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stdlib.hfa @ 3ee8853

Last change on this file since 3ee8853 was 5f31bf0, checked in by Peter A. Buhr <pabuhr@…>, 14 months ago
simplify 32/64-bit random-number constructors
Property mode set to `100644`
File size: 20.7 KB

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1	//
2	// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// stdlib --
8	//
9	// Author : Peter A. Buhr
10	// Created On : Thu Jan 28 17:12:35 2016
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Sat Sep 2 18:29:35 2023
13	// Update Count : 780
14	//
15
16	#pragma once
17
18	#include "bits/defs.hfa" // OPTIONAL_THREAD
19	#include "bits/align.hfa" // libAlign
20	#include "bits/random.hfa" // prng
21	#include <Exception.hfa>
22	#include <heap.hfa>
23
24	#include <stdlib.h> // alloc, strto, ato*
25	#include <errno.h>
26
27	// Reduce includes by explicitly defining these routines.
28	extern "C" {
29	void * memalign( size_t alignment, size_t size ); // malloc.h
30	void * pvalloc( size_t size ); // malloc.h
31	void * memset( void * dest, int fill, size_t size ); // string.h
32	void * memcpy( void * dest, const void * src, size_t size ); // string.h
33	} // extern "C"
34
35	//---------------------------------------
36
37	#ifndef EXIT_FAILURE
38	#define EXIT_FAILURE 1 // failing exit status
39	#define EXIT_SUCCESS 0 // successful exit status
40	#endif // ! EXIT_FAILURE
41
42	//---------------------------------------
43
44	#include "common.hfa"
45
46	//---------------------------------------
47
48	static inline forall( T & \| sized(T) ) {
49	// CFA safe equivalents, i.e., implicit size specification
50
51	T * malloc( void ) {
52	if ( _Alignof(T) <= libAlign() ) return (T *)malloc( sizeof(T) ); // C allocation
53	else return (T *)memalign( _Alignof(T), sizeof(T) );
54	} // malloc
55
56	T * aalloc( size_t dim ) {
57	if ( _Alignof(T) <= libAlign() ) return (T *)aalloc( dim, sizeof(T) ); // C allocation
58	else return (T *)amemalign( _Alignof(T), dim, sizeof(T) );
59	} // aalloc
60
61	T * calloc( size_t dim ) {
62	if ( _Alignof(T) <= libAlign() ) return (T *)calloc( dim, sizeof(T) ); // C allocation
63	else return (T *)cmemalign( _Alignof(T), dim, sizeof(T) );
64	} // calloc
65
66	T * resize( T * ptr, size_t size ) { // CFA resize, eliminate return-type cast
67	if ( _Alignof(T) <= libAlign() ) return (T )resize( (void )ptr, size ); // CFA resize
68	else return (T )resize( (void )ptr, _Alignof(T), size ); // CFA resize
69	} // resize
70
71	T * realloc( T * ptr, size_t size ) { // CFA realloc, eliminate return-type cast
72	if ( _Alignof(T) <= libAlign() ) return (T )realloc( (void )ptr, size ); // C realloc
73	else return (T )realloc( (void )ptr, _Alignof(T), size ); // CFA realloc
74	} // realloc
75
76	T * memalign( size_t align ) {
77	return (T *)memalign( align, sizeof(T) ); // C memalign
78	} // memalign
79
80	T * amemalign( size_t align, size_t dim ) {
81	return (T *)amemalign( align, dim, sizeof(T) ); // CFA amemalign
82	} // amemalign
83
84	T * cmemalign( size_t align, size_t dim ) {
85	return (T *)cmemalign( align, dim, sizeof(T) ); // CFA cmemalign
86	} // cmemalign
87
88	T * aligned_alloc( size_t align ) {
89	return (T *)aligned_alloc( align, sizeof(T) ); // C aligned_alloc
90	} // aligned_alloc
91
92	int posix_memalign( T ** ptr, size_t align ) {
93	return posix_memalign( (void **)ptr, align, sizeof(T) ); // C posix_memalign
94	} // posix_memalign
95
96	T * valloc( void ) {
97	return (T *)valloc( sizeof(T) ); // C valloc
98	} // valloc
99
100	T * pvalloc( void ) {
101	return (T *)pvalloc( sizeof(T) ); // C pvalloc
102	} // pvalloc
103	} // distribution
104
105	/*
106	FIX ME : fix alloc interface after Ticker Number 214 is resolved, define and add union to S_fill. Then, modify postfix-fill functions to support T * with nmemb, char, and T object of any size. Finally, change alloc_internal.
