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Diffstat (limited to 'usr/src/lib/libbc/libc/gen/common/random.c')
| -rw-r--r-- | usr/src/lib/libbc/libc/gen/common/random.c | 384 |
1 files changed, 0 insertions, 384 deletions
diff --git a/usr/src/lib/libbc/libc/gen/common/random.c b/usr/src/lib/libbc/libc/gen/common/random.c deleted file mode 100644 index 1fdee713fe..0000000000 --- a/usr/src/lib/libbc/libc/gen/common/random.c +++ /dev/null @@ -1,384 +0,0 @@ -/* - * CDDL HEADER START - * - * The contents of this file are subject to the terms of the - * Common Development and Distribution License, Version 1.0 only - * (the "License"). You may not use this file except in compliance - * with the License. - * - * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE - * or http://www.opensolaris.org/os/licensing. - * See the License for the specific language governing permissions - * and limitations under the License. - * - * When distributing Covered Code, include this CDDL HEADER in each - * file and include the License file at usr/src/OPENSOLARIS.LICENSE. - * If applicable, add the following below this CDDL HEADER, with the - * fields enclosed by brackets "[]" replaced with your own identifying - * information: Portions Copyright [yyyy] [name of copyright owner] - * - * CDDL HEADER END - */ -/* - * Copyright 1999 Sun Microsystems, Inc. All rights reserved. - * Use is subject to license terms. - */ - -#pragma ident "%Z%%M% %I% %E% SMI" - -#include <stdio.h> -#include <stdlib.h> - -/* - * random.c: - * An improved random number generation package. In addition to the standard - * rand()/srand() like interface, this package also has a special state info - * interface. The initstate() routine is called with a seed, an array of - * bytes, and a count of how many bytes are being passed in; this array is then - * initialized to contain information for random number generation with that - * much state information. Good sizes for the amount of state information are - * 32, 64, 128, and 256 bytes. The state can be switched by calling the - * setstate() routine with the same array as was initiallized with initstate(). - * By default, the package runs with 128 bytes of state information and - * generates far better random numbers than a linear congruential generator. - * If the amount of state information is less than 32 bytes, a simple linear - * congruential R.N.G. is used. - * Internally, the state information is treated as an array of longs; the - * zeroeth element of the array is the type of R.N.G. being used (small - * integer); the remainder of the array is the state information for the - * R.N.G. Thus, 32 bytes of state information will give 7 longs worth of - * state information, which will allow a degree seven polynomial. (Note: the - * zeroeth word of state information also has some other information stored - * in it -- see setstate() for details). - * The random number generation technique is a linear feedback shift register - * approach, employing trinomials (since there are fewer terms to sum up that - * way). In this approach, the least significant bit of all the numbers in - * the state table will act as a linear feedback shift register, and will have - * period 2^deg - 1 (where deg is the degree of the polynomial being used, - * assuming that the polynomial is irreducible and primitive). The higher - * order bits will have longer periods, since their values are also influenced - * by pseudo-random carries out of the lower bits. The total period of the - * generator is approximately deg*(2**deg - 1); thus doubling the amount of - * state information has a vast influence on the period of the generator. - * Note: the deg*(2**deg - 1) is an approximation only good for large deg, - * when the period of the shift register is the dominant factor. With deg - * equal to seven, the period is actually much longer than the 7*(2**7 - 1) - * predicted by this formula. - */ - - - -/* - * For each of the currently supported random number generators, we have a - * break value on the amount of state information (you need at least this - * many bytes of state info to support this random number generator), a degree - * for the polynomial (actually a trinomial) that the R.N.G. is based on, and - * the separation between the two lower order coefficients of the trinomial. - */ - -#define TYPE_0 0 /* linear congruential */ -#define BREAK_0 8 -#define DEG_0 0 -#define SEP_0 0 - -#define TYPE_1 1 /* x**7 + x**3 + 1 */ -#define BREAK_1 32 -#define DEG_1 7 -#define SEP_1 3 - -#define TYPE_2 2 /* x**15 + x + 1 */ -#define BREAK_2 64 -#define DEG_2 15 -#define SEP_2 1 - -#define TYPE_3 3 /* x**31 + x**3 + 1 */ -#define BREAK_3 128 -#define