Cr8-xyz/blender
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

BLI_rand: add BLI_rng_get_char_n

Browse Source 
Use to fill an array of bytes to random values.
This commit is contained in:
Campbell Barton
2016-06-12 00:38:49 +10:00
parent 4ec1c76afc
commit dccf5afbef
3 changed files with 46 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
source/blender/blenlib/BLI_rand.h
View File

@@ -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);

40
source/blender/blenlib/intern/rand.c
View File

@@ -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);

19
tests/gtests/blenlib/BLI_array_store_test.cc
View File

@@ -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);