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x.json2.decoder2: improve decoder, add checker (part 1) (#22545)
This commit is contained in:
Hitalo Souza
GitHub
parent
e4ffc7f224
commit
8556353b43
2 changed files with 759 additions and 12 deletions
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@ -2,18 +2,29 @@ module decoder2
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import time
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// Node represents a node in a JSON decoder tree.
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// Node represents a node in a JSON decoder tree. Used to decode object in JSON.
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struct Node {
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key_pos int // The position of the key in the JSON string.
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key_len int // The length of the key in the JSON string.
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children ?[]Node // The children nodes of the current node.
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}
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// ValueInfo represents the position and length of a value, like string, number, array, object key and object value in a JSON string.
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struct ValueInfo {
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position int // The position of the value in the JSON string.
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value_kind ValueKind // The kind of the value.
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mut:
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length int // The length of the value in the JSON string.
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}
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// Decoder represents a JSON decoder.
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struct Decoder {
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json string // json is the JSON data to be decoded.
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mut:
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idx int // idx is the current index of the decoder.
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values_info []ValueInfo
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idx int // idx is byte offset from the start in json
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checker_idx int // checker_idx is the current index of the decoder.
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value_info_idx int // value_info_idx is the current index of the values_info.
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}
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pub enum ValueKind {
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@ -23,34 +34,466 @@ pub enum ValueKind {
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string_
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number
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boolean
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null
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}
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// check_json checks if the JSON string is valid.
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fn check_json(val string) ! {
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fn check_if_json_match[T](val string) ! {
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// check if the JSON string is empty
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if val == '' {
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return error('empty string')
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}
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// check if generic type matches the JSON type
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value_kind := get_value_kind(val[0])
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$if T is $option {
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// TODO
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} $else $if T is $sumtype {
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// TODO
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} $else $if T is $alias {
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// TODO
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} $else $if T is $string {
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if value_kind != .string_ {
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return error('Expected string, but got ${value_kind}')
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}
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} $else $if T is time.Time {
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if value_kind != .string_ {
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return error('Expected string, but got ${value_kind}')
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}
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} $else $if T is $map {
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if value_kind != .object {
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return error('Expected object, but got ${value_kind}')
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}
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} $else $if T is $array {
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if value_kind != .array {
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return error('Expected array, but got ${value_kind}')
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}
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} $else $if T is $struct {
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if value_kind != .object {
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return error('Expected object, but got ${value_kind}')
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}
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} $else $if T in [$enum, $int, $float] {
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if value_kind != .number {
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return error('Expected number, but got ${value_kind}')
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}
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} $else $if T is bool {
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if value_kind != .boolean {
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return error('Expected boolean, but got ${value_kind}')
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}
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} $else {
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return error('cannot encode value with ${value_kind} type')
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}
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}
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fn (mut checker Decoder) error(message string) ! {
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json := if checker.json.len < checker.checker_idx + 5 {
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checker.json
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} else {
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checker.json[0..checker.checker_idx + 5]
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}
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mut error_message := '\n'
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last_new_line := json.last_index_u8(`\n`)
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if last_new_line != -1 {
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error_message += json[last_new_line..checker.checker_idx]
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} else {
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error_message += json[0..checker.checker_idx]
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}
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error_message += [json[checker.checker_idx]].bytestr()
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error_message += '\n'
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if last_new_line != -1 {
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error_message += ' '.repeat(checker.checker_idx - last_new_line)
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} else {
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error_message += ' '.repeat(checker.checker_idx)
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}
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error_message += '^ ${message}'
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return error(error_message)
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}
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// check_json checks if the JSON string is valid.
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fn (mut checker Decoder) check_json_format(val string) ! {
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checker_end := checker.json.len
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// check if the JSON string is empty
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if val == '' {
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return checker.error('empty string')
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}
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// check if generic type matches the JSON type
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value_kind := get_value_kind(val[checker.checker_idx])
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start_idx_position := checker.checker_idx
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checker.values_info << ValueInfo{
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position: start_idx_position
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length: 0
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value_kind: value_kind
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}
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value_info_index := checker.values_info.len - 1
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match value_kind {
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.unknown {
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return checker.error('unknown value kind')
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}
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.null {
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// check if the JSON string is a null value
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if checker_end - checker.checker_idx <= 3 {
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return checker.error('EOF error: expecting `null`')
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}
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is_not_ok := unsafe {
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vmemcmp(checker.json.str + checker.checker_idx, 'null'.str, 4)
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}
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if is_not_ok != 0 {
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return checker.error('invalid null value. Got `${checker.json[checker.checker_idx..
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checker.checker_idx + 4]}` instead of `null`')
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}
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checker.checker_idx += 3
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}
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.object {
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checker.checker_idx++
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for val[checker.checker_idx] != `}` {
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// check if the JSON string is an empty object
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if checker_end - checker.checker_idx <= 2 {
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continue
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}
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if val[checker.checker_idx] != `"` {
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checker.checker_idx++
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}
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// skip whitespace
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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if checker.checker_idx >= checker_end - 1 {
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break
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}
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checker.checker_idx++
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}
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if val[checker.checker_idx] == `}` {
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continue
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}
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match val[checker.checker_idx] {
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`"` {
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// Object key
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checker.check_json_format(val)!
