converToImage.cpp

#pragma once

#include "opencv2/core/core.hpp"
#include <opencv2/highgui/highgui.hpp>
#include <opencv/cv.h>
#include <opencv/highgui.h>

using namespace cv;
#define TMPIMAGEPATH "tmpImage.image"
static const std::string base64_chars = 
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	"abcdefghijklmnopqrstuvwxyz"
	"0123456789+/";


static inline bool is_base64(unsigned char c) {
	return (isalnum(c) || (c == '+') || (c == '/'));
}


class ConvertToImage
{
	std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len) {
		std::string ret;
		int i = 0;
		int j = 0;
		unsigned char char_array_3[3];
		unsigned char char_array_4[4];

		while (in_len--) {
			char_array_3[i++] = *(bytes_to_encode++);
			if (i == 3) {
				char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
				char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
				char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
				char_array_4[3] = char_array_3[2] & 0x3f;

				for(i = 0; (i <4) ; i++)
					ret += base64_chars[char_array_4[i]];
				i = 0;
			}
		}

		if (i)
		{
			for(j = i; j < 3; j++)
				char_array_3[j] = '\0';

			char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
			char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
			char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
			char_array_4[3] = char_array_3[2] & 0x3f;

			for (j = 0; (j < i + 1); j++)
				ret += base64_chars[char_array_4[j]];

			while((i++ < 3))
				ret += '=';

		}

		return ret;

	}
	std::vector<BYTE> base64_decode(std::string const& encoded_string) {
		int in_len = encoded_string.size();
		int i = 0;
		int j = 0;
		int in_ = 0;
		BYTE char_array_4[4], char_array_3[3];
		std::vector<BYTE> ret;

		while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
			char_array_4[i++] = encoded_string[in_]; in_++;
			if (i ==4) {
				for (i = 0; i <4; i++)
					char_array_4[i] = base64_chars.find(char_array_4[i]);

				char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
				char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
				char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

				for (i = 0; (i < 3); i++)
					ret.push_back(char_array_3[i]);
				i = 0;
			}
		}

		if (i) {
			for (j = i; j <4; j++)
				char_array_4[j] = 0;

			for (j = 0; j <4; j++)
				char_array_4[j] = base64_chars.find(char_array_4[j]);

			char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
			char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
			char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

			for (j = 0; (j < i - 1); j++) ret.push_back(char_array_3[j]);
		}

		return ret;
	}
public:
	Mat convertBase64ToMat(string base64, char* tmpPath =TMPIMAGEPATH) {
		std::vector<BYTE> decodedData   = base64_decode(base64);	//make lower performance 
		BYTE* str = new BYTE[decodedData.size()];
		for(int i=0; i<decodedData.size(); i++) {
			str[i] = decodedData[i];
		}
		FILE* fp = fopen(tmpPath, "wb");
		fwrite(str, sizeof(BYTE), decodedData.size(), fp);
		fclose (fp);
		Mat img=imread(tmpPath);
		return img;
	}
	Mat convertBase64ToMat(string base64, char* tmpPath, int& w, int& h) {
		std::vector<BYTE> decodedData   = base64_decode(base64);	//make lower performance 
		BYTE* str = new BYTE[decodedData.size()];
		for(int i=0; i<decodedData.size(); i++) {
			str[i] = decodedData[i];
		}
		FILE* fp = fopen(tmpPath, "wb");
		fwrite(str, sizeof(BYTE), decodedData.size(), fp);
		fclose (fp);
		Mat img=imread(tmpPath);
		w=img.rows; h=img.cols;
		return img;
	}
};