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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include <vespa/vespalib/util/binary_hamming_distance.h>
#include <vespa/vespalib/util/require.h>
#include <vespa/vespalib/gtest/gtest.h>
#include <cstdlib>
#include <cstring>
#include <vector>
using namespace vespalib;
constexpr size_t ALIGN = 8;
constexpr size_t ALLOC_SZ = 256;
void flip_one_bit(void *memory, const void *other_memory, size_t sz) {
auto buf = (uint8_t *)memory;
auto other_buf = (const uint8_t *)other_memory;
while (true) {
size_t byte_idx = random() % sz;
size_t bit_idx = random() % 8;
uint8_t cmp = other_buf[byte_idx];
uint8_t old = buf[byte_idx];
uint8_t bit = 1u << bit_idx;
if ((old & bit) == (cmp & bit)) {
uint8_t new_val = old ^ bit;
REQUIRE(old != new_val);
buf[byte_idx] = new_val;
return;
}
}
}
std::vector<void *> allocated;
void *my_alloc(int unalignment = 0) {
void *mem;
int r = posix_memalign(&mem, ALIGN, ALLOC_SZ);
REQUIRE_EQ(0, r);
allocated.push_back(mem);
uintptr_t addr = (uintptr_t) mem;
addr += unalignment;
return (void *)addr;
}
void check_with_flipping(void *mem_a, void *mem_b, size_t sz) {
memset(mem_a, 0, sz);
memset(mem_b, 0, sz);
size_t dist = 0;
EXPECT_EQ(binary_hamming_distance(mem_a, mem_b, sz), dist);
while (dist * 2 < sz) {
flip_one_bit(mem_a, mem_b, sz);
++dist;
EXPECT_EQ(binary_hamming_distance(mem_a, mem_b, sz), dist);
flip_one_bit(mem_b, mem_a, sz);
++dist;
EXPECT_EQ(binary_hamming_distance(mem_a, mem_b, sz), dist);
}
}
void check_with_sizes(void *mem_a, void *mem_b) {
for (size_t sz : { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 16, 32, 63, 64, 65 }) {
check_with_flipping(mem_a, mem_b, sz);
}
}
TEST(BinaryHammingTest, aligned_usage) {
void *mem_a = my_alloc(0);
void *mem_b = my_alloc(0);
check_with_sizes(mem_a, mem_b);
}
TEST(BinaryHammingTest, one_unaligned) {
void *mem_a = my_alloc(3);
void *mem_b = my_alloc(0);
check_with_sizes(mem_a, mem_b);
}
TEST(BinaryHammingTest, other_unaligned) {
void *mem_a = my_alloc(0);
void *mem_b = my_alloc(7);
check_with_sizes(mem_a, mem_b);
}
TEST(BinaryHammingTest, both_unaligned) {
void *mem_a = my_alloc(2);
void *mem_b = my_alloc(6);
check_with_sizes(mem_a, mem_b);
}
int main(int argc, char* argv[]) {
::testing::InitGoogleTest(&argc, argv);
int r = RUN_ALL_TESTS();
for (void * mem : allocated) {
free(mem);
}
return r;
}
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