avr-crypto-lib/keysize_descriptor.c

166 行
4.1 KiB
C

/* keysize_descriptor.c */
/*
This file is part of the AVR-Crypto-Lib.
Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* \file keysize_descriptor.c
* \author Daniel Otte
* \email bg@nerilex.org
* \date 2009-01-07
* \license GPLv3 or later
*/
#include <stdint.h>
#include <stdlib.h>
#include <avr/pgmspace.h>
#include "keysize_descriptor.h"
uint8_t is_valid_keysize_P(PGM_VOID_P ks_desc, uint16_t keysize){
uint8_t type;
type = pgm_read_byte(ks_desc++);
if (type == KS_TYPE_TERMINATOR) {
return 0;
}
if (type == KS_TYPE_LIST) {
uint8_t items;
uint16_t item;
items = pgm_read_byte(ks_desc++);
while (items--) {
item = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
if (item == keysize) {
return 1;
}
}
ks_desc = (uint8_t*)ks_desc - 2;
}
if (type == KS_TYPE_RANGE) {
uint16_t max, min;
min = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
max = pgm_read_word(ks_desc);
if (min <= keysize && keysize <= max) {
return 1;
}
}
if (type == KS_TYPE_ARG_RANGE) {
uint16_t max, min, dist, offset;
min = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
max = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
dist = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
offset = pgm_read_word(ks_desc);
if (min <= keysize && keysize <= max && (keysize % dist == offset)) {
return 1;
}
}
if (type > KS_TYPE_ARG_RANGE) {
/* bad error, you may insert a big warning message here */
return 0;
}
return is_valid_keysize_P((uint8_t*)ks_desc + 1, keysize); /* search the next record */
}
uint16_t get_keysize(PGM_VOID_P ks_desc){
uint8_t type;
uint16_t keysize;
type = pgm_read_byte(ks_desc);
if(type==KS_TYPE_LIST){
ks_desc = (uint8_t*)ks_desc + 1;
}
ks_desc = (uint8_t*)ks_desc + 1;
keysize = pgm_read_word(ks_desc);
return keysize;
}
uint16_t get_keysizes(PGM_VOID_P ks_desc, uint16_t** list){
uint8_t type;
uint16_t items;
uint8_t i;
type = pgm_read_byte(ks_desc);
ks_desc = (uint8_t*)ks_desc + 1;
if(type==KS_TYPE_LIST){
items = pgm_read_byte(ks_desc);
ks_desc = (uint8_t*)ks_desc + 1;
if(!*list){
*list = malloc(items*2);
if(!*list){
return 0;
}
}
for(i=0; i<items; ++i){
((uint16_t*)(*list))[i] = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
}
return items;
}
if(type==KS_TYPE_ARG_RANGE){
uint16_t min, max, distance, offset;
min = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
max = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
distance = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
offset = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
items = (max-min)/distance+1;
if(min%distance!=offset){
--items;
min += (distance-(min%distance-offset))%distance;
}
if(!*list){
*list = malloc(items*2);
if(!*list){
return 0;
}
}
i=0;
while(min<=max){
((uint16_t*)*list)[i++] = min;
min += distance;
}
return i;
}
if(type==KS_TYPE_RANGE){
uint16_t min, max, distance=8, offset=0;
min = pgm_read_word(ks_desc);
ks_desc = (uint8_t*)ks_desc + 2;
max = pgm_read_word(ks_desc);
items = (max-min)/distance+1;
if(min%distance!=offset){
--items;
min += (distance-(min%distance-offset))%distance;
}
if(!*list){
*list = malloc(items*2);
if(!*list){
return 0;
}
}
i=0;
while(min<=max){
((uint16_t*)*list)[i++] = min;
min += distance;
}
return i;
}
return 0;
}