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authorRoberto Ierusalimschy <roberto@inf.puc-rio.br>2019-07-17 16:00:24 -0300
committerRoberto Ierusalimschy <roberto@inf.puc-rio.br>2019-07-17 16:00:24 -0300
commit4eefef07ab1c136f901d816822c79336fa89336d (patch)
treece2232ba8a09287899af1ac07af0c902800bfae6 /lmathlib.c
parent9c28ed05c95cb6854d917ac3e3ed7be9ae109480 (diff)
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'math.randomseed()' returns the seeds it used
A call to 'math.randomseed()' returns the two components of the seed it set, so that they can be used to set that same seed again.
Diffstat (limited to 'lmathlib.c')
-rw-r--r--lmathlib.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/lmathlib.c b/lmathlib.c
index f6f0b426..1d310b2d 100644
--- a/lmathlib.c
+++ b/lmathlib.c
@@ -605,20 +605,24 @@ static void setseed (Rand64 *state, lua_Unsigned n1, lua_Unsigned n2) {
605static void randseed (lua_State *L, RanState *state) { 605static void randseed (lua_State *L, RanState *state) {
606 lua_Unsigned seed1 = (lua_Unsigned)time(NULL); 606 lua_Unsigned seed1 = (lua_Unsigned)time(NULL);
607 lua_Unsigned seed2 = (lua_Unsigned)(size_t)L; 607 lua_Unsigned seed2 = (lua_Unsigned)(size_t)L;
608 lua_pushinteger(L, seed1);
609 lua_pushinteger(L, seed2);
608 setseed(state->s, seed1, seed2); 610 setseed(state->s, seed1, seed2);
609} 611}
610 612
611 613
612static int math_randomseed (lua_State *L) { 614static int math_randomseed (lua_State *L) {
613 RanState *state = (RanState *)lua_touserdata(L, lua_upvalueindex(1)); 615 RanState *state = (RanState *)lua_touserdata(L, lua_upvalueindex(1));
614 if (lua_isnone(L, 1)) 616 if (lua_isnone(L, 1)) {
615 randseed(L, state); 617 randseed(L, state);
618 return 2; /* return seeds */
619 }
616 else { 620 else {
617 lua_Integer n1 = luaL_checkinteger(L, 1); 621 lua_Integer n1 = luaL_checkinteger(L, 1);
618 lua_Integer n2 = luaL_optinteger(L, 2, 0); 622 lua_Integer n2 = luaL_optinteger(L, 2, 0);
619 setseed(state->s, n1, n2); 623 setseed(state->s, n1, n2);
624 return 0;
620 } 625 }
621 return 0;
622} 626}
623 627
624 628
@@ -635,6 +639,7 @@ static const luaL_Reg randfuncs[] = {
635static void setrandfunc (lua_State *L) { 639static void setrandfunc (lua_State *L) {
636 RanState *state = (RanState *)lua_newuserdatauv(L, sizeof(RanState), 0); 640 RanState *state = (RanState *)lua_newuserdatauv(L, sizeof(RanState), 0);
637 randseed(L, state); /* initialize with a "random" seed */ 641 randseed(L, state); /* initialize with a "random" seed */
642 lua_pop(L, 2); /* remove pushed seeds */
638 luaL_setfuncs(L, randfuncs, 1); 643 luaL_setfuncs(L, randfuncs, 1);
639} 644}
640 645