/*
********************************************************************
*
* PCX_COMM.C - PCX_LIB Library Common Functions
*
* Version: 1.00B
*
* History: 91/02/14 - Created
* 91/04/01 - Release 1.00A
* 91/04/03 - fixed "segread" call.
* 91/04/07 - Release 1.00B
*
* Compiler: Microsoft C V6.0
*
* Author: Ian Ashdown, P.Eng.
* byHeart Software
* 620 Ballantree Road
* West Vancouver, B.C.
* Canada V7S 1W3
* Tel. (604) 922-6148
* Fax. (604) 987-7621
*
* Copyright: Public Domain
*
********************************************************************
*/
/*
********************************************************************
*
* PORTABILITY NOTES
*
* 1. While this program is written in ANSI C, it uses a
* number of function calls that are specific to the
* Microsoft C V6.0 library. These are documented as
* follows for the purposes of porting this program to
* other compilers and/or processors:
*
* int86x - execute 80x86 interrupt routine (far data)
* segread - get current 80x86 segment register values
*
******************************************************************
*/
/* INCLUDE FILES */
#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include "pcx_int.h"
/* FORWARD REFERENCES */
/* GLOBALS */
/* PUBLIC FUNCTIONS */
/*
*****************************************************************
*
* PCX_OPEN - Open PCX Workblock
*
* Purpose: To allocate and initialize a PCX image file
* workblock.
*
* Setup: PCX_WORKBLK *pcx_open
* (
* char *fname,
* BOOL wrt_flag
* )
*
* Where: fname is a PCX image file name.
* wrt_flag is a Boolean flag which if TRUE
* indicates that the PCX image file is to be
* opened for writing; otherwise it is opened
* for reading.
*
* Return: A pointer to a PCX image file workblock if
* successful; otherwise NULL.
*
********************************************************************
*/
PCX_WORKBLK *pcx_open
(
char *fname,
BOOL wrt_flag
)
{
PCX_WORKBLK *wbp; /* PCX image file workblock pointer */
/* Allocate a workblock */
if ((wbp = (PCX_WORKBLK *) malloc(sizeof(PCX_WORKBLK))) == NULL)
return (NULL);
/* Open the PCX image file in binary mode */
if (wrt_flag == FALSE)
wbp->fp = fopen(fname, "rb"); /* Open for reading */
else
wbp->fp = fopen(fname, "wb"); /* Open for writing */
if (wbp->fp == NULL) /* Check for successful file opening */
{
free(wbp); /* Free the workblock memory */
return (NULL);
}
return (wbp); /* Return the workblock pointer */
}
/*
********************************************************************
*
* PCX_CLOSE - Close PCX Workblock
*
* Purpose: To close a PCX image file and release its
* workblock memory.
*
* Setup: BOOL pcx_close
* (
* PCX_WORKBLK *wbp
* )
*
* Where: wbp is a PCX image file workblock pointer.
*
* Return: TRUE if successful; otherwise FALSE.
*
********************************************************************
*/
BOOL pcx_close
(
PCX_WORKBLK *wbp
)
{
free(wbp->palettep);
/* Free the extended palette (if it exists)*/
free(wbp); /* Free the PCX image file workblock */
if (fclose(wbp->fp) == EOF) /* Close the PCX image file */
return (FALSE);
return (TRUE);
}
/*
********************************************************************
*
* PCX_ISVGA - Check For VGA Display Adapter
*
* Purpose: To determine whether a display adapter supports
* VGA BIOS service routines.
*
* Setup: BOOL pcx_isvga(void)
*
* Return: TRUE if display adapter is VGA-compatible;
* otherwise FALSE.
*
********************************************************************
*/
BOOL pcx_isvga(void)
{
unsigned char *vinfop; /* VGA information buffer pointer */
union REGS regs; /* 80x86 register values */
struct SREGS sregs; /* 80x86 segment register values */
/* Allocate a VGA functionality/state information buffer */
if ((vinfop = (unsigned char *) malloc(sizeof(unsigned char) *
64)) ==
NULL)
return (FALSE);
/* Attempt to read the VGA information */
regs.h.ah = 0x1b; /* Select "Return VGA Info" BIOS routine*/
regs.x.bx = 0; /* Implementation type */
/* Get the VGA information buffer offset value */
regs.x.di = (unsigned int) vinfop;
segread(&sregs); /* Get the current DS segment register value */
sregs.es = sregs.ds;
int86x(0x10, ®s, ®s, &sregs);/* Call BIOS video service */
free(vinfop); /* Free the VGA information buffer */
/* The value 0x1b is returned in register AL only if a VGA */
/* display adapter is present */
if (regs.h.al == 0x1b)
return (TRUE);
else
return (FALSE);
}
/* End of File */