final changes

bitmaps_imp/README.md

@@ -0,0 +1,2 @@
+# bitops_in_c
+bitops_in_c

bitmaps_imp/bitarr.c

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+/*
+ * =====================================================================================
+ *
+ *       Filename:  bitarr.c
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  Sunday 04 March 2018 06:23:30  IST
+ *       Revision:  1.0
+ *       Compiler:  gcc
+ *
+ *         Author:  Er. Abhishek Sagar, Networking Developer (AS), sachinites@gmail.com
+ *        Company:  Brocade Communications(Jul 2012- Mar 2016), Current : Juniper Networks(Apr 2017 - Present)
+ *        
+ *        This file is part of the SPFComputation distribution (https://github.com/sachinites).
+ *        Copyright (c) 2017 Abhishek Sagar.
+ *        This program is free software: you can redistribute it and/or modify
+ *        it under the terms of the GNU General Public License as published by  
+ *        the Free Software Foundation, version 3.
+ *
+ *        This program is distributed in the hope that it will be useful, but 
+ *        WITHOUT ANY WARRANTY; without even the implied warranty of 
+ *        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+ *        General Public License for more details.
+ *
+ *        You should have received a copy of the GNU General Public License 
+ *        along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * =====================================================================================
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <memory.h>
+#include "bitsop.h"
+#include "bitarr.h"
+
+#define CHAR_SIZE   8
+
+void
+init_bit_array(bit_array_t *bitarr, unsigned int n_bits){
+
+    unsigned int n_byte_blocks = n_bits/CHAR_SIZE;
+
+    if(n_bits % CHAR_SIZE)
+        n_byte_blocks++;
+    if(!bitarr->array)
+        bitarr->array = calloc(1, n_byte_blocks);
+    else
+        memset(bitarr->array, 0, n_byte_blocks);
+    bitarr->size = n_bits;
+    bitarr->trail_bits = n_bits % CHAR_SIZE;
+}
+
+void
+set_bit(bit_array_t *bitarr, unsigned int index){
+
+    if(index >= bitarr->size){
+        printf("%u is out of array bounds [%u,%u]\n", 
+            index, 0, bitarr->size -1);
+        return;
+    }
+
+    unsigned byte_block = 0,
+             residual_bit = 0;
+
+    byte_block = index / CHAR_SIZE;
+    residual_bit = index % CHAR_SIZE;
+
+#if 0    
+    assert(bitarr->size/CHAR_SIZE == byte_block && 
+        bitarr->trail_bits >= residual_bit);
+#endif
+
+    char *ptr = bitarr->array + byte_block;
+    SET_BIT((*ptr), (CHAR_SIZE - residual_bit));
+}
+
+void
+unset_bit(bit_array_t *bitarr, unsigned int index){
+
+    if(index >= bitarr->size){
+        printf("%u is out of array bounds [%u,%u]\n", 
+            index, 0, bitarr->size -1);
+        return;
+    }
+
+    unsigned byte_block = 0,
+             residual_bit = 0;
+
+    byte_block = index / CHAR_SIZE;
+    residual_bit = index % CHAR_SIZE;
+
+#if 0
+    assert(bitarr->size/CHAR_SIZE == byte_block && 
+        bitarr->trail_bits >= residual_bit);
+#endif
+
+    char *ptr = bitarr->array + byte_block;
+    UNSET_BIT((*ptr), (CHAR_SIZE - residual_bit));
+}
+
+char
+is_bit_set(bit_array_t *bitarr, unsigned int index){
+
+    
+    if(index >= bitarr->size){
+        printf("%u is out of array bounds [%u,%u]\n", 
+            index, 0, bitarr->size -1);
+        return 0;
+    }
+
+    unsigned byte_block = 0,
+             residual_bit = 0;
+
+    byte_block = index / CHAR_SIZE;
+    residual_bit = index % CHAR_SIZE;
+    
+#if 0
+    assert(bitarr->size/CHAR_SIZE == byte_block && 
+        bitarr->trail_bits >= residual_bit);
+#endif
+    char *ptr = bitarr->array + byte_block;
+    return (char)(IS_BIT_SET((*ptr), (CHAR_SIZE - residual_bit)));
+}
+
+unsigned int
+get_next_available_bit(bit_array_t *bitarr){
+
+    unsigned int i = 0;
+    for(; i < bitarr->size; i++){
+        if(is_bit_set(bitarr, i))
+            continue;
+        return i;
+    }
+    return 0xFFFFFFFF;
+}
+
+void
+print_bit_array(bit_array_t *bitarr){
+
+    unsigned int i = 0, index = 0,
+                 byte_blocks = 0,
+                 residual_bits = 0;
+
+    int j = 0;
+
+    byte_blocks = bitarr->size / CHAR_SIZE;
+    residual_bits = bitarr->size % CHAR_SIZE;
+    //assert(bitarr->trail_bits >= residual_bit);
+    char *ptr = bitarr->array;
+    char byte = 0;
+
+    for( ; i < byte_blocks; i++){
+        byte = *(ptr+i);
+        for(j = 7; j >= 0; j--, index++){
+            printf("[%u] : %c\n", index, IS_BIT_SET(byte, j) ? '1' : '0');
+        }
+    }
+
+    if(!residual_bits)
+        return;
+
+    byte = *(ptr+i);
+    for(j = 7; j >= CHAR_SIZE - residual_bits; j--, index++){
+        printf("[%u] : %c\n", index, IS_BIT_SET(byte, j) ? '1' : '0');
+    }
+}
+
+#if 0
+int
+main(int argc, char **argv){
+
+    bit_array_t *arr = calloc(1, sizeof(bit_array_t));
+    init_bit_array(arr, 15);
+    set_bit(arr, 11);
+    set_bit(arr, 21);
+    set_bit(arr, 30);
+    set_bit(arr, 3);
+    set_bit(arr, 33);
+    print_bit_array(arr);
+    unset_bit(arr, 11);
+    print_bit_array(arr);
+    return 0;
+}
+#endif

