gotosocial/vendor/github.com/uptrace/bun/dialect/pgdialect/array_parser.go

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package pgdialect
import (
"bytes"
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"encoding/hex"
"fmt"
"io"
)
type arrayParser struct {
b []byte
i int
buf []byte
err error
}
func newArrayParser(b []byte) *arrayParser {
p := &arrayParser{
b: b,
i: 1,
}
if len(b) < 2 || b[0] != '{' || b[len(b)-1] != '}' {
p.err = fmt.Errorf("bun: can't parse array: %q", b)
}
return p
}
func (p *arrayParser) NextElem() ([]byte, error) {
if p.err != nil {
return nil, p.err
}
c, err := p.readByte()
if err != nil {
return nil, err
}
switch c {
case '}':
return nil, io.EOF
case '"':
b, err := p.readSubstring()
if err != nil {
return nil, err
}
if p.peek() == ',' {
p.skipNext()
}
return b, nil
default:
b := p.readSimple()
if bytes.Equal(b, []byte("NULL")) {
b = nil
}
if p.peek() == ',' {
p.skipNext()
}
return b, nil
}
}
func (p *arrayParser) readSimple() []byte {
p.unreadByte()
if i := bytes.IndexByte(p.b[p.i:], ','); i >= 0 {
b := p.b[p.i : p.i+i]
p.i += i
return b
}
b := p.b[p.i : len(p.b)-1]
p.i = len(p.b) - 1
return b
}
func (p *arrayParser) readSubstring() ([]byte, error) {
c, err := p.readByte()
if err != nil {
return nil, err
}
p.buf = p.buf[:0]
for {
if c == '"' {
break
}
next, err := p.readByte()
if err != nil {
return nil, err
}
if c == '\\' {
switch next {
case '\\', '"':
p.buf = append(p.buf, next)
c, err = p.readByte()
if err != nil {
return nil, err
}
default:
p.buf = append(p.buf, '\\')
c = next
}
continue
}
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if c == '\'' && next == '\'' {
p.buf = append(p.buf, next)
c, err = p.readByte()
if err != nil {
return nil, err
}
continue
}
p.buf = append(p.buf, c)
c = next
}
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if bytes.HasPrefix(p.buf, []byte("\\x")) && len(p.buf)%2 == 0 {
data := p.buf[2:]
buf := make([]byte, hex.DecodedLen(len(data)))
n, err := hex.Decode(buf, data)
if err != nil {
return nil, err
}
return buf[:n], nil
}
return p.buf, nil
}
func (p *arrayParser) valid() bool {
return p.i < len(p.b)
}
func (p *arrayParser) readByte() (byte, error) {
if p.valid() {
c := p.b[p.i]
p.i++
return c, nil
}
return 0, io.EOF
}
func (p *arrayParser) unreadByte() {
p.i--
}
func (p *arrayParser) peek() byte {
if p.valid() {
return p.b[p.i]
}
return 0
}
func (p *arrayParser) skipNext() {
p.i++
}