Complete uuid4 implementation

README.md

@@ -1,3 +1,3 @@
 # UUID4 Generator
 
-Incomplete test implementation of a UUID4 generator
+Test implementation of a UUID4 generator

src/uuid4.c

@@ -1,5 +1,4 @@
 #include "wapp.h"
-#include <inttypes.h>
 #include <stdio.h>
 
 typedef struct uuid4 UUID4;
@@ -9,34 +8,35 @@ struct uuid4 {
 };
 
 UUID4 gen_uuid4(XOR256State *state);
-void print_uuid4(UUID4 uuid);
+void stringify_uuid4(UUID4 uuid, char *dst, u64 len);
 
 int main(void) {
   XOR256State state = wapp_init_xor_256_state();
+  UUID4 uuid = gen_uuid4(&state);
+  char buf[40] = {0};
 
-	for (int i = 0; i < 100000; ++i) {
-		UUID4 uuid = gen_uuid4(&state);
-		print_uuid4(uuid);
-	}
+  for (int i = 0; i < 1000; ++i) {
+    UUID4 uuid = gen_uuid4(&state);
+    stringify_uuid4(uuid, buf, 40);
+    printf("%s\n", buf);
+  }
 
   return 0;
 }
 
 UUID4 gen_uuid4(XOR256State *state) {
-	persistent u64 and_mask = 0xffffffffffff0fff;
-	persistent u64 or_mask  = 0x0000000000004000;
-	UUID4 uuid = { .high = wapp_xorshift_256_generate(state), .low = wapp_xorshift_256_generate(state) };
-	uuid.high &= and_mask;
-	uuid.high |= or_mask;
-	return uuid;
+  UUID4 uuid = { .high = wapp_xorshift_256_generate(state), .low = wapp_xorshift_256_generate(state) };
+  uuid.high = (uuid.high & 0xffffffffffff0fff) | 0x0000000000004000;
+  uuid.low  = (uuid.low  & 0xbfffffffffffffff) | 0x8000000000000000;
+  return uuid;
 }
 
-void print_uuid4(UUID4 uuid) {
-	u64 a = uuid.high >> 32;
-	u64 b = (uuid.high << 32) >> 48;
-	u64 c = (uuid.high << 48) >> 48;
-	u64 d = uuid.low >> 48;
-	u64 e = (uuid.low << 16) >> 16;
+void stringify_uuid4(UUID4 uuid, char *dst, u64 len) {
+  u64 a = uuid.high >> 32;
+  u64 b = (uuid.high << 32) >> 48;
+  u64 c = (uuid.high << 48) >> 48;
+  u64 d = uuid.low >> 48;
+  u64 e = (uuid.low << 16) >> 16;
 
-	printf("%.8llx-%.4llx-%.4llx-%.4llx-%.12llx\n", a, b, c, d, e);
+  snprintf(dst, len, "%.8llx-%.4llx-%.4llx-%.4llx-%.12llx", a, b, c, d, e);
 }