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1 /* |
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2 ** $Id: lmem.c,v 1.70.1.1 2007/12/27 13:02:25 roberto Exp $ |
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3 ** Interface to Memory Manager |
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4 ** See Copyright Notice in lua.h |
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5 */ |
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6 |
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7 |
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8 #include <stddef.h> |
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9 |
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10 #define lmem_c |
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11 #define LUA_CORE |
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12 |
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13 #include "lua.h" |
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14 |
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15 #include "ldebug.h" |
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16 #include "ldo.h" |
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17 #include "lmem.h" |
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18 #include "lobject.h" |
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19 #include "lstate.h" |
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20 |
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21 |
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22 |
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23 /* |
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24 ** About the realloc function: |
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25 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize); |
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26 ** (`osize' is the old size, `nsize' is the new size) |
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27 ** |
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28 ** Lua ensures that (ptr == NULL) iff (osize == 0). |
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29 ** |
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30 ** * frealloc(ud, NULL, 0, x) creates a new block of size `x' |
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31 ** |
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32 ** * frealloc(ud, p, x, 0) frees the block `p' |
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33 ** (in this specific case, frealloc must return NULL). |
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34 ** particularly, frealloc(ud, NULL, 0, 0) does nothing |
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35 ** (which is equivalent to free(NULL) in ANSI C) |
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36 ** |
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37 ** frealloc returns NULL if it cannot create or reallocate the area |
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38 ** (any reallocation to an equal or smaller size cannot fail!) |
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39 */ |
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40 |
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41 |
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42 |
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43 #define MINSIZEARRAY 4 |
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44 |
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45 |
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46 void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems, |
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47 int limit, const char *errormsg) { |
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48 void *newblock; |
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49 int newsize; |
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50 if (*size >= limit/2) { /* cannot double it? */ |
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51 if (*size >= limit) /* cannot grow even a little? */ |
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52 luaG_runerror(L, errormsg); |
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53 newsize = limit; /* still have at least one free place */ |
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54 } |
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55 else { |
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56 newsize = (*size)*2; |
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57 if (newsize < MINSIZEARRAY) |
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58 newsize = MINSIZEARRAY; /* minimum size */ |
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59 } |
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60 newblock = luaM_reallocv(L, block, *size, newsize, size_elems); |
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61 *size = newsize; /* update only when everything else is OK */ |
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62 return newblock; |
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63 } |
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64 |
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65 |
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66 void *luaM_toobig (lua_State *L) { |
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67 luaG_runerror(L, "memory allocation error: block too big"); |
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68 return NULL; /* to avoid warnings */ |
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69 } |
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70 |
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71 |
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72 |
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73 /* |
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74 ** generic allocation routine. |
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75 */ |
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76 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { |
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77 global_State *g = G(L); |
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78 lua_assert((osize == 0) == (block == NULL)); |
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79 block = (*g->frealloc)(g->ud, block, osize, nsize); |
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80 if (block == NULL && nsize > 0) |
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81 luaD_throw(L, LUA_ERRMEM); |
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82 lua_assert((nsize == 0) == (block == NULL)); |
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83 g->totalbytes = (g->totalbytes - osize) + nsize; |
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84 return block; |
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85 } |
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86 |