107	Or, just follow the instructions below for that.
108
109	1. Replace the current forall-block that contains defintions of S_fill and S_realloc with following:
110	forall( T & \| sized(T) ) {
111	union U_fill { char c; T * a; T t; };
112	struct S_fill { char tag; U_fill(T) fill; };
113	struct S_realloc { inline T *; };
114	}
115
116	2. Replace all current postfix-fill functions with following for updated S_fill:
117	S_fill(T) ?`fill( char a ) { S_fill(T) ret = {'c'}; ret.fill.c = a; return ret; }
118	S_fill(T) ?`fill( T a ) { S_fill(T) ret = {'t'}; memcpy(&ret.fill.t, &a, sizeof(T)); return ret; }
119	S_fill(T) ?`fill( T a[], size_t nmemb ) { S_fill(T) ret = {'a', nmemb}; ret.fill.a = a; return ret; }
120
121	3. Replace the alloc_internal$ function which is outside ttype forall-block with following function:
122	T * alloc_internal$( void * Resize, T * Realloc, size_t Align, size_t Dim, S_fill(T) Fill) {
123	T * ptr = NULL;
124	size_t size = sizeof(T);
125	size_t copy_end = 0;
126
127	if(Resize) {
128	ptr = (T) (void ) resize( (int )Resize, Align, Dim size );
129	} else if (Realloc) {
130	if (Fill.tag != '0') copy_end = min(malloc_size( Realloc ), Dim * size);
131	ptr = (T) (void ) realloc( (int )Realloc, Align, Dim size );
132	} else {
133	ptr = (T) (void ) memalign( Align, Dim * size );
134	}
135
136	if(Fill.tag == 'c') {
137	memset( (char )ptr + copy_end, (int)Fill.fill.c, Dim size - copy_end );
138	} else if(Fill.tag == 't') {
139	for ( int i = copy_end; i <= Dim * size - size ; i += size ) {
140	memcpy( (char *)ptr + i, &Fill.fill.t, size );
141	}
142	} else if(Fill.tag == 'a') {
143	memcpy( (char )ptr + copy_end, Fill.fill.a, min(Dim size - copy_end, size * Fill.nmemb) );
144	}
145
146	return ptr;
147	} // alloc_internal$
148	*/
149
150	typedef struct S_align { inline size_t; } T_align;
151	typedef struct S_resize { inline void *; } T_resize;
152
153	forall( T & ) {
154	struct S_fill { char tag; char c; size_t size; T * at; char t[50]; };
155	struct S_realloc { inline T *; };
156	}
157
158	static inline T_align ?`align ( size_t a ) { return (T_align){a}; }
159	static inline T_resize ?`resize ( void * a ) { return (T_resize){a}; }
160
161	static inline forall( T & \| sized(T) ) {
162	S_fill(T) ?`fill ( T t ) {
163	S_fill(T) ret = { 't' };
164	size_t size = sizeof(T);
165	if ( size > sizeof(ret.t) ) {
166	abort( "ERROR: const object of size greater than 50 bytes given for dynamic memory fill\n" );
167	} // if
168	memcpy( &ret.t, &t, size );
169	return ret;
170	}
171	S_fill(T) ?`fill ( zero_t ) = void; // FIX ME: remove this once ticket 214 is resolved
172	S_fill(T) ?`fill ( T * a ) { return (S_fill(T)){ 'T', '0', 0, a }; } // FIX ME: remove this once ticket 214 is resolved
173	S_fill(T) ?`fill ( char c ) { return (S_fill(T)){ 'c', c }; }
174	S_fill(T) ?`fill ( T a[], size_t nmemb ) { return (S_fill(T)){ 'a', '0', nmemb * sizeof(T), a }; }
175
176	S_realloc(T) ?`realloc ( T * a ) { return (S_realloc(T)){a}; }
177
178	T * alloc_internal$( void * Resize, T * Realloc, size_t Align, size_t Dim, S_fill(T) Fill ) {
179	T * ptr = NULL;
180	size_t size = sizeof(T);
181	size_t copy_end = 0;
182
183	if ( Resize ) {
184	ptr = (T) (void ) resize( (void )Resize, Align, Dim size );
185	} else if ( Realloc ) {
186	if ( Fill.tag != '0' ) copy_end = min(malloc_size( Realloc ), Dim * size );
187	ptr = (T ) (void ) realloc( (void )Realloc, Align, Dim size );
188	} else {
189	ptr = (T ) (void ) memalign( Align, Dim * size );
190	}
191
192	if ( Fill.tag == 'c' ) {
193	memset( (char )ptr + copy_end, (int)Fill.c, Dim size - copy_end );
194	} else if ( Fill.tag == 't' ) {
195	for ( i; copy_end ~ Dim * size ~ size ) {
196	#pragma GCC diagnostic push
