Diffstat (limited to 'pwmanager/libcrypt/mpi/mpi-scan.c') (more/less context) (ignore whitespace changes)
-rw-r--r-- | pwmanager/libcrypt/mpi/mpi-scan.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/pwmanager/libcrypt/mpi/mpi-scan.c b/pwmanager/libcrypt/mpi/mpi-scan.c new file mode 100644 index 0000000..90699cd --- a/dev/null +++ b/pwmanager/libcrypt/mpi/mpi-scan.c | |||
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1 | /* mpi-scan.c - MPI functions | ||
2 | *Copyright (C) 1998, 2001, 2002, 2003 Free Software Foundation, Inc. | ||
3 | * | ||
4 | * This file is part of Libgcrypt. | ||
5 | * | ||
6 | * Libgcrypt is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU Lesser General Public License as | ||
8 | * published by the Free Software Foundation; either version 2.1 of | ||
9 | * the License, or (at your option) any later version. | ||
10 | * | ||
11 | * Libgcrypt 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 Lesser General Public License for more details. | ||
15 | * | ||
16 | * You should have received a copy of the GNU Lesser General Public | ||
17 | * License along with this program; if not, write to the Free Software | ||
18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA | ||
19 | */ | ||
20 | |||
21 | #include <config.h> | ||
22 | #include <stdio.h> | ||
23 | #include <stdlib.h> | ||
24 | #include "mpi-internal.h" | ||
25 | #include "longlong.h" | ||
26 | |||
27 | /**************** | ||
28 | * Scan through an mpi and return byte for byte. a -1 is returned to indicate | ||
29 | * the end of the mpi. Scanning is done from the lsb to the msb, returned | ||
30 | * values are in the range of 0 .. 255. | ||
31 | * | ||
32 | * FIXME: This code is VERY ugly! | ||
33 | */ | ||
34 | int | ||
35 | _gcry_mpi_getbyte( gcry_mpi_t a, unsigned idx ) | ||
36 | { | ||
37 | int i, j; | ||
38 | unsigned n; | ||
39 | mpi_ptr_t ap; | ||
40 | mpi_limb_t limb; | ||
41 | |||
42 | ap = a->d; | ||
43 | for(n=0,i=0; i < a->nlimbs; i++ ) { | ||
44 | limb = ap[i]; | ||
45 | for( j=0; j < BYTES_PER_MPI_LIMB; j++, n++ ) | ||
46 | if( n == idx ) | ||
47 | return (limb >> j*8) & 0xff; | ||
48 | } | ||
49 | return -1; | ||
50 | } | ||
51 | |||
52 | |||
53 | /**************** | ||
54 | * Put a value at position IDX into A. idx counts from lsb to msb | ||
55 | */ | ||
56 | void | ||
57 | _gcry_mpi_putbyte( gcry_mpi_t a, unsigned idx, int xc ) | ||
58 | { | ||
59 | int i, j; | ||
60 | unsigned n; | ||
61 | mpi_ptr_t ap; | ||
62 | mpi_limb_t limb, c; | ||
63 | |||
64 | c = xc & 0xff; | ||
65 | ap = a->d; | ||
66 | for(n=0,i=0; i < a->alloced; i++ ) { | ||
67 | limb = ap[i]; | ||
68 | for( j=0; j < BYTES_PER_MPI_LIMB; j++, n++ ) | ||
69 | if( n == idx ) { | ||
70 | #if BYTES_PER_MPI_LIMB == 4 | ||
71 | if( j == 0 ) | ||
72 | limb = (limb & 0xffffff00) | c; | ||
73 | else if( j == 1 ) | ||
74 | limb = (limb & 0xffff00ff) | (c<<8); | ||
75 | else if( j == 2 ) | ||
76 | limb = (limb & 0xff00ffff) | (c<<16); | ||
77 | else | ||
78 | limb = (limb & 0x00ffffff) | (c<<24); | ||
79 | #elif BYTES_PER_MPI_LIMB == 8 | ||
80 | if( j == 0 ) | ||
81 | limb = (limb & 0xffffffffffffff00) | c; | ||
82 | else if( j == 1 ) | ||
83 | limb = (limb & 0xffffffffffff00ff) | (c<<8); | ||
84 | else if( j == 2 ) | ||
85 | limb = (limb & 0xffffffffff00ffff) | (c<<16); | ||
86 | else if( j == 3 ) | ||
87 | limb = (limb & 0xffffffff00ffffff) | (c<<24); | ||
88 | else if( j == 4 ) | ||
89 | limb = (limb & 0xffffff00ffffffff) | (c<<32); | ||
90 | else if( j == 5 ) | ||
91 | limb = (limb & 0xffff00ffffffffff) | (c<<40); | ||
92 | else if( j == 6 ) | ||
93 | limb = (limb & 0xff00ffffffffffff) | (c<<48); | ||
94 | else | ||
95 | limb = (limb & 0x00ffffffffffffff) | (c<<56); | ||
96 | #else | ||
97 | #error please enhance this function, its ugly - i know. | ||
98 | #endif | ||
99 | if( a->nlimbs <= i ) | ||
100 | a->nlimbs = i+1; | ||
101 | ap[i] = limb; | ||
102 | return; | ||
103 | } | ||
104 | } | ||
105 | abort(); /* index out of range */ | ||
106 | } | ||
107 | |||
108 | |||
109 | /**************** | ||
110 | * Count the number of zerobits at the low end of A | ||
111 | */ | ||
112 | unsigned | ||
113 | _gcry_mpi_trailing_zeros( gcry_mpi_t a ) | ||
114 | { | ||
115 | unsigned n, count = 0; | ||
116 | |||
117 | for(n=0; n < a->nlimbs; n++ ) { | ||
118 | if( a->d[n] ) { | ||
119 | unsigned nn; | ||
120 | mpi_limb_t alimb = a->d[n]; | ||
121 | |||
122 | count_trailing_zeros( nn, alimb ); | ||
123 | count += nn; | ||
124 | break; | ||
125 | } | ||
126 | count += BITS_PER_MPI_LIMB; | ||
127 | } | ||
128 | return count; | ||
129 | |||
130 | } | ||
131 | |||
132 | |||