hashcash.c

#pragma once
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strlcat.c>
#include <strlcpy.c>
#include <base64.c>
#include <sha-256.c>
#include <explode.c>
#ifdef __cplusplus
extern "C" {
#endif

typedef union {
	uint64_t u64;
	unsigned char uc[8];
	uint8_t u8[8];
} multiint;

// EMSCRIPTEN_KEEPALIVE
char * generateHashcash(const char * hashcashString) { // input in format 1:diff:date:resource::random::
	// printf("generateHashcash Called with string %s\n", hashcashString);
	unsigned int counterPos = strlen(hashcashString)+1;
	unsigned char * hashcash = malloc(sizeof(char)*(counterPos+69)); // 69. we can't use more than 69 bytes for the counter, right?
	strlcpy(hashcash, hashcashString, counterPos+(69-1));
	multiint counter;
	counter.u64 = 0x0000000000000000ULL;;
	int counterSize = sizeof(counter.u64);
	char * whereToStartWriting = (hashcash+counterPos)-1;
	uint8_t hash[32];
	unsigned char i = 0, j = 0;
	unsigned short int leadingZeros = 0;
	//	// get difficulty {
	char **list;
	size_t len, hehe_u_thot_imma_use_i;
	explode(hashcash, ":", &list, &len);
	unsigned short int difficulty = atoi(list[1]); // 1:20:* where 20 is the diff
	for(hehe_u_thot_imma_use_i = 0; hehe_u_thot_imma_use_i < len; ++hehe_u_thot_imma_use_i)
		free(list[hehe_u_thot_imma_use_i]);
	free(list);

	//	\\								}
	while (1) {
		Base64encode(whereToStartWriting, counter.u8, counterSize);
		calc_sha_256(hash, hashcash, strlen(hashcash));
		i = 0;
		leadingZeros = 0;
		while(1) {
			if(hash[i] != 0) {
				break;
			}
			i++;
		}
		leadingZeros = 8*i;
		// if(x <= 0) leadingZeros+=8;
		if(hash[i] <= 1) leadingZeros+=7;
		if(hash[i] <= 3) leadingZeros+=6;
		if(hash[i] <= 7) leadingZeros+=5;
		if(hash[i] <= 15) leadingZeros+=4;
		if(hash[i] <= 31) leadingZeros+=3;
		if(hash[i] <= 63) leadingZeros+=2;
		if(hash[i] <= 127) leadingZeros+=1;
		if(leadingZeros >= difficulty) {
			// fprintf(stderr, "0x");
			// for(int zt = 0; zt < 32; zt++) {
			// 	fprintf(stderr, "%02x", hash[zt]);
			// }
			// fprintf(stderr, "\n");
			break;
		}
		counter.u64++;
	}
	return hashcash;
}

#ifdef __cplusplus
}
#endif