206 lines
4.9 KiB
C
206 lines
4.9 KiB
C
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Note: keep project includes in alphabetical order...
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdarg.h>
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#include "stdlib/random/base.h"
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#include "stdlib/random/base/minstd.h"
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#include "stdlib/random/base/minstd_shuffle.h"
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#include "stdlib/random/base/mt19937.h"
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#include "stdlib/random/base/randu.h"
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// Define the default PRNG:
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static const enum STDLIB_BASE_RANDOM_RANDU_PRNG STDLIB_BASE_RANDOM_RANDU_DEFAULT = STDLIB_BASE_RANDOM_RANDU_MT19937;
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/**
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* Returns a pointer to a dynamically allocated PRNG.
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*
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* ## Notes
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*
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* - The user is responsible for freeing the allocated memory.
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*
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* @param nargs number of provided optional arguments
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* @param [prng] PRNG to allocate
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* @param [seed] PRNG seed
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* @param [len] seed array length
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* @return pointer to a dynamically allocated PRNG or, if unable to allocate memory, a null pointer
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*
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* @example
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* #include <stdlib.h>
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* #include <stdio.h>
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* #include <stdint.h>
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* #include "stdlib/random/base.h"
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* #include "stdlib/random/base/randu.h"
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*
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* // Create a PRNG:
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* struct BasePRNGObject *obj = stdlib_base_random_randu_allocate( 0 );
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* if ( obj == NULL ) {
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* fprintf( stderr, "Error allocating PRNG.\n" );
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* exit( 1 );
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* }
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*
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* double r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* // Free allocated memory:
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* stdlib_base_random_randu_free( obj );
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*/
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struct BasePRNGObject * stdlib_base_random_randu_allocate( const int nargs, ... ) {
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enum STDLIB_BASE_RANDOM_RANDU_PRNG prng;
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struct BasePRNGObject *obj;
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va_list args;
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va_start( args, nargs );
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if ( nargs < 1 ) {
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prng = STDLIB_BASE_RANDOM_RANDU_DEFAULT;
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} else {
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prng = va_arg( args, enum STDLIB_BASE_RANDOM_RANDU_PRNG );
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}
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if ( prng == STDLIB_BASE_RANDOM_RANDU_MINSTD ) {
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int32_t seed;
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if ( nargs > 1 ) {
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seed = va_arg( args, int32_t );
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} else {
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seed = rand();
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}
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obj = stdlib_base_random_minstd_allocate( seed );
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} else if ( prng == STDLIB_BASE_RANDOM_RANDU_MINSTD_SHUFFLE ) {
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int32_t seed;
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if ( nargs > 1 ) {
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seed = va_arg( args, int32_t );
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} else {
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seed = rand();
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}
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obj = stdlib_base_random_minstd_shuffle_allocate( seed );
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} else if ( prng == STDLIB_BASE_RANDOM_RANDU_MT19937 ) {
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int64_t seed_length;
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uint32_t *seed;
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if ( nargs < 2 ) {
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uint32_t tseed[] = { (uint32_t)rand() };
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seed = tseed;
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seed_length = 1;
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} else if ( nargs == 3 ) {
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seed = va_arg( args, uint32_t * );
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seed_length = va_arg( args, int64_t );
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} else {
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// Incompatible number of arguments...
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va_end( args );
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return NULL;
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}
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obj = stdlib_base_random_mt19937_allocate( seed, seed_length );
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} else {
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// How did we get here? A non-implemented PRNG?
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obj = NULL;
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}
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va_end( args );
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return obj;
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}
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/**
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* Returns a pseudorandom double-precision floating-point number on the interval `[0,1)`.
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*
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* ## Notes
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*
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* - The function returns `NAN` if provided a `NULL` pointer.
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*
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* @param obj PRNG object
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* @return pseudorandom number
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*
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* @example
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* #include <stdlib.h>
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* #include <stdio.h>
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* #include <stdint.h>
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* #include "stdlib/random/base.h"
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* #include "stdlib/random/base/randu.h"
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*
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* // Create a PRNG:
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* struct BasePRNGObject *obj = stdlib_base_random_randu_allocate( 0 );
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* if ( obj == NULL ) {
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* fprintf( stderr, "Error allocating PRNG.\n" );
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* exit( 1 );
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* }
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*
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* double r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* // Free allocated memory:
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* stdlib_base_random_randu_free( obj );
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*/
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double stdlib_base_random_randu( struct BasePRNGObject *obj ) {
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return stdlib_base_prng_normalized( obj );
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}
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/**
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* Frees a PRNG's allocated memory.
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*
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* @param obj PRNG object
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*
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* @example
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* #include <stdlib.h>
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* #include <stdio.h>
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* #include <stdint.h>
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* #include "stdlib/random/base.h"
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* #include "stdlib/random/base/randu.h"
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*
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* // Create a PRNG:
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* struct BasePRNGObject *obj = stdlib_base_random_randu_allocate( 0 );
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* if ( obj == NULL ) {
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* fprintf( stderr, "Error allocating PRNG.\n" );
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* exit( 1 );
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* }
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*
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* double r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* r = stdlib_base_random_randu( obj );
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*
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* // ...
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*
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* // Free allocated memory:
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* stdlib_base_random_randu_free( obj );
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*/
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void stdlib_base_random_randu_free( struct BasePRNGObject *obj ) {
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stdlib_base_prng_free( obj );
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}
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