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#ifndef COMMIT_SLAB_H
#define COMMIT_SLAB_H
/*
* define_commit_slab(slabname, elemtype) creates boilerplate code to define
* a new struct (struct slabname) that is used to associate a piece of data
* of elemtype to commits, and a few functions to use that struct.
*
* After including this header file, using:
*
* define_commit_slab(indegee, int);
*
* will let you call the following functions:
*
* - int *indegree_at(struct indegree *, struct commit *);
*
* This function locates the data associated with the given commit in
* the indegree slab, and returns the pointer to it.
*
* - void init_indegree(struct indegree *);
* void init_indegree_with_stride(struct indegree *, int);
*
* Initializes the indegree slab that associates an array of integers
* to each commit. 'stride' specifies how big each array is. The slab
* that id initialied by the variant without "_with_stride" associates
* each commit with an array of one integer.
*/
/* allocate ~512kB at once, allowing for malloc overhead */
#ifndef COMMIT_SLAB_SIZE
#define COMMIT_SLAB_SIZE (512*1024-32)
#endif
#define define_commit_slab(slabname, elemtype) \
\
struct slabname { \
unsigned slab_size; \
unsigned stride; \
unsigned slab_count; \
elemtype **slab; \
}; \
static int stat_ ##slabname## realloc; \
\
static void init_ ##slabname## _with_stride(struct slabname *s, \
unsigned stride) \
{ \
unsigned int elem_size; \
if (!stride) \
stride = 1; \
s->stride = stride; \
elem_size = sizeof(struct slabname) * stride; \
s->slab_size = COMMIT_SLAB_SIZE / elem_size; \
s->slab_count = 0; \
s->slab = NULL; \
} \
\
static void init_ ##slabname(struct slabname *s) \
{ \
init_ ##slabname## _with_stride(s, 1); \
} \
\
static void clear_ ##slabname(struct slabname *s) \
{ \
int i; \
for (i = 0; i < s->slab_count; i++) \
free(s->slab[i]); \
s->slab_count = 0; \
free(s->slab); \
s->slab = NULL; \
} \
\
static elemtype *slabname## _at(struct slabname *s, \
const struct commit *c) \
{ \
int nth_slab, nth_slot, ix; \
\
ix = c->index * s->stride; \
nth_slab = ix / s->slab_size; \
nth_slot = ix % s->slab_size; \
\
if (s->slab_count <= nth_slab) { \
int i; \
s->slab = xrealloc(s->slab, \
(nth_slab + 1) * sizeof(s->slab)); \
stat_ ##slabname## realloc++; \
for (i = s->slab_count; i <= nth_slab; i++) \
s->slab[i] = NULL; \
s->slab_count = nth_slab + 1; \
} \
if (!s->slab[nth_slab]) \
s->slab[nth_slab] = xcalloc(s->slab_size, \
sizeof(**s->slab)); \
return &s->slab[nth_slab][nth_slot]; \
} \
\
static int stat_ ##slabname## realloc
#endif /* COMMIT_SLAB_H */
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