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for val[checker.checker_idx] != `:` {
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if checker.checker_idx >= checker_end - 1 {
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return checker.error('EOF error: key colon not found')
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}
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if val[checker.checker_idx] !in [` `, `\t`, `\n`] {
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return checker.error('invalid value after object key')
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}
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checker.checker_idx++
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}
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}
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`[`, `{`, `0`...`9`, `-`, `n`, `t`, `f` {
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// skip
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}
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`}` {
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return
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}
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`]` {
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return checker.error('Expecting key. Found closing bracket')
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}
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`,` {
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return checker.error('invalid object key')
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}
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`:` {
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return checker.error('empty object key')
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}
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else {
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return checker.error('`${[val[checker.checker_idx]].bytestr()}` is an invalid object key')
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}
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}
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if val[checker.checker_idx] != `:` {
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return checker.error('Expecting `:` after object key')
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}
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// skip `:`
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checker.checker_idx++
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// skip whitespace
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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checker.checker_idx++
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}
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match val[checker.checker_idx] {
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`"`, `[`, `{`, `0`...`9`, `-`, `n`, `t`, `f` {
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for val[checker.checker_idx] != `}` {
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if checker.checker_idx >= checker_end - 1 {
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return checker.error('EOF error: object value not closed')
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}
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checker.check_json_format(val)!
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// whitespace
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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checker.checker_idx++
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}
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if val[checker.checker_idx] == `}` {
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break
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}
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if checker.checker_idx >= checker_end - 1 {
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return checker.error('EOF error: braces are not closed')
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}
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if val[checker.checker_idx] == `,` {
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checker.checker_idx++
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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checker.checker_idx++
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}
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if val[checker.checker_idx] != `"` {
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return checker.error('Expecting object key')
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} else {
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break
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}
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} else {
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if val[checker.checker_idx] == `}` {
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break
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} else {
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return
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}
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}
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}
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}
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else {
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return checker.error('invalid object value')
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}
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}
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}
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if checker.checker_idx < checker_end - 1 {
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checker.checker_idx++
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}
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}
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.array {
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// check if the JSON string is an empty array
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if checker_end >= checker.checker_idx + 2 {
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checker.checker_idx++
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if val[checker.checker_idx] == `]` {
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return
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}
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} else {
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return checker.error('EOF error: There are not enough length for an array')
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}
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for val[checker.checker_idx] != `]` {
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// skip whitespace
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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if checker.checker_idx >= checker_end - 1 {
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break
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}
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checker.checker_idx++
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}
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if val[checker.checker_idx] == `]` {
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return
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}
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if checker.checker_idx >= checker_end - 1 {
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return checker.error('EOF error: array not closed')
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}
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checker.check_json_format(val)!
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// whitespace
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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checker.checker_idx++
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}
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if val[checker.checker_idx] == `]` {
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break
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}
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if checker.checker_idx >= checker_end - 1 {
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return checker.error('EOF error: braces are not closed')
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}
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if val[checker.checker_idx] == `,` {
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checker.checker_idx++
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for val[checker.checker_idx] in [` `, `\t`, `\n`] {
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checker.checker_idx++
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}
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if val[checker.checker_idx] == `]` {
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return checker.error('Cannot use `,`, before `]`')
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}
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continue
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} else {
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if val[checker.checker_idx] == `]` {
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break
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} else {
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return checker.error('`]` after value')
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}
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}
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}
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}
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.string_ {
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// check if the JSON string is a valid string
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if checker.checker_idx >= checker_end - 1 {
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return checker.error('EOF error: string not closed')
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}
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checker.checker_idx++
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// check if the JSON string is a valid escape sequence
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for val[checker.checker_idx] != `"` && val[checker.checker_idx - 1] != `\\` {
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if val[checker.checker_idx] == `\\` {
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if checker.checker_idx + 1 >= checker_end - 1 {
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return checker.error('invalid escape sequence')
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}
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escaped_char := val[checker.checker_idx + 1]
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match escaped_char {
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`/`, `b`, `f`, `n`, `r`, `t`, `"`, `\\` {}
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`u` {
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// check if the JSON string is a valid unicode escape sequence
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escaped_char_last_index := checker.checker_idx + 5
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if escaped_char_last_index < checker_end - 1 {
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// 2 bytes for the unicode escape sequence `\u`
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checker.checker_idx += 2
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for checker.checker_idx < escaped_char_last_index {
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match val[checker.checker_idx] {
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`0`...`9`, `a`...`f`, `A`...`F` {
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checker.checker_idx++
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}
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else {
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return checker.error('invalid unicode escape sequence')
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}
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}
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}
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// REVIEW: Should we increment the index here?
