commit-slab-impl.h

   1 #ifndef COMMIT_SLAB_IMPL_H
   2 #define COMMIT_SLAB_IMPL_H
   3
   4 #define MAYBE_UNUSED __attribute__((__unused__))
   5
   6 #define implement_static_commit_slab(slabname, elemtype) \
   7         implement_commit_slab(slabname, elemtype, static MAYBE_UNUSED)
   8
   9 #define implement_shared_commit_slab(slabname, elemtype) \
  10         implement_commit_slab(slabname, elemtype, )
  11
  12 #define implement_commit_slab(slabname, elemtype, scope)                \
  13                                                                         \
  14 scope void init_ ##slabname## _with_stride(struct slabname *s,          \
  15                                                    unsigned stride)     \
  16 {                                                                       \
  17         unsigned int elem_size;                                         \
  18         if (!stride)                                                    \
  19                 stride = 1;                                             \
  20         s->stride = stride;                                             \
  21         elem_size = sizeof(elemtype) * stride;                          \
  22         s->slab_size = COMMIT_SLAB_SIZE / elem_size;                    \
  23         s->slab_count = 0;                                              \
  24         s->slab = NULL;                                                 \
  25 }                                                                       \
  26                                                                         \
  27 scope void init_ ##slabname(struct slabname *s)                         \
  28 {                                                                       \
  29         init_ ##slabname## _with_stride(s, 1);                          \
  30 }                                                                       \
  31                                                                         \
  32 scope void clear_ ##slabname(struct slabname *s)                        \
  33 {                                                                       \
  34         unsigned int i;                                                 \
  35         for (i = 0; i < s->slab_count; i++)                             \
  36                 free(s->slab[i]);                                       \
  37         s->slab_count = 0;                                              \
  38         FREE_AND_NULL(s->slab);                                         \
  39 }                                                                       \
  40                                                                         \
  41 scope elemtype *slabname## _at_peek(struct slabname *s,                 \
  42                                                   const struct commit *c, \
  43                                                   int add_if_missing)   \
  44 {                                                                       \
  45         unsigned int nth_slab, nth_slot;                                \
  46                                                                         \
  47         nth_slab = c->index / s->slab_size;                             \
  48         nth_slot = c->index % s->slab_size;                             \
  49                                                                         \
  50         if (s->slab_count <= nth_slab) {                                \
  51                 unsigned int i;                                         \
  52                 if (!add_if_missing)                                    \
  53                         return NULL;                                    \
  54                 REALLOC_ARRAY(s->slab, nth_slab + 1);                   \
  55                 for (i = s->slab_count; i <= nth_slab; i++)             \
  56                         s->slab[i] = NULL;                              \
  57                 s->slab_count = nth_slab + 1;                           \
  58         }                                                               \
  59         if (!s->slab[nth_slab]) {                                       \
  60                 if (!add_if_missing)                                    \
  61                         return NULL;                                    \
  62                 s->slab[nth_slab] = xcalloc(s->slab_size,               \
  63                                             sizeof(**s->slab) * s->stride);             \
  64         }                                                               \
  65         return &s->slab[nth_slab][nth_slot * s->stride];                \
  66 }                                                                       \
  67                                                                         \
  68 scope elemtype *slabname## _at(struct slabname *s,                      \
  69                                              const struct commit *c)    \
  70 {                                                                       \
  71         return slabname##_at_peek(s, c, 1);                             \
  72 }                                                                       \
  73                                                                         \
  74 scope elemtype *slabname## _peek(struct slabname *s,                    \
  75                                              const struct commit *c)    \
  76 {                                                                       \
  77         return slabname##_at_peek(s, c, 0);                             \
  78 }                                                                       \
  79                                                                         \
  80 struct slabname
  81
  82 /*
  83  * Note that this redundant forward declaration is required
  84  * to allow a terminating semicolon, which makes instantiations look
  85  * like function declarations.  I.e., the expansion of
  86  *
  87  *    implement_commit_slab(indegree, int, static);
  88  *
  89  * ends in 'struct indegree;'.  This would otherwise
  90  * be a syntax error according (at least) to ISO C.  It's hard to
  91  * catch because GCC silently parses it by default.
  92  */
  93
  94 #endif  /* COMMIT_SLAB_IMPL_H */