29 ** ('osize' is the old size, 'nsize' is the new size)
31 ** - frealloc(ud, p, x, 0) frees the block 'p' and returns NULL.
35 ** - frealloc(ud, NULL, x, s) creates a new block of size 's'
36 ** (no matter 'x'). Returns NULL if it cannot create the new block.
38 ** - otherwise, frealloc(ud, b, x, y) reallocates the block 'b' from
39 ** size 'x' to size 'y'. Returns NULL if it cannot reallocate the
40 ** block to the new size.
47 #define callfrealloc(g,block,os,ns)    ((*g->frealloc)(g->ud, block, os, ns))  argument
58 #define cantryagain(g)	(completestate(g) && !g->gcstopem)
65 ** First allocation will fail except when freeing a block (frees never
69 static void *firsttry (global_State *g, void *block, size_t os, size_t ns) {  in firsttry()  argument
73     return callfrealloc(g, block, os, ns);  in firsttry()
76 #define firsttry(g,block,os,ns)    callfrealloc(g, block, os, ns)  argument
90 ** Minimum size for arrays during parsing, to avoid overhead of
91 ** reallocating to size 1, then 2, and then 4. All these arrays
97 void *luaM_growaux_ (lua_State *L, void *block, int nelems, int *psize,  in luaM_growaux_()  argument
100   int size = *psize;  in luaM_growaux_()  local
101   if (nelems + 1 <= size)  /* does one extra element still fit? */  in luaM_growaux_()
102     return block;  /* nothing to be done */  in luaM_growaux_()
103   if (size >= limit / 2) {  /* cannot double it? */  in luaM_growaux_()
104     if (l_unlikely(size >= limit))  /* cannot grow even a little? */  in luaM_growaux_()
106     size = limit;  /* still have at least one free place */  in luaM_growaux_()
109     size *= 2;  in luaM_growaux_()
110     if (size < MINSIZEARRAY)  in luaM_growaux_()
111       size = MINSIZEARRAY;  /* minimum size */  in luaM_growaux_()
113   lua_assert(nelems + 1 <= size && size <= limit);  in luaM_growaux_()
115   newblock = luaM_saferealloc_(L, block, cast_sizet(*psize) * size_elems,  in luaM_growaux_()
116                                          cast_sizet(size) * size_elems);  in luaM_growaux_()
117   *psize = size;  /* update only when everything else is OK */  in luaM_growaux_()
123 ** In prototypes, the size of the array is also its number of
128 void *luaM_shrinkvector_ (lua_State *L, void *block, int *size,  in luaM_shrinkvector_()  argument
131   size_t oldsize = cast_sizet((*size) * size_elem);  in luaM_shrinkvector_()
134   newblock = luaM_saferealloc_(L, block, oldsize, newsize);  in luaM_shrinkvector_()
135   *size = final_n;  in luaM_shrinkvector_()
143   luaG_runerror(L, "memory allocation error: block too big");  in luaM_toobig()
150 void luaM_free_ (lua_State *L, void *block, size_t osize) {  in luaM_free_()  argument
152   lua_assert((osize == 0) == (block == NULL));  in luaM_free_()
153   callfrealloc(g, block, osize, 0);  in luaM_free_()
154   g->GCdebt -= osize;  in luaM_free_()
162 static void *tryagain (lua_State *L, void *block,  in tryagain()  argument
167     return callfrealloc(g, block, osize, nsize);  /* try again */  in tryagain()
176 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {  in luaM_realloc_()  argument
179   lua_assert((osize == 0) == (block == NULL));  in luaM_realloc_()
180   newblock = firsttry(g, block, osize, nsize);  in luaM_realloc_()
182     newblock = tryagain(L, block, osize, nsize);  in luaM_realloc_()
187   g->GCdebt = (g->GCdebt + nsize) - osize;  in luaM_realloc_()
192 void *luaM_saferealloc_ (lua_State *L, void *block, size_t osize,  in luaM_saferealloc_()  argument
194   void *newblock = luaM_realloc_(L, block, osize, nsize);  in luaM_saferealloc_()
201 void *luaM_malloc_ (lua_State *L, size_t size, int tag) {  in luaM_malloc_()  argument
202   if (size == 0)  in luaM_malloc_()
206     void *newblock = firsttry(g, NULL, tag, size);  in luaM_malloc_()
208       newblock = tryagain(L, NULL, tag, size);  in luaM_malloc_()
212     g->GCdebt += size;  in luaM_malloc_()