forked from mirror/go-json
131 lines
2.5 KiB
Go
131 lines
2.5 KiB
Go
package json
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type intDecoder struct {
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op func(uintptr, int64)
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}
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func newIntDecoder(op func(uintptr, int64)) *intDecoder {
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return &intDecoder{op: op}
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}
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var (
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pow10i64 = [...]int64{
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1e00, 1e01, 1e02, 1e03, 1e04, 1e05, 1e06, 1e07, 1e08, 1e09,
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1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18,
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}
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)
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func (d *intDecoder) parseInt(b []byte) int64 {
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isNegative := false
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if b[0] == '-' {
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b = b[1:]
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isNegative = true
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}
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maxDigit := len(b)
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sum := int64(0)
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for i := 0; i < maxDigit; i++ {
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c := int64(b[i]) - 48
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digitValue := pow10i64[maxDigit-i-1]
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sum += c * digitValue
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}
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if isNegative {
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return -1 * sum
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}
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return sum
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}
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var (
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numTable = [256]bool{
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'0': true,
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'1': true,
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'2': true,
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'3': true,
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'4': true,
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'5': true,
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'6': true,
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'7': true,
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'8': true,
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'9': true,
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}
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)
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func (d *intDecoder) decodeStreamByte(s *stream) ([]byte, error) {
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for {
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switch s.char() {
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case ' ', '\n', '\t', '\r':
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s.progress()
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continue
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case '-':
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start := s.cursor
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for s.progress() {
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if numTable[s.char()] {
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continue
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}
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break
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}
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num := s.buf[start:s.cursor]
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s.reset()
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if len(num) < 2 {
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return nil, errInvalidCharacter(s.char(), "number(integer)", s.totalOffset())
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}
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return num, nil
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case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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start := s.cursor
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for s.progress() {
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if numTable[s.char()] {
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continue
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}
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break
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}
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num := s.buf[start:s.cursor]
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s.reset()
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return num, nil
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default:
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return nil, errInvalidCharacter(s.char(), "number(integer)", s.totalOffset())
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}
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}
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return nil, errUnexpectedEndOfJSON("number(integer)", s.totalOffset())
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}
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func (d *intDecoder) decodeByte(buf []byte, cursor int64) ([]byte, int64, error) {
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for {
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switch buf[cursor] {
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case ' ', '\n', '\t', '\r':
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cursor++
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continue
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case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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start := cursor
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cursor++
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LOOP:
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if numTable[buf[cursor]] {
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cursor++
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goto LOOP
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}
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num := buf[start:cursor]
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return num, cursor, nil
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default:
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return nil, 0, errInvalidCharacter(buf[cursor], "number(integer)", cursor)
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}
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}
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return nil, 0, errUnexpectedEndOfJSON("number(integer)", cursor)
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}
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func (d *intDecoder) decodeStream(s *stream, p uintptr) error {
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bytes, err := d.decodeStreamByte(s)
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if err != nil {
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return err
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}
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d.op(p, d.parseInt(bytes))
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return nil
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}
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func (d *intDecoder) decode(buf []byte, cursor int64, p uintptr) (int64, error) {
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bytes, c, err := d.decodeByte(buf, cursor)
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if err != nil {
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return 0, err
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}
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cursor = c
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d.op(p, d.parseInt(bytes))
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return cursor, nil
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}
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