bigint/bigint_io.c

   1 /* bigint_io.c */
   2 /*
   3     This file is part of the ARM-Crypto-Lib.
   4     Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
   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 #include "cli.h"
  21 #include "hexdigit_tab.h"
  22 #include "bigint.h"
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 void bigint_print_hex(const bigint_t *a) {
  27         if (a->length_W == 0) {
  28                 cli_putc('0');
  29                 return;
  30         }
  31         if (a->info&BIGINT_NEG_MASK) {
  32                 cli_putc('-');
  33         }
  34         size_t idx;
  35         uint8_t print_zero = 0;
  36         uint8_t *p, x, y;
  37         p = (uint8_t*)&(a->wordv[a->length_W - 1]) + sizeof(bigint_word_t) - 1;
  38         for (idx = a->length_W * sizeof(bigint_word_t); idx > 0; --idx) {
  39                 x = *p >> 4;
  40                 y = *p & 0xf;
  41                 if (x != 0 || print_zero != 0) {
  42                         cli_putc(pgm_read_byte(&hexdigit_tab_lc_P[x]));
  43                 }
  44                 if (x) {
  45                         print_zero = 1;
  46                 }
  47                 if (y != 0 || print_zero != 0) {
  48                         cli_putc(pgm_read_byte(&hexdigit_tab_lc_P[y]));
  49                 }
  50                 if (y) {
  51                         print_zero = 1;
  52                 }
  53                 --p;
  54         }
  55 }
  56
  57 #define BLOCKSIZE 32
  58
  59 static uint8_t char2nibble(char c) {
  60         if (c >= '0' && c <= '9') {
  61                 return c - '0';
  62         }
  63         c |= 'A' ^ 'a'; /* to lower case */
  64         if ( c>= 'a' && c <= 'f') {
  65                 return c - 'a' + 10;
  66         }
  67         return 0xff;
  68 }
  69
  70 static uint16_t read_byte(void) {
  71         uint8_t t1, t2;
  72         char c;
  73         c = cli_getc_cecho();
  74         if (c == '-') {
  75                 return 0x0500;
  76         }
  77         t1 = char2nibble(c);
  78         if (t1 == 0xff) {
  79                 return 0x0100;
  80         }
  81         c = cli_getc_cecho();
  82         t2 = char2nibble(c);
  83         if (t2 == 0xff) {
  84                 return 0x0200|t1;
  85         }
  86         return (t1 << 4)|t2;
  87 }
  88
  89 uint8_t bigint_read_hex_echo(bigint_t *a) {
  90         uint16_t allocated = 0;
  91         uint8_t  shift4 = 0;
  92         uint16_t  t, idx = 0;
  93         uint8_t *buf = NULL;
  94         a->length_W = 0;
  95         a->wordv = NULL;
  96         a->info = 0;
  97         for (;;) {
  98                 if (allocated - idx < 1) {
  99                         uint8_t *p;
 100                         p = realloc(buf, (allocated += BLOCKSIZE) * sizeof(bigint_word_t));
 101                         if (p == NULL) {
 102                                 cli_putstr("\r\nERROR: Out of memory!");
 103                                 free(buf);
 104                                 return 0xff;
 105                         }
 106                         memset((uint8_t*)p + (allocated - BLOCKSIZE) * sizeof(bigint_word_t), 0, BLOCKSIZE * sizeof(bigint_word_t));
 107                         buf = p;
 108                 }
 109                 t = read_byte();
 110                 if (idx == 0) {
 111                         if (t & 0x0400) {
 112                                 /* got minus */
 113                                 a->info |= BIGINT_NEG_MASK;
 114                                 continue;
 115                         } else {
 116                                 if (t == 0x0100) {
 117                                         free(a->wordv);
 118                                         a->wordv = NULL;
 119                                         return 1;
 120                                 }
 121                         }
 122                 }
 123                 if (t <= 0x00ff) {
 124                         buf[idx++] = (uint8_t)t;
 125                 } else {
 126                         if (t & 0x0200) {
 127                                 shift4 = 1;
 128                                 buf[idx++] = (uint8_t)((t & 0x0f) << 4);
 129                         }
 130                         break;
 131                 }
 132         }
 133         /* we have to reverse the byte array */
 134         uint8_t tmp;
 135         uint8_t *p, *q;
 136         a->length_W = (idx + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
 137         p = buf;
 138         q = buf + idx - 1;
 139         while (q > p) {
 140                 tmp = *p;
 141                 *p = *q;
 142                 *q = tmp;
 143                 p++; q--;
 144         }
 145         a->wordv = (bigint_word_t*)buf;
 146         bigint_adjust(a);
 147         if (shift4) {
 148                 bigint_shiftright(a, 4);
 149         }
 150         if(a->length_W == 1 && a->wordv[0] == 0){
 151             a->length_W = 0;
 152             a->info = 0;
 153         }
 154         return 0;
 155 }