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petabyt/gist:3b1733728f9da6eb61db5eb423753468

Created December 26, 2023 01:30
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  1. petabyt created this gist Dec 26, 2023.
    233 changes: 233 additions & 0 deletions gistfile1.txt
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,233 @@
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>

    #define JSON_OBJ '{'
    #define JSON_ARR '['
    #define JSON_STR 's'
    #define JSON_NUM 'n'

    #define JSON_END_OBJ '}'
    #define JSON_END_ARR ']'
    #define JSON_COMMA ','
    #define JSON_KEY ':'

    struct Parse {
    char *b;
    char *intent;
    char intent_type;
    char intent_key[16];
    int intent_i;

    char type;
    char *str;
    int str_len;
    unsigned int value;
    };

    static int next(struct Parse *p) {
    char *b = p->b;

    while (*b == ' ' || *b == '\n') {
    b++;
    }

    if (*b == '\0') return 1;

    int type;

    if (*b == '{') {
    type = JSON_OBJ;
    } else if (*b == '[') {
    type = JSON_ARR;
    } else if (*b == '\"') {
    type = JSON_STR;
    b++;
    p->str = b;
    p->str_len = 0;
    while (*b != '\"') {
    b++;
    p->str_len++;
    if (*b == '\\') {
    b += 2;
    p->str_len += 2;
    }
    }
    } else if (*b == '\'') {
    type = JSON_STR;
    b++;
    p->str = b;
    p->str_len = 0;
    while (*b != '\'') {
    b++;
    p->str_len++;
    }
    } else if (*b >= '0' && *b <= '9') {
    type = JSON_NUM;
    unsigned int v = 0;
    while (*b >= '0' && *b <= '9') {
    v *= 10;
    v += (*b) - '0';
    b++;
    }
    p->value = v;
    b--;
    } else if (*b == ':') {
    type = JSON_KEY;
    } else if (*b == '}') {
    type = JSON_END_OBJ;
    } else if (*b == ']') {
    type = JSON_END_ARR;
    } else if (*b == ',') {
    type = JSON_COMMA;
    } else {
    printf("Unknown tok %c (%s)\n", *b, b);
    exit(1);
    return 1;
    }

    printf("Tok: %c\n", type);
    p->type = type;

    b++;
    p->b = b;

    return 0;
    }

    static int next_intent(struct Parse *p) {
    struct Parse p2;
    p2.b = p->intent;

    if (next(&p2)) return 1;

    if (p2.type == JSON_ARR) {
    next(&p2);
    if (p2.type == JSON_STR) {
    strncpy(p->intent_key, p2.str, p2.str_len);
    p->intent_type = JSON_STR;
    } else if (p2.type == JSON_NUM) {
    p->intent_i = (int)p2.value;
    p->intent_type = JSON_NUM;
    }
    }

    if (next(&p2)) return 1;

    p->intent = p2.b;

    return 0;
    }

    static int parse_block(struct Parse *p, int skip);

    static int parse_array(struct Parse *p, int skip) {
    int i = 0;
    while (!next(p)) {
    int ignore = 1;
    if (!skip) {
    if (p->intent_i == i) {
    next_intent(p);
    ignore = 0;
    }
    }

    if (p->type == JSON_STR) {
    if (!ignore) return 1;
    } else if (p->type == JSON_NUM) {
    if (!ignore) return 1;
    } else if (p->type == JSON_OBJ) {
    parse_block(p, ignore);
    if (!ignore) return 1;
    } else if (p->type == JSON_ARR) {
    parse_array(p, ignore);
    if (!ignore) return 1;
    } else if (p->type == JSON_END_ARR) {
    return 0;
    } else if (p->type == JSON_COMMA) {
    i++;
    continue;
    } else {
    printf("arr: unexpected type %c\n", p->type);
    }
    }

    return 1;
    }

    static int parse_block(struct Parse *p, int skip) {
    while (!next(p)) {
    if (p->type == JSON_STR) {
    int ignore = 1;
    if (!skip && p->intent_type == JSON_STR) {
    if (!strncmp(p->str, p->intent_key, p->str_len)) {
    ignore = 0;
    next_intent(p);
    }
    }
    next(p);
    if (p->type == JSON_KEY) {
    next(p);
    if (p->type == JSON_OBJ) {
    if (parse_block(p, ignore)) return 1;
    } else if (p->type == JSON_ARR) {
    if (parse_array(p, ignore)) return 1;
    }

    if (!ignore) return 1;
    }
    next(p);
    if (p->type == JSON_END_OBJ) {
    return 0;
    } else if (p->type != JSON_COMMA) {
    printf("Expected comma, %c\n", p->type);
    }
    } else if (p->type == JSON_END_OBJ) {
    return 0;
    } else {
    printf("key: nexpected type %c\n", p->type);
    }
    }

    return 1;
    }

    int json_get(struct Parse *p, char *text, char *intent) {
    p->intent = intent;
    p->b = text;
    next_intent(p);

    next(p);
    if (p->type == JSON_OBJ) {
    parse_block(p, 0);
    }

    return 1;
    }

    int main() {
    FILE *f = fopen("c.txt", "rb");
    if (!f) {
    puts("File err");
    return 1;
    }

    fseek(f, 0, SEEK_END);
    long size = ftell(f);
    fseek(f, 0, SEEK_SET);

    char *data = (char *)malloc(size + 1);
    fread(data, 1, size, f);
    fclose(f);
    data[size] = '\0';

    struct Parse p;
    json_get(&p, data, "['amendments'][10]");

    char *buf = malloc(p.str_len);
    strncpy(buf, p.str, p.str_len + 1);
    buf[p.str_len] = '\0';
    printf("Result: %s\n", buf);

    return 0;
    }