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simpleRandom.cc
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1 #include "simpleRandom.h"
2 #include <math.h>
3 #if defined(SunOS) || defined(Linux) || defined(OSF1)
4 #include <strings.h>
5 #else
6 #include <bstring.h>
7 #endif
8 
9 
10 /*
11  * Shuffle the bytes into little-endian order within words, as per the
12  * MD5 spec. Note: this code works regardless of the byte order.
13  */
14 void
15 simpleRandom::byteSwap(word32 *buf, unsigned words)
16 {
17  xbyte *p = (xbyte *)buf;
18 
19  do {
20  *buf++ = (word32)((unsigned)p[3] << 8 | p[2]) << 16 |
21  ((unsigned)p[1] << 8 | p[0]);
22  p += 4;
23  } while (--words);
24 }
25 
26 /*
27  * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
28  * initialization constants.
29  */
30 void
31 simpleRandom::xMD5Init(struct xMD5Context *ctx)
32 {
33  ctx->buf[0] = 0x67452301;
34  ctx->buf[1] = 0xefcdab89;
35  ctx->buf[2] = 0x98badcfe;
36  ctx->buf[3] = 0x10325476;
37 
38  ctx->bytes[0] = 0;
39  ctx->bytes[1] = 0;
40 }
41 
42 /*
43  * Update context to reflect the concatenation of another buffer full
44  * of bytes.
45  */
46 void
47 simpleRandom::xMD5Update(struct xMD5Context *ctx, xbyte const *buf, unsigned int len)
48 {
49  word32 t;
50 
51  /* Update byte count */
52 
53  t = ctx->bytes[0];
54  if ((ctx->bytes[0] = t + len) < t)
55  ctx->bytes[1]++; /* Carry from low to high */
56 
57  t = 64 - (t & 0x3f); /* Space available in ctx->in (at least 1) */
58  if ( t > len) {
59  bcopy(buf, (xbyte *)ctx->in + 64 - (unsigned)t, len);
60  return;
61  }
62  /* First chunk is an odd size */
63  bcopy(buf,(xbyte *)ctx->in + 64 - (unsigned)t, (unsigned)t);
64  byteSwap(ctx->in, 16);
65  xMD5Transform(ctx->buf, ctx->in);
66  buf += (unsigned)t;
67  len -= (unsigned)t;
68 
69  /* Process data in 64-byte chunks */
70  while (len >= 64) {
71  bcopy(buf, ctx->in, 64);
72  byteSwap(ctx->in, 16);
73  xMD5Transform(ctx->buf, ctx->in);
74  buf += 64;
75  len -= 64;
76  }
77 
78  /* Handle any remaining bytes of data. */
79  bcopy(buf, ctx->in, len);
80 }
81 
82 /*
83  * Final wrapup - pad to 64-byte boundary with the bit pattern
84  * 1 0* (64-bit count of bits processed, MSB-first)
85  */
86 void
87 simpleRandom::xMD5Final(xbyte bdigest[16], struct xMD5Context *ctx)
88 {
89  int count = (int)(ctx->bytes[0] & 0x3f); /* Bytes in ctx->in */
90  xbyte *p = (xbyte *)ctx->in + count; /* First unused byte */
91 
92  /* Set the first char of padding to 0x80. There is always room. */
93  *p++ = 0x80;
94 
95  /* Bytes of padding needed to make 56 bytes (-8..55) */
96  count = 56 - 1 - count;
97 
98  if (count < 0) { /* Padding forces an extra block */
99  bzero(p, count+8);
100  byteSwap(ctx->in, 16);
101  xMD5Transform(ctx->buf, ctx->in);
102  p = (xbyte *)ctx->in;
103  count = 56;
104  }
105  bzero(p, count+8);
106  byteSwap(ctx->in, 14);
107 
108  /* Append length in bits and transform */
109  ctx->in[14] = ctx->bytes[0] << 3;
110  ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
111  xMD5Transform(ctx->buf, ctx->in);
112 
113  byteSwap(ctx->buf, 4);
114  bcopy(ctx->buf, bdigest, 16);
115  bzero(ctx,sizeof(*ctx));
116 }
117 
118 
119 /* The four core functions - F1 is optimized somewhat */
120 
121 /* #define F1(x, y, z) (x & y | ~x & z) */
122 #define F1(x, y, z) (z ^ (x & (y ^ z)))
123 #define F2(x, y, z) F1(z, x, y)
124 #define F3(x, y, z) (x ^ y ^ z)
125 #define F4(x, y, z) (y ^ (x | ~z))
126 
127 /* This is the central step in the MD5 algorithm. */
128 #define MD5STEP(f,w,x,y,z,in,s) \
129  (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
130 
131 /*
132  * The core of the MD5 algorithm, this alters an existing MD5 hash to
133  * reflect the addition of 16 longwords of new data. MD5Update blocks
134  * the data and converts bytes into longwords for this routine.
