/
scanner.go
119 lines (104 loc) · 3.07 KB
/
scanner.go
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/*
* The MIT License (MIT)
*
* Copyright (c) 2018 Aliaksandr Valialkin
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Author: Aliaksandr Valialkin <valyala@gmail.com>
*/
package libconfig
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")