109 lines
1.8 KiB
C
109 lines
1.8 KiB
C
#include <ctype.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#define ARR_LEN(X) (sizeof(X) / sizeof(X[0]))
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typedef enum {
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STATE_START,
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STATE_INVALID,
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STATE_OBJ,
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STATE_ARR,
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STATE_END,
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} states;
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states handle_start(char input);
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states handle_obj(char input);
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states handle_arr(char input);
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states state_machine(states current, char input);
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bool check_input(const char *text);
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// clang-format off
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const char *inputs[] = {
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"{}",
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"[]",
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"{ }",
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"[ ]",
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" {}",
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" []",
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"{} ",
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"[] ",
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"{",
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"[",
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"}",
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"]",
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"{f}",
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"[8]",
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};
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// clang-format on
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int main(int argc, char *argv[]) {
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for (int i = 0; i < ARR_LEN(inputs); ++i) {
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printf("%20s is %s\n", inputs[i],
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check_input(inputs[i]) ? "VALID" : "INVALID");
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}
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return EXIT_SUCCESS;
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}
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bool check_input(const char *text) {
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states current = STATE_START;
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for (const char *c = &(text[0]); *c != '\0'; ++c) {
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current = state_machine(current, *c);
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}
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return current == STATE_END;
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}
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states handle_start(char input) {
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if (isspace(input)) {
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return STATE_START;
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}
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switch (input) {
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case '{':
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return STATE_OBJ;
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case '[':
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return STATE_ARR;
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default:
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return STATE_INVALID;
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}
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}
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states handle_obj(char input) {
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if (isspace(input)) {
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return STATE_OBJ;
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} else if (input == '}') {
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return STATE_END;
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}
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return STATE_INVALID;
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}
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states handle_arr(char input) {
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if (isspace(input)) {
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return STATE_ARR;
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} else if (input == ']') {
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return STATE_END;
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}
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return STATE_INVALID;
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}
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states state_machine(states current, char input) {
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switch (current) {
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case STATE_START:
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return handle_start(input);
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case STATE_OBJ:
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return handle_obj(input);
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case STATE_ARR:
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return handle_arr(input);
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default:
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return current;
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}
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}
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