197	#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
198	assert( size <= sizeof(Fill.t) );
199	memcpy( (char *)ptr + i, &Fill.t, size );
200	#pragma GCC diagnostic pop
201	}
202	} else if ( Fill.tag == 'a' ) {
203	memcpy( (char )ptr + copy_end, Fill.at, min(Dim size - copy_end, Fill.size) );
204	} else if ( Fill.tag == 'T' ) {
205	memcpy( (char )ptr + copy_end, Fill.at, Dim size );
206	}
207
208	return ptr;
209	} // alloc_internal$
210
211	forall( TT... \| { T * alloc_internal$( void , T , size_t, size_t, S_fill(T), TT ); } ) {
212	T * alloc_internal$( void , T , size_t Align, size_t Dim, S_fill(T) Fill, T_resize Resize, TT rest ) {
213	return alloc_internal$( Resize, (T*)0p, Align, Dim, Fill, rest);
214	}
215
216	T * alloc_internal$( void , T , size_t Align, size_t Dim, S_fill(T) Fill, S_realloc(T) Realloc, TT rest ) {
217	return alloc_internal$( (void*)0p, Realloc, Align, Dim, Fill, rest);
218	}
219
220	T * alloc_internal$( void * Resize, T * Realloc, size_t, size_t Dim, S_fill(T) Fill, T_align Align, TT rest ) {
221	return alloc_internal$( Resize, Realloc, Align, Dim, Fill, rest);
222	}
223
224	T * alloc_internal$( void * Resize, T * Realloc, size_t Align, size_t Dim, S_fill(T), S_fill(T) Fill, TT rest ) {
225	return alloc_internal$( Resize, Realloc, Align, Dim, Fill, rest );
226	}
227
228	T * alloc( TT all ) {
229	return alloc_internal$( (void)0p, (T)0p, (_Alignof(T) > libAlign() ? _Alignof(T) : libAlign()), (size_t)1, (S_fill(T)){'0'}, all );
230	}
231
232	T * alloc( size_t dim, TT all ) {
233	return alloc_internal$( (void)0p, (T)0p, (_Alignof(T) > libAlign() ? _Alignof(T) : libAlign()), dim, (S_fill(T)){'0'}, all );
234	}
235	} // distribution TT
236	} // distribution T
237
238	static inline forall( T & \| sized(T) ) {
239	// CFA safe initialization/copy, i.e., implicit size specification, non-array types
240	T * memset( T * dest, char fill ) {
241	return (T *)memset( dest, fill, sizeof(T) );
242	} // memset
243
244	T * memcpy( T * dest, const T * src ) {
245	return (T *)memcpy( dest, src, sizeof(T) );
246	} // memcpy
247
248	// CFA safe initialization/copy, i.e., implicit size specification, array types
249	T * amemset( T dest[], char fill, size_t dim ) {
250	return (T )(void )memset( dest, fill, dim * sizeof(T) ); // C memset
251	} // amemset
252
253	T * amemcpy( T dest[], const T src[], size_t dim ) {
254	return (T )(void )memcpy( dest, src, dim * sizeof(T) ); // C memcpy
255	} // amemcpy
256	} // distribution
257
258	// CFA deallocation for multiple objects
259	static inline forall( T & ) // FIX ME, problems with 0p in list
260	void free( T * ptr ) {
261	free( (void *)ptr ); // C free
262	} // free
263	static inline forall( T &, TT... \| { void free( TT ); } )
264	void free( T * ptr, TT rest ) {
265	free( ptr );
266	free( rest );
267	} // free
268
269	// CFA allocation/deallocation and constructor/destructor, non-array types
270	static inline forall( T & \| sized(T), TT... \| { void ?{}( T &, TT ); } )
271	T * new( TT p ) {
272	return &((T )malloc()){ p }; // run constructor
273	} // new
274
275	static inline forall( T & \| { void ^?{}( T & ); } )
276	void delete( T * ptr ) {
277	// special case for 0-sized object => always call destructor
278	if ( ptr \|\| sizeof(ptr) == 0 ) { // ignore null but not 0-sized objects
279	^(*ptr){}; // run destructor
280	} // if
281	free( ptr ); // always call free
282	} // delete
283	static inline forall( T &, TT... \| { void ^?{}( T & ); void delete( TT ); } )
284	void delete( T * ptr, TT rest ) {
285	delete( ptr );
286	delete( rest );
287	} // delete
288
289	// CFA allocation/deallocation and constructor/destructor, array types
