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<?php
declare(strict_types=1);
namespace Nsfisis\Waddiwasi\Execution;
use Nsfisis\Waddiwasi\Structure\Types\RefType;
use function assert;
use function count;
use function is_float;
use function is_int;
use function is_null;
final class Stack
{
/**
* @var list<Frame>
*/
private array $frames = [];
private ?Frame $currentFrame = null;
/**
* @param list<int|float|Ref|Frame|Label> $entries
*/
public function __construct(
private array $entries,
) {
}
public function pushFrame(Frame $frame): void
{
if ($this->getCallStackLimit() <= count($this->frames)) {
throw new StackOverflowException();
}
$this->push($frame);
$this->frames[] = $frame;
$this->currentFrame = $frame;
}
public function pushLabel(Label $label): void
{
$this->push($label);
}
public function pushValue(int|float|Ref $val): void
{
$this->push($val);
}
public function pushBool(bool $value): void
{
$this->pushValue((int)$value);
}
public function pushRefNull(RefType $type): void
{
$this->pushValue(Ref::RefNull($type));
}
public function pushRefFunc(int $addr): void
{
$this->pushValue(Ref::RefFunc($addr));
}
public function pushRefExtern(int $addr): void
{
$this->pushValue(Ref::RefExtern($addr));
}
public function clear(): void
{
$this->frames = [];
$this->currentFrame = null;
$this->entries = [];
}
public function popFrame(): Frame
{
$result = $this->pop();
assert($result instanceof Frame);
array_pop($this->frames);
if (count($this->frames) === 0) {
$this->currentFrame = null;
} else {
$this->currentFrame = end($this->frames);
}
return $result;
}
public function popValue(): int|float|Ref
{
$result = $this->pop();
assert(
is_int($result) || is_float($result) || $result instanceof Ref,
'Expected a value on the stack, but got ' . print_r($result, true),
);
return $result;
}
/**
* @return list<int|float|Ref>
*/
public function popNValues(int $n): array
{
$results = [];
for ($i = 0; $i < $n; $i++) {
$results[] = $this->popValue();
}
return $results;
}
public function popInt(): int
{
$v = $this->popValue();
assert(is_int($v), "Expected an int on top of the stack, but got " . self::getValueTypeName($v));
return $v;
}
/**
* @return F32
*/
public function popFloat(): float
{
$v = $this->popValue();
assert(is_float($v), "Expected a float on top of the stack, but got " . self::getValueTypeName($v));
return $v;
}
public function popRef(): Ref
{
$v = $this->popValue();
assert($v instanceof Ref, "Expected a Ref on top of the stack, but got " . self::getValueTypeName($v));
return $v;
}
/**
* @return list<int|float|Ref>
*/
public function popValuesToLabel(): array
{
$results = [];
while (!$this->isEmpty()) {
$top = $this->pop();
if ($top instanceof Label) {
break;
} else {
assert(is_int($top) || is_float($top) || $top instanceof Ref);
$results[] = $top;
}
}
return $results;
}
public function popEntriesToCurrentFrame(): void
{
while (!$this->isEmpty()) {
if ($this->pop() instanceof Frame) {
break;
}
}
array_pop($this->frames);
if (count($this->frames) === 0) {
$this->currentFrame = null;
} else {
$this->currentFrame = end($this->frames);
}
}
public function top(): int|float|Ref|Frame|Label|null
{
$n = array_key_last($this->entries);
return $n === null ? null : $this->entries[$n];
}
public function count(): int
{
return count($this->entries);
}
public function isEmpty(): bool
{
return $this->count() === 0;
}
public function currentFrame(): Frame
{
assert($this->currentFrame !== null);
return $this->currentFrame;
}
public function getCallStackLimit(): int
{
return 1024;
}
private function push(int|float|Ref|Frame|Label $entry): void
{
$this->entries[] = $entry;
}
private function pop(): int|float|Ref|Frame|Label|null
{
return array_pop($this->entries);
}
private static function getValueTypeName(int|float|Ref|Frame|Label|null $value): string
{
return match (true) {
is_null($value) => 'null',
is_int($value) => 'int',
is_float($value) => 'float',
$value instanceof Ref => 'Ref',
$value instanceof Frame => 'Frame',
$value instanceof Label => 'Label',
};
}
}
|
