xref: /curl/scripts/schemetable.c (revision d6447b1b)
1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9  *
10  * This software is licensed as described in the file COPYING, which
11  * you should have received as part of this distribution. The terms
12  * are also available at https://curl.se/docs/copyright.html.
13  *
14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15  * copies of the Software, and permit persons to whom the Software is
16  * furnished to do so, under the terms of the COPYING file.
17  *
18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
20  *
21  * SPDX-License-Identifier: curl
22  *
23  ***************************************************************************/
24 #include <stdio.h>
25 #include <curl/curl.h>
26 
27 /*
28  * Use this tool to generate an updated table for the Curl_getn_scheme_handler
29  * function in url.c.
30  */
31 
32 struct detail {
33   const char *n;
34   const char *ifdef;
35 };
36 
37 static const struct detail scheme[] = {
38   {"dict", "#ifndef CURL_DISABLE_DICT" },
39   {"file", "#ifndef CURL_DISABLE_FILE" },
40   {"ftp", "#ifndef CURL_DISABLE_FTP" },
41   {"ftps", "#if defined(USE_SSL) && !defined(CURL_DISABLE_FTP)" },
42   {"gopher", "#ifndef CURL_DISABLE_GOPHER" },
43   {"gophers", "#if defined(USE_SSL) && !defined(CURL_DISABLE_GOPHER)" },
44   {"http", "#ifndef CURL_DISABLE_HTTP" },
45   {"https", "#if defined(USE_SSL) && !defined(CURL_DISABLE_HTTP)" },
46   {"imap", "#ifndef CURL_DISABLE_IMAP" },
47   {"imaps", "#if defined(USE_SSL) && !defined(CURL_DISABLE_IMAP)" },
48   {"ldap", "#ifndef CURL_DISABLE_LDAP" },
49   {"ldaps", "#if !defined(CURL_DISABLE_LDAP) && \\\n"
50    "  !defined(CURL_DISABLE_LDAPS) && \\\n"
51    "  ((defined(USE_OPENLDAP) && defined(USE_SSL)) || \\\n"
52    "   (!defined(USE_OPENLDAP) && defined(HAVE_LDAP_SSL)))" },
53   {"mqtt", "#ifndef CURL_DISABLE_MQTT" },
54   {"pop3", "#ifndef CURL_DISABLE_POP3" },
55   {"pop3s", "#if defined(USE_SSL) && !defined(CURL_DISABLE_POP3)" },
56   {"rtmp", "#ifdef USE_LIBRTMP" },
57   {"rtmpt", "#ifdef USE_LIBRTMP" },
58   {"rtmpe", "#ifdef USE_LIBRTMP" },
59   {"rtmpte", "#ifdef USE_LIBRTMP" },
60   {"rtmps", "#ifdef USE_LIBRTMP" },
61   {"rtmpts", "#ifdef USE_LIBRTMP" },
62   {"rtsp", "#ifndef CURL_DISABLE_RTSP" },
63   {"scp", "#if defined(USE_SSH) && !defined(USE_WOLFSSH)" },
64   {"sftp", "#if defined(USE_SSH)" },
65   {"smb", "#if !defined(CURL_DISABLE_SMB) && defined(USE_CURL_NTLM_CORE) && \\\n"
66    "  (SIZEOF_CURL_OFF_T > 4)" },
67   {"smbs", "#if defined(USE_SSL) && !defined(CURL_DISABLE_SMB) && \\\n"
68    "  defined(USE_CURL_NTLM_CORE) && (SIZEOF_CURL_OFF_T > 4)" },
69   {"smtp", "#ifndef CURL_DISABLE_SMTP" },
70   {"smtps", "#if defined(USE_SSL) && !defined(CURL_DISABLE_SMTP)" },
71   {"telnet", "#ifndef CURL_DISABLE_TELNET" },
72   {"tftp", "#ifndef CURL_DISABLE_TFTP" },
73   {"ws", "#if defined(USE_WEBSOCKETS) && !defined(CURL_DISABLE_HTTP)" },
74   {"wss", "#if defined(USE_WEBSOCKETS) && \\\n"
75    "  defined(USE_SSL) && !defined(CURL_DISABLE_HTTP)" },
76   { NULL, NULL }
77 };
78 
calc(const char * s,int add,int shift)79 unsigned int calc(const char *s, int add, int shift)
80 {
81   const char *so = s;
82   unsigned int c = add;
83   while(*s) {
84     c <<= shift;
