<?php
declare(strict_types=1);
namespace ParagonIE\Iaso;
use ParagonIE\ConstantTime\Binary;
use ParagonIE\Iaso\Result\Assoc;
use ParagonIE\Iaso\Result\Bare;
use ParagonIE\Iaso\Result\Ordered;
/**
* Class Parser
* @package ParagonIE\Iaso
*/
class Parser
{
/**
* @param string $json
* @param Contract $contract
* @return ResultSet
*/
public function parse(string $json, Contract $contract): ResultSet
{
$state = new ParseState(
$json,
$contract,
0,
Binary::safeStrlen($json)
);
while ($state->moreToRead()) {
$state = $this->continueParsing($state);
}
if (empty($state->result)) {
if (!empty($state->stack)) {
$res = \array_pop($state->stack);
$state->result = $res['obj'];
}
}
return $state->result;
}
/**
* @param ParseState $state
* @return ParseState
* @throws JSONError
*/
protected function continueParsing(ParseState $state): ParseState
{
$chr = $state->getChar();
switch ($chr) {
case "\x09":
case "\x0a":
case "\x0d":
case "\x20":
// Continue on whitespace.
while (\preg_match('#(\x09|\x0a|\x0d|\x20)#', $state->getChar())) {
++$state->pos;
}
return $state;
case '{':
// We're parsing an object.
\array_push(
$state->stack,
[
'type' => '{',
'begin' => $state->pos,
'end' => null,
'obj' => new Assoc()
]
);
break;
case '[':
// We're parsing an array.
\array_push(
$state->stack,
[
'type' => '[',
'begin' => $state->pos,
'end' => null,
'obj' => new Ordered()
]
);
break;
case '/*':
// Multiline comment
$pos = \strpos($state->data, '*/', $state->pos);
if ($pos === false) {
throw new JSONError('Unclosed multiline comment');
}
$state->pos = $pos + 1;
break;
case '//':
// Single-line comment
$pos = \strpos($state->data, "\n", $state->pos);
if ($pos === false) {
// Maybe this is before the ending?
$state->pos = $state->length - 2;
}
break;
case ']':
$state = $this->closeArray($state);
break;
case '}':
$state = $this->closeObject($state);
break;
case ',':
// We don't expect a , in the middle of an object declaration
$soft = $state->softPop();
if (!empty($soft['pending'])) {
throw new JSONError('Unexpected ,');
}
// Continue
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
$state = $this->parseNumeric($state);
break;
case 'n':
case 'N':
if (\strtolower(Binary::safeSubstr($state->data, $state->pos, 4)) !== 'null') {
throw new JSONError('Unexpected character "' . $chr . '"');
}
$state = $this->parseNull($state);
break;
case 't':
case 'T':
if (\strtolower(Binary::safeSubstr($state->data, $state->pos, 4)) !== 'true') {
throw new JSONError('Unexpected character "' . $chr . '"');
}
$state = $this->parseBool($state, true);
break;
case 'f':
case 'F':
if (\strtolower(Binary::safeSubstr($state->data, $state->pos, 5)) !== 'false') {
throw new JSONError('Unexpected character "' . $chr . '"');
}
$state = $this->parseBool($state, false);
break;
case '"':
// This can either be:
// - A string (i.e. in an array)
// - An object's key
// - An object's value
$state = $this->parseString($state);
break;
default:
throw new JSONError('Unexpected character "' . $chr . '" (ASCII: ' . \ord($chr) . ')');
}
++$state->pos;
return $state;
}
/**
* @param ParseState $state
* @throws JSONError
* @return ParseState
*/
protected function closeArray(ParseState $state): ParseState
{
if (empty($state->stack)) {
throw new JSONError('Cannot pop from empty stack');
}
// We're closing out an array
$pop = \array_pop($state->stack);
if (empty($pop['type'])) {
throw new JSONError('Corrupted stack');
}
if ($pop['type'] !== '[') {
throw new JSONError('Unexpected ]');
}
return $state->passToParent($pop['obj']);
}
/**
* @param ParseState $state
* @throws JSONError
* @return ParseState
*/
protected function closeObject(ParseState $state): ParseState
{
if (empty($state->stack)) {
throw new JSONError('Cannot pop from empty stack');
}
// We're closing out an object
$pop = \array_pop($state->stack);
if (empty($pop['type'])) {
throw new JSONError('Corrupted stack');
}
if ($pop['type'] !== '{') {
throw new JSONError('Unexpected }');
}
return $state->passToParent($pop['obj']);
}
/**
* @param ParseState $state
* @param bool $expect
* @return ParseState
* @throws JSONError
*/
protected function parseBool(ParseState $state, bool $expect = false): ParseState
{
if (empty($state->stack) && $state->pos === 0) {
$state->pos = Binary::safeStrlen($state->data) - 1;
$state->result = new Bare($expect, 'bool');
return $state;
}
$popped = $state->softPop();
if (empty($popped['type'])) {
throw new JSONError('Corrupted stack');
}
if ($popped['type'] === '[') {
$popped['obj'][] = $expect;
} elseif ($popped['type'] === '{') {
$idx = $state->getLastIndex();
if (empty($state->stack[$idx]['pending'])) {
// Uh oh. Dangling bool value.
throw new JSONError('Unexpected boolean value');
}
$key = $state->stack[$idx]['pending'];
$state->stack[$idx]['obj'][$key] = $expect;
// We don't need this anymore. Unset it.
