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