mirror of https://bitbucket.org/ausocean/av.git
96 lines
2.2 KiB
Go
96 lines
2.2 KiB
Go
|
/*
|
||
|
|
NAME
|
||
|
|
bytescanner.go
|
||
|
|
|
||
|
|
AUTHOR
|
||
|
|
Dan Kortschak <dan@ausocean.org>
|
||
|
|
|
||
|
|
LICENSE
|
||
|
|
This is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)
|
||
|
|
|
||
|
|
It is free software: you can redistribute it and/or modify them
|
||
|
|
under the terms of the GNU General Public License as published by the
|
||
|
|
Free Software Foundation, either version 3 of the License, or (at your
|
||
|
|
option) any later version.
|
||
|
|
|
||
|
|
It is distributed in the hope that it will be useful, but WITHOUT
|
||
|
|
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
||
|
|
for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public License
|
||
|
|
in gpl.txt. If not, see http://www.gnu.org/licenses.
|
||
|
|
*/
|
||
|
|
|
||
|
|
// Package bytescan implements a byte-level scanner.
|
||
|
|
package codecutil
|
||
|
|
|
||
|
|
import "io"
|
||
|
|
|
||
|
|
// ByteScanner is a byte scanner.
|
||
|
|
type ByteScanner struct {
|
||
|
|
buf []byte
|
||
|
|
off int
|
||
|
|
|
||
|
|
// r is the source of data for the scanner.
|
||
|
|
r io.Reader
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewByteScanner returns a scanner initialised with an io.Reader and a read buffer.
|
||
|
|
func NewByteScanner(r io.Reader, buf []byte) *ByteScanner {
|
||
|
|
return &ByteScanner{r: r, buf: buf[:0]}
|
||
|
|
}
|
||
|
|
|
||
|
|
// ScanUntil scans the scanner's underlying io.Reader until a delim byte
|
||
|
|
// has been read, appending all read bytes to dst. The resulting appended data,
|
||
|
|
// the last read byte and whether the last read byte was the delimiter.
|
||
|
|
func (c *ByteScanner) ScanUntil(dst []byte, delim byte) (res []byte, b byte, err error) {
|
||
|
|
outer:
|
||
|
|
for {
|
||
|
|
var i int
|
||
|
|
for i, b = range c.buf[c.off:] {
|
||
|
|
if b != delim {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
dst = append(dst, c.buf[c.off:c.off+i+1]...)
|
||
|
|
c.off += i + 1
|
||
|
|
break outer
|
||
|
|
}
|
||
|
|
dst = append(dst, c.buf[c.off:]...)
|
||
|
|
err = c.reload()
|
||
|
|
if err != nil {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return dst, b, err
|
||
|
|
}
|
||
|
|
|
||
|
|
// ReadByte is an unexported ReadByte.
|
||
|
|
func (c *ByteScanner) ReadByte() (byte, error) {
|
||
|
|
if c.off >= len(c.buf) {
|
||
|
|
err := c.reload()
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
}
|
||
|
|
b := c.buf[c.off]
|
||
|
|
c.off++
|
||
|
|
return b, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// reload re-fills the scanner's buffer.
|
||
|
|
func (c *ByteScanner) reload() error {
|
||
|
|
n, err := c.r.Read(c.buf[:cap(c.buf)])
|
||
|
|
c.buf = c.buf[:n]
|
||
|
|
if err != nil {
|
||
|
|
if err != io.EOF {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if n == 0 {
|
||
|
|
return io.EOF
|
||
|
|
}
|
||
|
|
}
|
||
|
|
c.off = 0
|
||
|
|
return nil
|
||
|
|
}
|