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#ifndef ALLOC_H
#define ALLOC_H
struct alloc_state;
struct tree;
struct commit;
struct tag;
struct repository;
void *alloc_blob_node(struct repository *r);
void *alloc_tree_node(struct repository *r);
void init_commit_node(struct commit *c);
void *alloc_commit_node(struct repository *r);
void *alloc_tag_node(struct repository *r);
void *alloc_object_node(struct repository *r);
struct alloc_state *allocate_alloc_state(void);
void clear_alloc_state(struct alloc_state *s);
#define alloc_nr(x) (((x)+16)*3/2)
/**
* Dynamically growing an array using realloc() is error prone and boring.
*
* Define your array with:
*
* - a pointer (`item`) that points at the array, initialized to `NULL`
* (although please name the variable based on its contents, not on its
* type);
*
* - an integer variable (`alloc`) that keeps track of how big the current
* allocation is, initialized to `0`;
*
* - another integer variable (`nr`) to keep track of how many elements the
* array currently has, initialized to `0`.
*
* Then before adding `n`th element to the item, call `ALLOC_GROW(item, n,
* alloc)`. This ensures that the array can hold at least `n` elements by
* calling `realloc(3)` and adjusting `alloc` variable.
*
* ------------
* sometype *item;
* size_t nr;
* size_t alloc
*
* for (i = 0; i < nr; i++)
* if (we like item[i] already)
* return;
*
* // we did not like any existing one, so add one
* ALLOC_GROW(item, nr + 1, alloc);
* item[nr++] = value you like;
* ------------
*
* You are responsible for updating the `nr` variable.
*
* If you need to specify the number of elements to allocate explicitly
* then use the macro `REALLOC_ARRAY(item, alloc)` instead of `ALLOC_GROW`.
*
* Consider using ALLOC_GROW_BY instead of ALLOC_GROW as it has some
* added niceties.
*
* DO NOT USE any expression with side-effect for 'x', 'nr', or 'alloc'.
*/
#define ALLOC_GROW(x, nr, alloc) \
do { \
if ((nr) > alloc) { \
if (alloc_nr(alloc) < (nr)) \
alloc = (nr); \
else \
alloc = alloc_nr(alloc); \
REALLOC_ARRAY(x, alloc); \
} \
} while (0)
/*
* Similar to ALLOC_GROW but handles updating of the nr value and
* zeroing the bytes of the newly-grown array elements.
*
* DO NOT USE any expression with side-effect for any of the
* arguments.
*/
#define ALLOC_GROW_BY(x, nr, increase, alloc) \
do { \
if (increase) { \
size_t new_nr = nr + (increase); \
if (new_nr < nr) \
BUG("negative growth in ALLOC_GROW_BY"); \
ALLOC_GROW(x, new_nr, alloc); \
memset((x) + nr, 0, sizeof(*(x)) * (increase)); \
nr = new_nr; \
} \
} while (0)
#endif
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