// Copyright 2016 Viacheslav Chimishuk <vchimishuk@yandex.ru>//// This file is part of Chub.//// Chub is free software: you can redistribute it and/or modify// it 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.//// Chub 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// along with Chub. If not, see <http://www.gnu.org/licenses/>. package cue import (	"bytes"	"errors"	"fmt"	"strconv"	"strings"	"unicode") var illegalTimeFormatError = errors.New("Illegal time format.") // parseCommand retrive string line and parses it with the following algorythm:// * first word in the line is command name (cmd return value)// * all rest words are command's parameters// * if parameter includes more than one word it should be wrapped with ' or "func parseCommand(line string) (cmd string, params []string, err error) {	line = strings.TrimSpace(line)	params = make([]string, 0) 	// Find cmd.	i := strings.IndexFunc(line, unicode.IsSpace)	if i < 0 { // We have only command without any parameters.		cmd = line		return	}	cmd = line[:i]	line = strings.TrimSpace(line[i:]) 	// Split parameters.	l := len(line)	var quotedChar byte = 0	param := bytes.NewBufferString("")	for i = 0; i < l; i++ {		c := line[i] 		if quotedChar == 0 { // We are not in quote mode now, so we can enter into.			if isQuoteChar(c) {				// Quote can be started only at the beginnig of the parameter,				// but not in the middle.				if param.Len() != 0 {					err = errors.New("Unexpected quortation character.")					return				}				quotedChar = c			} else if unicode.IsSpace(rune(c)) {				// In not quote mode space starts new parameter.				// But don't save empty parameters.				if param.Len() != 0 {					params = append(params, param.String())					param = bytes.NewBufferString("")				}			} else {				if c == '\\' { // Escape sequence in the text.					if i+1 >= l {						err = fmt.Errorf("Unfinished escape sequence.")						return					} 					s, e := parseEscapeSequence(line[i : i+2])					if e != nil {						err = e						return					}					param.WriteByte(s)					i++				} else {					param.WriteByte(c)				}			}		} else {			if c == quotedChar { // Close quote.				quotedChar = 0			} else {				if c == '\\' { // Escape sequence in the text.					if i+1 >= l {						err = fmt.Errorf("Unfinished escape sequence.")						return					} 					s, e := parseEscapeSequence(line[i : i+2])					if e != nil {						err = e						return					}					param.WriteByte(s)					i++				} else {					param.WriteByte(c)				}			}		}	} 	params = append(params, param.String()) 	return} // parseEscapeSequence returns escape character by it's string "source code" equivalent.func parseEscapeSequence(seq string) (char byte, err error) {	var m = map[string]byte{		"\\\"": '"',		"\\'":  '\'',		"\\\\": '\\',		"\\n":  '\n',		"\\t":  '\t',	} 	char, ok := m[seq]	if !ok {		err = fmt.Errorf("Usupported escape sequence '%s'.", seq)	} 	return} // isQuoteChar returns true if given char is string quoted char:// " or '.func isQuoteChar(char byte) bool {	return char == '\'' || char == '"'} // parserTime parses time string and returns separate values.// Input string format: mm:ss:fffunc parseTime(length string) (min int, sec int, frames int, err error) {	parts := strings.Split(length, ":")	if len(parts) != 3 {		err = illegalTimeFormatError		return	} 	min, err = strconv.Atoi(parts[0])	if err != nil {		err = illegalTimeFormatError		return	} 	sec, err = strconv.Atoi(parts[1])	if err != nil {		err = illegalTimeFormatError		return	}	if sec > 59 {		err = illegalTimeFormatError		return	} 	frames, err = strconv.Atoi(parts[2])	if err != nil {		err = illegalTimeFormatError		return	}	if frames > 74 {		if frames > 99 {			err = illegalTimeFormatError			return		}		// Some Tools generate sloppy frame counts		// Use remainder for frames but increment seconds		frames = frames % 74		sec++	} 	return}