Import code from previous AssetBuilder version

thirdparty/libtomcrypt/prngs/rng_make_prng.c

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+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ */
+#include "tomcrypt.h"
+
+#ifdef LTC_RNG_MAKE_PRNG
+/**
+  @file rng_make_prng.c
+  portable way to get secure random bits to feed a PRNG  (Tom St Denis)
+*/
+
+/**
+  Create a PRNG from a RNG
+  @param bits     Number of bits of entropy desired (64 ... 1024)
+  @param wprng    Index of which PRNG to setup
+  @param prng     [out] PRNG state to initialize
+  @param callback A pointer to a void function for when the RNG is slow, this can be NULL
+  @return CRYPT_OK if successful
+*/
+int rng_make_prng(int bits, int wprng, prng_state *prng,
+                  void (*callback)(void))
+{
+   unsigned char buf[256];
+   int err;
+
+   LTC_ARGCHK(prng != NULL);
+
+   /* check parameter */
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err;
+   }
+
+   if (bits < 64 || bits > 1024) {
+      return CRYPT_INVALID_PRNGSIZE;
+   }
+
+   if ((err = prng_descriptor[wprng].start(prng)) != CRYPT_OK) {
+      return err;
+   }
+
+   bits = ((bits/8)+((bits&7)!=0?1:0)) * 2;
+   if (rng_get_bytes(buf, (unsigned long)bits, callback) != (unsigned long)bits) {
+      return CRYPT_ERROR_READPRNG;
+   }
+
+   if ((err = prng_descriptor[wprng].add_entropy(buf, (unsigned long)bits, prng)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = prng_descriptor[wprng].ready(prng)) != CRYPT_OK) {
+      return err;
+   }
+
+   #ifdef LTC_CLEAN_STACK
+      zeromem(buf, sizeof(buf));
+   #endif
+   return CRYPT_OK;
+}
+#endif /* #ifdef LTC_RNG_MAKE_PRNG */
+
+
+/* ref:         HEAD -> master, tag: v1.18.2 */
+/* git commit:  7e7eb695d581782f04b24dc444cbfde86af59853 */
+/* commit time: 2018-07-01 22:49:01 +0200 */