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#include <gtest/gtest.h>
#include <memory>
#include <cmath>
TEST(Empty, Empty)
{
}
int get_op(int8_t *& PC) {
return *(PC++);
}
size_t get_arg(int8_t*& PC, int size) {
switch (size) {
case 0:
return *(PC++);
case 1:
return *(((unsigned short*&)PC)++);
case 2:
return *(((unsigned int*&)PC)++);
case 3:
return *(((size_t*&)PC)++);
}
return 0;
}
TEST(Pointer, byte)
{
int8_t data[] = { 42, 0 };
int8_t* PC = data;
ASSERT_EQ(42, get_op(PC));
ASSERT_EQ(data + 1, PC);
}
TEST(Pointer, int16)
{
int8_t data[] = { 1, 42, 0, 3};
int8_t* PC = data;
get_op(PC);
ASSERT_EQ(42U, get_arg(PC, 1));
ASSERT_EQ(data + 3, PC);
}
TEST(Pointer, int32)
{
int8_t data[] = { 1, 42, 0, 3, 0, 1 };
int8_t* PC = data;
get_op(PC);
ASSERT_EQ(0x0003002aU, get_arg(PC, 2));
ASSERT_EQ(data + 5, PC);
}
TEST(Pointer, int64)
{
int8_t data[] = { 1, 42, 0, 3, 0, 1, 0, 0, 0 };
int8_t* PC = data;
get_op(PC);
ASSERT_EQ(0x010003002aU, get_arg(PC, 3));
ASSERT_EQ(data + 9, PC);
}
/*
* Value will be either a double, undefined, null, string, array, object,
* function, boolean.
*
* Pointer values (like string, array, object, function) can be shared pointers
* via intrusive pointer implementation. This way we can get a reference
* counting garbage collection.
*
*/
struct Value
{
Value(double v)
{
m_value.as_double = v;
}
Value(int tag, void* pointer)
{
assert(tag && "Zero tag is plain double");
assert(!((size_t)pointer >> 48) && "Use only pointers to the heap.");
m_value.as_pointer.pointer = (size_t)pointer;
m_value.as_pointer.tag = tag;
m_value.as_pointer.nan = 0x1fff;
}
struct NanPointer
{
size_t pointer:48;
size_t tag:3;
size_t nan:13;
};
struct CheckType
{
size_t payload: 48;
size_t check:16;
};
union {
double as_double;
NanPointer as_pointer;
CheckType to_check;
} m_value;
static_assert(sizeof(size_t) == 8, "unsupported arch");
static_assert(sizeof(double) == 8, "unsupported arch");
bool is_double() const
{
return m_value.to_check.check <= 0xFFF8;
}
double get_double() const
{
assert(is_double());
return m_value.as_double;
}
int get_tag() {
assert(!is_double());
return m_value.as_pointer.tag;
}
void* get_pointer() const {
return (void*)(size_t) m_value.as_pointer.pointer;
}
};
TEST(NaNBox, PlainDoubles)
{
double a = floor(rand() / RAND_MAX);
double values[] = {
0.0, 2.89, 3.14, 0.0 / 1.0, 1.0 / a
};
for (auto value: values)
{
Value box(value);
ASSERT_TRUE(box.is_double());
ASSERT_EQ(value, box.get_double());
Value box2(-value);
ASSERT_TRUE(box2.is_double());
ASSERT_EQ(-value, box2.get_double());
}
}
TEST(NaNBox, Border)
{
Value v(2, nullptr);
ASSERT_TRUE(std::isnan(v.m_value.as_double));
ASSERT_FALSE(std::isinf(v.m_value.as_double));
}
TEST(NaNBox, IsNaN)
{
Value v2(std::sqrt(-1.0));
ASSERT_TRUE(v2.is_double());
}
TEST(NaNBox, Pointers)
{
std::vector<std::unique_ptr<int>> pointers;
int n = 1024;
pointers.reserve(n);
for (int i = 0; i < n; ++i)
{
pointers.emplace_back(std::make_unique<int>(i));
}
for (auto& value: pointers)
{
Value box(1, value.get());
ASSERT_FALSE(box.is_double());
ASSERT_EQ(value.get(), box.get_pointer());
}
}
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