DOS pCon.c

#include <dos.h>
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include "MoreTypes.h"

const SCREEN_WIDTH = 80, SCREEN_HEIGHT = 25;
const ushort SCREEN_SEG = 0xB800;
const SCREEN_SIZE = 80*25;

// Text image structs
const ulong FILE_MAGIC = 0x58464754; // TGFX
struct TxtGFXHeader {
    ulong magic;
    ushort Width;
    ushort Height;
};
struct TxtGFX {
    int Size;
    int Width;
    int Height;
    ushort* Image;
};

ushort *ScreenBuff;

extern struct TxtGFX LoadGFX(char* filename) {
    FILE *filePtr;
    struct TxtGFXHeader Header;
    struct TxtGFX Img;

    filePtr = fopen(filename, "rb");
    if (!filePtr) {
        printf("Error opening file: ");
        printf(filename);
        printf("!\r\n");
        return Img;
    }

    // Read header to check it's a valid file
    fread(&Header, sizeof(struct TxtGFXHeader), 1, filePtr);
    if (Header.magic != FILE_MAGIC) {
        printf("Error: corrupt or invalid TGF file!\r\n");
        return Img;
    }
    Img.Size = Header.Width * Header.Height * sizeof(ushort);
    Img.Width = Header.Width;
    Img.Height = Header.Height;
    Img.Image = malloc(Img.Size);           // Create buffer for image
    if (Img.Image == 0) {
        printf("Error allocating memory for new image!\r\n");
        return Img;
    }
    fread(Img.Image, Img.Size, 1, filePtr); // Read actual image into buffer

    fclose(filePtr);
    return Img;
}