First commit

5 files changed, 160 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..4ffc5a4
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,13 @@
+CC=gcc
+OUTPUT_MULTIPLIER=0x6ab64cc1
+
+rel:
+	mkdir -p ./build
+	$(CC) -Wall -Werror -pedantic -O2 -march=x86-64-v3 -mavx2 -std=gnu23 -DOUTPUT_MULTIPLIER=${OUTPUT_MULTIPLIER} -shared -fPIC ./xorshift.c -o ./build/libxorshift.so
+
+debug:
+	mkdir -p ./build
+	$(CC) -Wall -Werror -pedantic -O2 -march=x86-64-v3 -mavx2 -std=gnu23 -ggdb -DOUTPUT_MULTIPLIER=${OUTPUT_MULTIPLIER} -shared -fPIC ./xorshift.c -o ./build/libxorshift.so
+
+clean:
+	rm -rf ./build
diff --git a/include/xorshift.h b/include/xorshift.h
new file mode 100644
index 0000000..0e58967
--- /dev/null
+++ b/include/xorshift.h
@@ -0,0 +1,4 @@
+bool initialize_states();
+uint32_t get_random_output();
+uint32_t get_uniform_uint( uint32_t min, uint32_t max );
+void clear_rng_state();
diff --git a/structs.h b/structs.h
new file mode 100644
index 0000000..34c923b
--- /dev/null
+++ b/structs.h
@@ -0,0 +1,6 @@
+struct rng_state{
+	size_t state_idx;
+	uint32_t states[16];
+	uint32_t gen_period_ctr;
+	uint8_t period_end_ctr;
+};
diff --git a/tests/test_statistical_properties.py b/tests/test_statistical_properties.py
new file mode 100755
index 0000000..1346293
--- /dev/null
+++ b/tests/test_statistical_properties.py
@@ -0,0 +1,73 @@
+#!/usr/bin/python3 -u
+import sys;
+import argparse;
+from ctypes import *;
+import numpy as np;
+
+aparser = argparse.ArgumentParser();
+aparser.add_argument( "--count", type=int, required=True, help="Amount of number combinations to generate" );
+aparser.add_argument( "--num-count", type=int, required=True, help="Amount of numbers in each combination generated" );
+aparser.add_argument( "--min", type=int, required=True, help="Minimum number" );
+aparser.add_argument( "--max", type=int, required=True, help="Maximum number" );
+args = aparser.parse_args();
+del aparser;
+
+if ( args.max <= args.min ):
+	del args;
+	print( "Error: maximum number must be more than minimum" );
+	sys.exit( -1 );
+
+libxorshift = CDLL( "../build/libxorshift.so" );
+libxorshift.initialize_states.restype = c_bool;
+libxorshift.get_uniform_uint.restype = c_uint;
+libxorshift.get_uniform_uint.argtypes = [c_uint, c_uint];
+
+if ( libxorshift.initialize_states() is c_bool(False) ):
+	print( "Error: failed to initialize RNG states" );
+	del libxorshift;
+	sys.exit( -1 );
+
+generated_combinations = [];
+generated_sum = 0;
+
+current_combination = [];
+gen_num = 0;
+
+for c_count in range( 0, args.count ):
+	for bcount in range( 0, args.num_count ):
+		gen_num = int( libxorshift.get_uniform_uint(c_uint(args.min), c_uint(args.max)) );
+		generated_sum += gen_num;
+		current_combination.append( gen_num );
+	generated_combinations.append( current_combination );
+	current_combination = [];
+
+del current_combination, gen_num;
+
+print( "Statistical properties results" );
+print( "-----" );
+
+print( "Each combination's mean value" );
+print( "-----" );
+
+combination_str = None;
+
+for gen_combination in generated_combinations:
+	combination_str = ", ".join( list(map(str, gen_combination)) );
+	print( f"Combination {combination_str} has mean {np.mean(gen_combination)}" );
+
+del combination_str;
+
+print( "-----" );
+print( "Overall statistical properties" );
+print( "-----" );
+
+print( f"Expected mean overall: {(args.max / 2) * args.num_count}" );
+print( f"Actual overall mean: {generated_sum / args.count}" );
+
+print( "-----" );
+
+del generated_sum, generated_combinations;
+
+del libxorshift;
+del args;
+sys.exit( 0 );
diff --git a/xorshift.c b/xorshift.c
new file mode 100644
index 0000000..6fdd5fb
--- /dev/null
+++ b/xorshift.c
@@ -0,0 +1,64 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <unistd.h>
+#include <assert.h>
+#include <limits.h>
+#include <sys/random.h>
+#include <string.h>
+#include "structs.h"
+
+struct rng_state global_rng_state;
+
+__attribute__((visibility("default"))) bool initialize_states(){
+	assert( (sizeof(uint32_t) * CHAR_BIT) == 32 );
+	memset( (void*)&global_rng_state, 0, sizeof(struct rng_state) );
+	ssize_t state_bytes_read = 0;
+	if ( (state_bytes_read = getrandom((void*)&global_rng_state.states, 16 * sizeof(uint32_t), GRND_NONBLOCK)) == -1 )
+		return false;
+	if ( (size_t)state_bytes_read < (16 * sizeof(uint32_t)) ){
+		errno = EIO;
+		return false;
+	}
+	global_rng_state.state_idx = global_rng_state.states[7] & 0x0f;
+	errno = 0;
+	return true;
+}
+
+__attribute__((visibility("default"))) uint32_t get_random_output(){
+	size_t use_state = global_rng_state.state_idx;
+	global_rng_state.state_idx = global_rng_state.states[use_state] & 0x0f;
+	if ( global_rng_state.gen_period_ctr >= 0xffffffff ){
+		global_rng_state.period_end_ctr++;
+		if ( global_rng_state.period_end_ctr >= 16 ){
+			assert( initialize_states() == true );
+			global_rng_state.period_end_ctr = 0;
+		}
+		global_rng_state.gen_period_ctr = 0;
+	}
+	global_rng_state.gen_period_ctr++;
+	global_rng_state.states[use_state] ^= global_rng_state.states[use_state] >> 11;
+	global_rng_state.states[use_state] ^= global_rng_state.states[use_state] << 7;
+	global_rng_state.states[use_state] ^= global_rng_state.states[use_state] >> 16;
+	return global_rng_state.states[use_state] * OUTPUT_MULTIPLIER;
+}
+
+__attribute__((visibility("default"))) uint32_t get_uniform_uint( uint32_t min, uint32_t max ){
+	if ( max <= min )
+		return min;
+	uint32_t ncount = (max - min) + 1;
+	uint32_t upper_bound = 0xffffffff - (0xffffffff % ncount);
+	uint32_t gen_output = get_random_output();
+	if ( gen_output > upper_bound ){
+		while ( gen_output > upper_bound )
+			gen_output = get_random_output();
+	}
+	return (gen_output % max) + min;
+}
+
+__attribute__((visibility("default"))) void clear_rng_state(){
+	memset( (void*)&global_rng_state, 0, sizeof(struct rng_state) );
+	return;
+}