1 files changed, 51 insertions, 0 deletions
diff --git a/wasm/solver.c b/wasm/solver.c
new file mode 100644
index 0000000..f1c4fa6
--- /dev/null
+++ b/wasm/solver.c
@@ -0,0 +1,51 @@
+#include "sha256.h"
+
+unsigned char challenge[32];
+
+char validate_hash(unsigned char *hash, unsigned char zero_bit_count) {
+	unsigned char q = zero_bit_count / 8;
+	unsigned char r = zero_bit_count % 8;
+
+	for (unsigned char i = 0; i < q; i++) {
+		if (hash[i] != 0) {
+			return 0;
+		}
+	}
+	if (r > 0) {
+		unsigned char mask = (unsigned char)(0xFF << (8 - r));
+		if (hash[q] & mask) {
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+unsigned char *get_challenge_ptr() {
+	return challenge;
+}
+
+unsigned long long solve(unsigned char difficulty) {
+	unsigned long long nonce;
+	SHA256_CTX context;
+
+	unsigned char hash[32];
+
+	nonce = 0;
+
+	while(1) {
+		sha256_init(&context);
+		sha256_update(&context, challenge, sizeof(challenge));
+		sha256_update(&context, (unsigned char*)(&nonce), sizeof(nonce));
+		sha256_final(&context, hash);
+
+		if(validate_hash(hash, difficulty)) {
+			// we did it!!
+			break;
+		}
+
+		nonce++;
+	}
+
+	return nonce;
+}