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/*
*
* Copyright 2017, Google Inc.
* All rights reserved.
*
* 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 Google Inc. 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 THE COPYRIGHT HOLDERS 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 THE COPYRIGHT
* OWNER 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.
*
*/
#include "src/core/lib/support/arena.h"
#include <grpc/support/alloc.h>
#include <grpc/support/atm.h>
#include <grpc/support/log.h>
#include <grpc/support/useful.h>
#define ROUND_UP_TO_ALIGNMENT_SIZE(x) \
(((x) + GPR_MAX_ALIGNMENT - 1u) & ~(GPR_MAX_ALIGNMENT - 1u))
typedef struct zone {
size_t size_begin;
size_t size_end;
gpr_atm next_atm;
} zone;
struct gpr_arena {
gpr_atm size_so_far;
zone initial_zone;
};
gpr_arena *gpr_arena_create(size_t initial_size) {
initial_size = ROUND_UP_TO_ALIGNMENT_SIZE(initial_size);
gpr_arena *a = gpr_zalloc(sizeof(gpr_arena) + initial_size);
a->initial_zone.size_end = initial_size;
return a;
}
size_t gpr_arena_destroy(gpr_arena *arena) {
gpr_atm size = gpr_atm_no_barrier_load(&arena->size_so_far);
zone *z = (zone *)gpr_atm_no_barrier_load(&arena->initial_zone.next_atm);
gpr_free(arena);
while (z) {
zone *next_z = (zone *)gpr_atm_no_barrier_load(&z->next_atm);
gpr_free(z);
z = next_z;
}
return (size_t)size;
}
void *gpr_arena_alloc(gpr_arena *arena, size_t size) {
size = ROUND_UP_TO_ALIGNMENT_SIZE(size);
size_t start =
(size_t)gpr_atm_no_barrier_fetch_add(&arena->size_so_far, size);
zone *z = &arena->initial_zone;
while (start > z->size_end) {
zone *next_z = (zone *)gpr_atm_acq_load(&z->next_atm);
if (next_z == NULL) {
size_t next_z_size = (size_t)gpr_atm_no_barrier_load(&arena->size_so_far);
next_z = gpr_zalloc(sizeof(zone) + next_z_size);
next_z->size_begin = z->size_end;
next_z->size_end = z->size_end + next_z_size;
if (!gpr_atm_rel_cas(&z->next_atm, (gpr_atm)NULL, (gpr_atm)next_z)) {
gpr_free(next_z);
next_z = (zone *)gpr_atm_acq_load(&z->next_atm);
}
}
z = next_z;
}
if (start + size > z->size_end) {
return gpr_arena_alloc(arena, size);
}
GPR_ASSERT(start >= z->size_begin);
GPR_ASSERT(start + size <= z->size_end);
return ((char *)(z + 1)) + start - z->size_begin;
}
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