1 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 : *
3 : * ***** BEGIN LICENSE BLOCK *****
4 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5 : *
6 : * The contents of this file are subject to the Mozilla Public License Version
7 : * 1.1 (the "License"); you may not use this file except in compliance with
8 : * the License. You may obtain a copy of the License at
9 : * http://www.mozilla.org/MPL/
10 : *
11 : * Software distributed under the License is distributed on an "AS IS" basis,
12 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13 : * for the specific language governing rights and limitations under the
14 : * License.
15 : *
16 : * The Original Code is mozilla.org code.
17 : *
18 : * The Initial Developer of the Original Code is
19 : * Boris Zbarsky <bzbarsky@mit.edu>.
20 : * Portions created by the Initial Developer are Copyright (C) 2001
21 : * the Initial Developer. All Rights Reserved.
22 : *
23 : * Contributor(s):
24 : * Christian Biesinger <cbiesinger@web.de>
25 : * Mats Palmgren <mats.palmgren@bredband.net>
26 : *
27 : * Alternatively, the contents of this file may be used under the terms of
28 : * either the GNU General Public License Version 2 or later (the "GPL"), or
29 : * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
30 : * in which case the provisions of the GPL or the LGPL are applicable instead
31 : * of those above. If you wish to allow use of your version of this file only
32 : * under the terms of either the GPL or the LGPL, and not to allow others to
33 : * use your version of this file under the terms of the MPL, indicate your
34 : * decision by deleting the provisions above and replace them with the notice
35 : * and other provisions required by the GPL or the LGPL. If you do not delete
36 : * the provisions above, a recipient may use your version of this file under
37 : * the terms of any one of the MPL, the GPL or the LGPL.
38 : *
39 : * ***** END LICENSE BLOCK ***** */
40 :
41 : #ifndef nsReadLine_h__
42 : #define nsReadLine_h__
43 :
44 : #include "prmem.h"
45 : #include "nsIInputStream.h"
46 :
47 : /**
48 : * @file
49 : * Functions to read complete lines from an input stream.
50 : *
51 : * To properly use the helper function in here (NS_ReadLine) the caller
52 : * needs to declare a pointer to an nsLineBuffer, call
53 : * NS_InitLineBuffer on it, and pass it to NS_ReadLine every time it
54 : * wants a line out.
55 : *
56 : * When done, the pointer should be freed using PR_Free.
57 : */
58 :
59 : /**
60 : * @internal
61 : * Buffer size. This many bytes will be buffered. If a line is longer than this,
62 : * the partial line will be appended to the out parameter of NS_ReadLine and the
63 : * buffer will be emptied.
64 : * Note: if you change this constant, please update the regression test in
65 : * netwerk/test/unit/test_readline.js accordingly (bug 397850).
66 : */
67 : #define kLineBufferSize 4096
68 :
69 : /**
70 : * @internal
71 : * Line buffer structure, buffers data from an input stream.
72 : * The buffer is empty when |start| == |end|.
73 : * Invariant: |start| <= |end|
74 : */
75 : template<typename CharT>
76 : class nsLineBuffer {
77 : public:
78 : CharT buf[kLineBufferSize+1];
79 : CharT* start;
80 : CharT* end;
81 : };
82 :
83 : /**
84 : * Initialize a line buffer for use with NS_ReadLine.
85 : *
86 : * @param aBufferPtr
87 : * Pointer to pointer to a line buffer. Upon successful return,
88 : * *aBufferPtr will contain a valid pointer to a line buffer, for use
89 : * with NS_ReadLine. Use PR_Free when the buffer is no longer needed.
90 : *
91 : * @retval NS_OK Success.
92 : * @retval NS_ERROR_OUT_OF_MEMORY Not enough memory to allocate the line buffer.
93 : *
94 : * @par Example:
95 : * @code
96 : * nsLineBuffer* lb;
97 : * rv = NS_InitLineBuffer(&lb);
98 : * if (NS_SUCCEEDED(rv)) {
99 : * // do stuff...
