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Add keyword support

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This commit is contained in:
Abdelrahman Said
2023-06-17 22:10:48 +01:00
parent aff2735b9f
commit ed9b5fb638
2 changed files with 168 additions and 32 deletions
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192
src/lexer/lexer_states.c
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@@ -3,28 +3,28 @@
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_KEYWORD_LENGTH 5
#define MAX_STACK_CAPACITY 1024
// clang-format off
typedef enum {
// GENERAL STATES
// GENERAL STATES
LEXER_STATE_START,
LEXER_STATE_ERROR,
LEXER_STATE_VALUE,
LEXER_STATE_KEYWORD,
// COLLECTION STATES
LEXER_STATE_OBJECT_START,
LEXER_STATE_OBJECT,
LEXER_STATE_OBJECT_END,
LEXER_STATE_ARRAY_START,
LEXER_STATE_ARRAY,
LEXER_STATE_ARRAY_END,
LEXER_STATE_LAST_COLLECTION,
// OBJECT STATES
LEXER_STATE_KEY,
// NUMBER STATES
// COLLECTION STATES
LEXER_STATE_OBJECT_START,
LEXER_STATE_OBJECT,
LEXER_STATE_OBJECT_END,
LEXER_STATE_ARRAY_START,
LEXER_STATE_ARRAY,
LEXER_STATE_ARRAY_END,
LEXER_STATE_LAST_COLLECTION,
// OBJECT STATES
LEXER_STATE_KEY,
// NUMBER STATES
LEXER_STATE_DECIMAL,
LEXER_STATE_NUMBER,
LEXER_STATE_FRACTION,
@@ -32,32 +32,45 @@ typedef enum {
LEXER_STATE_EXP_SIGN,
LEXER_STATE_POWER,
LEXER_STATE_NUMBER_END,
// STRING STATES
LEXER_STATE_STRING,
LEXER_STATE_STRING_END,
LEXER_STATE_ESCAPE_SEQUENCE,
LEXER_STATE_UNICODE_HEX,
// STRING STATES
LEXER_STATE_STRING,
LEXER_STATE_STRING_END,
LEXER_STATE_ESCAPE_SEQUENCE,
LEXER_STATE_UNICODE_HEX,
// KEYWORD STATES
LEXER_STATE_TRUE,
LEXER_STATE_FALSE,
LEXER_STATE_NULL,
LEXER_STATE_KEYWORD_END,
COUNT_LEXER_STATES,
} lexer_state_t;
// clang-format on
typedef struct {
lexer_state_t stack[MAX_STACK_CAPACITY];
u64 size;
} state_stack_t;
typedef struct {
u64 size;
char str[MAX_KEYWORD_LENGTH + 1];
} keyword_t;
struct lexer {
lexer_state_t current;
state_stack_t stack;
u64 line;
u64 column;
char current_keyword[MAX_KEYWORD_LENGTH + 1];
keyword_t keyword;
};
void stack_push(state_stack_t *stack, lexer_state_t value);
lexer_state_t stack_pop(state_stack_t *stack);
void append_to_keyword(keyword_t *kw, char input);
void clear_keyword(keyword_t *kw);
bool strequal(const char *first, const char *second);
void lexer_state_machine(lexer_t *lexer, char input);
lexer_state_t handle_lexer_start(char input);
lexer_state_t handle_last_collection(char input);
@@ -76,6 +89,11 @@ lexer_state_t handle_exponent(char input);
lexer_state_t handle_exp_sign(char input);
lexer_state_t handle_power(lexer_t *lexer, char input);
lexer_state_t handle_number_end(lexer_t *lexer, char input);
lexer_state_t handle_keyword(char input);
lexer_state_t handle_true(lexer_t *lexer, char input);
lexer_state_t handle_false(lexer_t *lexer, char input);
lexer_state_t handle_null(lexer_t *lexer, char input);
lexer_state_t handle_keyword_end(lexer_t *lexer, char input);
bool validate_json(char *json) {
lexer_t lexer = {0};
@@ -112,6 +130,23 @@ lexer_state_t stack_pop(state_stack_t *stack) {
return state;
}
void append_to_keyword(keyword_t *kw, char input) {
if (kw->size + 1 > MAX_KEYWORD_LENGTH) {
return;
}
kw->str[(kw->size)++] = input;
}
void clear_keyword(keyword_t *kw) {
memset(kw->str, 0, MAX_KEYWORD_LENGTH + 1);
kw->size = 0;
}
bool strequal(const char *first, const char *second) {
return strcmp(first, second) == 0;
}
void lexer_state_machine(lexer_t *lexer, char input) {
switch (lexer->current) {
case LEXER_STATE_START:
@@ -120,19 +155,17 @@ void lexer_state_machine(lexer_t *lexer, char input) {
case LEXER_STATE_VALUE:
lexer->current = handle_value(lexer, input);
break;
case LEXER_STATE_KEYWORD:
break;
case LEXER_STATE_OBJECT_START:
stack_push(&(lexer->stack), LEXER_STATE_OBJECT);
// break is left intentionally here to utilise the fallthrough behaviour of
// the switch statement
// break is left out intentionally here to utilise the fallthrough behaviour
// of the switch statement
case LEXER_STATE_OBJECT:
lexer->current = handle_object(lexer, input);
break;
case LEXER_STATE_ARRAY_START:
stack_push(&(lexer->stack), LEXER_STATE_ARRAY);
// break is left intentionally here to utilise the fallthrough behaviour of
// the switch statement
// break is left out intentionally here to utilise the fallthrough behaviour
// of the switch statement
case LEXER_STATE_ARRAY:
lexer->current = handle_array(lexer, input);
break;
@@ -182,6 +215,18 @@ void lexer_state_machine(lexer_t *lexer, char input) {
break;
case LEXER_STATE_UNICODE_HEX:
break;
case LEXER_STATE_TRUE:
lexer->current = handle_true(lexer, input);
break;
case LEXER_STATE_FALSE:
lexer->current = handle_false(lexer, input);
break;
case LEXER_STATE_NULL:
lexer->current = handle_null(lexer, input);
break;
case LEXER_STATE_KEYWORD_END:
lexer->current = handle_keyword_end(lexer, input);
break;
case LEXER_STATE_LAST_COLLECTION:
lexer->current = handle_last_collection(input);
break;
@@ -282,7 +327,9 @@ lexer_state_t handle_value(lexer_t *lexer, char input) {
case 't':
case 'f':
case 'n':
return LEXER_STATE_KEYWORD;
append_to_keyword(&(lexer->keyword), input);
return handle_keyword(input);
}
return LEXER_STATE_ERROR;
@@ -426,3 +473,92 @@ lexer_state_t handle_number_end(lexer_t *lexer, char input) {
return collection_end ? handle_collection_end(lexer, input)
: LEXER_STATE_ERROR;
}
lexer_state_t handle_keyword(char input) {
switch (input) {
case 't':
return LEXER_STATE_TRUE;
case 'f':
return LEXER_STATE_FALSE;
case 'n':
return LEXER_STATE_NULL;
}
return LEXER_STATE_ERROR;
}
lexer_state_t handle_true(lexer_t *lexer, char input) {
char current[MAX_KEYWORD_LENGTH + 1];
strcpy(current, lexer->keyword.str);
append_to_keyword(&(lexer->keyword), input);
bool return_state_true = (strequal(current, "t") && input == 'r') ||
(strequal(current, "tr") && input == 'u');
bool return_state_end = strequal(current, "tru") && input == 'e';
if (return_state_true) {
return LEXER_STATE_TRUE;
} else if (return_state_end) {
return LEXER_STATE_KEYWORD_END;
}
return LEXER_STATE_ERROR;
}
lexer_state_t handle_false(lexer_t *lexer, char input) {
char current[MAX_KEYWORD_LENGTH + 1];
strcpy(current, lexer->keyword.str);
append_to_keyword(&(lexer->keyword), input);
bool return_state_false = (strequal(current, "f") && input == 'a') ||
(strequal(current, "fa") && input == 'l') ||
(strequal(current, "fal") && input == 's');
bool return_state_end = strequal(current, "fals") && input == 'e';
if (return_state_false) {
return LEXER_STATE_FALSE;
} else if (return_state_end) {
return LEXER_STATE_KEYWORD_END;
}
return LEXER_STATE_ERROR;
}
lexer_state_t handle_null(lexer_t *lexer, char input) {
char current[MAX_KEYWORD_LENGTH + 1];
strcpy(current, lexer->keyword.str);
append_to_keyword(&(lexer->keyword), input);
bool return_state_null = (strequal(current, "n") && input == 'u') ||
(strequal(current, "nu") && input == 'l');
bool return_state_end = strequal(current, "nul") && input == 'l';
if (return_state_null) {
return LEXER_STATE_NULL;
} else if (return_state_end) {
return LEXER_STATE_KEYWORD_END;
}
return LEXER_STATE_ERROR;
}
lexer_state_t handle_keyword_end(lexer_t *lexer, char input) {
clear_keyword(&(lexer->keyword));
if (isspace(input)) {
return LEXER_STATE_KEYWORD_END;
} else if (input == ',') {
return lexer->stack.stack[lexer->stack.size - 1];
}
bool collection_end = input == '}' || input == ']';
return collection_end ? handle_collection_end(lexer, input)
: LEXER_STATE_ERROR;
}