Commit: dccf5afbef67ffd0201da26cc6603c1f42d3668f
Author: Campbell Barton
Date: Sun Jun 12 00:38:49 2016 +1000
Branches: master
https://developer.blender.org/rBdccf5afbef67ffd0201da26cc6603c1f42d3668f
BLI_rand: add BLI_rng_get_char_n
Use to fill an array of bytes to random values.
===================================================================
M source/blender/blenlib/BLI_rand.h
M source/blender/blenlib/intern/rand.c
M tests/gtests/blenlib/BLI_array_store_test.cc
===================================================================
diff --git a/source/blender/blenlib/BLI_rand.h
b/source/blender/blenlib/BLI_rand.h
index 7b84ddd..f36d2fa 100644
--- a/source/blender/blenlib/BLI_rand.h
+++ b/source/blender/blenlib/BLI_rand.h
@@ -49,6 +49,7 @@ void BLI_rng_free(struct RNG *rng) ATTR_NONNULL(1);
void BLI_rng_seed(struct RNG *rng, unsigned int seed) ATTR_NONNULL(1);
void BLI_rng_srandom(struct RNG *rng, unsigned int seed)
ATTR_NONNULL(1);
+void BLI_rng_get_char_n(RNG *rng, char *bytes, size_t bytes_len)
ATTR_NONNULL(1, 2);
int BLI_rng_get_int(struct RNG *rng) ATTR_WARN_UNUSED_RESULT
ATTR_NONNULL(1);
unsigned int BLI_rng_get_uint(struct RNG *rng) ATTR_WARN_UNUSED_RESULT
ATTR_NONNULL(1);
double BLI_rng_get_double(struct RNG *rng) ATTR_WARN_UNUSED_RESULT
ATTR_NONNULL(1);
diff --git a/source/blender/blenlib/intern/rand.c
b/source/blender/blenlib/intern/rand.c
index 66c568a..40d9a3d 100644
--- a/source/blender/blenlib/intern/rand.c
+++ b/source/blender/blenlib/intern/rand.c
@@ -46,6 +46,7 @@
#define MULTIPLIER 0x5DEECE66Dll
#define MASK 0x0000FFFFFFFFFFFFll
+#define MASK_BYTES 2
#define ADDEND 0xB
#define LOWSEED 0x330E
@@ -107,6 +108,45 @@ BLI_INLINE void rng_step(RNG *rng)
rng->X = (MULTIPLIER * rng->X + ADDEND) & MASK;
}
+void BLI_rng_get_char_n(RNG *rng, char *bytes, size_t bytes_len)
+{
+ size_t last_len = 0;
+ size_t trim_len = bytes_len;
+
+#define RAND_STRIDE (sizeof(rng->X) - MASK_BYTES)
+
+ if (trim_len > RAND_STRIDE) {
+ last_len = trim_len % RAND_STRIDE;
+ trim_len = trim_len - last_len;
+ }
+ else {
+ trim_len = 0;
+ last_len = bytes_len;
+ }
+
+ const char *data_src = (void *)&(rng->X);
+ size_t i = 0;
+ while (i != trim_len) {
+ BLI_assert(i < trim_len);
+#ifdef __BIG_ENDIAN__
+ for (size_t j = (RAND_STRIDE + MASK_BYTES) - 1; j != MASK_BYTES
- 1; j--)
+#else
+ for (size_t j = 0; j != RAND_STRIDE; j++)
+#endif
+ {
+ bytes[i++] = data_src[j];
+ }
+ rng_step(rng);
+ }
+ if (last_len) {
+ for (size_t j = 0; j != last_len; j++) {
+ bytes[i++] = data_src[j];
+ }
+ }
+
+#undef RAND_STRIDE
+}
+
int BLI_rng_get_int(RNG *rng)
{
rng_step(rng);
diff --git a/tests/gtests/blenlib/BLI_array_store_test.cc
b/tests/gtests/blenlib/BLI_array_store_test.cc
index 33fb454..b71dc45 100644
--- a/tests/gtests/blenlib/BLI_array_store_test.cc
+++ b/tests/gtests/blenlib/BLI_array_store_test.cc
@@ -528,15 +528,6 @@ static unsigned int rand_range_i(RNG *rng, unsigned int
min_i, unsigned int max_
return min_i + value;
}
-static void rand_bytes(RNG *rng, char *data, int data_len)
-{
- BLI_assert(data_len != 0);
- while (data_len--) {
- *data = BLI_rng_get_uint(rng) % 256;
- data++;
- }
-}
-
static void testbuffer_list_state_random_data(
ListBase *lb,
const size_t stride,
@@ -548,7 +539,7 @@ static void testbuffer_list_state_random_data(
char *data = (char *)MEM_mallocN(data_len, __func__);
if (lb->last == NULL) {
- rand_bytes(rng, data, data_len);
+ BLI_rng_get_char_n(rng, data, data_len);
}
else {
TestBuffer *tb_last = (TestBuffer *)lb->last;
@@ -557,7 +548,7 @@ static void testbuffer_list_state_random_data(
}
else {
memcpy(data, tb_last->data, tb_last->data_len);
- rand_bytes(rng, &data[tb_last->data_len], data_len -
tb_last->data_len);
+ BLI_rng_get_char_n(rng, &data[tb_last->data_len],
data_len - tb_last->data_len);
}
/* perform multiple small mutations to the array. */
@@ -583,7 +574,7 @@ static void testbuffer_list_state_random_data(
data_len += stride;
data = (char
*)MEM_reallocN((void *)data, data_len);
memmove(&data[offset + stride],
&data[offset], data_len - (offset + stride));
- rand_bytes(rng, &data[offset],
stride);
+ BLI_rng_get_char_n(rng,
&data[offset], stride);
}
break;
}
@@ -608,7 +599,7 @@ static void testbuffer_list_state_random_data(
{
if (data_len > 0) {
const unsigned int offset =
rand_range_i(rng, 0, data_len - stride, stride);
- rand_bytes(rng, &data[offset],
stride);
+ BLI_rng_get_char_n(rng,
&data[offset], stride);
}
break;
}
@@ -667,7 +658,7 @@ static void random_chunk_generate(
const size_t chunk_size_bytes = stride * chunk_count;
for (int i = 0; i < chunks_per_buffer; i++) {
char *data_chunk = (char *)MEM_mallocN(chunk_size_bytes,
__func__);
- rand_bytes(rng, data_chunk, chunk_size_bytes);
+ BLI_rng_get_char_n(rng, data_chunk, chunk_size_bytes);
testchunk_list_add(lb, data_chunk, chunk_size_bytes);
}
BLI_rng_free(rng);
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