forked from cockroachdb/cockroach
/
encode.go
134 lines (123 loc) · 3.16 KB
/
encode.go
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// Copyright 2015 The Cockroach Authors.
//
// 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.
//
// Author: Peter Mattis (peter@cockroachlabs.com)
// This code was derived from https://github.com/youtube/vitess.
//
// Copyright 2012, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file
package parser
import (
"fmt"
"strings"
)
var (
dontEscape = byte(255)
// encodeMap specifies how to escape binary data with '\'.
encodeMap [256]byte
hexMap [256][]byte
)
func encodeSQLString(in string) string {
// See http://www.postgresql.org/docs/9.4/static/sql-syntax-lexical.html
start := 0
buf := make([]byte, 0, len(in)+3)
for i := range in {
ch := in[i]
if encodedChar := encodeMap[ch]; encodedChar != dontEscape {
if start == 0 {
buf = append(buf, 'e', '\'') // begin e'xxx' string
}
buf = append(buf, in[start:i]...)
buf = append(buf, '\\', encodedChar)
start = i + 1
}
}
if start == 0 {
buf = append(buf, '\'') // begin 'xxx' string if nothing was escaped
}
buf = append(buf, in[start:]...)
buf = append(buf, '\'')
return string(buf)
}
func encodeSQLIdent(s string) string {
if _, ok := reservedKeywords[strings.ToUpper(s)]; ok {
return fmt.Sprintf("\"%s\"", s)
}
// The string needs quoting if it does not match the ident format.
if isIdent(s) {
return s
}
// The only character that requires escaping is a double quote.
buf := make([]byte, 0, len(s)+2)
buf = append(buf, '"')
start := 0
for i, n := 0, len(s); i < n; i++ {
ch := s[i]
if ch == '"' {
if start != i {
buf = append(buf, s[start:i]...)
}
start = i + 1
buf = append(buf, ch, ch) // add extra copy of ch
}
}
if start < len(s) {
buf = append(buf, s[start:]...)
}
buf = append(buf, '"')
return string(buf)
}
func encodeSQLBytes(in string) string {
start := 0
buf := make([]byte, 0, len(in)+3)
buf = append(buf, "b'"...)
for i := range in {
ch := in[i]
if encodedChar := encodeMap[ch]; encodedChar != dontEscape {
buf = append(buf, in[start:i]...)
buf = append(buf, '\\', encodedChar)
start = i + 1
} else if ch >= 0x80 {
buf = append(buf, hexMap[ch]...)
start = i + 1
}
}
buf = append(buf, in[start:]...)
buf = append(buf, '\'')
return string(buf)
}
func init() {
encodeRef := map[byte]byte{
'\x00': '0',
'\b': 'b',
'\f': 'f',
'\n': 'n',
'\r': 'r',
'\t': 't',
'\\': '\\',
'\'': '\'',
}
for i := range encodeMap {
encodeMap[i] = dontEscape
}
for i := range encodeMap {
if to, ok := encodeRef[byte(i)]; ok {
encodeMap[byte(i)] = to
}
}
for i := range hexMap {
hexMap[i] = []byte(fmt.Sprintf("\\x%02x", i))
}
}