$state->stack[$idx]['pending'] = null;
} else {
throw new JSONError('Unexpected parent type');
}
$state->pos += ($expect ? 4 : 5);
return $state;
}
/**
* @param ParseState $state
* @return ParseState
* @throws JSONError
*/
protected function parseNull(ParseState $state): ParseState
{
if (empty($state->stack) && $state->pos === 0) {
$state->pos = Binary::safeStrlen($state->data) - 1;
$state->result = new Bare();
return $state;
}
$popped = $state->softPop();
if (empty($popped['type'])) {
throw new JSONError('Corrupted stack');
}
if ($popped['type'] === '[') {
$popped['obj'][] = null;
} elseif ($popped['type'] === '{') {
$idx = $state->getLastIndex();
if (empty($state->stack[$idx]['pending'])) {
// Uh oh. Dangling bool value.
throw new JSONError('Unexpected null value');
}
$key = $state->stack[$idx]['pending'];
$state->stack[$idx]['obj'][$key] = null;
// We don't need this anymore. Unset it.
$state->stack[$idx]['pending'] = null;
} else {
throw new JSONError('Unexpected parent type');
}
$state->pos += 4;
return $state;
}
/**
* @param ParseState $state
* @return ParseState
* @throws JSONError
*/
protected function parseNumeric(ParseState $state): ParseState
{
$start = $pos = $state->pos;
$period = false;
$len = 0;
do {
++$pos;
if (!\ctype_digit($state->data[$pos])) {
if ($state->data[$pos] === '.') {
// Allow only one.
if ($period) {
throw new JSONError('Unexpected period (.) character.');
}
$period = true;
} else {
// Stop parsing
break;
}
}
++$len;
} while ($pos < $state->length);
$numeric = Binary::safeSubstr($state->data, $start, $len + 1);
if ($period) {
$result = (float) $numeric;
} else {
$result = (int) $numeric;
}
if (empty($state->stack) && $state->pos === 0) {
$state->pos = Binary::safeStrlen($state->data) - 1;
$state->result = new Bare($result, $period ? 'float' : 'int');
return $state;
}
$popped = $state->softPop();
if (empty($popped['type'])) {
throw new JSONError('Corrupted stack');
}
if ($popped['type'] === '[') {
$popped['obj'][] = $result;
} elseif ($popped['type'] === '{') {
$idx = $state->getLastIndex();
if (empty($state->stack[$idx]['pending'])) {
// Uh oh. Dangling numeric value.
throw new JSONError('Unexpected numeric value');
}
$key = $state->stack[$idx]['pending'];
$state->stack[$idx]['obj'][$key] = $result;
// We don't need this anymore. Unset it.
$state->stack[$idx]['pending'] = null;
} else {
throw new JSONError('Unexpected parent type');
}
$state->pos += $len;
return $state;
}
/**
* @param ParseState $state
* @return ParseState
* @throws JSONError
*/
protected function parseString(ParseState $state): ParseState
{
$start = $pos = $state->pos;
$len = 0;
do {
++$pos;
++$len;
$search = \strpos($state->data, '"', $pos);
if ($search !== false) {
$pos = $search;
$len = $pos - $start;
}
$escaped = $state->data[$pos - 1] === '\\';
} while ($escaped && $pos < $state->length);
$idx = $state->getLastIndex();
if (empty($state->stack) && $state->pos === 0) {
$string = \str_replace(
'\"',
'"',
Binary::safeSubstr($state->data, $start + 1, $len - 1)
);
$state->pos = Binary::safeStrlen($state->data) - 1;
$state->result = new Bare($string, 'string');
return $state;
}
$popped = $state->softPop();
// This is the string we parsed.
$string = \str_replace(
'\"',
'"',
Binary::safeSubstr($state->data, $start + 1, $len - 1)
);
// Strip whitespace
while (\preg_match('/[\x09\x0a\x20]/', $state->data[$pos + 1]) && $pos < $state->length) {
++$pos;
}
if ($popped['type'] === '{') {
if (isset($popped['pending'])) {
// We're finalizing this entry with another string.
if ($state->data[$pos + 1] === ':') {
throw new JSONError('Unexpected :');
}
// Assign the value.
$key = $state->stack[$idx]['pending'];
$state->stack[$idx]['obj'][$key] = $string;
// We don't need this anymore. Unset it.
$state->stack[$idx]['pending'] = null;
} else {
// We're expecting a value for this later.
if ($state->data[$pos + 1] !== ':') {
throw new JSONError('Expected ":", got "' . $state->data[$pos + 1] . '" instead.');
}
$state->stack[$idx]['pending'] = $string;
++$pos;
}
} elseif ($popped['type'] === '[') {
// We don't expect key:value pairs inside of a [] array
if ($state->data[$pos + 1] === ':') {
throw new JSONError('Unexpected :');
}
$state->data[$idx]['obj'][] = $string;
}
$state->pos = $pos;
return $state;
}
}
|
Download
