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Diffstat (limited to 'commit-slab.h')
| -rw-r--r-- | commit-slab.h | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/commit-slab.h b/commit-slab.h new file mode 100644 index 0000000000..7d481638af --- /dev/null +++ b/commit-slab.h @@ -0,0 +1,98 @@ +#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 */ |