| /* |
| ** $Id: lmem.c $ |
| ** Interface to Memory Manager |
| ** See Copyright Notice in lua.h |
| */ |
| |
| #define lmem_c |
| #define LUA_CORE |
| |
| #include "lprefix.h" |
| |
| |
| #include <stddef.h> |
| |
| #include "lua.h" |
| |
| #include "ldebug.h" |
| #include "ldo.h" |
| #include "lgc.h" |
| #include "lmem.h" |
| #include "lobject.h" |
| #include "lstate.h" |
| |
| |
| #if defined(HARDMEMTESTS) |
| #define hardtest(L,os,s) /* force a GC whenever possible */ \ |
| if ((s) > (os) && (G(L))->gcrunning) luaC_fullgc(L, 1); |
| #else |
| #define hardtest(L,os,s) ((void)0) |
| #endif |
| |
| |
| |
| /* |
| ** About the realloc function: |
| ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize); |
| ** ('osize' is the old size, 'nsize' is the new size) |
| ** |
| ** * frealloc(ud, NULL, x, s) creates a new block of size 's' (no |
| ** matter 'x'). |
| ** |
| ** * frealloc(ud, p, x, 0) frees the block 'p' |
| ** (in this specific case, frealloc must return NULL); |
| ** particularly, frealloc(ud, NULL, 0, 0) does nothing |
| ** (which is equivalent to free(NULL) in ISO C) |
| ** |
| ** frealloc returns NULL if it cannot create or reallocate the area |
| ** (any reallocation to an equal or smaller size cannot fail!) |
| */ |
| |
| |
| |
| #define MINSIZEARRAY 4 |
| |
| |
| void *luaM_growaux_ (lua_State *L, void *block, int nelems, int *psize, |
| int size_elems, int limit, const char *what) { |
| void *newblock; |
| int size = *psize; |
| if (nelems + 1 <= size) /* does one extra element still fit? */ |
| return block; /* nothing to be done */ |
| if (size >= limit / 2) { /* cannot double it? */ |
| if (unlikely(size >= limit)) /* cannot grow even a little? */ |
| luaG_runerror(L, "too many %s (limit is %d)", what, limit); |
| size = limit; /* still have at least one free place */ |
| } |
| else { |
| size *= 2; |
| if (size < MINSIZEARRAY) |
| size = MINSIZEARRAY; /* minimum size */ |
| } |
| lua_assert(nelems + 1 <= size && size <= limit); |
| /* 'limit' ensures that multiplication will not overflow */ |
| newblock = luaM_realloc_(L, block, cast_sizet(*psize) * size_elems, |
| cast_sizet(size) * size_elems); |
| if (unlikely(newblock == NULL)) |
| luaM_error(L); |
| *psize = size; /* update only when everything else is OK */ |
| return newblock; |
| } |
| |
| |
| void *luaM_shrinkvector_ (lua_State *L, void *block, int *size, |
| int final_n, int size_elem) { |
| global_State *g = G(L); |
| void *newblock; |
| size_t oldsize = cast_sizet((*size) * size_elem); |
| size_t newsize = cast_sizet(final_n * size_elem); |
| lua_assert(newsize <= oldsize); |
| newblock = (*g->frealloc)(g->ud, block, oldsize, newsize); |
| if (unlikely(newblock == NULL && final_n > 0)) /* allocation failed? */ |
| luaM_error(L); |
| else { |
| g->GCdebt += newsize - oldsize; |
| *size = final_n; |
| return newblock; |
| } |
| } |
| |
| |
| l_noret luaM_toobig (lua_State *L) { |
| luaG_runerror(L, "memory allocation error: block too big"); |
| } |
| |
| |
| /* |
| ** Free memory |
| */ |
| void luaM_free_ (lua_State *L, void *block, size_t osize) { |
| global_State *g = G(L); |
| lua_assert((osize == 0) == (block == NULL)); |
| (*g->frealloc)(g->ud, block, osize, 0); |
| g->GCdebt -= osize; |
| } |
| |
| |
| /* |
| ** In case of allocation fail, this function will call the GC to try |
| ** to free some memory and then try the allocation again. |
| ** (It should not be called when shrinking a block, because then the |
| ** interpreter may be in the middle of a collection step.) |
| */ |
| static void *tryagain (lua_State *L, void *block, |
| size_t osize, size_t nsize) { |
| global_State *g = G(L); |
| if (ttisnil(&g->nilvalue)) { /* is state fully build? */ |
| luaC_fullgc(L, 1); /* try to free some memory... */ |
| return (*g->frealloc)(g->ud, block, osize, nsize); /* try again */ |
| } |
| else return NULL; /* cannot free any memory without a full state */ |
| } |
| |
| |
| /* |
| ** generic allocation routine. |
| */ |
| void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { |
| void *newblock; |
| global_State *g = G(L); |
| lua_assert((osize == 0) == (block == NULL)); |
| hardtest(L, osize, nsize); |
| newblock = (*g->frealloc)(g->ud, block, osize, nsize); |
| if (unlikely(newblock == NULL && nsize > 0)) { |
| if (nsize > osize) /* not shrinking a block? */ |
| newblock = tryagain(L, block, osize, nsize); |
| if (newblock == NULL) /* still no memory? */ |
| return NULL; |
| } |
| lua_assert((nsize == 0) == (newblock == NULL)); |
| g->GCdebt = (g->GCdebt + nsize) - osize; |
| return newblock; |
| } |
| |
| |
| void *luaM_saferealloc_ (lua_State *L, void *block, size_t osize, |
| size_t nsize) { |
| void *newblock = luaM_realloc_(L, block, osize, nsize); |
| if (unlikely(newblock == NULL && nsize > 0)) /* allocation failed? */ |
| luaM_error(L); |
| return newblock; |
| } |
| |
| |
| void *luaM_malloc_ (lua_State *L, size_t size, int tag) { |
| hardtest(L, 0, size); |
| if (size == 0) |
| return NULL; /* that's all */ |
| else { |
| global_State *g = G(L); |
| void *newblock = (*g->frealloc)(g->ud, NULL, tag, size); |
| if (unlikely(newblock == NULL)) { |
| newblock = tryagain(L, NULL, tag, size); |
| if (newblock == NULL) |
| luaM_error(L); |
| } |
| g->GCdebt += size; |
| return newblock; |
| } |
| } |