#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

enum { MAXIMUM_SIZE = 4096 };

struct FileContent {
    ssize_t size;
    char *data;
};

ssize_t inputAmount(int fd, char *buf) {
    ssize_t symbols = 0;
    while (symbols < MAXIMUM_SIZE) {
        ssize_t readPart = read(fd, buf + symbols, MAXIMUM_SIZE - symbols);
        if (readPart == -1) {
            return -1;
        } else if (readPart == 0){
            return symbols;
        }
        symbols += readPart;
    }
    return symbols;
}

struct FileContent read_file(int fd) {
    ssize_t symbols = 0, readedSymbols = 0, memSize = 1;
    struct FileContent badExit = { -1, NULL };
    char *data = malloc(sizeof(*data));
    char buf[MAXIMUM_SIZE];
    if (!data) {
        return badExit;
    }

    int reading = 1;
    while (reading) {
        ssize_t reading = inputAmount(fd, buf);
        if (reading == -1) {
            free(data);
            return badExit;
        }
        if (!reading) {
            break;
        }

        while (readedSymbols + symbols >= memSize) {
            memSize *= 2;
        }
        char * copydata = realloc(data, memSize * sizeof(*copydata));
        if (!copydata) {
            free(data);
            return badExit;
        }
        data = copydata;
        memcpy(data + readedSymbols, buf, symbols);
        readedSymbols += symbols;
    }

    data[readedSymbols] = 0;
    badExit.size = readedSymbols;
    badExit.data = data;
    return badExit;
};

int main(int argc, char **argv) {
    int fd = open("in.txt", O_RDONLY);
    printf("%d\n", fd);
    struct FileContent kek = read_file(fd);
    printf("%d\n", kek.size);
    for (int i = 0; i < kek.size; ++i) {
        printf("%c", kek.data[i]);
    }
    printf("\n");
    free(kek.data);
    return 0;
}