src/stdlib/simpleparse.h


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#pragma once

// This file defines some functions to make it easy to parse simply formatted
// strings **correctly** without memory bugs.
//
//     strparse(input_str, format...) - parse a string
//
// Examples:
//
//     const char *filename; long line_num;
//     const char *err = NULL;
//     if ((err=strparse("foo.c:12", &filename, ":", &line_num)))
//         errx(1, "Failed to parse file:line at: ", err);
//
//     const char *item1, *item2;
//     if ((err=strparse("one, two", &item1, ",", PARSE_WHITESPACE, &item2)))
//         errx(1, "Failed to parse items at: ", err);

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

#include "mapmacro.h"

typedef struct {
    char c;
} some_char_t;
#define PARSE_SOME_OF(chars) ((some_char_t *)chars)
#define PARSE_WHITESPACE PARSE_SOME_OF(" \t\r\n\v")
typedef enum { PARSE_LITERAL, PARSE_LONG, PARSE_DOUBLE, PARSE_BOOL, PARSE_STRING, PARSE_SOME_OF } parse_type_e;

typedef struct {
    parse_type_e type;
    void *dest;
} parse_element_t;

#define _parse_type(dest)                                                                                              \
    _Generic((dest),                                                                                                   \
        some_char_t *: PARSE_SOME_OF,                                                                                  \
        const char *: PARSE_LITERAL,                                                                                   \
        char *: PARSE_LITERAL,                                                                                         \
        const char **: PARSE_STRING,                                                                                   \
        char **: PARSE_STRING,                                                                                         \
        double *: PARSE_DOUBLE,                                                                                        \
        long *: PARSE_LONG,                                                                                            \
        bool *: PARSE_BOOL)

#define as_void_star(x) ((void *)x)
#define strparse(str, ...)                                                                                             \
    simpleparse(str, sizeof((const void *[]){__VA_ARGS__}) / sizeof(void *),                                           \
                (parse_type_e[]){MAP_LIST(_parse_type, __VA_ARGS__)}, (void *[]){MAP_LIST(as_void_star, __VA_ARGS__)})
#define fparse(file, ...)                                                                                              \
    ({                                                                                                                 \
        char *_file_contents = NULL;                                                                                   \
        size_t _capacity;                                                                                              \
        ssize_t _just_read = getdelim(&_file_contents, &_capacity, '\0', file);                                        \
        const char *_parse_err = _just_read > 0 ? strparse(_file_contents, __VA_ARGS__) : "No such file";              \
        if (_file_contents) free(_file_contents);                                                                      \
        _parse_err;                                                                                                    \
    })

const char *simpleparse(const char *str, int n, parse_type_e types[n], void *destinations[n]);