100 : * PR_Free(lb);
101 : * }
102 : * @endcode
103 : */
104 : template<typename CharT>
105 : nsresult
106 919 : NS_InitLineBuffer (nsLineBuffer<CharT> ** aBufferPtr) {
107 919 : *aBufferPtr = PR_NEW(nsLineBuffer<CharT>);
108 919 : if (!(*aBufferPtr))
109 0 : return NS_ERROR_OUT_OF_MEMORY;
110 :
111 919 : (*aBufferPtr)->start = (*aBufferPtr)->end = (*aBufferPtr)->buf;
112 919 : return NS_OK;
113 : }
114 :
115 : /**
116 : * Read a line from an input stream. Lines are separated by '\r' (0x0D) or '\n'
117 : * (0x0A), or "\r\n" or "\n\r".
118 : *
119 : * @param aStream
120 : * The stream to read from
121 : * @param aBuffer
122 : * The line buffer to use. Must have been inited with
123 : * NS_InitLineBuffer before. A single line buffer must not be used with
124 : * different input streams.
125 : * @param aLine [out]
126 : * The string where the line will be stored.
127 : * @param more [out]
128 : * Whether more data is available in the buffer. If true, NS_ReadLine may
129 : * be called again to read further lines. Otherwise, further calls to
130 : * NS_ReadLine will return an error.
131 : *
132 : * @retval NS_OK
133 : * Read successful
134 : * @retval error
135 : * Input stream returned an error upon read. See
136 : * nsIInputStream::read.
137 : */
138 : template<typename CharT, class StreamType, class StringType>
139 : nsresult
140 56652 : NS_ReadLine (StreamType* aStream, nsLineBuffer<CharT> * aBuffer,
141 : StringType & aLine, bool *more)
142 : {
143 56652 : CharT eolchar = 0; // the first eol char or 1 after \r\n or \n\r is found
144 :
145 56652 : aLine.Truncate();
146 :
147 1365 : while (1) { // will be returning out of this loop on eol or eof
148 58017 : if (aBuffer->start == aBuffer->end) { // buffer is empty. Read into it.
149 : PRUint32 bytesRead;
150 2352 : nsresult rv = aStream->Read(aBuffer->buf, kLineBufferSize, &bytesRead);
151 2352 : if (NS_FAILED(rv) || NS_UNLIKELY(bytesRead == 0)) {
152 742 : *more = false;
153 742 : return rv;
154 : }
155 1610 : aBuffer->start = aBuffer->buf;
156 1610 : aBuffer->end = aBuffer->buf + bytesRead;
157 1610 : *(aBuffer->end) = '\0';
158 : }
159 :
160 : /*
161 : * Walk the buffer looking for an end-of-line.
162 : * There are 3 cases to consider:
163 : * 1. the eol char is the last char in the buffer
164 : * 2. the eol char + one more char at the end of the buffer
165 : * 3. the eol char + two or more chars at the end of the buffer
166 : * we need at least one char after the first eol char to determine if
167 : * it's a \r\n or \n\r sequence (and skip over it), and we need one
168 : * more char after the end-of-line to set |more| correctly.
169 : */
170 57275 : CharT* current = aBuffer->start;
171 57275 : if (NS_LIKELY(eolchar == 0)) {
172 1902046 : for ( ; current < aBuffer->end; ++current) {
173 1901114 : if (*current == '\n' || *current == '\r') {
174 56325 : eolchar = *current;
175 56325 : *current++ = '\0';
176 56325 : aLine.Append(aBuffer->start);
177 56325 : break;
178 : }
179 : }
180 : }
181 57275 : if (NS_LIKELY(eolchar != 0)) {
182 113948 : for ( ; current < aBuffer->end; ++current) {
183 56541 : if ((eolchar == '\r' && *current == '\n') ||
184 : (eolchar == '\n' && *current == '\r')) {
185 631 : eolchar = 1;
186 631 : continue;
187 : }
188 55910 : aBuffer->start = current;
189 55910 : *more = true;
190 55910 : return NS_OK;
191 : }
192 : }
193 :
194 1365 : if (eolchar == 0)
195 932 : aLine.Append(aBuffer->start);
196 1365 : aBuffer->start = aBuffer->end; // mark the buffer empty
197 : }
198 : }
199 :
200 : #endif // nsReadLine_h__
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