
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}
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// TODO: If i < len(str), we should return an error.
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return r, nil
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}
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