/*
 * reads all the BMP informations out of the file and stores them into
 * the dataStructure defined in BMP.h
 *
 * all routines written by Yannick Suter aka AsC/Nowadays! 1998
 *
 * no comments. if you have questions email me: [asc@netlink.ch]
*/ 


#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>

#include "BMP.H"

extern FILE *BMPf;
extern BITMAPFILEHEADER bmp_filehead;
extern BITMAPINFOHEADER bmp_infohead;

extern unsigned char infile2[100];
extern unsigned char bmp_4bitpal[4*16];
extern unsigned char bmp_8bitpal[4*256];
extern unsigned char *bmpdata;

void read_BMPfilehead(){
    unsigned char rbuf[4];
    unsigned short *t;

    printf(" : READING [BMP] filehead\n");

    bmp_filehead.bfType = read_word();
    bmp_filehead.bfSize = read_dword();
    bmp_filehead.bfReserved1 = read_word();
    bmp_filehead.bfReserved2 = read_word();
    bmp_filehead.bfOffBits = read_dword();
}

void read_BMPinfohead(){
    unsigned char rbuf[4];
    unsigned short *t;

    printf(" : READING [BMP] infohead\n");

    bmp_infohead.biSize = read_dword();
    bmp_infohead.biWidth = read_dword();
    bmp_infohead.biHeight = read_dword();
    bmp_infohead.biPlanes = read_word();
    bmp_infohead.biBitCount = read_word();
    bmp_infohead.biCompression = read_dword();
    bmp_infohead.biSizeImage = read_dword();
    bmp_infohead.biXPelsPerMeter = read_dword();
    bmp_infohead.biYPelsPerMeter = read_dword();
    bmp_infohead.biClrUsed = read_dword();
    bmp_infohead.biClrImportant = read_dword();
}

void read_BMPpalette(){
    int x;

    printf(" : READING [BMP] bitmap palette\n");
    if(bmp_infohead.biBitCount == 4) fread(&bmp_4bitpal,1,16*4,BMPf);
    if(bmp_infohead.biBitCount == 8) fread(&bmp_8bitpal,1,256*4,BMPf);
}

void read_BMPdata(){
    printf(" : READING [BMP] image data\n");

    if(bmp_infohead.biBitCount == 4) {
        bmpdata = (unsigned char *)malloc(bmp_infohead.biSizeImage>>1);
        fread(bmpdata,1,bmp_infohead.biSizeImage>>1,BMPf);
    }

    if(bmp_infohead.biBitCount == 8) {
        bmpdata = (unsigned char *)malloc(bmp_infohead.biSizeImage);
        fread(bmpdata,1,bmp_infohead.biSizeImage,BMPf);
    }

    if(bmp_infohead.biBitCount == 24) {
        bmpdata = (unsigned char *)malloc(bmp_infohead.biSizeImage);
        fread(bmpdata,1,bmp_infohead.biSizeImage,BMPf);
    }
}

void read_BMP(char *filename){
    if ((BMPf = fopen(filename,"rb")) != NULL){
        printf("  OPEN [BMP] file [%s]\n",infile2);

        read_BMPfilehead();
        read_BMPinfohead();
        if(bmp_infohead.biBitCount<=8)read_BMPpalette();
        read_BMPdata();

        fclose(BMPf);

    } else { printf(" : couldn't open BMPfile [%s]",infile2);}
}