clearification of keysize descriptor stuff
[arm-crypto-lib.git] / bcal / keysize_descriptor.c
1 /* keysize_descriptor.c */
2 /*
3     This file is part of the ARM-Crypto-Lib.
4     Copyright (C) 2009  Daniel Otte (daniel.otte@rub.de)
5
6     This program 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 3 of the License, or
9     (at your option) any later version.
10
11     This program 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.
15
16     You should have received a copy of the GNU General Public License
17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
18 */
19 /**
20  * \file    keysize_descriptor.c 
21  * \author  Daniel Otte
22  * \email   daniel.otte@rub.de
23  * \date    2009-01-07
24  * \license GPLv3 or later
25  */
26
27 #include <stdint.h>
28 #include <stdlib.h>
29 #include "keysize_descriptor.h"
30
31 #define KS8 ((uint8_t*)ks_desc)
32 uint8_t is_valid_keysize_P(const void* ks_desc, uint16_t keysize){
33         uint8_t type;
34         type = KS8[0];
35         ks_desc = KS8 + 1;
36         if(type==KS_TYPE_TERMINATOR)
37                 return 0;
38         if(type==KS_TYPE_LIST){
39                 uint8_t items;
40                 uint16_t item;
41                 items = KS8[0];
42                 ks_desc = KS8 + 1;
43                 while(items--){
44                         item = KS8[1] * 256 + KS8[0];
45                         ks_desc = KS8 + 2;
46                         if(item==keysize)
47                                 return 1;
48                 }
49                 ks_desc = KS8 - 2;
50         }
51         if(type==KS_TYPE_RANGE){
52                 uint16_t max, min;
53                 min = KS8[1] * 256 + KS8[0];
54                 ks_desc = (uint8_t*)ks_desc + 2;
55                 max = KS8[1] * 256 + KS8[0];
56                 if(min <= keysize && keysize <= max)
57                         return 1;
58         }
59         if(type==KS_TYPE_ARG_RANGE){
60                 uint16_t max, min, dist, offset;
61                 min     = KS8[1] * 256 + KS8[0];
62                 max     = KS8[3] * 256 + KS8[2];
63                 dist    = KS8[5] * 256 + KS8[4];
64                 offset  = KS8[7] * 256 + KS8[6];
65                 ks_desc = KS8 + 6;
66                 if(min <= keysize && keysize <= max && (keysize % dist == offset))
67                         return 1;
68         }
69         if(type>KS_TYPE_ARG_RANGE){
70                 /* bad error, you may insert a big warning message here */
71                 return 0;
72         }
73         return is_valid_keysize_P(KS8+1, keysize); /* search the next record */
74 }
75
76 uint16_t get_keysize(const void* ks_desc){
77         uint8_t type;
78         uint16_t keysize;
79         type = *((uint8_t*)ks_desc);
80         if(type==KS_TYPE_LIST){
81                 ks_desc = (uint8_t*)ks_desc + 1;
82         }
83         ks_desc = (uint8_t*)ks_desc + 1;
84         keysize = *((uint8_t*)ks_desc);
85         return keysize;
86 }
87
88 uint16_t get_keysizes(const void* ks_desc, uint16_t** list){
89         uint8_t type;
90         uint16_t items;
91         uint8_t i;
92         type = *((uint8_t*)ks_desc);
93         ks_desc = (uint8_t*)ks_desc + 1;
94         if(type==KS_TYPE_LIST){
95                 items = *((uint8_t*)ks_desc);
96                 ks_desc = (uint8_t*)ks_desc + 1;
97                 if(!*list){
98                         *list = malloc(items*2);
99                         if(!*list){
100                                 return 0;
101                         }
102                 }
103                 for(i=0; i<items; ++i){
104                         ((uint16_t*)(*list))[i] = *((uint16_t*)ks_desc);
105                         ks_desc = (uint8_t*)ks_desc + 2;
106                 }
107                 return items;
108         }
109         if(type==KS_TYPE_ARG_RANGE){
110                 uint16_t min, max, distance, offset;
111                 min = *((uint16_t*)ks_desc);
112                 ks_desc = (uint8_t*)ks_desc + 2;
113                 max = *((uint16_t*)ks_desc);
114                 ks_desc = (uint8_t*)ks_desc + 2;
115                 distance = *((uint16_t*)ks_desc);
116                 ks_desc = (uint8_t*)ks_desc + 2;
117                 offset = *((uint16_t*)ks_desc);
118                 items = (max-min)/distance+1;
119                 if(min%distance!=offset){
120                         --items;
121                         min += (distance-(min%distance-offset))%distance;
122                 }
123                 if(!*list){
124                         *list = malloc(items*2);
125                         if(!*list){
126                                 return 0;
127                         }
128                 }
129                 i=0;
130                 while(min<max){
131                         ((uint16_t*)*list)[i++] = min;
132                         min += distance;
133                 }
134                 return i;
135         }
136         if(type==KS_TYPE_RANGE){
137                 uint16_t min, max, distance=8, offset=0;
138                 min = *((uint16_t*)ks_desc);
139                 ks_desc = (uint8_t*)ks_desc + 2;
140                 max = *((uint16_t*)ks_desc);
141                 items = (max-min)/distance+1;
142                 if(min%distance!=offset){
143                         --items;
144                         min += (distance-(min%distance-offset))%distance;
145                 }
146                 if(!*list){
147                         *list = malloc(items*2);
148                         if(!*list){
149                                 return 0;
150                         }
151                 }
152                 i=0;
153                 while(min<max){
154                         ((uint16_t*)*list)[i++] = min;
155                         min += distance;
156                 }
157                 return i;
158         }
159         return 0;
160 }