github.com/hugh712/snapd@v0.0.0-20200910133618-1a99902bd583/spdx/scanner.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2016 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package spdx
    21  
    22  import (
    23  	"bufio"
    24  	"io"
    25  )
    26  
    27  type Scanner struct {
    28  	*bufio.Scanner
    29  }
    30  
    31  func spdxSplit(data []byte, atEOF bool) (advance int, token []byte, err error) {
    32  	// skip WS
    33  	start := 0
    34  	for ; start < len(data); start++ {
    35  		if data[start] != ' ' && data[start] != '\n' {
    36  			break
    37  		}
    38  	}
    39  	if start == len(data) {
    40  		return start, nil, nil
    41  	}
    42  
    43  	switch data[start] {
    44  	// found ( or )
    45  	case '(', ')':
    46  		return start + 1, data[start : start+1], nil
    47  	}
    48  
    49  	for i := start; i < len(data); i++ {
    50  		switch data[i] {
    51  		// token finished
    52  		case ' ', '\n':
    53  			return i + 1, data[start:i], nil
    54  			// found ( or ) - we need to rescan it
    55  		case '(', ')':
    56  			return i, data[start:i], nil
    57  		}
    58  	}
    59  	if atEOF && len(data) > start {
    60  		return len(data), data[start:], nil
    61  	}
    62  	return start, nil, nil
    63  }
    64  
    65  func NewScanner(r io.Reader) *Scanner {
    66  	scanner := bufio.NewScanner(r)
    67  	scanner.Split(spdxSplit)
    68  	return &Scanner{scanner}
    69  }