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C / C++ BASE64 檔案 編解碼 資料來源: https://github.com/timothychan29475600/base64_encode_decode GITHUB: https://github.com/jash-git/CPP_Base64_File #include #include #include #include using namespace std; #define ERROR_INVALID_ARG -1 #define ERROR_INVALID_OP -2 #define ERROR_INVALID_SYN -3 #define ERROR_OPEN_FILE -4 #define OPERATION_SUCCESS 0 //https://github.com/timothychan29475600/base64_encode_decode const char base64_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; FILE *input01, *output01; FILE *input02, *output02; int encode64(FILE *input_file, FILE* output_file); int decode64(FILE *input_file, FILE* output_file); void pause() { printf("Press Enter key to continue..."); fgetc(stdin); } int main(int argc, char* argv[]) { input01 = fopen("input.png","rb"); output01 = fopen("output.txt","w"); encode64(input01,output01); fclose(input01); fclose(output01); input02 = fopen("output.txt","rb"); output02 = fopen("output.png","wb"); decode64(input02,output02); pause(); return 0; } int encode64(FILE* input_file, FILE* output_file){ //Variables Declaration int decode_buffer = 0; int byteCount = 1; int temp; char raw_byte = 0; char out_byte = 0; //Read and encode while(fread(&raw_byte,sizeof(char),1,input_file)){ temp = raw_byte & ~(-1<<8); decode_buffer = (decode_buffer << 8) + temp; if(byteCount % 3 == 0){ //Every 3 byte -> 4 base64 char for(temp = 0; temp < 4; temp++){ out_byte = base64_table[(decode_buffer>>(6*(3-temp)) & 0b00111111)]; fprintf(output_file,"%c",out_byte); } decode_buffer = 0; } byteCount ++; } if(byteCount % 3){ //If padding is needed for(temp = 0;temp < byteCount %3; temp++) decode_buffer = (decode_buffer << 8) ; //Fill the missing 1 or 2 byte for(temp = 0; temp < 4-(byteCount%3); temp++){ //If fill 1 byte -> Get 3 char; if fill 2 byte -> get 2 char => 4-fill_no out_byte = base64_table[(decode_buffer>>(6*(3-temp)) & 0b00111111)]; fprintf(output_file,"%c",out_byte); } for(temp = 0;temp < byteCount %3; temp++) fprintf(output_file,"="); } return OPERATION_SUCCESS; } int decode64(FILE* input_file, FILE* output_file){ int decode_buffer = 0; int byteCount = 1; int paddingCount = 0; int i; char raw_byte=0; char resolved_byte = 0; unsigned char temp; //Read and decode while(fread(&raw_byte,sizeof(char),1,input_file)){ if(raw_byte == '='){ //If a padding is encountered raw_byte = 'A'; //Turn it into 0 paddingCount ++; } //Decode the character char* pt = strchr(base64_table,(unsigned char)raw_byte); if(!pt){//Unable to resolve character return ERROR_INVALID_SYN; } resolved_byte = pt-base64_table; resolved_byte = resolved_byte & ~(-1<<6); //Mask the byte to ensure all the bit except the last 6 is zero decode_buffer = (decode_buffer<<6) + resolved_byte; if(byteCount%4 == 0){ //Every 4 base64 char -> 3 byte for(i=0;i<3-paddingCount;i++){ temp = (decode_buffer>>(8*(2-i))) & ~(-1<<8); fwrite(&temp,sizeof(char),1,output_file); } decode_buffer = 0; } byteCount++; } return OPERATION_SUCCESS; }