DEG_3 31 -#define SEP_3 3 - -#define TYPE_4 4 /* x**63 + x + 1 */ -#define BREAK_4 256 -#define DEG_4 63 -#define SEP_4 1 - - -/* - * Array versions of the above information to make code run faster -- relies - * on fact that TYPE_i == i. - */ - -#define MAX_TYPES 5 /* max number of types above */ - -static struct _randomjunk { - int degrees[MAX_TYPES]; - int seps[MAX_TYPES]; - long randtbl[ DEG_3 + 1 ]; -/* - * fptr and rptr are two pointers into the state info, a front and a rear - * pointer. These two pointers are always rand_sep places aparts, as they cycle - * cyclically through the state information. (Yes, this does mean we could get - * away with just one pointer, but the code for random() is more efficient this - * way). The pointers are left positioned as they would be from the call - * initstate(1, randtbl, 128) - * (The position of the rear pointer, rptr, is really 0 (as explained above - * in the initialization of randtbl) because the state table pointer is set - * to point to randtbl[1] (as explained below). - */ - long *fptr, *rptr; -/* - * The following things are the pointer to the state information table, - * the type of the current generator, the degree of the current polynomial - * being used, and the separation between the two pointers. - * Note that for efficiency of random(), we remember the first location of - * the state information, not the zeroeth. Hence it is valid to access - * state[-1], which is used to store the type of the R.N.G. - * Also, we remember the last location, since this is more efficient than - * indexing every time to find the address of the last element to see if - * the front and rear pointers have wrapped. - */ - long *state; - int rand_type, rand_deg, rand_sep; - long *end_ptr; -} *__randomjunk, *_randomjunk(void), _randominit = { - /* - * Initially, everything is set up as if from : - * initstate(1, &randtbl, 128); - * Note that this initialization takes advantage of the fact - * that srandom() advances the front and rear pointers 10*rand_deg - * times, and hence the rear pointer which starts at 0 will also - * end up at zero; thus the zeroeth element of the state - * information, which contains info about the current - * position of the rear pointer is just - * MAX_TYPES*(rptr - state) + TYPE_3 == TYPE_3. - */ - { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 }, - { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 }, - { TYPE_3, - (long)0x9a319039, (long)0x32d9c024, (long)0x9b663182, (long)0x5da1f342, - (long)0xde3b81e0, (long)0xdf0a6fb5, (long)0xf103bc02, (long)0x48f340fb, - (long)0x7449e56b, (long)0xbeb1dbb0, (long)0xab5c5918, (long)0x946554fd, - (long)0x8c2e680f, (long)0xeb3d799f, (long)0xb11ee0b7, (long)0x2d436b86, - (long)0xda672e2a, (long)0x1588ca88, (long)0xe369735d, (long)0x904f35f7, - (long)0xd7158fd6, (long)0x6fa6f051, (long)0x616e6b96, (long)0xac94efdc, - (long)0x36413f93, (long)0xc622c298, (long)0xf5a42ab8, (long)0x8a88d77b, - (long)0xf5ad9d0e, (long)0x8999220b, (long)0x27fb47b9 }, - &_randominit.randtbl[ SEP_3 + 1 ], - &_randominit.randtbl[1], - &_randominit.randtbl[1], - TYPE_3, DEG_3, SEP_3, - &_randominit.randtbl[ DEG_3 + 1] -}; - -long random(void); - -static struct _randomjunk * -_randomjunk(void) -{ - struct _randomjunk *rp = __randomjunk; - - if (rp == 0) { - rp = (struct _randomjunk *)malloc(sizeof (*rp)); - if (rp == 0) - return (0); - *rp = _randominit; - __randomjunk = rp; - } - return (rp); -} - -/* - * srandom: - * Initialize the random number generator based on the given seed. If the - * type is the trivial no-state-information type, just remember the seed. - * Otherwise, initializes state[] based on the given "seed" via a linear - * congruential generator. Then, the pointers are set to known locations - * that are exactly rand_sep places apart. Lastly, it cycles the state - * information a given number of times to get rid of any initial dependencies - * introduced by the L.C.R.N.G. - * Note that the initialization of randtbl[] for default usage relies on - * values produced by this routine. - */ - -void -srandom(unsigned x) -{ - struct _randomjunk *rp = _randomjunk(); - int i; - - if (rp == 0) - return; - if (rp->rand_type == TYPE_0) { - rp->state[0] = x; - } else { - rp->state[0] = x; - for (i = 1; i < rp->rand_deg; i++) { - rp->state[i] = 1103515245*rp->state[i - 1] + 12345; - } - rp->fptr = &rp->state[rp->rand_sep]; - rp->rptr = &rp->state[0]; - for (i = 0; i < 10 * rp->rand_deg; i++) - random(); - } -} - - - -/* - * initstate: - * Initialize the state information in the given array of n bytes for - * future random number generation. Based on the number of bytes we - * are given, and the break values for the different R.N.G.'s, we