7-Bit Deompression done!

Author: rahul10puchd

decompression7.c

@@ -0,0 +1,191 @@
+// this is decompression of 5 byte
+#include"header.h"
+#include"prototype.h"
+int decompression7(char *open_encr,char *open_key,char *str)
+{
+
+//	printf("in function----->%s\n",__func__);
+	
+	unsigned char *buff=NULL,ch,d,c,e,f,m;
+	unsigned int efd,efd2,fd2,fd3,i=0,count,count1,length,j,n,r;	
+	
+char decr1[]=".decompressed";
+	
+	char *decr;
+	
+	decr=malloc(strlen(str) + strlen(decr1) + 1);
+	
+
+    strcpy(decr, str);
+    strcat(decr, decr1);
+    printf("decompressed file name is---> %s\n",decr);
+	efd=open(open_key,O_RDONLY);
+	efd2=open(str,O_RDONLY);
+	fd2=open(open_encr,O_RDONLY);
+	fd3=open(decr,O_WRONLY | O_CREAT);
+	
+
+	count=lseek(efd2,0,SEEK_END); 
+	count1=lseek(efd,0,SEEK_END); //master array
+	length=lseek(fd2,0,SEEK_END); //encrypted file
+	lseek(efd2,0,SEEK_SET);
+	lseek(efd,0,SEEK_SET);
+	lseek(fd2,0,SEEK_SET);
+//	printf("no. of characters in actual file && encrypted file is : %d && %d\n",count,length);
+	buff=(char*)malloc(sizeof(char)*(count1));
+
+	count1=read(efd,buff,(count1));
+//	printf("master array is : %s\n and no. of characters-----: %d\n",buff,count1);
+	j=1,f=0; 
+	while(i<length)
+	{
+
+		r =read(fd2,&ch,1);
+		if(f==0)
+		{
+//			printf("in ---->f(0)\n");	
+//			printf("character is read......yeah!----->%c && %d\n",ch,ch);
+			c = ch;
+			d = ch;
+			c = c >> 1;
+			if(j<count)
+			{
+				write(fd3,(buff+c),1);
+//				printf("the written charracter is %c\n",*(buff+c));
+				j++;
+			}
+
+		
+		}
+		if(f==1)
+		{	
+//			printf("in ---->f(1)\n");	
+//			printf("character is read......yeah!----->%c && %d\n",ch,ch);
+			c = ch;
+			e = ch;
+			d = d << 7;
+			d = d >> 1;
+			c = c >> 2;
+			d = d | c;
+
+			if(j<count)
+			{
+				write(fd3,(buff+d),1);
+//				printf("the written charracter is %c\n",*(buff+d));
+				j++;
+			}
+
+		
+		}
+		if(f==2)
+		{	
+
+//			printf("in ---->f(2)\n");	
+			c = ch;
+			d = ch;
+			e = e << 6;
+			e = e >> 1;
+			c = c >> 3;
+			c = c | e;
+			if(j<count)
+			{
+				write(fd3,(buff+c),1);
+//				printf("the written charracter is %c\n",*(buff+c));
+				j++;
+			}
+
+		}
+		if(f==3)
+		{	
+//			printf("in ---->f(3)\n");	
+//			printf("character is read......yeah!----->%c && %d\n",ch,ch);
+			c = ch;
+			e = ch;
+			d = d << 5;
+			d = d >> 1;
+			c = c >> 4;
+			d = d | c;
+		
+			
+			if(j<count)
+			{
+				write(fd3,(buff+d),1);
+//				printf("the written charracter is %c\n",*(buff+d));
+				j++;
+			}
+
+		}
+		if(f==4)
+		{	
+//			printf("in ---->f(4)\n");	
+//			printf("character is read......yeah!----->%c && %d\n",ch,ch);
+			c = ch;
+			d = ch;
+			e = e << 4;
+			e = e >> 1;
+			c = c >> 5;
+			c = c | e; 
+			if(j<count)
+			{
+				write(fd3,(buff+c),1);
+//				printf("the written charracter is %c\n",*(buff+c));
+				j++;
+			}
+
+		}
+		if(f==5)
+		{	
+//			printf("in ---->f(5)\n");	
+			c = ch;
+			e = ch;
+			d = d << 3;
+			d = d >> 1;
+			c = c >> 6;
+			d = d | c;
+			if(j<count)
+			{
+				write(fd3,(buff+d),1);
+//				printf("the written charracter is %c\n",*(buff+d));
+				j++;
+			}
+
+		}
+		if(f==6)
+		{	
+//			printf("in ---->f(6)\n");	
+//			printf("character is read......yeah!----->%c && %d\n",ch,ch);
+			c = ch;
+			m = ch;
+			e = e << 2;
+			e = e >> 1;
+			c = c >> 7;
+			c = c | e;
+			m = m << 1;
+			m = m >> 1;
+			if(j<count)
+			{
+				write(fd3,(buff+c),1);
+//				printf("the written charracter is %c\n",*(buff+c));
+				j++;
+			}
+			if(j<count)
+			{
+				write(fd3,(buff+m),1);
+//				printf("the written charracter is %c\n",*(buff+m));
+				j++;
+			}
+
+
+		}
+		i++;
+		f++;
+		if(f==7)
+		f=0;
+	}
+	close(fd2);
+	close(fd3);
+	close(efd);
+	return 0;
+	
+}
+