290	forall( T & \| sized(T), TT... \| { void ?{}( T &, TT ); } ) T * anew( size_t dim, TT p );
291	forall( T & \| sized(T) \| { void ^?{}( T & ); } ) void adelete( T arr[] );
292	forall( T & \| sized(T) \| { void ^?{}( T & ); }, TT... \| { void adelete( TT ); } ) void adelete( T arr[], TT rest );
293
294	//---------------------------------------
295
296	static inline {
297	int strto( const char sptr[], char * eptr[], int base ) { return (int)strtol( sptr, eptr, base ); }
298	unsigned int strto( const char sptr[], char * eptr[], int base ) { return (unsigned int)strtoul( sptr, eptr, base ); }
299	long int strto( const char sptr[], char * eptr[], int base ) { return strtol( sptr, eptr, base ); }
300	unsigned long int strto( const char sptr[], char * eptr[], int base ) { return strtoul( sptr, eptr, base ); }
301	long long int strto( const char sptr[], char * eptr[], int base ) { return strtoll( sptr, eptr, base ); }
302	unsigned long long int strto( const char sptr[], char * eptr[], int base ) { return strtoull( sptr, eptr, base ); }
303
304	float strto( const char sptr[], char * eptr[] ) { return strtof( sptr, eptr ); }
305	double strto( const char sptr[], char * eptr[] ) { return strtod( sptr, eptr ); }
306	long double strto( const char sptr[], char * eptr[] ) { return strtold( sptr, eptr ); }
307	} // distribution
308
309	float _Complex strto( const char sptr[], char * eptr[] );
310	double _Complex strto( const char sptr[], char * eptr[] );
311	long double _Complex strto( const char sptr[], char * eptr[] );
312
313	ExceptionDecl( out_of_range );
314	ExceptionDecl( invalid_argument );
315
316	forall( T \| { T strto( const char sptr[], char * eptr[], int ); } )
317	T convert( const char sptr[] );
318
319	static inline {
320	int ato( const char sptr[] ) { return (int)strtol( sptr, 0p, 10 ); }
321	unsigned int ato( const char sptr[] ) { return (unsigned int)strtoul( sptr, 0p, 10 ); }
322	long int ato( const char sptr[] ) { return strtol( sptr, 0p, 10 ); }
323	unsigned long int ato( const char sptr[] ) { return strtoul( sptr, 0p, 10 ); }
324	long long int ato( const char sptr[] ) { return strtoll( sptr, 0p, 10 ); }
325	unsigned long long int ato( const char sptr[] ) { return strtoull( sptr, 0p, 10 ); }
326
327	float ato( const char sptr[] ) { return strtof( sptr, 0p ); }
328	double ato( const char sptr[] ) { return strtod( sptr, 0p ); }
329	long double ato( const char sptr[] ) { return strtold( sptr, 0p ); }
330
331	float _Complex ato( const char sptr[] ) { return strto( sptr, 0p ); }
332	double _Complex ato( const char sptr[] ) { return strto( sptr, 0p ); }
333	long double _Complex ato( const char sptr[] ) { return strto( sptr, 0p ); }
334	} // distribution
335
336	//---------------------------------------
337
338	forall( E \| { int ?<?( E, E ); } ) {
339	E * bsearch( E key, const E * vals, size_t dim );
340	size_t bsearch( E key, const E * vals, size_t dim );
341	E * bsearchl( E key, const E * vals, size_t dim );
342	size_t bsearchl( E key, const E * vals, size_t dim );
343	E * bsearchu( E key, const E * vals, size_t dim );
344	size_t bsearchu( E key, const E * vals, size_t dim );
345	} // distribution
346
347	forall( K, E \| { int ?<?( K, K ); K getKey( const E & ); } ) {
348	E * bsearch( K key, const E * vals, size_t dim );
349	size_t bsearch( K key, const E * vals, size_t dim );
350	E * bsearchl( K key, const E * vals, size_t dim );
351	size_t bsearchl( K key, const E * vals, size_t dim );
352	E * bsearchu( K key, const E * vals, size_t dim );
353	size_t bsearchu( K key, const E * vals, size_t dim );
354	} // distribution
355
356	forall( E \| { int ?<?( E, E ); } ) {
357	void qsort( E * vals, size_t dim );
358	} // distribution
359
360	//---------------------------------------
