Merge branch 'rh/remote-hg-bzr-updates' (early part)
[git/git.git] / commit-slab.h
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1#ifndef COMMIT_SLAB_H
2#define COMMIT_SLAB_H
3
4/*
5 * define_commit_slab(slabname, elemtype) creates boilerplate code to define
6 * a new struct (struct slabname) that is used to associate a piece of data
7 * of elemtype to commits, and a few functions to use that struct.
8 *
9 * After including this header file, using:
10 *
11 * define_commit_slab(indegee, int);
12 *
13 * will let you call the following functions:
14 *
15 * - int *indegree_at(struct indegree *, struct commit *);
16 *
17 * This function locates the data associated with the given commit in
18 * the indegree slab, and returns the pointer to it.
19 *
20 * - void init_indegree(struct indegree *);
21 * void init_indegree_with_stride(struct indegree *, int);
22 *
23 * Initializes the indegree slab that associates an array of integers
24 * to each commit. 'stride' specifies how big each array is. The slab
25 * that id initialied by the variant without "_with_stride" associates
26 * each commit with an array of one integer.
27 */
28
29/* allocate ~512kB at once, allowing for malloc overhead */
30#ifndef COMMIT_SLAB_SIZE
31#define COMMIT_SLAB_SIZE (512*1024-32)
32#endif
33
34#define define_commit_slab(slabname, elemtype) \
35 \
36struct slabname { \
37 unsigned slab_size; \
38 unsigned stride; \
39 unsigned slab_count; \
40 elemtype **slab; \
41}; \
42static int stat_ ##slabname## realloc; \
43 \
44static void init_ ##slabname## _with_stride(struct slabname *s, \
45 unsigned stride) \
46{ \
47 unsigned int elem_size; \
48 if (!stride) \
49 stride = 1; \
50 s->stride = stride; \
d7a1d629 51 elem_size = sizeof(elemtype) * stride; \
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52 s->slab_size = COMMIT_SLAB_SIZE / elem_size; \
53 s->slab_count = 0; \
54 s->slab = NULL; \
55} \
56 \
57static void init_ ##slabname(struct slabname *s) \
58{ \
59 init_ ##slabname## _with_stride(s, 1); \
60} \
61 \
62static void clear_ ##slabname(struct slabname *s) \
63{ \
64 int i; \
65 for (i = 0; i < s->slab_count; i++) \
66 free(s->slab[i]); \
67 s->slab_count = 0; \
68 free(s->slab); \
69 s->slab = NULL; \
70} \
71 \
72static elemtype *slabname## _at(struct slabname *s, \
73 const struct commit *c) \
74{ \
d7a1d629 75 int nth_slab, nth_slot; \
a84b794a 76 \
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77 nth_slab = c->index / s->slab_size; \
78 nth_slot = c->index % s->slab_size; \
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79 \
80 if (s->slab_count <= nth_slab) { \
81 int i; \
82 s->slab = xrealloc(s->slab, \
83 (nth_slab + 1) * sizeof(s->slab)); \
84 stat_ ##slabname## realloc++; \
85 for (i = s->slab_count; i <= nth_slab; i++) \
86 s->slab[i] = NULL; \
87 s->slab_count = nth_slab + 1; \
88 } \
89 if (!s->slab[nth_slab]) \
90 s->slab[nth_slab] = xcalloc(s->slab_size, \
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91 sizeof(**s->slab) * s->stride); \
92 return &s->slab[nth_slab][nth_slot * s->stride]; \
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93} \
94 \
95static int stat_ ##slabname## realloc
96
97#endif /* COMMIT_SLAB_H */