// vector.h
#ifndef VECTOR_H
#define VECTOR_H

#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#define vector_header(name, type) \
    struct { \
        size_t size; \
        size_t cap; \
        type *data; \
    } name \

#define vector_init(vec) \
    do { \
        (vec).size = 0, \
        (vec).cap = 0, \
        (vec).data = NULL; \
    } while(0)

#define vector_push(vec, value) \
    do { \
        if (vec.size >= vec.cap) { \
            int cap = vec.cap ? vec.cap * 2 : 8; \
            void* data = realloc(vec.data, cap * sizeof(*vec.data)); \
            if (!data) { \
                fprintf(stderr, "vector_push: realloc failed\n"); \
                exit(1); \
            } \
            (vec).cap = cap; \
            (vec).data = data; \
        } \
        (vec).data[(vec).size++] = value; \
    } while(0)

#define vector_pop(vec) \
    ((vec).data[--(vec).size])

#define vector_at(vec, idx) \
    (((vec).data)[idx])

#define vector_idx(vec, ptr) \
    ((ptr) - (vec).data)

#define vector_free(vec) \
    do { \
        free((vec).data); \
        (vec).data = NULL; \
        (vec).size = (vec).cap = 0; \
    } while(0)

#endif