CODE:

#include 
#include 
#include 

struct{
	unsigned long  Size;
	long           Width;
	long           Height;
	unsigned short Planes;
	unsigned short BitCount;
	unsigned long  Compression;
	unsigned long  SizeImage;
	long           XPixPerMeter;
	long           YPixPerMeter;
	unsigned long  ClrUsed;
	unsigned long  ClrImporant;
}INFO={40,0,0,1,24,0,0,0,0,0,0};

int main(int argc,char *argv[])
{
	int i;
	int namelen,fsize;
	int width,height;
	FILE *in,*out,*tmp;
	char data;
	
	if((tmp=tmpfile())==NULL)return -1;
	fwrite("FILE2BMP",sizeof(char),strlen("FILE2BMP"),tmp);
	
	for(i=1;argv[i]!=NULL;++i){
		
		if((in=fopen(argv[i],"rb"))==NULL)continue;
		printf("open : %s\n",argv[i]);
		
		//ファイル名書き込み
		namelen=strlen(argv[i]);
		fwrite(&namelen,sizeof(int),1,tmp);
		fwrite(argv[i],sizeof(char),namelen,tmp);
		
		//ファイルサイズ書き込み
		fseek(in,0,SEEK_END);
		fsize=ftell(in);
		fwrite(&fsize,sizeof(int),1,tmp);
		
		//ファイル読み込み＆書き込み
		fseek(in,0,SEEK_SET);
		while(fread(&data,sizeof(char),1,in))fwrite(&data,sizeof(char),1,tmp);
		fclose(in);
	}
	if((fsize=ftell(tmp))>8){
		if((out=fopen("f2b.bmp","wb"))==NULL){
			fclose(tmp);
			return -1;
		}
		
		i=(fsize%3)?fsize/3:fsize/3+1;
		width=(int)sqrt(i)+1;
		width+=(width%4)?4-(width%4):0;
		height=(i%width)?i/width+1:i%width;
		fsize=width*height*3+54;
		
		//ファイルヘッダ書き込み
		fseek(tmp,0,SEEK_SET);
		fwrite("BM",sizeof(char),2,out);
		fwrite(&fsize,sizeof(int),1,out);
		i=0;
		fwrite(&i,sizeof(int),1,out);
		i=54;
		fwrite(&i,sizeof(int),1,out);
		
		fsize-=54;
		//情報ヘッダ書き込み
		INFO.Width=width;
		INFO.Height=height;
		INFO.SizeImage=fsize;
		fwrite(&INFO,sizeof(INFO),1,out);
		
		//画像データ書き込み
		for(i=0;i<fsize;++i){
			if(fread(&data,sizeof(char),1,tmp));
			else data=0;
			fwrite(&data,sizeof(char),1,out);
		}
		fclose(out);
	}
	fclose(tmp);
	return 0;
}