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/* nbdkit
* Copyright Red Hat
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Red Hat nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* Simple implementation of a vector.
*
* Appending to the end is cheap. Inserting in the middle is more
* expensive. The vector can be a list of anything, eg. ints,
* structs, pointers.
*
* The vector is implemented as a struct with three fields:
*
* struct <name> {
* <type> *ptr; Pointer to array of items.
* size_t len; Number of valid items (ptr[0] .. ptr[len-1]).
* size_t cap; Capacity, size of the array allocated.
* };
* typedef struct <name> <name>;
*
* Note you can just access the struct fields directly. That is
* intentional, they are not private!
*
* When defining a vector type you give the <name> to use for the new
* vector type, and the <type> of each element:
*
* DEFINE_VECTOR_TYPE (<name>, <type>);
*
* This also defines functions called "<name>_reserve",
* "<name>_append", etc.
*
* <name>_reserve (&vector, n) reserves n additional elements beyond
* the current capacity. This is a wrapper around "realloc" and might
* fail (returning -1). If it succeeds (returning 0) then you are
* allowed to call <name>_append (&vector, elem) up to n times and it
* will not fail.
*
* <name>_append (&vector, elem) appends the new element at the end of
* the array (at ptr[len]), increasing the length. This may need to
* reallocate the array if there is not sufficient capacity.
*
* <name>_insert and <name>_remove insert and remove single elements
* in the middle of the array. <name>_insert may have to extend the
* array, so it may fail, while <name>_remove can never fail.
*
* There are various other methods, see the macros below.
*
* For example, you could define a list of ints as:
*
* DEFINE_VECTOR_TYPE (int_vector, int);
* int_vector myints = empty_vector;
*
* where "myints.ptr[]" will be an array of ints and "myints.len" will
* be the number of ints. There are no get/set accessors. To iterate
* over myints you can use the ".ptr" field directly:
*
* for (size_t i = 0; i < myints.len; ++i)
* printf ("%d\n", myints.ptr[i]);
*
* Initializing with "empty_vector", or assigning the compound literal
* "(int_vector)empty_vector", sets .ptr = NULL and .len = 0
*
* Because the implementation uses realloc, the .ptr array may move,
* so you should not save the address of array elements.
*
* There are predefined types in "string-vector.h" and
* "const-string-vector.h" for storing lists of strings.
*/
#ifndef NBDKIT_VECTOR_H
#define NBDKIT_VECTOR_H
#include <stdbool.h>
#include <assert.h>
#include <string.h>
#include "compiler-macros.h"
#include "static-assert.h"
#ifdef __clang__
#pragma clang diagnostic ignored "-Wunused-function"
#pragma clang diagnostic ignored "-Wduplicate-decl-specifier"
#endif
#define DEFINE_VECTOR_TYPE(name, type) \
struct name { \
type *ptr; /* Pointer to array of items. */ \
size_t len; /* Number of valid items in the array. */ \
size_t cap; /* Maximum number of items. */ \
}; \
typedef struct name name; \
\
/* Reserve n elements at the end of the vector. Note space is \
* allocated and capacity is increased, but the vector length is \
* not increased and the new elements are not initialized. \
*/ \
static inline int __attribute__ ((__unused__)) \
name##_reserve (name *v, size_t n) \
{ \
return generic_vector_reserve ((struct generic_vector *)v, n, \
sizeof (type), false); \
} \
\
/* Same as _reserve, but reserve exactly this number of elements \
* without any overhead. Useful if you know ahead of time that you \
* will never need to extend the vector. \
*/ \
static inline int __attribute__ ((__unused__)) \
name##_reserve_exactly (name *v, size_t n) \
{ \
return generic_vector_reserve ((struct generic_vector *)v, \
n, sizeof (type), true); \
} \
\
/* Same as _reserve, but the allocation will be page aligned. Note \
* that the machine page size must be divisible by sizeof (type). \
