Change seed for lua 5.3

lseed.c

/*
  Only for lua 5.3 
  
  You can use lua_changeseed(L, seed) to change a seed for a lua VM.
  
  lua_State *L = luaL_newstate();
  lua_changeseed(L, myseed);
  */

#include "lstate.h"
#include "lobject.h"
#include "lstring.h"

#if !defined(LUAI_HASHLIMIT)
#define LUAI_HASHLIMIT		5
#endif

static unsigned int luaS_hash_ (const char *str, size_t l, unsigned int seed) {
  unsigned int h = seed ^ cast(unsigned int, l);
  size_t step = (l >> LUAI_HASHLIMIT) + 1;
  for (; l >= step; l -= step)
    h ^= ((h<<5) + (h>>2) + cast_byte(str[l - 1]));
  return h;
}

static void
changelists(GCObject *p, unsigned int seed) {
	while (p != NULL) {
		TString *ts;
		switch (p->tt) {
		case LUA_TSHRSTR:
			ts = gco2ts(p);
			ts->hash = luaS_hash_(getstr(ts), ts->shrlen, seed);
			break;
		case LUA_TLNGSTR:
			ts = gco2ts(p);
			ts->extra = 0;
			break;
		}
		p = p->next;
	}
}

static void
rearrange(stringtable *tb, unsigned int seed) {
	int i;
	int size = tb->size;
	for (i=0;i<size;i++) {
		TString *ts = tb->hash[i];
		tb->hash[i] = NULL;
		while (ts != NULL) {
			int nidx = lmod(ts->hash, size);
			TString *next = ts->u.hnext;
			ts->u.hnext = tb->hash[nidx];
			tb->hash[nidx] = ts;
			ts = next;
		}
	}
}

void
lua_changeseed(lua_State *L, unsigned int seed) {
	global_State *g = G(L);
	g->seed = seed;
	changelists(g->allgc, seed);
	changelists(g->fixedgc, seed);
	rearrange(&g->strt, seed);
}