choose - * the best (largest) one we can and set things up for it. srandom() is - * then called to initialize the state information. - * Note that on return from srandom(), we set state[-1] to be the type - * multiplexed with the current value of the rear pointer; this is so - * successive calls to initstate() won't lose this information and will - * be able to restart with setstate(). - * Note: the first thing we do is save the current state, if any, just like - * setstate() so that it doesn't matter when initstate is called. - * Returns a pointer to the old state. - * - * Arguments: - * seed: seed for R. N. G. - * arg_state: pointer to state array - * n: # bytes of state info - */ - -char * -initstate(unsigned seed, char *arg_state, int n) -{ - struct _randomjunk *rp = _randomjunk(); - char *ostate; - - if (rp == 0) - return (0); - ostate = (char *)(&rp->state[-1]); - - if (rp->rand_type == TYPE_0) rp->state[-1] = rp->rand_type; - else rp->state[-1] = - MAX_TYPES*(rp->rptr - rp->state) + rp->rand_type; - if (n < BREAK_0) { - fprintf(stderr, - "initstate: state array too small, ignored; minimum size is %d bytes\n", - BREAK_0); - return (0); - } else if (n < BREAK_1) { - rp->rand_type = TYPE_0; - rp->rand_deg = DEG_0; - rp->rand_sep = SEP_0; - } else if (n < BREAK_2) { - rp->rand_type = TYPE_1; - rp->rand_deg = DEG_1; - rp->rand_sep = SEP_1; - } else if (n < BREAK_3) { - rp->rand_type = TYPE_2; - rp->rand_deg = DEG_2; - rp->rand_sep = SEP_2; - } else if (n < BREAK_4) { - rp->rand_type = TYPE_3; - rp->rand_deg = DEG_3; - rp->rand_sep = SEP_3; - } else { - rp->rand_type = TYPE_4; - rp->rand_deg = DEG_4; - rp->rand_sep = SEP_4; - } - rp->state = &((long *)arg_state)[1]; /* first location */ - rp->end_ptr = &rp->state[rp->rand_deg]; /* set end_ptr before srandom */ - srandom(seed); - rp->state[-1] = (rp->rand_type == TYPE_0) ? rp->rand_type - : MAX_TYPES * (rp->rptr - rp->state) + rp->rand_type; - return (ostate); -} - - -/* - * setstate: - * Restore the state from the given state array. - * Note: it is important that we also remember the locations of the pointers - * in the current state information, and restore the locations of the pointers - * from the old state information. This is done by multiplexing the pointer - * location into the zeroeth word of the state information. - * Note that due to the order in which things are done, it is OK to call - * setstate() with the same state as the current state. - * Returns a pointer to the old state information. - */ - -char * -setstate(char *arg_state) -{ - struct _randomjunk *rp = _randomjunk(); - long *new_state; - int type; - int rear; - char *ostate; - - if (rp == 0) - return (0); - new_state = (long *)arg_state; - type = new_state[0] % MAX_TYPES; - rear = new_state[0] / MAX_TYPES; - ostate = (char *)(&rp->state[-1]); - - rp->state[-1] = (rp->rand_type == TYPE_0) ? rp->rand_type - : MAX_TYPES*(rp->rptr - rp->state) + rp->rand_type; - switch (type) { - case TYPE_0: - case TYPE_1: - case TYPE_2: - case TYPE_3: - case TYPE_4: - rp->rand_type = type; - rp->rand_deg = rp->degrees[type]; - rp->rand_sep = rp->seps[type]; - break; - - default: - fprintf(stderr, "setstate: invalid state info; not changed.\n"); - } - rp->state = &new_state[1]; - if (rp->rand_type != TYPE_0) { - rp->rptr = &rp->state[rear]; - rp->fptr = &rp->state[(rear + rp->rand_sep) % rp->rand_deg]; - } - rp->end_ptr = &rp->state[rp->rand_deg]; /* set end_ptr too */ - return (ostate); -} - - -/* - * random: - * If we are using the trivial TYPE_0 R.N.G., just do the old linear - * congruential bit. Otherwise, we do our fancy trinomial stuff, which is the - * same in all ther other cases due to all the global variables that have been - * set up. The basic operation is to add the number at the rear pointer into - * the one at the front pointer. Then both pointers are advanced to the next - * location cyclically in the table. The value returned is the sum generated, - * reduced to 31 bits by throwing away the "least random" low bit. - * Note: the code takes advantage of the fact that both the front and - * rear pointers can't wrap on the same call by not testing the rear - * pointer if the front one has wrapped. - * Returns a 31-bit random number. - */ - -long -random(void) -{ - struct _randomjunk *rp = _randomjunk(); - long i; - - if (rp == 0) - return (0); - if (rp->rand_type == TYPE_0) { - i = rp->state[0] = (rp->state[0]*1103515245 + 12345)&0x7fffffff; - } else { - *rp->fptr += *rp->rptr; - i = (*rp->fptr >> 1)&0x7fffffff; /* chucking least random bit */ - if (++rp->fptr >= rp->end_ptr) { - rp->fptr = rp->state; - ++rp->rptr; - } else if (++rp->rptr >= rp->end_ptr) - rp->rptr = rp->state; - } - return (i); -} |