156 lines
4.7 KiB
C
156 lines
4.7 KiB
C
#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(indegree, 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. The location to
|
|
* store the data is allocated as necessary.
|
|
*
|
|
* - int *indegree_peek(struct indegree *, struct commit *);
|
|
*
|
|
* This function is similar to indegree_at(), but it will return NULL
|
|
* until a call to indegree_at() was made for the commit.
|
|
*
|
|
* - 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 is initialized by the variant without "_with_stride" associates
|
|
* each commit with an array of one integer.
|
|
*
|
|
* - void clear_indegree(struct indegree *);
|
|
*
|
|
* Empties the slab. The slab can be reused with the same stride
|
|
* without calling init_indegree() again or can be reconfigured to a
|
|
* different stride by calling init_indegree_with_stride().
|
|
*
|
|
* Call this function before the slab falls out of scope to avoid
|
|
* leaking memory.
|
|
*/
|
|
|
|
/* allocate ~512kB at once, allowing for malloc overhead */
|
|
#ifndef COMMIT_SLAB_SIZE
|
|
#define COMMIT_SLAB_SIZE (512*1024-32)
|
|
#endif
|
|
|
|
#define MAYBE_UNUSED __attribute__((__unused__))
|
|
|
|
#define define_commit_slab(slabname, elemtype) \
|
|
\
|
|
struct slabname { \
|
|
unsigned slab_size; \
|
|
unsigned stride; \
|
|
unsigned slab_count; \
|
|
elemtype **slab; \
|
|
}; \
|
|
static int stat_ ##slabname## realloc; \
|
|
\
|
|
static MAYBE_UNUSED 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; \
|
|
} \
|
|
\
|
|
static MAYBE_UNUSED void init_ ##slabname(struct slabname *s) \
|
|
{ \
|
|
init_ ##slabname## _with_stride(s, 1); \
|
|
} \
|
|
\
|
|
static MAYBE_UNUSED 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 MAYBE_UNUSED elemtype *slabname## _at_peek(struct slabname *s, \
|
|
const struct commit *c, \
|
|
int add_if_missing) \
|
|
{ \
|
|
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) { \
|
|
int i; \
|
|
if (!add_if_missing) \
|
|
return NULL; \
|
|
REALLOC_ARRAY(s->slab, nth_slab + 1); \
|
|
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]) { \
|
|
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]; \
|
|
} \
|
|
\
|
|
static MAYBE_UNUSED elemtype *slabname## _at(struct slabname *s, \
|
|
const struct commit *c) \
|
|
{ \
|
|
return slabname##_at_peek(s, c, 1); \
|
|
} \
|
|
\
|
|
static MAYBE_UNUSED 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
|
|
*
|
|
* define_commit_slab(indegree, int);
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* Statically initialize a commit slab named "var". Note that this
|
|
* evaluates "stride" multiple times! Example:
|
|
*
|
|
* struct indegree indegrees = COMMIT_SLAB_INIT(1, indegrees);
|
|
*
|
|
*/
|
|
#define COMMIT_SLAB_INIT(stride, var) { \
|
|
COMMIT_SLAB_SIZE / sizeof(**((var).slab)) / (stride), \
|
|
(stride), 0, NULL \
|
|
}
|
|
|
|
#endif /* COMMIT_SLAB_H */
|