1 /* Generic support for headers.
2 Copyright (C) 1997, 1998 Free Software Foundation, Inc.
4 This file is part of GNU Wget.
6 GNU Wget is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 GNU Wget is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with Wget; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
35 /* This file contains the generic routines for work with headers.
36 Currently they are used only by HTTP in http.c, but they can be
37 used by anything that cares about RFC822-style headers.
39 Header is defined in RFC2068, as quoted below. Note that this
40 definition is not HTTP-specific -- it is virtually
41 indistinguishable from the one given in RFC822 or RFC1036.
43 message-header = field-name ":" [ field-value ] CRLF
46 field-value = *( field-content | LWS )
48 field-content = <the OCTETs making up the field-value
49 and consisting of either *TEXT or combinations
50 of token, tspecials, and quoted-string>
52 The public functions are header_get() and header_process(), which
56 /* Get a header from read-buffer RBUF and return it in *HDR.
58 As defined in RFC2068 and elsewhere, a header can be folded into
59 multiple lines if the continuation line begins with a space or
60 horizontal TAB. Also, this function will accept a header ending
61 with just LF instead of CRLF.
63 The header may be of arbitrary length; the function will allocate
64 as much memory as necessary for it to fit. It need not contain a
65 `:', thus you can use it to retrieve, say, HTTP status line.
67 The trailing CRLF or LF are stripped from the header, and it is
68 zero-terminated. #### Is this well-behaved? */
70 header_get (struct rbuf *rbuf, char **hdr, enum header_get_flags flags)
75 *hdr = (char *)xmalloc (bufsize);
79 /* #### Use DO_REALLOC? */
81 *hdr = (char *)xrealloc (*hdr, (bufsize <<= 1));
82 res = RBUF_READCHAR (rbuf, *hdr + i);
85 if ((*hdr)[i] == '\n')
87 if (!((flags & HG_NO_CONTINUATIONS)
89 || (i == 1 && (*hdr)[0] == '\r')))
92 /* If the header is non-empty, we need to check if
93 it continues on to the other line. We do that by
94 peeking at the next character. */
95 res = rbuf_peek (rbuf, &next);
100 /* If the next character is HT or SP, just continue. */
101 if (next == '\t' || next == ' ')
104 /* The header ends. */
106 /* Get rid of '\r'. */
107 if (i > 0 && (*hdr)[i - 1] == '\r')
108 (*hdr)[i - 1] = '\0';
117 DEBUGP (("%s\n", *hdr));
121 /* Check whether HEADER begins with NAME and, if yes, skip the `:' and
122 the whitespace, and call PROCFUN with the arguments of HEADER's
123 contents (after the `:' and space) and ARG. Otherwise, return 0. */
125 header_process (const char *header, const char *name,
126 int (*procfun) (const char *, void *),
129 /* Check whether HEADER matches NAME. */
130 while (*name && (TOLOWER (*name) == TOLOWER (*header)))
132 if (*name || *header++ != ':')
135 header += skip_lws (header);
137 return ((*procfun) (header, arg));
140 /* Helper functions for use with header_process(). */
142 /* Extract a long integer from HEADER and store it to CLOSURE. If an
143 error is encountered, return 0, else 1. */
145 header_extract_number (const char *header, void *closure)
147 const char *p = header;
150 for (result = 0; ISDIGIT (*p); p++)
151 result = 10 * result + (*p - '0');
153 /* Failure if no number present. */
157 /* Skip trailing whitespace. */
160 /* Indicate failure if trailing garbage is present. */
164 *(long *)closure = result;
168 /* Strdup HEADER, and place the pointer to CLOSURE. */
170 header_strdup (const char *header, void *closure)
172 *(char **)closure = xstrdup (header);
176 /* Write the value 1 into the integer pointed to by CLOSURE. */
178 header_exists (const char *header, void *closure)
184 /* Skip LWS (linear white space), if present. Returns number of
185 characters to skip. */
187 skip_lws (const char *string)
189 const char *p = string;
191 while (*p == ' ' || *p == '\t' || *p == '\r' || *p == '\n')