github.com/night-codes/go-json@v0.9.15/internal/decoder/number.go (about)

     1  package decoder
     2  
     3  import (
     4  	"encoding/json"
     5  	"strconv"
     6  	"unsafe"
     7  
     8  	"github.com/night-codes/go-json/internal/errors"
     9  )
    10  
    11  type numberDecoder struct {
    12  	stringDecoder *stringDecoder
    13  	op            func(unsafe.Pointer, json.Number)
    14  	structName    string
    15  	fieldName     string
    16  }
    17  
    18  func newNumberDecoder(structName, fieldName string, op func(unsafe.Pointer, json.Number)) *numberDecoder {
    19  	return &numberDecoder{
    20  		stringDecoder: newStringDecoder(structName, fieldName),
    21  		op:            op,
    22  		structName:    structName,
    23  		fieldName:     fieldName,
    24  	}
    25  }
    26  
    27  func (d *numberDecoder) DecodeStream(s *Stream, depth int64, p unsafe.Pointer) error {
    28  	bytes, err := d.decodeStreamByte(s)
    29  	if err != nil {
    30  		return err
    31  	}
    32  	if len(bytes) == 0 {
    33  		return nil
    34  	}
    35  	if _, err := strconv.ParseFloat(*(*string)(unsafe.Pointer(&bytes)), 64); err != nil {
    36  		return errors.ErrSyntax(err.Error(), s.totalOffset())
    37  	}
    38  	d.op(p, json.Number(string(bytes)))
    39  	s.reset()
    40  	return nil
    41  }
    42  
    43  func (d *numberDecoder) Decode(ctx *RuntimeContext, cursor, depth int64, p unsafe.Pointer) (int64, error) {
    44  	bytes, c, err := d.decodeByte(ctx.Buf, cursor)
    45  	if err != nil {
    46  		return 0, err
    47  	}
    48  	if len(bytes) == 0 {
    49  		return c, nil
    50  	}
    51  	if _, err := strconv.ParseFloat(*(*string)(unsafe.Pointer(&bytes)), 64); err != nil {
    52  		return 0, errors.ErrSyntax(err.Error(), c)
    53  	}
    54  	cursor = c
    55  	s := *(*string)(unsafe.Pointer(&bytes))
    56  	d.op(p, json.Number(s))
    57  	return cursor, nil
    58  }
    59  
    60  func (d *numberDecoder) decodeStreamByte(s *Stream) ([]byte, error) {
    61  	start := s.cursor
    62  	for {
    63  		switch s.char() {
    64  		case ' ', '\n', '\t', '\r':
    65  			s.cursor++
    66  			continue
    67  		case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
    68  			return floatBytes(s), nil
    69  		case 'n':
    70  			if err := nullBytes(s); err != nil {
    71  				return nil, err
    72  			}
    73  			return nil, nil
    74  		case '"':
    75  			return d.stringDecoder.decodeStreamByte(s)
    76  		case nul:
    77  			if s.read() {
    78  				continue
    79  			}
    80  			goto ERROR
    81  		default:
    82  			goto ERROR
    83  		}
    84  	}
    85  ERROR:
    86  	if s.cursor == start {
    87  		return nil, errors.ErrInvalidBeginningOfValue(s.char(), s.totalOffset())
    88  	}
    89  	return nil, errors.ErrUnexpectedEndOfJSON("json.Number", s.totalOffset())
    90  }
    91  
    92  func (d *numberDecoder) decodeByte(buf []byte, cursor int64) ([]byte, int64, error) {
    93  	for {
    94  		switch buf[cursor] {
    95  		case ' ', '\n', '\t', '\r':
    96  			cursor++
    97  			continue
    98  		case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
    99  			start := cursor
   100  			cursor++
   101  			for floatTable[buf[cursor]] {
   102  				cursor++
   103  			}
   104  			num := buf[start:cursor]
   105  			return num, cursor, nil
   106  		case 'n':
   107  			if err := validateNull(buf, cursor); err != nil {
   108  				return nil, 0, err
   109  			}
   110  			cursor += 4
   111  			return nil, cursor, nil
   112  		case '"':
   113  			return d.stringDecoder.decodeByte(buf, cursor)
   114  		default:
   115  			return nil, 0, errors.ErrUnexpectedEndOfJSON("json.Number", cursor)
   116  		}
   117  	}
   118  }