1 files changed, 126 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/prng/random.c b/libc-top-half/musl/src/prng/random.c
new file mode 100644
index 0000000..daac028
--- /dev/null
+++ b/libc-top-half/musl/src/prng/random.c
@@ -0,0 +1,126 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include "lock.h"
+#include "fork_impl.h"
+
+/*
+this code uses the same lagged fibonacci generator as the
+original bsd random implementation except for the seeding
+which was broken in the original
+*/
+
+static uint32_t init[] = {
+0x00000000,0x5851f42d,0xc0b18ccf,0xcbb5f646,
+0xc7033129,0x30705b04,0x20fd5db4,0x9a8b7f78,
+0x502959d8,0xab894868,0x6c0356a7,0x88cdb7ff,
+0xb477d43f,0x70a3a52b,0xa8e4baf1,0xfd8341fc,
+0x8ae16fd9,0x742d2f7a,0x0d1f0796,0x76035e09,
+0x40f7702c,0x6fa72ca5,0xaaa84157,0x58a0df74,
+0xc74a0364,0xae533cc4,0x04185faf,0x6de3b115,
+0x0cab8628,0xf043bfa4,0x398150e9,0x37521657};
+
+static int n = 31;
+static int i = 3;
+static int j = 0;
+static uint32_t *x = init+1;
+#if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
+static volatile int lock[1];
+volatile int *const __random_lockptr = lock;
+#endif
+
+static uint32_t lcg31(uint32_t x) {
+	return (1103515245*x + 12345) & 0x7fffffff;
+}
+
+static uint64_t lcg64(uint64_t x) {
+	return 6364136223846793005ull*x + 1;
+}
+
+static void *savestate() {
+	x[-1] = (n<<16)|(i<<8)|j;
+	return x-1;
+}
+
+static void loadstate(uint32_t *state) {
+	x = state+1;
+	n = x[-1]>>16;
+	i = (x[-1]>>8)&0xff;
+	j = x[-1]&0xff;
+}
+
+static void __srandom(unsigned seed) {
+	int k;
+	uint64_t s = seed;
+
+	if (n == 0) {
+		x[0] = s;
+		return;
+	}
+	i = n == 31 || n == 7 ? 3 : 1;
+	j = 0;
+	for (k = 0; k < n; k++) {
+		s = lcg64(s);
+		x[k] = s>>32;
+	}
+	/* make sure x contains at least one odd number */
+	x[0] |= 1;
+}
+
+void srandom(unsigned seed) {
+	LOCK(lock);
+	__srandom(seed);
+	UNLOCK(lock);
+}
+
+char *initstate(unsigned seed, char *state, size_t size) {
+	void *old;
+
+	if (size < 8)
+		return 0;
+	LOCK(lock);
+	old = savestate();
+	if (size < 32)
+		n = 0;
+	else if (size < 64)
+		n = 7;
+	else if (size < 128)
+		n = 15;
+	else if (size < 256)
+		n = 31;
+	else
+		n = 63;
+	x = (uint32_t*)state + 1;
+	__srandom(seed);
+	savestate();
+	UNLOCK(lock);
+	return old;
+}
+
+char *setstate(char *state) {
+	void *old;
+
+	LOCK(lock);
+	old = savestate();
+	loadstate((uint32_t*)state);
+	UNLOCK(lock);
+	return old;
+}
+
+long random(void) {
+	long k;
+
+	LOCK(lock);
+	if (n == 0) {
+		k = x[0] = lcg31(x[0]);
+		goto end;
+	}
+	x[i] += x[j];
+	k = x[i]>>1;
+	if (++i == n)
+		i = 0;
+	if (++j == n)
+		j = 0;
+end:
+	UNLOCK(lock);
+	return k;
+}