*/ \
static inline int __attribute__ ((__unused__)) \
name##_reserve_page_aligned (name *v, size_t n) \
{ \
return generic_vector_reserve_page_aligned ((struct generic_vector *)v, \
n, sizeof (type)); \
} \
\
/* Insert at i'th element. i=0 => beginning i=len => append */ \
static inline int __attribute__ ((__unused__)) \
name##_insert (name *v, type elem, size_t i) \
{ \
assert (i <= v->len); \
if (v->len >= v->cap) { \
if (name##_reserve (v, 1) == -1) return -1; \
} \
memmove (&v->ptr[i+1], &v->ptr[i], (v->len-i) * sizeof (elem)); \
v->ptr[i] = elem; \
v->len++; \
return 0; \
} \
\
/* Append a new element to the end of the vector. */ \
static inline int __attribute__ ((__unused__)) \
name##_append (name *v, type elem) \
{ \
return name##_insert (v, elem, v->len); \
} \
\
/* Remove i'th element. i=0 => beginning i=len-1 => end */ \
static inline void __attribute__ ((__unused__)) \
name##_remove (name *v, size_t i) \
{ \
assert (i < v->len); \
memmove (&v->ptr[i], &v->ptr[i+1], (v->len-i-1) * sizeof (type)); \
v->len--; \
} \
\
/* Remove all elements and deallocate the vector. */ \
static inline void __attribute__ ((__unused__)) \
name##_reset (name *v) \
{ \
free (v->ptr); \
v->ptr = NULL; \
v->len = v->cap = 0; \
} \
\
/* Iterate over the vector, calling f() on each element. */ \
static inline void __attribute__ ((__unused__)) \
name##_iter (name *v, void (*f) (type elem)) \
{ \
size_t i; \
for (i = 0; i < v->len; ++i) \
f (v->ptr[i]); \
} \
\
/* Sort the elements of the vector. */ \
static inline void __attribute__ ((__unused__)) \
name##_sort (name *v, \
int (*compare) (const type *p1, const type *p2)) \
{ \
qsort (v->ptr, v->len, sizeof (type), (void *) compare); \
} \
\
/* Search for an exactly matching element in the vector using a \
* binary search. Returns a pointer to the element or NULL. \
*/ \
static inline type * __attribute__ ((__unused__)) \
name##_search (const name *v, const void *key, \
int (*compare) (const void *key, const type *v)) \
{ \
return bsearch (key, v->ptr, v->len, sizeof (type), \
(void *) compare); \
} \
\
/* Make a new vector with the same elements. */ \
static inline int __attribute__ ((__unused__)) \
name##_duplicate (name *v, name *copy) \
{ \
/* Note it's allowed for v and copy to be the same pointer. */ \
type const *vptr = v->ptr; \
type *newptr; \
const size_t len = v->len * sizeof (type); \
\
newptr = malloc (len); \
if (newptr == NULL) return -1; \
memcpy (newptr, vptr, len); \
copy->ptr = newptr; \
copy->len = copy->cap = v->len; \
return 0; \
} \
\
/* End with duplicate declaration, so callers must supply ';'. */ \
struct name
#define empty_vector { .ptr = NULL, .len = 0, .cap = 0 }
/* This macro should only be used if:
* - the vector contains pointers, and
* - the pointed-to objects are:
* - neither const- nor volatile-qualified, and
* - allocated with malloc() or equivalent.
*/
#define ADD_VECTOR_EMPTY_METHOD(name) \
/* Call free() on each element of the vector, then reset the vector. \
*/ \
static inline void __attribute__ ((__unused__)) \
name##_empty (name *v) \
{ \
size_t i; \
for (i = 0; i < v->len; ++i) { \
STATIC_ASSERT (TYPE_IS_POINTER (v->ptr[i]), \
_vector_contains_pointers); \
free (v->ptr[i]); \
} \
name##_reset (v); \
} \
\
/* Force callers to supply ';'. */ \
struct name
/* Convenience macro tying together DEFINE_VECTOR_TYPE() and
* ADD_VECTOR_EMPTY_METHOD(). Inherit and forward the requirement for a
* trailing semicolon from ADD_VECTOR_EMPTY_METHOD() to the caller.
*/
#define DEFINE_POINTER_VECTOR_TYPE(name, type) \
DEFINE_VECTOR_TYPE (name, type); \
ADD_VECTOR_EMPTY_METHOD (name)
struct generic_vector {
void *ptr;
size_t len;
size_t cap;
};
extern int generic_vector_reserve (struct generic_vector *v,
size_t n, size_t itemsize,
bool exactly);
extern int generic_vector_reserve_page_aligned (struct generic_vector *v,
size_t n, size_t itemsize);
#endif /* NBDKIT_VECTOR_H */
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