bitmaps_imp/bitarr.h

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+/*
+ * =====================================================================================
+ *
+ *       Filename:  bitarr.h
+ *
+ *    Description:  Interface to Bit Array
+ *
+ *        Version:  1.0
+ *        Created:  Sunday 04 March 2018 06:20:07  IST
+ *       Revision:  1.0
+ *       Compiler:  gcc
+ *
+ *         Author:  Er. Abhishek Sagar, Networking Developer (AS), sachinites@gmail.com
+ *        Company:  Brocade Communications(Jul 2012- Mar 2016), Current : Juniper Networks(Apr 2017 - Present)
+ *        
+ *        This file is part of the BIT Array distribution (https://github.com/sachinites).
+ *        Copyright (c) 2017 Abhishek Sagar.
+ *        This program is free software: you can redistribute it and/or modify
+ *        it under the terms of the GNU General Public License as published by  
+ *        the Free Software Foundation, version 3.
+ *
+ *        This program is distributed in the hope that it will be useful, but 
+ *        WITHOUT ANY WARRANTY; without even the implied warranty of 
+ *        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+ *        General Public License for more details.
+ *
+ *        You should have received a copy of the GNU General Public License 
+ *        along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * =====================================================================================
+ */
+
+#ifndef __BIT_ARRAY__
+#define __BIT_ARRAY__
+
+typedef struct _bit_array{
+    unsigned int size;
+    char *array;
+    char trail_bits;
+} bit_array_t;
+
+void 
+init_bit_array(bit_array_t *bitarr, unsigned int size);
+
+void
+set_bit(bit_array_t *bitarr, unsigned int index);
+
+void
+unset_bit(bit_array_t *bitarr, unsigned int index);
+
+char
+is_bit_set(bit_array_t *bitarr, unsigned int index);
+
+unsigned int
+get_next_available_bit(bit_array_t *bitarr);
+
+#endif /* __BIT_ARRAY__ */

bitmaps_imp/bitsop.h

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+/* Assuming least significant bit starts from 0th bit*/
+
+#ifndef __BITS__
+#define __BITS__
+
+#define IS_BIT_SET(n, pos)	((n & (1 << (pos))) != 0)
+#define TOGGLE_BIT(n, pos)	(n = n ^ (1 << (pos)))
+#define COMPLEMENT(num)	   	(num = num ^ 0xFFFFFFFF)
+#define UNSET_BIT(n, pos)  	(n = n & ((1 << pos) ^ 0xFFFFFFFF))
+#define SET_BIT(n, pos)     (n = n | 1 << pos)
+
+#endif
+

