1 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* ***** BEGIN LICENSE BLOCK *****
3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4  *
5  * The contents of this file are subject to the Mozilla Public License Version
6  * 1.1 (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  * http://www.mozilla.org/MPL/
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10  * Software distributed under the License is distributed on an "AS IS" basis,
11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12  * for the specific language governing rights and limitations under the
13  * License.
14  *
15  * The Original Code is Mozilla Universal charset detector code.
16  *
17  * The Initial Developer of the Original Code is
18  * Netscape Communications Corporation.
19  * Portions created by the Initial Developer are Copyright (C) 2001
20  * the Initial Developer. All Rights Reserved.
21  *
22  * Contributor(s):
23  *          Shy Shalom <shooshX@gmail.com>
24  *
25  * Alternatively, the contents of this file may be used under the terms of
26  * either the GNU General Public License Version 2 or later (the "GPL"), or
27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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36  *
37  * ***** END LICENSE BLOCK ***** */
38 
39 #include "nsCharSetProber.h"
40 #include "prmem.h"
41 
42 //This filter applies to all scripts which do not use English characters
FilterWithoutEnglishLetters(const char * aBuf,PRUint32 aLen,char ** newBuf,PRUint32 & newLen)43 PRBool nsCharSetProber::FilterWithoutEnglishLetters(const char* aBuf, PRUint32 aLen, char** newBuf, PRUint32& newLen)
44 {
45   char *newptr;
46   char *prevPtr, *curPtr;
47 
48   PRBool meetMSB = PR_FALSE;
49   newptr = *newBuf = (char*)PR_Malloc(aLen);
50   if (!newptr)
51     return PR_FALSE;
52 
53   for (curPtr = prevPtr = (char*)aBuf; curPtr < aBuf+aLen; curPtr++)
54   {
55     if (*curPtr & 0x80)
56     {
57       meetMSB = PR_TRUE;
58     }
59     else if (*curPtr < 'A' || (*curPtr > 'Z' && *curPtr < 'a') || *curPtr > 'z')
60     {
61       //current char is a symbol, most likely a punctuation. we treat it as segment delimiter
62       if (meetMSB && curPtr > prevPtr)
63       //this segment contains more than single symbol, and it has upper ASCII, we need to keep it
64       {
65         while (prevPtr < curPtr) *newptr++ = *prevPtr++;
66         prevPtr++;
67         *newptr++ = ' ';
68         meetMSB = PR_FALSE;
69       }
70       else //ignore current segment. (either because it is just a symbol or just an English word)
71         prevPtr = curPtr+1;
72     }
73   }
74   if (meetMSB && curPtr > prevPtr)
75     while (prevPtr < curPtr) *newptr++ = *prevPtr++;
76 
77   newLen = newptr - *newBuf;
78 
79   return PR_TRUE;
80 }
81 
82 //This filter applies to all scripts which contain both English characters and upper ASCII characters.
FilterWithEnglishLetters(const char * aBuf,PRUint32 aLen,char ** newBuf,PRUint32 & newLen)83 PRBool nsCharSetProber::FilterWithEnglishLetters(const char* aBuf, PRUint32 aLen, char** newBuf, PRUint32& newLen)
84 {
85   //do filtering to reduce load to probers
86   char *newptr;
87   char *prevPtr, *curPtr;
88   PRBool isInTag = PR_FALSE;
89 
90   newptr = *newBuf = (char*)PR_Malloc(aLen);
91   if (!newptr)
92     return PR_FALSE;
93 
94   for (curPtr = prevPtr = (char*)aBuf; curPtr < aBuf+aLen; curPtr++)
95   {
96     if (*curPtr == '>')
97       isInTag = PR_FALSE;
98     else if (*curPtr == '<')
99       isInTag = PR_TRUE;
100 
101     if (!(*curPtr & 0x80) &&
102         (*curPtr < 'A' || (*curPtr > 'Z' && *curPtr < 'a') || *curPtr > 'z') )
103     {
104       if (curPtr > prevPtr && !isInTag) // Current segment contains more than just a symbol
105                                         // and it is not inside a tag, keep it.
106       {
107         while (prevPtr < curPtr) *newptr++ = *prevPtr++;
108         prevPtr++;
109         *newptr++ = ' ';
110       }
111       else
112         prevPtr = curPtr+1;
113     }
114   }
115 
116   // If the current segment contains more than just a symbol
117   // and it is not inside a tag then keep it.
118   if (!isInTag)
119     while (prevPtr < curPtr)
120       *newptr++ = *prevPtr++;
121 
122   newLen = newptr - *newBuf;
123 
124   return PR_TRUE;
125 }
126