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-rw-r--r--commit-slab-impl.h94
1 files changed, 94 insertions, 0 deletions
diff --git a/commit-slab-impl.h b/commit-slab-impl.h
new file mode 100644
index 0000000000..ac1e6d409a
--- /dev/null
+++ b/commit-slab-impl.h
@@ -0,0 +1,94 @@
+#ifndef COMMIT_SLAB_IMPL_H
+#define COMMIT_SLAB_IMPL_H
+
+#define MAYBE_UNUSED __attribute__((__unused__))
+
+#define implement_static_commit_slab(slabname, elemtype) \
+ implement_commit_slab(slabname, elemtype, static MAYBE_UNUSED)
+
+#define implement_shared_commit_slab(slabname, elemtype) \
+ implement_commit_slab(slabname, elemtype, )
+
+#define implement_commit_slab(slabname, elemtype, scope) \
+ \
+scope void init_ ##slabname## _with_stride(struct slabname *s, \
+ unsigned stride) \
+{ \
+ unsigned int elem_size; \
+ if (!stride) \
+ stride = 1; \
+ s->stride = stride; \
+ elem_size = sizeof(elemtype) * stride; \
+ s->slab_size = COMMIT_SLAB_SIZE / elem_size; \
+ s->slab_count = 0; \
+ s->slab = NULL; \
+} \
+ \
+scope void init_ ##slabname(struct slabname *s) \
+{ \
+ init_ ##slabname## _with_stride(s, 1); \
+} \
+ \
+scope void clear_ ##slabname(struct slabname *s) \
+{ \
+ unsigned int i; \
+ for (i = 0; i < s->slab_count; i++) \
+ free(s->slab[i]); \
+ s->slab_count = 0; \
+ FREE_AND_NULL(s->slab); \
+} \
+ \
+scope elemtype *slabname## _at_peek(struct slabname *s, \
+ const struct commit *c, \
+ int add_if_missing) \
+{ \
+ unsigned int nth_slab, nth_slot; \
+ \
+ nth_slab = c->index / s->slab_size; \
+ nth_slot = c->index % s->slab_size; \
+ \
+ if (s->slab_count <= nth_slab) { \
+ unsigned int i; \
+ if (!add_if_missing) \
+ return NULL; \
+ REALLOC_ARRAY(s->slab, nth_slab + 1); \
+ for (i = s->slab_count; i <= nth_slab; i++) \
+ s->slab[i] = NULL; \
+ s->slab_count = nth_slab + 1; \
+ } \
+ if (!s->slab[nth_slab]) { \
+ if (!add_if_missing) \
+ return NULL; \
+ s->slab[nth_slab] = xcalloc(s->slab_size, \
+ sizeof(**s->slab) * s->stride); \
+ } \
+ return &s->slab[nth_slab][nth_slot * s->stride]; \
+} \
+ \
+scope elemtype *slabname## _at(struct slabname *s, \
+ const struct commit *c) \
+{ \
+ return slabname##_at_peek(s, c, 1); \
+} \
+ \
+scope elemtype *slabname## _peek(struct slabname *s, \
+ const struct commit *c) \
+{ \
+ return slabname##_at_peek(s, c, 0); \
+} \
+ \
+struct slabname
+
+/*
+ * Note that this redundant forward declaration is required
+ * to allow a terminating semicolon, which makes instantiations look
+ * like function declarations. I.e., the expansion of
+ *
+ * implement_commit_slab(indegree, int, static);
+ *
+ * ends in 'struct indegree;'. This would otherwise
+ * be a syntax error according (at least) to ISO C. It's hard to
+ * catch because GCC silently parses it by default.
+ */
+
+#endif /* COMMIT_SLAB_IMPL_H */