VictoriaMetrics/vendor/github.com/valyala/fastjson/scanner.go

95 lines
1.9 KiB
Go

package fastjson
import (
"errors"
)
// Scanner scans a series of JSON values. Values may be delimited by whitespace.
//
// Scanner may parse JSON lines ( http://jsonlines.org/ ).
//
// Scanner may be re-used for subsequent parsing.
//
// Scanner cannot be used from concurrent goroutines.
//
// Use Parser for parsing only a single JSON value.
type Scanner struct {
// b contains a working copy of json value passed to Init.
b []byte
// s points to the next JSON value to parse.
s string
// err contains the last error.
err error
// v contains the last parsed JSON value.
v *Value
// c is used for caching JSON values.
c cache
}
// Init initializes sc with the given s.
//
// s may contain multiple JSON values, which may be delimited by whitespace.
func (sc *Scanner) Init(s string) {
sc.b = append(sc.b[:0], s...)
sc.s = b2s(sc.b)
sc.err = nil
sc.v = nil
}
// InitBytes initializes sc with the given b.
//
// b may contain multiple JSON values, which may be delimited by whitespace.
func (sc *Scanner) InitBytes(b []byte) {
sc.Init(b2s(b))
}
// Next parses the next JSON value from s passed to Init.
//
// Returns true on success. The parsed value is available via Value call.
//
// Returns false either on error or on the end of s.
// Call Error in order to determine the cause of the returned false.
func (sc *Scanner) Next() bool {
if sc.err != nil {
return false
}
sc.s = skipWS(sc.s)
if len(sc.s) == 0 {
sc.err = errEOF
return false
}
sc.c.reset()
v, tail, err := parseValue(sc.s, &sc.c, 0)
if err != nil {
sc.err = err
return false
}
sc.s = tail
sc.v = v
return true
}
// Error returns the last error.
func (sc *Scanner) Error() error {
if sc.err == errEOF {
return nil
}
return sc.err
}
// Value returns the last parsed value.
//
// The value is valid until the Next call.
func (sc *Scanner) Value() *Value {
return sc.v
}
var errEOF = errors.New("end of s")