85     c += *s;
86     s++;
87   }
88   return c;
89 }
90 
91 unsigned int num[100];
92 unsigned int ix[100];
93 
showtable(int try,int init,int shift)94 static void showtable(int try, int init, int shift)
95 {
96   int nulls = 0;
97   int i;
98   for(i = 0; scheme[i].n; ++i)
99     num[i] = calc(scheme[i].n, init, shift);
100   for(i = 0; scheme[i].n; ++i)
101     ix[i] = num[i] % try;
102   printf("/*\n"
103          "   unsigned int c = %d\n"
104          "   while(l) {\n"
105          "     c <<= %d;\n"
106          "     c += Curl_raw_tolower(*s);\n"
107          "     s++;\n"
108          "     l--;\n"
109          "   }\n"
110          "*/\n", init, shift);
111 
112   printf("  static const struct Curl_handler * const protocols[%d] = {", try);
113 
114   /* generate table */
115   for(i=0; i < try; i++) {
116     int match = 0;
117     int j;
118     for(j=0; scheme[j].n; j++) {
119       if(ix[j] == i) {
120         printf("\n");
121         printf("%s\n", scheme[j].ifdef);
122         printf("    &Curl_handler_%s,\n", scheme[j].n);
123         printf("#else\n    NULL,\n");
124         printf("#endif");
125         match = 1;
126         nulls = 0;
127         break;
128       }
129     }
130     if(!match) {
131       if(!nulls || (nulls>10)) {
132         printf("\n   ");
133         nulls = 0;
134       }
135       printf(" NULL,", nulls);
136       nulls++;
137     }
138   }
139   printf("\n  };\n");
140 }
141 
main(void)142 int main(void)
143 {
144   int i;
145   int try;
146   int besttry = 9999;
147   int bestadd = 0;
148   int bestshift = 0;
149   int add;
150   int shift;
151   for(shift = 0; shift < 8; shift++) {
152     for(add = 0; add < 999; add++) {
153       for(i = 0; scheme[i].n; ++i) {
154         unsigned int v = calc(scheme[i].n, add, shift);
155         int j;
156         int badcombo = 0;
157         for(j=0; j < i; j++) {
158 
159           if(num[j] == v) {
160             /*
161             printf("NOPE: %u is a dupe (%s and %s)\n",
162                    v, scheme[i], scheme[j]);
163             */
164             badcombo = 1;
165             break;
166           }
167         }
168         if(badcombo)
169           break;
170         num[i] = v;
171       }
172 #if 0
173       for(i = 0; scheme[i].n; ++i) {
174         printf("%u - %s\n", num[i], scheme[i].n);
175       }
176 #endif
177       /* try different remainders to find smallest possible table */
178       for(try = 28; try < 199; try++) {
179         int good = 1;
180         for(i = 0; scheme[i].n; ++i) {
181           ix[i] = num[i] % try;
182         }
183         /* check for dupes */
184         for(i = 0; scheme[i].n && good; ++i) {
185           int j;
186           for(j=0; j < i; j++) {
187             if(ix[j] == ix[i]) {
188               /* printf("NOPE, try %u causes dupes (%d and %d)\n", try, j, i); */
189               good = 0;
190               break;
191             }
192           }
193         }
194         if(good) {
195           if(try < besttry) {
196             besttry = try;
197             bestadd = add;
198             bestshift = shift;
199           }
200           break;
201         }
202       }
203     }
204   }
205 
206   showtable(besttry, bestadd, bestshift);
207 }
208