#include <iso646.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>


enum {
    UNKNOWN_FAIL = 1,
    MALLOC_FAIL,
    NEEDARG_FAIL,
    FOPEN_FAIL,
    WRITE_FAIL
    };


/* arrccat -- function to copy arr2len bytes from arr2 to the arr1len'th position of arr1. returns *newarr, and stores the length */
/* of newarr[] in arr1len (that's why it needs to be a pointer to arr1len and not just a long unsigned integer).                  */
char *arrccat(char *arr1, char *arr2, size_t *arr1len, size_t arr2len)
    {
    char *newarr;
    unsigned int i, i2;
    newarr = malloc(*arr1len+arr2len);
    i = i2 = 0;

    for(i = 0; i < *arr1len; i++)
	{
	newarr[i] = arr1[i];
	}

    for(i2 = 0; i2 < arr2len; i2++, i++)
	{
	newarr[i] = arr2[i2];
	}
    
    *arr1len = *arr1len+arr2len;

    return newarr;
    }

/* Condition should be one of the above enum'd strings. Info is optional; it can just be NULL when irrelevant. */
void throw(long unsigned int condition, void *info)
    {
    switch(condition)
	{
	case UNKNOWN_FAIL: printf("unknown failure\n");
	    exit(UNKNOWN_FAIL);
	case MALLOC_FAIL: printf("malloc failure\n");
	    exit(MALLOC_FAIL);
	case NEEDARG_FAIL: printf("usage: %s\n", (char *) info);
	    exit(NEEDARG_FAIL);
	case FOPEN_FAIL: printf("failed to open: %s\n", (char *) info);
	    exit(FOPEN_FAIL);
	case WRITE_FAIL: printf("failed to write: %s\n", (char *) info);
	    exit(WRITE_FAIL);
	default: printf("You shouldn't be seeing this.\nSomething is very wrong.\n");
	    exit(-256);
	}
    }

/* mastrcat -- improved string concat function. returns a pointer to the first element in a buffer containing the strings str1 */
/* and str2 joined end-to-end. */ 
char *mastrcat(char *str1, char *str2)
    {
    unsigned long int nbi, stri, nbsize;
    char *nbuf;
    nbi = stri = 0;
    nbsize = (strlen(str1) + strlen(str2));
    nbuf = malloc(nbsize);

    for(stri = 0; str1[stri] != '\0'; nbi++, stri++)
        {
        nbuf[nbi] = str1[stri];
        }

    for(stri = 0; str2[stri] != '\0'; nbi++, stri++)
        {
        nbuf[nbi] = str2[stri];
        }
    
    return nbuf;
        }