361
362	extern "C" { // override C version
363	void srandom( unsigned int seed );
364	long int random( void ); // GENERATES POSITIVE AND NEGATIVE VALUES
365	// For positive values, use unsigned int, e.g., unsigned int r = random() % 100U;
366	} // extern "C"
367
368	static inline {
369	long int random( long int l, long int u ) { if ( u < l ) [u, l] = [l, u]; return lrand48() % (u - l + 1) + l; } // [l,u]
370	long int random( long int u ) { return random( 0, u - 1 ); } // [0,u)
371	unsigned long int random( void ) { return lrand48(); }
372	unsigned long int random( unsigned long int u ) { return lrand48() % u; } // [0,u)
373	unsigned long int random( unsigned long int l, unsigned long int u ) { if ( u < l ) [u, l] = [l, u]; return lrand48() % (u - l + 1) + l; } // [l,u]
374
375	char random( void ) { return (unsigned long int)random(); }
376	char random( char u ) { return (unsigned long int)random( (unsigned long int)u ); } // [0,u)
377	char random( char l, char u ) { return random( (unsigned long int)l, (unsigned long int)u ); } // [l,u)
378	int random( void ) { return (long int)random(); }
379	int random( int u ) { return (long int)random( (long int)u ); } // [0,u]
380	int random( int l, int u ) { return random( (long int)l, (long int)u ); } // [l,u)
381	unsigned int random( void ) { return (unsigned long int)random(); }
382	unsigned int random( unsigned int u ) { return (unsigned long int)random( (unsigned long int)u ); } // [0,u]
383	unsigned int random( unsigned int l, unsigned int u ) { return random( (unsigned long int)l, (unsigned long int)u ); } // [l,u)
384	} // distribution
385
386	float random( void ); // [0.0, 1.0)
387	double random( void ); // [0.0, 1.0)
388	float _Complex random( void ); // [0.0, 1.0)+[0.0, 1.0)i
389	double _Complex random( void ); // [0.0, 1.0)+[0.0, 1.0)i
390	long double _Complex random( void ); // [0.0, 1.0)+[0.0, 1.0)i
391
392	//---------------------------------------
393
394	// Sequential Pseudo Random-Number Generator : generate repeatable sequence of values that appear random.
395	//
396	// Declaration :
397	// PRNG sprng = { 1009 } - set starting seed versus random seed
398	//
399	// Interface :
400	// set_seed( sprng, 1009 ) - set starting seed for ALL kernel threads versus random seed
401	// get_seed( sprng ) - read seed
402	// prng( sprng ) - generate random value in range [0,UINT_MAX]
403	// prng( sprng, u ) - generate random value in range [0,u)
404	// prng( sprng, l, u ) - generate random value in range [l,u]
405	// calls( sprng ) - number of generated random value so far
406	//
407	// Examples : generate random number between 5-21
408	// prng( sprng ) % 17 + 5; values 0-16 + 5 = 5-21
409	// prng( sprng, 16 + 1 ) + 5;
410	// prng( sprng, 5, 21 );
411	// calls( sprng );
412
413	forall( PRNG &, R )
414	trait basic_prng {
415	void set_seed( PRNG & prng, R seed ); // set seed
416	R get_seed( PRNG & prng ); // get seed
417	R prng( PRNG & prng );
418	void ?{}( PRNG & prng ); // random seed
419	void ?{}( PRNG & prng, R seed ); // fixed seed
420	}; // basic_prng
421
422	static inline forall( PRNG &, R \| basic_prng( PRNG, R ) \| { R ?%?( R, R ); } ) {
423	R prng( PRNG & prng, R u ) { return prng( prng ) % u; } // [0,u)
424	}
425	static inline forall( PRNG &, R \| basic_prng( PRNG, R ) \| { R ?+?( R, R ); R ?-?( R, R ); R ?%?( R, R ); void ?{}( R &, one_t ); } ) {
426	R prng( PRNG & prng, R l, R u ) { return prng( prng, u - l + (R){1} ) + l; } // [l,u]
427	}
428
429	struct PRNG32 {
430	uint32_t callcnt; // call count
431	uint32_t seed; // current seed
432	PRNG_STATE_32_T state; // random state
433	}; // PRNG
434
435	static inline {
