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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: url.c,v 1.3 2001/01/20 12:06:21 mdw Exp $ |
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4 | * |
5 | * Parsing and construction of url-encoded name/value pairs |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: url.c,v $ |
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33 | * Revision 1.3 2001/01/20 12:06:21 mdw |
34 | * Be more conservative in base-64 encoding. |
35 | * |
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36 | * Revision 1.2 1999/09/03 08:02:05 mdw |
37 | * Make `#' a special character which needs escaping. |
38 | * |
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39 | * Revision 1.1 1999/06/01 09:49:48 mdw |
40 | * New files for url-encoding and decoding. |
41 | * |
42 | */ |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include <stdio.h> |
47 | #include <stdlib.h> |
48 | #include <string.h> |
49 | |
50 | #include "dstr.h" |
51 | #include "url.h" |
52 | |
53 | /*----- Main code ---------------------------------------------------------*/ |
54 | |
55 | /* --- @url_initenc@ --- * |
56 | * |
57 | * Arguments: @url_ectx *ctx@ = pointer to context block |
58 | * |
59 | * Returns: --- |
60 | * |
61 | * Use: Initializes a URL encoding context. |
62 | */ |
63 | |
64 | void url_initenc(url_ectx *ctx) |
65 | { |
66 | ctx->f = 0; |
67 | } |
68 | |
69 | /* --- @encode@ --- * |
70 | * |
71 | * Arguments: @dstr *d@ = pointer to output string |
72 | * @const char *p@ = pointer to thing to encode |
73 | * |
74 | * Returns: --- |
75 | * |
76 | * Use: Encodes the input string into the output string. |
77 | */ |
78 | |
79 | static void encode(dstr *d, const char *p) |
80 | { |
81 | while (*p) { |
82 | switch (*p) { |
83 | case ' ': |
84 | DPUTC(d, '+'); |
85 | break; |
86 | default: |
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87 | if (isalnum((unsigned char)*p)) |
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88 | DPUTC(d, *p); |
89 | else |
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90 | dstr_putf(d, "%%%02x", *p); |
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91 | break; |
92 | } |
93 | p++; |
94 | } |
95 | } |
96 | |
97 | /* --- @url_enc@ --- * |
98 | * |
99 | * Arguments: @url_ectx *ctx@ = pointer to encoding context |
100 | * @dstr *d@ = pointer to output string |
101 | * @const char *name@ = pointer to name |
102 | * @const char *value@ = pointer to value |
103 | * |
104 | * Returns: --- |
105 | * |
106 | * Use: Writes an assignment between @name@ and @value@ to the |
107 | * output string, encoding the values properly. |
108 | */ |
109 | |
110 | void url_enc(url_ectx *ctx, dstr *d, const char *name, const char *value) |
111 | { |
112 | if (ctx->f & URLF_SEP) |
113 | DPUTC(d, '&'); |
114 | encode(d, name); |
115 | DPUTC(d, '='); |
116 | encode(d, value); |
117 | DPUTZ(d); |
118 | ctx->f |= URLF_SEP; |
119 | } |
120 | |
121 | /* --- @url_initdec@ --- * |
122 | * |
123 | * Arguments: @url_dctx *ctx@ = pointer to context block |
124 | * @const char *p@ = string to read data from |
125 | * |
126 | * Returns: --- |
127 | * |
128 | * Use: Initializes a URL decoding context. |
129 | */ |
130 | |
131 | void url_initdec(url_dctx *ctx, const char *p) |
132 | { |
133 | ctx->p = p; |
134 | } |
135 | |
136 | /* --- @decode@ --- * |
137 | * |
138 | * Arguments: @dstr *d@ = pointer to output string |
139 | * @const char *p@ = pointer to input data |
140 | * @int eq@ = whether to stop at `=' characters |
141 | * |
142 | * Returns: Pointer to next available character. |
143 | * |
144 | * Use: Does a URL decode. |
145 | */ |
146 | |
147 | static const char *decode(dstr *d, const char *p, int eq) |
148 | { |
149 | if (!*p) |
150 | return (0); |
151 | for (;;) { |
152 | switch (*p) { |
153 | case '=': |
154 | if (eq) |
155 | return (p); |
156 | DPUTC(d, *p); |
157 | break; |
158 | case 0: |
159 | case '&': |
160 | return (p); |
161 | case '+': |
162 | DPUTC(d, ' '); |
163 | break; |
164 | case '%': { |
165 | unsigned int ch; |
166 | int n; |
167 | int x = sscanf(p + 1, "%2x%n", &ch, &n); |
168 | if (x == 1) { |
169 | DPUTC(d, ch); |
170 | p += n; |
171 | break; |
172 | } |
173 | } |
174 | default: |
175 | DPUTC(d, *p); |
176 | break; |
177 | } |
178 | p++; |
179 | } |
180 | } |
181 | |
182 | /* --- @url_dec@ --- * |
183 | * |
184 | * Arguments: @url_dctx *ctx@ = pointer to decode context |
185 | * @dstr *n@ = pointer to output string for name |
186 | * @dstr *v@ = pointer to output string for value |
187 | * |
188 | * Returns: Nonzero if it read something, zero if there's nothing left |
189 | * |
190 | * Use: Decodes the next name/value pair from a urlencoded string. |
191 | */ |
192 | |
193 | int url_dec(url_dctx *ctx, dstr *n, dstr *v) |
194 | { |
195 | const char *p = ctx->p; |
196 | size_t l = n->len; |
197 | |
198 | again: |
199 | if ((p = decode(n, p, 1)) == 0 || *p == 0) |
200 | return (0); |
201 | if (*p != '=') { |
202 | p++; |
203 | n->len = l; |
204 | goto again; |
205 | } |
206 | p++; |
207 | if ((p = decode(v, p, 0)) == 0) |
208 | return (0); |
209 | DPUTZ(n); |
210 | DPUTZ(v); |
211 | ctx->p = p; |
212 | return (1); |
213 | } |
214 | |
215 | /*----- That's all, folks -------------------------------------------------*/ |