added huffman decode and rgb support

Author: sundeshgupta

huffman-decode.cpp

@@ -90,4 +90,4 @@ int main(){
 	return 0;
 }
 
-blvbjeanvnkjvnjlearknjnakrnekndcjbhbllivuekrjhggefskvhfbvkjdbsrjgk
+// blvbjeanvnkjvnjlearknjnakrnekndcjbhbllivuekrjhggefskvhfbvkjdbsrjgk

huffman-decode_image.cpp

@@ -0,0 +1,100 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "stb_image_write.h"
+
+struct pixel{
+	int label;
+	pixel* left, *right;
+
+	pixel(int x):	label(x){
+		left = NULL;
+		right = NULL;
+	}
+
+};
+
+pixel* add(pixel* root, int i, string s, string label){
+
+	if(root == NULL){
+		root = new pixel(-1);
+	}
+
+	if(i == s.length()){
+		cout << s << " " << label << endl; 
+		root->label = stoi(label);
+		return root;
+	}
+
+	if(s[i] == '0'){
+		root->left = add(root->left, i+1, s, label);
+	}
+	else{
+		root->right = add(root->right, i+1, s, label);
+	}
+
+	return root;
+}
+
+void preoder(pixel* root, string s){
+	
+	if(root == NULL)
+		return;
+
+	if(root->label != -1){
+		cout << setfill(' ') << setw(3) << root->label 
+			<< " -> " << setw(7) << s << endl;  
+		return;
+	}
+
+	preoder(root->left, s + '0');
+	preoder(root->right, s + '1');
+
+	return;
+}
+
+int main()
+{
+	ifstream in("huffman_encoded.txt");
+	int n;
+	in>>n;
+	pixel* root = new pixel(-1);
+	for(int i=0; i<n; i++){
+		string a,b,c;
+		in>>a>>b>>c;
+		add(root, 0, c, a);
+	}
+
+	// for checking
+	preoder(root, "");
+
+	string w;
+	in >> w;
+
+	pixel* ptr = root;
+
+	int height, width, num_channel;
+
+	in>>height>>width>>num_channel;
+
+	uint8_t* rgb_image;
+    rgb_image = (uint8_t*) malloc(width*height*num_channel);
+	
+    int itr = 0;
+
+	for(auto i:w){
+		if(i=='0')
+			ptr = ptr->left;
+		else
+			ptr = ptr->right;
+		if(ptr->label != -1){
+			rgb_image[itr++] = char(ptr->label);
+			ptr = root;
+		}
+	}
+
+	stbi_write_png("image.png", width, height, num_channel, rgb_image, width*num_channel);
+
+	return 0;
+}

huffman_image.cpp

@@ -26,11 +26,14 @@ struct compare{
 
 string code[256];
 
+ofstream out("huffman_encoded.txt");
+
 void preoder(pixel* root, string s){
 
 	if(root->label != -1){
 		cout << setfill(' ') << setw(3) << root->label 
 			<< " -> " << setw(15) << s << setw(20) << fixed << setprecision(8) << root->freq << endl;  
+		out << root->label << " -> " << s << "\n";
 		code[root->label] = s; 
 		return;
 	}
@@ -42,25 +45,50 @@ void preoder(pixel* root, string s){
 }
 
 
-int main()
+int main(int argc, char** argv)
 {
-	int width, height, bpp;
+	int width, height, bpp, num_channel = 1;
 
-	uint8_t* rgb_image = stbi_load("colombia.jpg", &width, &height, &bpp, 1);
+	if (argc>2)
+	{
+		cout<<"Error: Too many arguments\n";
+		return 0;
+	}
+	if (argc==2)
+	{
+		if (string(argv[1])!="grey" && string(argv[1])!="rgb")
+		{
+			cout<<"Error: Invalid Argument\n";
+			return 0;
+		}
+		if (string(argv[1]) == "rgb")
+			num_channel = 3;
+	}
 
-	int image[height][width];
+	uint8_t* rgb_image = stbi_load("colombia.jpg", &width, &height, &bpp, num_channel);
+
+	int image[height][width][num_channel];
 	int itr = 0;
 	for (int i = 0; i < height; ++i)
 		for (int j = 0; j < width; ++j)
-			image[i][j] = rgb_image[itr++];
+			for(int k = 0; k < num_channel; ++k)
+				image[i][j][k] = rgb_image[itr++];
 
 	stbi_image_free(rgb_image);	
 
 	int hist[256] = {0}; 
 
-	for (int i = 0; i < height; i++) 
-	    for (int j = 0; j < width; j++) 
-	        hist[image[i][j]] += 1;
+	for (int i = 0; i < height; ++i) 
+	    for (int j = 0; j < width; ++j)
+	    	for (int k = 0; k < num_channel; ++k) 
+	        	hist[image[i][j][k]] += 1;
+
+	int nodes = 0; 
+	for (int i = 0; i < 256; i++)  
+	    if (hist[i] != 0) 
+	        nodes += 1; 
+
+	out<<nodes<<"\n";
 
 	int totpix = height*width;
 
@@ -69,8 +97,6 @@ int main()
 	for (int i = 0; i < 256; ++i)
 		freq[i] = ((float)hist[i])/totpix;
 
-
-
 	priority_queue<pixel*, vector<pixel*>, compare> pq;
 
 	for(int i = 0; i < 256; i++){
@@ -101,11 +127,16 @@ int main()
 	{
 		for (int j = 0; j < width; ++j)
 		{
-			compression_size += code[image[i][j]].size();
+			for (int k = 0; k < num_channel; ++k)
+			{
+				compression_size += code[image[i][j][k]].size();
+				out << code[image[i][j][k]];
+			}
 		}
 	}
-
-	cout << compression_size << " " << 256*256*8 << endl;
+	out << "\n";
+	out << height << " " << width << " " << num_channel << "\n";
+	cout << compression_size << " " << 256*256*8*num_channel << endl;
 
 
 	return 0;