436	void set_seed( PRNG32 & prng, uint32_t seed_ ) with( prng ) { seed = seed_; PRNG_SET_SEED_32( state, seed ); }
437	uint32_t get_seed( PRNG32 & prng ) __attribute__(( warn_unused_result )) with( prng ) { return seed; }
438	void ?{}( PRNG32 & prng, uint32_t seed ) with( prng ) { callcnt = 0; set_seed( prng, seed ); } // fixed seed
439	void ?{}( PRNG32 & prng ) with( prng ) { ?{}( prng, rdtscl() ); } // random seed
440	uint32_t prng( PRNG32 & prng ) __attribute__(( warn_unused_result )) with( prng ) { callcnt += 1; return PRNG_NAME_32( state ); } // [0,UINT_MAX]
441	uint32_t prng( PRNG32 & prng, uint32_t u ) __attribute__(( warn_unused_result )) { return prng( prng ) % u; } // [0,u)
442	uint32_t prng( PRNG32 & prng, uint32_t l, uint32_t u ) __attribute__(( warn_unused_result )) { return prng( prng, u - l + 1 ) + l; } // [l,u]
443	uint32_t calls( PRNG32 & prng ) __attribute__(( warn_unused_result )) with( prng ) { return callcnt; }
444	} // distribution
445
446	struct PRNG64 {
447	uint64_t callcnt; // call count
448	uint64_t seed; // current seed
449	PRNG_STATE_64_T state; // random state
450	}; // PRNG
451
452	static inline {
453	void set_seed( PRNG64 & prng, uint64_t seed_ ) with( prng ) { seed = seed_; PRNG_SET_SEED_64( state, seed ); }
454	uint64_t get_seed( PRNG64 & prng ) __attribute__(( warn_unused_result )) with( prng ) { return seed; }
455	void ?{}( PRNG64 & prng, uint64_t seed ) with( prng ) { callcnt = 0; set_seed( prng, seed ); } // fixed seed
456	void ?{}( PRNG64 & prng ) with( prng ) { ?{}( prng, rdtscl() ); } // random seed
457	uint64_t prng( PRNG64 & prng ) __attribute__(( warn_unused_result )) with( prng ) { callcnt += 1; return PRNG_NAME_64( state ); } // [0,UINT_MAX]
458	uint64_t prng( PRNG64 & prng, uint64_t u ) __attribute__(( warn_unused_result )) { return prng( prng ) % u; } // [0,u)
459	uint64_t prng( PRNG64 & prng, uint64_t l, uint64_t u ) __attribute__(( warn_unused_result )) { return prng( prng, u - l + 1 ) + l; } // [l,u]
460	uint64_t calls( PRNG64 & prng ) __attribute__(( warn_unused_result )) with( prng ) { return callcnt; }
461	} // distribution
462
463	// Set default random-generator size.
464	#if defined( __x86_64__ ) \|\| defined( __aarch64__ ) // 64-bit architecture
465	#define PRNG PRNG64
466	#else // 32-bit architecture
467	#define PRNG PRNG32
468	#endif // __x86_64__
469
470	// Concurrent Pseudo Random-Number Generator : generate repeatable sequence of values that appear random.
471	//
472	// Interface :
473	// set_seed( 1009 ) - fixed seed for all kernel threads versus random seed
474	// get_seed() - read seed
475	// prng() - generate random value in range [0,UINT_MAX]
476	// prng( u ) - generate random value in range [0,u)
477	// prng( l, u ) - generate random value in range [l,u]
478	//
479	// Examples : generate random number between 5-21
480	// prng() % 17 + 5; values 0-16 + 5 = 5-21
481	// prng( 16 + 1 ) + 5;
482	// prng( 5, 21 );
483
484	// Harmonize with concurrency/thread.hfa.
485	void set_seed( size_t seed_ ) OPTIONAL_THREAD; // set global seed
486	size_t get_seed() __attribute__(( warn_unused_result )); // get global seed
487	size_t prng( void ) __attribute__(( warn_unused_result )) OPTIONAL_THREAD; // [0,UINT_MAX]
488	static inline {
489	size_t prng( size_t u ) __attribute__(( warn_unused_result )) { return prng() % u; } // [0,u)
490	size_t prng( size_t l, size_t u ) __attribute__(( warn_unused_result )) { return prng( u - l + 1 ) + l; } // [l,u]
491	} // distribution
492
493	//---------------------------------------
494
495	extern bool threading_enabled( void ) OPTIONAL_THREAD;
496
497	// Local Variables: //
498	// mode: c //
499	// tab-width: 4 //
500	// End: //

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