bitmaps_imp/solution.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <memory.h>
+#include <arpa/inet.h>
+#include <math.h>
+
+/* Visit website : https://csepracticals.wixsite.com/csepracticals
+ * Use following Links to verify the results : 
+ * Link 1  : http://www.silisoftware.com/tools/ipconverter.php
+ * Link 2  : http://jodies.de/ipcalc
+ * 
+ * Solution to Assignment
+ * Level : Intermediate to Advanced, not for Beginner Programmers
+ *
+ * How to compile and run : 
+ * Compile : gcc -g -c solution.c -o solution.o
+ * Link    : gcc -g solution.o -o solution -lm
+ * Run     : ./solution
+ * */
+
+/*Bit Wise operations
+ *
+ * You must be familiar with Bitwise operations done
+ * in C. Please understand the below Macros
+ * */
+
+/*You must know the concept of Big endian and Little Endian Machines
+ * and what is the purpose of htonl and ntohl - Important*/
+
+/*Standard Functions suchs as inet_pton and inet_ntop have been used to
+ * make life easier. Understand the use of this Function. Google them.*/
+
+
+/*If you dont understand this assignment solution, you need to work on 
+ * your C language*/
+
+#define IS_BIT_SET(n, pos)  ((n & (1 << (pos))) != 0)
+#define TOGGLE_BIT(n, pos)  (n = n ^ (1 << (pos)))
+#define COMPLEMENT(num)     (num = num ^ 0xFFFFFFFF)
+#define UNSET_BIT(n, pos)   (n = n & ((1 << pos) ^ 0xFFFFFFFF))
+#define SET_BIT(n, pos)     (n = n | 1 << pos)
+
+
+#define PREFIX_LEN  15  /*Max length of IP address in A.B.C.D format*/
+#define MAX_MASK_LEN 32  /*Maximum mask value in decimal notation*/
+
+/*For example, if mask = 24 is passed as an argument, 
+ * function should return an unsigned integer equivalent to 
+ * below bit settings
+ * 11111111 11111111 11111111 00000000
+ * */
+static unsigned int
+get_mask_value_in_integer_format(char mask_value){
+
+    unsigned int mask = 0xFFFFFFFF;
+    char n_trail_bits = MAX_MASK_LEN - mask_value;
+    int i = 0;
+    for(; i < n_trail_bits; i++){
+        UNSET_BIT(mask, i);
+    }
+    return mask;
+}
+
+void
+get_broadcast_address(char *ip_addr, 
+                      char mask, 
+                      char *output_buffer){
+    
+    unsigned int ip_addr_integer = 0;
+
+    /*Convert ip address from A.B.C.D format to equivalent unsigned integer*/
+    inet_pton(AF_INET, ip_addr, &ip_addr_integer);
+    /* To understand below line, you need to google
+     * Little endian and big endian concept*/
+    ip_addr_integer =  htonl(ip_addr_integer);
+
+    unsigned int mask_integer_format = get_mask_value_in_integer_format(mask);
+    /*if mask_integer_format = 11111111 11111111 11111111 00000000, then below
+     * fn would return 00000000 00000000 00000000 11111111*/
+    COMPLEMENT(mask_integer_format); /*Revere the bits*/
+    /*now, Perform OR-ing*/
+    unsigned int broadcast_addr = ip_addr_integer | mask_integer_format;
+    broadcast_addr = htonl(broadcast_addr);
+    /*convert the broadcast address from interger to A.B.C.D format*/
+    inet_ntop(AF_INET, &broadcast_addr, output_buffer, PREFIX_LEN + 1);
+    output_buffer[PREFIX_LEN] = '\0';
+}
+
+unsigned int
+get_ip_integer_equivalent(char *ip_address){
+
+    unsigned int ip_addr_integer = 0;
+    /*Convert ip address from A.B.C.D format to equivalent unsigned integer*/
+    inet_pton(AF_INET, ip_address, &ip_addr_integer);
+    return htonl(ip_addr_integer);
+}
+
+void
+get_abcd_ip_format(unsigned int ip_address, 
+                    char *output_buffer){
+
+    /*Convert an ip address from Integer to A.B.C.D format*/
+    inet_ntop(AF_INET, &ip_address, output_buffer, PREFIX_LEN + 1);
+    output_buffer[PREFIX_LEN] = '\0';
+}
+
+/*Follow the steps explained in the course*/
+void
+get_network_id(char *ip_address, char mask, char *output_buffer){
+
