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// Copyright 2018 Mimecast Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "rbuffer.h"
rbuffer_s *rbuffer_new(const int size)
{
rbuffer_s *r = Malloc(rbuffer_s);
r->size = size;
r->read_pos = size-1;
r->write_pos = 0;
r->ring = Calloc(size, void*);
Mset(r->ring, 0, size, void*);
return r;
}
void rbuffer_destroy(rbuffer_s *r)
{
if (r) {
free(r->ring);
free(r);
}
}
bool rbuffer_insert(rbuffer_s* r, void *data)
{
if (r->write_pos == r->read_pos)
// Ring buffer is full
return false;
r->ring[r->write_pos] = data;
r->write_pos = (r->write_pos+1) % r->size;
return true;
}
bool rbuffer_has_next(rbuffer_s* r)
{
sig_atomic_t read_pos = (r->read_pos+1) % r->size;
if (read_pos == r->write_pos)
// No more items to read, buffer is empty
{
return false;
}
return true;
}
void* rbuffer_get_next(rbuffer_s* r)
{
sig_atomic_t read_pos = (r->read_pos+1) % r->size;
if (read_pos == r->write_pos)
// No more items to read, buffer is empty
{
return NULL;
}
void *data = r->ring[read_pos];
r->ring[read_pos] = NULL;
r->read_pos = read_pos;
return data;
}
void rbuffer_print(rbuffer_s* r)
{
Put("rbuffer_s (%p):", (void*)r);
Put("\tsize: %d", (int)r->size);
Put("\tread_pos: %d", r->read_pos);
Put("\twrite_pos: %d", r->write_pos);
Out("\toccupied slots: ");
for (int i = 0; i < r->size; ++i)
if (r->ring[i]) {
Out("%d:%p ", i, r->ring[i]);
}
Out("\n");
}
void rbuffer_test(void)
{
rbuffer_s *r = rbuffer_new(5);
assert(NULL == rbuffer_get_next(r));
assert(rbuffer_insert(r, (void*)1));
assert(rbuffer_insert(r, (void*)2));
assert(rbuffer_insert(r, (void*)3));
assert(rbuffer_insert(r, (void*)4));
assert(!rbuffer_insert(r, (void*)5));
rbuffer_print(r);
assert(rbuffer_has_next(r));
assert(1 == (long) rbuffer_get_next(r));
assert(2 == (long) rbuffer_get_next(r));
assert(3 == (long) rbuffer_get_next(r));
assert(4 == (long) rbuffer_get_next(r));
assert(!rbuffer_has_next(r));
assert(NULL == rbuffer_get_next(r));
assert(rbuffer_insert(r, (void*)1));
assert(1 == (long) rbuffer_get_next(r));
assert(rbuffer_insert(r, (void*)2));
assert(2 == (long) rbuffer_get_next(r));
assert(rbuffer_insert(r, (void*)3));
assert(3 == (long) rbuffer_get_next(r));
assert(rbuffer_insert(r, (void*)4));
assert(4 == (long) rbuffer_get_next(r));
assert(rbuffer_insert(r, (void*)5));
assert(5 == (long) rbuffer_get_next(r));
assert(NULL == rbuffer_get_next(r));
rbuffer_print(r);
assert(rbuffer_insert(r, (void*)1));
rbuffer_print(r);
assert(rbuffer_insert(r, (void*)2));
assert(1 == (long) rbuffer_get_next(r));
rbuffer_print(r);
assert(rbuffer_insert(r, (void*)3));
assert(2 == (long) rbuffer_get_next(r));
rbuffer_print(r);
assert(rbuffer_insert(r, (void*)4));
assert(3 == (long) rbuffer_get_next(r));
rbuffer_print(r);
assert(rbuffer_insert(r, (void*)5));
rbuffer_print(r);
assert(4 == (long) rbuffer_get_next(r));
rbuffer_print(r);
assert(5 == (long) rbuffer_get_next(r));
assert(NULL == rbuffer_get_next(r));
rbuffer_destroy(r);
}
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