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continue
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} else {
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return checker.error('short unicode escape sequence ${checker.json[checker.checker_idx..
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escaped_char_last_index + 1]}')
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}
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}
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else {
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return checker.error('unknown escape sequence')
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}
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}
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}
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checker.checker_idx++
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}
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}
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.number {
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// check if the JSON string is a valid float or integer
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mut is_negative := val[0] == `-`
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mut has_dot := false
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mut digits_count := 1
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if is_negative {
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checker.checker_idx++
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}
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for checker.checker_idx < checker_end - 1
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&& val[checker.checker_idx + 1] !in [`,`, `}`, `]`, ` `, `\t`, `\n`]
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&& checker.checker_idx < checker_end - 1 {
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if val[checker.checker_idx] == `.` {
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if has_dot {
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return checker.error('invalid float. Multiple dots')
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}
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has_dot = true
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checker.checker_idx++
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continue
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} else if val[checker.checker_idx] == `-` {
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if is_negative {
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return checker.error('invalid float. Multiple negative signs')
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}
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checker.checker_idx++
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continue
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} else {
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if val[checker.checker_idx] < `0` || val[checker.checker_idx] > `9` {
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return checker.error('invalid number')
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}
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}
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if digits_count >= 64 {
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return checker.error('number exceeds 64 digits')
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}
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digits_count++
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checker.checker_idx++
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}
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}
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.boolean {
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// check if the JSON string is a valid boolean
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match val[checker.checker_idx] {
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`t` {
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if checker_end - checker.checker_idx <= 3 {
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return checker.error('EOF error: expecting `true`')
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}
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is_not_ok := unsafe {
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vmemcmp(checker.json.str + checker.checker_idx, 'true'.str, 4)
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}
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if is_not_ok != 0 {
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return checker.error('invalid boolean value. Got `${checker.json[checker.checker_idx..
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checker.checker_idx + 4]}` instead of `true`')
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}
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checker.checker_idx += 3
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}
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`f` {
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if checker_end - checker.checker_idx <= 4 {
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return checker.error('EOF error: expecting `false`')
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}
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is_not_ok := unsafe {
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vmemcmp(checker.json.str + checker.checker_idx, 'false'.str, 5)
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}
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if is_not_ok != 0 {
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return checker.error('invalid boolean value. Got `${checker.json[checker.checker_idx..
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checker.checker_idx + 5]}` instead of `false`')
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}
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checker.checker_idx += 4
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}
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else {
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return checker.error('invalid boolean')
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}
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}
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}
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}
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checker.values_info[value_info_index].length = checker.checker_idx + 1 - start_idx_position
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if checker.checker_idx < checker_end - 1 {
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checker.checker_idx++
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}
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for checker.checker_idx < checker_end - 1 && val[checker.checker_idx] !in [`,`, `:`, `}`, `]`] {
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// get trash characters after the value
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if val[checker.checker_idx] !in [` `, `\t`, `\n`] {
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checker.error('invalid value. Unexpected character after ${value_kind} end')!
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} else {
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// whitespace
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}
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checker.checker_idx++
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}
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}
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// decode decodes a JSON string into a specified type.
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pub fn decode[T](val string) !T {
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check_json(val)!
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mut nodes := []Node{}
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mut decoder := Decoder{
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json: val
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json: val
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values_info: []ValueInfo{}
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}
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// TODO: needs performance improvements
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decoder.fulfill_nodes(mut nodes)
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decoder.check_json_format(val)!
|
||||
check_if_json_match[T](val)!
|
||||
|
||||
mut result := T{}
|
||||
decoder.decode_value(nodes, &result)
|
||||
decoder.decode_value(mut &result)!
|
||||
return result
|
||||
}
|
||||
|
||||
// decode_value decodes a value from the JSON nodes.
|
||||
fn (mut decoder Decoder) decode_value[T](nodes []Node, val &T) {
|
||||
fn (mut decoder Decoder) decode_value[T](mut val T) ! {
|
||||
$if val is $option {
|
||||
} $else $if T is string {
|
||||
} $else $if T is $sumtype {
|
||||
|
|
@ -64,6 +507,10 @@ fn (mut decoder Decoder) decode_value[T](nodes []Node, val &T) {
|
|||
} $else $if T is $map {
|
||||
} $else $if T is $array {
|
||||
} $else $if T is $struct {
|
||||
mut nodes := []Node{}
|
||||
// TODO: needs performance improvements
|
||||
decoder.fulfill_nodes(mut nodes)
|
||||
|
||||
decoder.decode_struct(nodes, val)
|
||||
} $else $if T is $enum {
|
||||
} $else $if T is $int {
|
||||
|
|
@ -81,7 +528,8 @@ fn get_value_kind(value rune) ValueKind {
|
|||
`t`, `f` { .boolean }
|
||||
`{` { .object }
|
||||
`[` { .array }
|
||||
`0`...`9` { .number }
|
||||
`0`...`9`, `-` { .number }
|
||||
`n` { .null }
|
||||
else { .unknown }
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue