Merge pull request #402 from markusgraube/pcg-random

Replace random_r with RNG from pcg32

CMakeLists.txt

@@ -90,6 +90,7 @@ set(exported_headers ${PROJECT_BINARY_DIR}/src_generated/ua_config.h
                      ${PROJECT_SOURCE_DIR}/examples/logger_stdout.h)
 set(internal_headers ${PROJECT_SOURCE_DIR}/src/ua_util.h
                      ${PROJECT_SOURCE_DIR}/deps/queue.h
+                     ${PROJECT_SOURCE_DIR}/deps/pcg_basic.h
                      ${PROJECT_SOURCE_DIR}/src/ua_types_encoding_binary.h
                      ${PROJECT_BINARY_DIR}/src_generated/ua_types_generated_encoding_binary.h
                      ${PROJECT_BINARY_DIR}/src_generated/ua_transport_generated.h
@@ -125,7 +126,8 @@ set(lib_sources ${PROJECT_SOURCE_DIR}/src/ua_types.c
                 ${PROJECT_SOURCE_DIR}/src/server/ua_services_view.c
                 ${PROJECT_SOURCE_DIR}/src/client/ua_client.c
                 ${PROJECT_SOURCE_DIR}/examples/networklayer_tcp.c
-                ${PROJECT_SOURCE_DIR}/examples/logger_stdout.c)
+                ${PROJECT_SOURCE_DIR}/examples/logger_stdout.c
+                ${PROJECT_SOURCE_DIR}/deps/pcg_basic.c)
                 ##TODO: make client stuff optional
 
 ## generate code from xml definitions

deps/pcg_basic.c

@@ -0,0 +1,116 @@
+/*
+ * PCG Random Number Generation for C.
+ *
+ * Copyright 2014 Melissa O'Neill <oneill@pcg-random.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * For additional information about the PCG random number generation scheme,
+ * including its license and other licensing options, visit
+ *
+ *       http://www.pcg-random.org
+ */
+
+/*
+ * This code is derived from the full C implementation, which is in turn
+ * derived from the canonical C++ PCG implementation. The C++ version
+ * has many additional features and is preferable if you can use C++ in
+ * your project.
+ */
+
+#include "pcg_basic.h"
+
+// state for global RNGs
+
+static pcg32_random_t pcg32_global = PCG32_INITIALIZER;
+
+// pcg32_srandom(initstate, initseq)
+// pcg32_srandom_r(rng, initstate, initseq):
+//     Seed the rng.  Specified in two parts, state initializer and a
+//     sequence selection constant (a.k.a. stream id)
+
+void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate, uint64_t initseq)
+{
+    rng->state = 0U;
+    rng->inc = (initseq << 1u) | 1u;
+    pcg32_random_r(rng);
+    rng->state += initstate;
+    pcg32_random_r(rng);
+}
+
+void pcg32_srandom(uint64_t seed, uint64_t seq)
+{
+    pcg32_srandom_r(&pcg32_global, seed, seq);
+}
+
+// pcg32_random()
+// pcg32_random_r(rng)
+//     Generate a uniformly distributed 32-bit random number
+
+uint32_t pcg32_random_r(pcg32_random_t* rng)
+{
+    uint64_t oldstate = rng->state;
+    rng->state = oldstate * 6364136223846793005ULL + rng->inc;
+    uint32_t xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u;
+    uint32_t rot = oldstate >> 59u;
+    return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
+}
+
+uint32_t pcg32_random()
+{
+    return pcg32_random_r(&pcg32_global);
+}
+
+
+// pcg32_boundedrand(bound):
+// pcg32_boundedrand_r(rng, bound):
+//     Generate a uniformly distributed number, r, where 0 <= r < bound
+
+uint32_t pcg32_boundedrand_r(pcg32_random_t* rng, uint32_t bound)
+{
+    // To avoid bias, we need to make the range of the RNG a multiple of
+    // bound, which we do by dropping output less than a threshold.
+    // A naive scheme to calculate the threshold would be to do
+    //
+    //     uint32_t threshold = 0x100000000ull % bound;
+    //
+    // but 64-bit div/mod is slower than 32-bit div/mod (especially on
+    // 32-bit platforms).  In essence, we do
+    //
+    //     uint32_t threshold = (0x100000000ull-bound) % bound;
+    //
+    // because this version will calculate the same modulus, but the LHS
+    // value is less than 2^32.
+
+    uint32_t threshold = -bound % bound;
+
+    // Uniformity guarantees that this loop will terminate.  In practice, it
+    // should usually terminate quickly; on average (assuming all bounds are
+    // equally likely), 82.25% of the time, we can expect it to require just
+    // one iteration.  In the worst case, someone passes a bound of 2^31 + 1
+    // (i.e., 2147483649), which invalidates almost 50% of the range.  In 
+    // practice, bounds are typically small and only a tiny amount of the range
+    // is eliminated.
+    for (;;) {
+        uint32_t r = pcg32_random_r(rng);
+        if (r >= threshold)
+            return r % bound;
+    }
+}
+
+
+uint32_t pcg32_boundedrand(uint32_t bound)
+{
+    return pcg32_boundedrand_r(&pcg32_global, bound);
+}
+

deps/pcg_basic.h

@@ -0,0 +1,78 @@
+/*
+ * PCG Random Number Generation for C.
+ *
+ * Copyright 2014 Melissa O'Neill <oneill@pcg-random.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * For additional information about the PCG random number generation scheme,
+ * including its license and other licensing options, visit
+ *
+ *     http://www.pcg-random.org
+ */
+
+/*
+ * This code is derived from the full C implementation, which is in turn
+ * derived from the canonical C++ PCG implementation. The C++ version
+ * has many additional features and is preferable if you can use C++ in
+ * your project.
+ */
+
+#ifndef PCG_BASIC_H_INCLUDED
+#define PCG_BASIC_H_INCLUDED 1
+
+#include <inttypes.h>
+
+#if __cplusplus
+extern "C" {
+#endif
+
+struct pcg_state_setseq_64 {    // Internals are *Private*.
+    uint64_t state;             // RNG state.  All values are possible.
+    uint64_t inc;               // Controls which RNG sequence (stream) is
+                                // selected. Must *always* be odd.
+};
+typedef struct pcg_state_setseq_64 pcg32_random_t;
+
+// If you *must* statically initialize it, here's one.
+
+#define PCG32_INITIALIZER   { 0x853c49e6748fea9bULL, 0xda3e39cb94b95bdbULL }
+
+// pcg32_srandom(initstate, initseq)
+// pcg32_srandom_r(rng, initstate, initseq):
+//     Seed the rng.  Specified in two parts, state initializer and a
+//     sequence selection constant (a.k.a. stream id)
+
+void pcg32_srandom(uint64_t initstate, uint64_t initseq);
+void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate,
+                     uint64_t initseq);
+
+// pcg32_random()
+// pcg32_random_r(rng)
+//     Generate a uniformly distributed 32-bit random number
+
+uint32_t pcg32_random(void);
+uint32_t pcg32_random_r(pcg32_random_t* rng);
+
+// pcg32_boundedrand(bound):
+// pcg32_boundedrand_r(rng, bound):
+//     Generate a uniformly distributed number, r, where 0 <= r < bound
+
+uint32_t pcg32_boundedrand(uint32_t bound);
+uint32_t pcg32_boundedrand_r(pcg32_random_t* rng, uint32_t bound);
+
+#if __cplusplus
+}
+#endif
+
+#endif // PCG_BASIC_H_INCLUDED

include/ua_types.h

@@ -29,6 +29,7 @@ extern "C" {
 #include "ua_config.h"
 #include "ua_statuscodes.h"
 
+
 /** A two-state logical value (true or false). */
 typedef bool UA_Boolean;
 #define UA_TRUE true

src/ua_types.c

@@ -3,6 +3,12 @@
 #include "ua_statuscodes.h"
 #include "ua_types_generated.h"
 
+/*************************/
+/* External Dependencies */
+/*************************/
+#include "pcg_basic.h"
+
+
 /*****************/
 /* Helper Macros */
 /*****************/
@@ -226,17 +232,19 @@ UA_Boolean UA_Guid_equal(const UA_Guid *g1, const UA_Guid *g2) {
 }
 
 UA_Guid UA_Guid_random(UA_UInt32 *seed) {
+    pcg32_random_t rng;
+    pcg32_srandom_r(&rng, *seed, UA_DateTime_now());
     UA_Guid result;
-    result.data1 = RAND(seed);
-    UA_UInt32 r = RAND(seed);
+    result.data1 = (UA_UInt32)pcg32_random_r(&rng);
+    UA_UInt32 r = (UA_UInt32)pcg32_random_r(&rng);
     result.data2 = (UA_UInt16) r;
     result.data3 = (UA_UInt16) (r >> 16);
-    r = RAND(seed);
+    r = (UA_UInt32)pcg32_random_r(&rng);
     result.data4[0] = (UA_Byte)r;
     result.data4[1] = (UA_Byte)(r >> 4);
     result.data4[2] = (UA_Byte)(r >> 8);
     result.data4[3] = (UA_Byte)(r >> 12);
-    r = RAND(seed);
+    r = (UA_UInt32)pcg32_random_r(&rng);
     result.data4[4] = (UA_Byte)r;
     result.data4[5] = (UA_Byte)(r >> 4);
     result.data4[6] = (UA_Byte)(r >> 8);

src/ua_util.h

@@ -86,13 +86,8 @@
 # include <winsock2.h> //needed for amalgation
 # include <windows.h>
 # undef SLIST_ENTRY
-# define RAND(SEED) (UA_UInt32)rand()
 #else
-  #ifdef __CYGWIN__
-  extern int rand_r (unsigned int *__seed);
-  #endif
-  # include <sys/time.h>
-  # define RAND(SEED) (UA_UInt32)rand_r(SEED)
+# include <sys/time.h>
 #endif
 
 /*************************/

tools/amalgamate.py

@@ -18,7 +18,7 @@ pos = outname.find(".")
 if pos > 0:
     outname = outname[:pos]
 include_re = re.compile("^#include (\".*\").*$")
-guard_re = re.compile("^#(?:(?:ifndef|define) [A-Z_]+_H_|endif /\* [A-Z_]+_H_ \*/)")
+guard_re = re.compile("^#(?:(?:ifndef|define) [A-Z_]+_H_|endif /\* [A-Z_]+_H_ \*/|endif // [A-Z_]+_H_)")
 includes = []
 
 print ("Starting amalgamating file "+ args.outfile)