1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
|
#include <stdint.h>
static void copy_bits(uint8_t *out, unsigned int out_pos, const uint8_t *in, unsigned int in_pos, unsigned int length)
{
unsigned int offset, chunk_size;
uint8_t temp, mask;
// skip untouched out bytes
offset = out_pos / 8;
out += offset;
out_pos -= offset * 8;
// skip untouched in bytes
offset = in_pos / 8;
in += offset;
in_pos -= offset * 8;
while(length > 0)
{
chunk_size = (in_pos < out_pos) ? 8 - out_pos : 8 - in_pos;
if(chunk_size == 0) chunk_size = 8;
if(chunk_size > length) chunk_size = length;
temp = ((*in) << in_pos);
temp >>= out_pos;
mask = 0xff << (8 - chunk_size);
mask = /*0xff ^*/ (mask >> out_pos);
*out |= mask & temp;
in_pos += chunk_size;
if(in_pos >= 8)
{
in++;
in_pos -= 8;
}
out_pos += chunk_size;
if(out_pos >= 8)
{
out++;
out_pos -= 8;
}
length -= chunk_size;
}
}
static void reverse_data(uint8_t *a, int len)
{
int i;
uint8_t temp;
for(i = len / 2 - 1; i >= 0; i--)
{
temp = a[i];
a[i] = a[len-1-i];
a[len-1-i] = temp;
}
}
static uint64_t reverse_bits(uint64_t a, int bits)
{
int i;
uint64_t b = 0;
for(i = 0; i < bits; i++)
{
b = (b << 1) | (a & 1);
a >>= 1;
}
return b;
}
static int64_t sign_extend(uint64_t a, int bits)
{
int64_t sret;;
if((a & (1 << (bits - 1))) != 0)
{
a = ((uint64_t)0xffffffffffffffffLL << bits) | a;
memcpy(&sret, &a, 8);
return sret;
}
return a;
}
#define B_SKIP 0
#define B_STR 1
#define B_INT 2
#define B_LSB 4
#define B_LE 8
#define B_SIGN 16
#define BSKIP B_SKIP
#define BSTR B_STR
#define BMSB B_INT
#define BLSB (B_INT|B_LSB)
#define BLE (B_INT|B_LE)
#define BSMSB (B_INT|B_SIGN)
#define BSLSB (B_INT|B_LSB|B_SIGN)
#define BSLE (B_INT|B_LE|B_SIGN)
#if BYTE_ORDER == LITTLE_ENDIAN
#define BMO BLE
#define BSMO BSLE
#else
#define BMO BMSB
#define BSMO BSMSB
#endif
static int lcrypt_bget(lua_State *L)
{
int count = 0, argc = lua_gettop(L);
size_t length;
const unsigned char *in = (const unsigned char*)luaL_checklstring(L, 1, &length);
int i, type, bits, offset = luaL_checkint(L, 2);
length *= 8;
for(i = 3; i <= argc && offset < (int)length; i += 2)
{
type = luaL_checkint(L, i);
if(i+1 > argc)
bits = length;
else
bits = luaL_checkint(L, i+1);
if(offset + bits > (int)length) bits = length - offset;
if(type == B_SKIP)
{
count--;
}
else if(type == B_STR)
{
int len = (bits + 7) / 8;
uint8_t data[len];
memset(data, 0, len);
copy_bits(data, 0, in, offset, bits);
lua_pushlstring(L, (char*)data, len);
}
else // integer
{
uint64_t ret = 0;
copy_bits((uint8_t*)&ret, sizeof(ret) * 8 - bits, in, offset, bits);
#if BYTE_ORDER == LITTLE_ENDIAN
reverse_data((uint8_t*)&ret, sizeof(ret));
#endif
if((type & B_LSB) == B_LSB) ret = reverse_bits(ret, bits);
#if BYTE_ORDER == LITTLE_ENDIAN
if((type & B_LE) == B_LE) reverse_data((uint8_t*)&ret, (bits+7)/8);
#else
if((type & B_LE) == B_LE) reverse_data((uint8_t*)&ret + 8-(bits+7)/8, (bits+7)/8);
#endif
if((type & B_SIGN) == B_SIGN)
lua_pushnumber(L, sign_extend(ret, bits));
else
lua_pushnumber(L, ret);
}
count++;
offset += bits;
}
return count;
}
static int lcrypt_bput(lua_State *L)
{
int argc = lua_gettop(L);
int i, type, bits = 0, offset = 0, len = 0;
size_t length;
for(i = 1; i <= argc; i += 3)
{
type = luaL_checkint(L, i+1);
if(type == B_STR && lua_isnil(L, i+2) == 1)
{
(void)luaL_checklstring(L, i, &length);
bits = (lua_isnil(L, i+2) == 1) ? length * 8 : luaL_checkint(L, i+2);
if(bits > (int)length * 8) bits = length * 8;
}
else
{
bits = luaL_checkint(L, i+2);
}
len += bits;
}
len = (len + 7) / 8;
uint8_t ret[len];
memset(ret, 0, len);
for(i = 1; i <= argc; i += 3)
{
type = luaL_checkint(L, i+1);
if(type == B_STR)
{
const uint8_t *in = (const uint8_t *)luaL_checklstring(L, i, &length);
bits = (lua_isnil(L, i+2) == 1) ? length * 8 : luaL_checkint(L, i+2);
if(bits > (int)length * 8) bits = length * 8;
copy_bits(ret, offset, in, 0, bits);
}
else if(type != B_SKIP) // integer
{
uint64_t in;
bits = luaL_checkint(L, i+2);
if((type & B_SIGN) == B_SIGN)
{
int64_t sin = luaL_checknumber(L, i);
memcpy(&in, &sin, 8);
}
else
{
in = luaL_checknumber(L, i);
}
#if BYTE_ORDER == LITTLE_ENDIAN
reverse_data((uint8_t*)&in, sizeof(in));
#endif
if((type & B_LSB) == B_LSB)
{
in = reverse_bits(in, 64);
copy_bits(ret, offset, (uint8_t*)&in, 0, bits);
}
else if((type & B_LE) == B_LE)
{
reverse_data((uint8_t*)&in, sizeof(in));
copy_bits(ret, offset, (uint8_t*)&in, 0, bits);
}
else
copy_bits(ret, offset, (uint8_t*)&in, sizeof(in) * 8 - bits, bits);
}
offset += bits;
}
lua_pushlstring(L, (char*)ret, len);
return 1;
}
static void lcrypt_start_bits(lua_State *L)
{
ADD_FUNCTION(L, bget); ADD_FUNCTION(L, bput);
ADD_CONSTANT(L, BSKIP); ADD_CONSTANT(L, BSTR); ADD_CONSTANT(L, BMSB); ADD_CONSTANT(L, BLSB);
ADD_CONSTANT(L, BLE); ADD_CONSTANT(L, BSMSB); ADD_CONSTANT(L, BSLSB); ADD_CONSTANT(L, BSLE);
ADD_CONSTANT(L, BMO); ADD_CONSTANT(L, BSMO);
}
|
