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5191 | serge | 1 | /* objalloc.h -- routines to allocate memory for objects |
6324 | serge | 2 | Copyright (C) 1997-2015 Free Software Foundation, Inc. |
5191 | serge | 3 | Written by Ian Lance Taylor, Cygnus Solutions. |
4 | |||
5 | This program is free software; you can redistribute it and/or modify it |
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6 | under the terms of the GNU General Public License as published by the |
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7 | Free Software Foundation; either version 2, or (at your option) any |
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8 | later version. |
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9 | |||
10 | This program is distributed in the hope that it will be useful, |
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 | GNU General Public License for more details. |
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14 | |||
15 | You should have received a copy of the GNU General Public License |
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16 | along with this program; if not, write to the Free Software |
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17 | Foundation, 51 Franklin Street - Fifth Floor, |
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18 | Boston, MA 02110-1301, USA. */ |
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19 | |||
20 | #ifndef OBJALLOC_H |
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21 | #define OBJALLOC_H |
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22 | |||
23 | #include "ansidecl.h" |
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24 | |||
25 | /* These routines allocate space for an object. The assumption is |
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26 | that the object will want to allocate space as it goes along, but |
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27 | will never want to free any particular block. There is a function |
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28 | to free a block, which also frees all more recently allocated |
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29 | blocks. There is also a function to free all the allocated space. |
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30 | |||
31 | This is essentially a specialization of obstacks. The main |
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32 | difference is that a block may not be allocated a bit at a time. |
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33 | Another difference is that these routines are always built on top |
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34 | of malloc, and always pass an malloc failure back to the caller, |
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35 | unlike more recent versions of obstacks. */ |
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36 | |||
37 | /* This is what an objalloc structure looks like. Callers should not |
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38 | refer to these fields, nor should they allocate these structure |
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39 | themselves. Instead, they should only create them via |
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40 | objalloc_init, and only access them via the functions and macros |
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41 | listed below. The structure is only defined here so that we can |
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42 | access it via macros. */ |
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43 | |||
44 | struct objalloc |
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45 | { |
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46 | char *current_ptr; |
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47 | unsigned int current_space; |
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48 | void *chunks; |
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49 | }; |
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50 | |||
51 | /* Work out the required alignment. */ |
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52 | |||
53 | struct objalloc_align { char x; double d; }; |
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54 | |||
55 | #if defined (__STDC__) && __STDC__ |
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56 | #ifndef offsetof |
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57 | #include |
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58 | #endif |
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59 | #endif |
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60 | #ifndef offsetof |
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61 | #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER) |
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62 | #endif |
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63 | #define OBJALLOC_ALIGN offsetof (struct objalloc_align, d) |
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64 | |||
65 | /* Create an objalloc structure. Returns NULL if malloc fails. */ |
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66 | |||
67 | extern struct objalloc *objalloc_create (void); |
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68 | |||
69 | /* Allocate space from an objalloc structure. Returns NULL if malloc |
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70 | fails. */ |
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71 | |||
72 | extern void *_objalloc_alloc (struct objalloc *, unsigned long); |
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73 | |||
74 | /* The macro version of objalloc_alloc. We only define this if using |
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75 | gcc, because otherwise we would have to evaluate the arguments |
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76 | multiple times, or use a temporary field as obstack.h does. */ |
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77 | |||
78 | #if defined (__GNUC__) && defined (__STDC__) && __STDC__ |
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79 | |||
80 | /* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and |
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81 | does not implement __extension__. But that compiler doesn't define |
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82 | __GNUC_MINOR__. */ |
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83 | #if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__) |
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84 | #define __extension__ |
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85 | #endif |
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86 | |||
87 | #define objalloc_alloc(o, l) \ |
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88 | __extension__ \ |
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89 | ({ struct objalloc *__o = (o); \ |
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90 | unsigned long __len = (l); \ |
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91 | if (__len == 0) \ |
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92 | __len = 1; \ |
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93 | __len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1); \ |
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94 | (__len != 0 && __len <= __o->current_space \ |
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95 | ? (__o->current_ptr += __len, \ |
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96 | __o->current_space -= __len, \ |
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97 | (void *) (__o->current_ptr - __len)) \ |
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98 | : _objalloc_alloc (__o, __len)); }) |
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99 | |||
100 | #else /* ! __GNUC__ */ |
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101 | |||
102 | #define objalloc_alloc(o, l) _objalloc_alloc ((o), (l)) |
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103 | |||
104 | #endif /* ! __GNUC__ */ |
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105 | |||
106 | /* Free an entire objalloc structure. */ |
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107 | |||
108 | extern void objalloc_free (struct objalloc *); |
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109 | |||
110 | /* Free a block allocated by objalloc_alloc. This also frees all more |
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111 | recently allocated blocks. */ |
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112 | |||
113 | extern void objalloc_free_block (struct objalloc *, void *); |
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114 | |||
115 | #endif /* OBJALLOC_H */=>> |