upload

Author: sundeshgupta

improved-huffman-decode_image.cpp

@@ -0,0 +1,134 @@
+#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;
+	}
+
+};
+
+bool flag[256];
+int cnt = 256;
+
+pixel* add(pixel* root, int i, string s, string label, int level = 0){
+
+	if(root == NULL){
+		root = new pixel(cnt++);
+	}
+
+	if(i == s.length()){
+		cout << s << " " << (stoi(label)) << " " << label << endl; 
+		root->label = stoi(label);
+		if(level > 3){
+			flag[root->label] = 1;
+		}
+		return root;
+	}
+
+	if(s[i] == '0'){
+		root->left = add(root->left, i+1, s, label, level+1);
+	}
+	else{
+		root->right = add(root->right, i+1, s, label, level+1);
+	}
+
+	return root;
+}
+
+void preoder(pixel* root, string s){
+	
+	if(root == NULL)
+		return;
+
+	if(root->label < 256){
+		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("improved_huffman_encoded.txt");
+	int n;
+	in>>n;
+	pixel* root = new pixel(cnt++);
+	for(int i=0; i<n; i++){
+		string b, c;
+		string a;
+		in>>a>>b>>c;
+		add(root, 0, c, a);
+	}
+
+	// for checking
+	preoder(root, "");
+
+	string w;
+	in >> w;
+
+	pixel* ptr = root;
+	pixel* tmp = 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;
+	bool f = 0;
+	int level = 0;
+	for(auto i:w){
+		if(f){
+			if(i == '0'){
+				// do nothing
+			}
+			else{
+				ptr = tmp;
+			}
+			f = 0;
+			continue;
+		}
+
+		if(i=='0')
+			ptr = ptr->left;
+		else
+			ptr = ptr->right;
+		
+		level += 1;
+
+		if(level == 3)
+			tmp = ptr;
+
+		if(ptr->label < 256){
+			
+			rgb_image[itr++] = ptr->label;
+			
+			level = 0;
+
+			if(flag[ptr->label])
+				f = 1;
+			
+			ptr = root;
+		}
+	}
+
+	stbi_write_png("improved_image.png", width, height, num_channel, rgb_image, width*num_channel);
+
+
+	return 0;
+}