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 All trailing whitespace is stripped from the header, and it is
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 == ' ')
105 /* Strip trailing whitespace. (*hdr)[i] is the newline;
106 decrement I until it points to the last available
108 while (i > 0 && ISSPACE ((*hdr)[i - 1]))
119 DEBUGP (("%s\n", *hdr));
123 /* Check whether HEADER begins with NAME and, if yes, skip the `:' and
124 the whitespace, and call PROCFUN with the arguments of HEADER's
125 contents (after the `:' and space) and ARG. Otherwise, return 0. */
127 header_process (const char *header, const char *name,
128 int (*procfun) (const char *, void *),
131 /* Check whether HEADER matches NAME. */
132 while (*name && (TOLOWER (*name) == TOLOWER (*header)))
134 if (*name || *header++ != ':')
137 header += skip_lws (header);
139 return ((*procfun) (header, arg));
142 /* Helper functions for use with header_process(). */
144 /* Extract a long integer from HEADER and store it to CLOSURE. If an
145 error is encountered, return 0, else 1. */
147 header_extract_number (const char *header, void *closure)
149 const char *p = header;
152 for (result = 0; ISDIGIT (*p); p++)
153 result = 10 * result + (*p - '0');
155 /* Failure if no number present. */
159 /* Skip trailing whitespace. */
162 /* Indicate failure if trailing garbage is present. */
166 *(long *)closure = result;
170 /* Strdup HEADER, and place the pointer to CLOSURE. */
172 header_strdup (const char *header, void *closure)
174 *(char **)closure = xstrdup (header);
178 /* Write the value 1 into the integer pointed to by CLOSURE. */
180 header_exists (const char *header, void *closure)
186 /* Skip LWS (linear white space), if present. Returns number of
187 characters to skip. */
189 skip_lws (const char *string)
191 const char *p = string;
193 while (*p == ' ' || *p == '\t' || *p == '\r' || *p == '\n')