// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package doc

import (
	
	
)

// firstSentenceLen returns the length of the first sentence in s.
// The sentence ends after the first period followed by space and
// not preceded by exactly one uppercase letter.
//
func firstSentenceLen( string) int {
	var , ,  rune
	for ,  := range  {
		if  == '\n' ||  == '\r' ||  == '\t' {
			 = ' '
		}
		if  == ' ' &&  == '.' && (!unicode.IsUpper() || unicode.IsUpper()) {
			return 
		}
		if  == '。' ||  == '.' {
			return 
		}
		, ,  = , , 
	}
	return len()
}

const (
	keepNL = 1 << iota
)

// clean replaces each sequence of space, \n, \r, or \t characters
// with a single space and removes any trailing and leading spaces.
// If the keepNL flag is set, newline characters are passed through
// instead of being change to spaces.
func clean( string,  int) string {
	var  []byte
	 := byte(' ')
	for  := 0;  < len(); ++ {
		 := []
		if (&keepNL) == 0 &&  == '\n' ||  == '\r' ||  == '\t' {
			 = ' '
		}
		if  != ' ' ||  != ' ' {
			 = append(, )
			 = 
		}
	}
	// remove trailing blank, if any
	if  := len();  > 0 &&  == ' ' {
		 = [0 : -1]
	}
	return string()
}

// Synopsis returns a cleaned version of the first sentence in s.
// That sentence ends after the first period followed by space and
// not preceded by exactly one uppercase letter. The result string
// has no \n, \r, or \t characters and uses only single spaces between
// words. If s starts with any of the IllegalPrefixes, the result
// is the empty string.
//
func ( string) string {
	 = clean([0:firstSentenceLen()], 0)
	for ,  := range IllegalPrefixes {
		if strings.HasPrefix(strings.ToLower(), ) {
			return ""
		}
	}
	 = convertQuotes()
	return 
}

var IllegalPrefixes = []string{
	"copyright",
	"all rights",
	"author",
}