+    unsigned int mask_integer_format = get_mask_value_in_integer_format(mask);
+    unsigned int ip_address_integer = 0 ;
+    inet_pton(AF_INET, ip_address, &ip_address_integer);
+    unsigned int network_id = ip_address_integer & mask_integer_format;
+    network_id = htonl(network_id);
+    inet_ntop(AF_INET, &network_id, output_buffer, PREFIX_LEN + 1);     
+}
+
+unsigned int
+get_subnet_cardinality(char mask_value){
+
+    return pow(2, MAX_MASK_LEN - mask_value) -2 ;
+}
+
+/*Follow the steps explained in the course*/
+int /*Return 0 if true, -1 if false*/
+check_ip_subnet_membser_ship(char *network_id, 
+                             char mask, 
+                             char *check_ip){
+
+    unsigned int check_ip_integer = 0;
+    inet_pton(AF_INET, check_ip, &check_ip_integer);
+    unsigned int mask_integer = get_mask_value_in_integer_format(mask);
+    unsigned int calculated_nw_id = check_ip_integer & mask_integer;
+    unsigned int network_id_integer = 0;
+    inet_pton(AF_INET, network_id, &network_id_integer);  
+    if(network_id_integer == check_ip_integer)
+        return 0;
+    return -1;
+}
+
+int
+main(int argc, char **argv){
+
+/*Testing get_broadcast_address()*/
+{ 
+    printf("Testing Q1..\n");   
+    char ip_address[PREFIX_LEN + 1],
+         output_buffer[PREFIX_LEN + 1];
+    memset(ip_address, 0, PREFIX_LEN + 1);
+    memcpy(ip_address, "192.168.2.10", strlen("192.168.2.10"));
+    ip_address[strlen(ip_address)] = '\0';
+    char mask = 24;
+    memset(output_buffer, 0 , PREFIX_LEN + 1);
+    get_broadcast_address(ip_address, mask, output_buffer);
+    printf("broadcast address  = %s\n", output_buffer);
+    printf("Testing Q1 Done.\n");   
+}
+
+/*Testing get_ip_integer_equivalent()*/
+{ 
+    printf("Testing Q2..\n");   
+    char ip_address[PREFIX_LEN + 1];
+    memset(ip_address, 0, PREFIX_LEN + 1);
+    memcpy(ip_address, "192.168.2.10", strlen("192.168.2.10"));
+    ip_address[strlen(ip_address)] = '\0';
+    unsigned int a = get_ip_integer_equivalent(ip_address);
+    printf("a = %u\n", a);
+    printf("Testing Q2 Done.\n");   
+}
+
+
+/*Testing get_abcd_ip_format()*/
+{
+    char output_buffer[PREFIX_LEN + 1];
+    memset(output_buffer, 0 , PREFIX_LEN + 1);
+    unsigned int a = 2058138165; 
+    printf("Testing Q3..\n");   
+    get_abcd_ip_format(htonl(a), output_buffer);
+    printf("IP address in A.B.C.D format = %s\n", output_buffer); 
+    printf("Testing Q3 Done.\n");   
+}
+
+
+/*Testing get_network_id()*/
+{ 
+    printf("Testing Q4..\n");   
+    char ip_address[PREFIX_LEN + 1],
+         output_buffer[PREFIX_LEN + 1];
+    memset(ip_address, 0, PREFIX_LEN + 1);
+    memcpy(ip_address, "192.168.2.10", strlen("192.168.2.10"));
+    ip_address[strlen(ip_address)] = '\0';
+    char mask = 20;
+    memset(output_buffer, 0 , PREFIX_LEN + 1);
+    get_network_id(ip_address, mask, output_buffer);
+    printf("Network Id = %s/%u\n", output_buffer, mask);
+    printf("Testing Q4 Done.\n");   
+}
+
+/*Testing get_subnet_cardinality() */
+{
+    printf("Testing Q5..\n");    
+    char mask = 24;
+    printf("Cardinality = %u\n", get_subnet_cardinality(mask));
+    printf("Testing Q5 Done.\n");
+}
+
+{
+/*Testing check_ip_subnet_membser_ship()*/    
+    printf("Testing Q6..\n");
+    char network_id[PREFIX_LEN + 1];
+    strncpy(network_id, "192.168.1.0", strlen("192.168.1.0"));
+    network_id[PREFIX_LEN] = '\0';
+
+    char mask = 24;
+
+    char ip_address[PREFIX_LEN + 1];
+    strncpy(ip_address, "192.168.1.10",  strlen("192.168.1.10"));
+
+    int res = check_ip_subnet_membser_ship(network_id, mask, ip_address);
+    printf("IP Subnet check Result = %s\n", res == 0 ? "Membership true": "Membership false");
+    printf("Testing Q6 Done.\n");
+}
+
+    return 0;
+}