135  */
136 void
137 simpleRandom::xMD5Transform(word32 buf[4], word32 const in[16])
138 {
139  word32 a, b, c, d;
140 
141  a = buf[0];
142  b = buf[1];
143  c = buf[2];
144  d = buf[3];
145 
146  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
147  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
148  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
149  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
150  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
151  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
152  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
153  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
154  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
155  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
156  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
157  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
158  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
159  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
160  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
161  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
162 
163  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
164  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
165  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
166  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
167  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
168  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
169  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
170  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
171  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
172  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
173  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
174  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
175  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
176  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
177  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
178  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
179 
180  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
181  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
182  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
183  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
184  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
185  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
186  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
187  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
188  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
189  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
190  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
191  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
192  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
193  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
194  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
195  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
196 
197  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
198  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
199  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
200  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
201  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
202  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
203  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
204  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
205  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
206  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
207  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
208  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
209  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
210  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
211  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
212  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
213 
214  buf[0] += a;
215  buf[1] += b;
216  buf[2] += c;
217  buf[3] += d;
218 }
219 
220 
221 void simpleRandom::MD5(xbyte *dest, const xbyte *orig, unsigned int len)
222 {
223  struct xMD5Context context;
224 
225  xMD5Init(&context);
226  xMD5Update(&context, orig, len);
227  xMD5Final(dest, &context);
228 }
229 
230 /*****************************************************************/
231 
232 simpleRandom::simpleRandom()
233 {
234  digest[0] = 7657635;
235  digest[1] = 5565649;
236  digest[2] = 9827729;
237  digest[3] = 9892898;
238 
239 
240 }
241 
242 simpleRandom::simpleRandom( const int iseed)
243 {
244  digest[0] = iseed;
245  digest[1] = 565649;
246  digest[2] = 6827729;
247  digest[3] = 2892898;
248 
249 }
250 
251 float simpleRandom::gauss(const float mean, const float sigma)
252 {
253 #define BIGNUMBER 100000
254 
255  float y = 0.;
256  while(y == 0.)
257  {
258  y = rnd(0,BIGNUMBER);
259  }
260  float z = rnd(0,BIGNUMBER);
261 
262  y /= BIGNUMBER;
263  z /= BIGNUMBER;
264 
265  float x = z * 6.283185;
266 
267 #if defined(SunOS) || defined(Linux)
268  float result = mean + sigma* sin(x) * sqrt(-2 * log(y) );
269 #else
270  float result = mean + sigma* sinf(x) * sqrtf(-2 * logf(y) );
271 #endif
272 
273  return result;
274 }
275 
276 float simpleRandom::rnd(int low, int high)
277 {
278  unsigned int range = high - low;
279  unsigned int mask = 0;
280  unsigned int num;
281  int r;
282 
283  for (r = range; r; r >>= 1)
284  mask |= r;
285 
286  do {
287  MD5((xbyte*)digest,(const xbyte *) digest, sizeof(digest));
288  num = digest[0] & mask;
289  } while (num > range);
290 
291  return num + low;
292 }