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


/* Error constants */
enum
    {
    UNKNOWN_FAIL = 1,
    MALLOC_FAIL,
    NEEDARG_FAIL,
    FOPEN_FAIL,
    WRITE_FAIL,
    TIME_FAIL,
    MISC_FAIL
    };

/* Standard data identifiers for nodes */
enum
    {
    CHAR = 1,
    INT,
    LONG,
    DOUBLE,
    CHARP,
    INTP,
    LONGP,
    DOUBLEP,
    NODEP
    };

/* node - node type suitable for being a member in a linked list. */
/* name - the name of the data in this node */
/* data - pointer to arbitrary data */
/* type - implementation-defined identifier for what kind of data this node holds */
typedef struct LNODE
    {
    struct LNODE *previous;
    char *name;
    void *data;
    int type;
    struct LNODE *next;
    } node;


/* 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);
	case TIME_FAIL: printf("time error: %s\n", (char *) info);
	    exit(TIME_FAIL);
	case MISC_FAIL: printf("%s\n", (char *) info);
	    exit(MISC_FAIL);
	default: printf("You shouldn't be seeing this.\nSomething is very wrong.\n");
	    exit(-256);
	}
    }


/* 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;
    }

/* 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;
    }

/* open stdin if path is null */
FILE *file_open(char *path, char *mode)
    {
    FILE *fd;

    fd = 0;
    

    if(!mode)
	{
	return(NULL);
	}

    if(path == NULL || !strcmp(path, "-"))
	{
	fd = fopen("/dev/stdin", mode);
	}
    else
	{
	fd = fopen(path, mode);
	}

    if(!fd)
	{
	return(NULL);
	}
    

    return(fd);
    }


/* return a buffer containing the contents of fd, or NULL if failure. Store the size of the new buffer in newsize; -1 on fail. */
char *file_read(FILE *fd, int *newsize)
    {
    int bufsize, c, i;
    
    char *buf, *tmpbuf;

    /* bufsize is arbitrary */
    bufsize = 4096;
    c = i = 0;

    buf = tmpbuf = 0;


    if( !(buf = malloc(bufsize)))
	{
	*newsize = -1;
	return(NULL);
	}

    for(i = 0; (c = fgetc(fd)) != EOF; i++)
	{
	if(i >= bufsize)
	    {
	    if( !(tmpbuf = malloc(bufsize *= 2)))
		{
		*newsize = -1;
		return(NULL);
		}

	    memcpy(tmpbuf, buf, i-1);
	    free(buf);
	    buf = tmpbuf;
	    }
	
	buf[i] = c;
	}

    
    *newsize = i;
    return(buf);
    }


node *node_create()
    {
    node *newnode;

    newnode = 0;


    ;


    return(newnode);
    }

int node_free(node *todel)
    {
    node *nodep;

    
    nodep = todel->previous;
    nodep->next = todel->next;

    
    free(todel->name);
    free(todel->data);
    free(todel);
    

    return(0);
    }


/* concat - return a buffer of size new_size containing s1 and s2 concatenated. */
char *concat(char *a1, char *a2, int a1_size, int a2_size)
    {
    char *newbuf;

    newbuf = 0;


    if( !(newbuf = malloc(a1_size+a2_size)))
	{
	throw(MALLOC_FAIL, "concat: couldn't create buffer");
	}

    
    if(a1_size)
	{
	memcpy(newbuf, a1, a1_size);
	}

    if(a2_size)
	{
	memcpy((newbuf + a1_size), a2, a2_size);
	}

    
    return(newbuf);
    }