/************************************************************************/
/*									*/
/* This routine is responsible for creating a memory image of a 	*/
/* disk file.  It allocates the necessary memory space, then reads the	*/
/* file into that space in a reasonably efficient manner.		*/
/* Should not be called without doing vex_init() first.			*/
/*									*/
/*	Inputs:		fp		Open file pointer		*/
/*									*/
/*	Output:		return value	Number of bytes read		*/
/*									*/
/* Created August 6 1996 by CJL						*/
/* Rewritten Jan 2 1997 by CJL						*/
/* Stolen almost unmodified from $DFIO 20 August 1998 by CJL		*/
/*									*/
/************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "mk4_vex.h"
#include "mk4_util.h"

int
read_file (FILE *fp)
    {
    size_t nb;
    int fd;
    size_t size;
    struct stat file_status;
    char *ptr;
    extern char *vexstart, *vexend;
					/* Map stream pointer onto file */
					/* descriptor, and make stat() call */
					/* to figure out file size */
    if ((fd = fileno (fp)) < 0)
	{
	msg ("Problem with stream pointer in read_file()", 2);
	return (-1);
	}
    if (fstat (fd, &file_status) != 0)
	{
	msg ("Problem making stat call in read_file()", 2);
	return (-1);
	}
    size = file_status.st_size;
					/* Allocate memory for entire file */
					/* plus 1 for null termination */
    if ((ptr = (char *)malloc (size+1)) == NULL)
	{
	msg ("Memory allocation error in read_file()", 2);
	return (-1);
	}
					/* Make sure we are at start of file */
    rewind (fp);
					/* Read file in a single call, let */
					/* system figure out best buffering */
    nb = fread (ptr, sizeof(char), size, fp);
					/* Did it go OK? */
    if (nb != size)
	{
	msg ("Error, expected %zu bytes, read %zu bytes", 2, size, nb);
	return (-1);
	}

    vexstart = ptr;
    vexend = ptr + nb;
					/* Null terminate string */
    *vexend = '\0';

    return (nb);
    }