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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "mojo/system/raw_shared_buffer.h"
#include "base/logging.h"
namespace mojo {
namespace system {
// static
RawSharedBuffer* RawSharedBuffer::Create(size_t num_bytes) {
DCHECK_GT(num_bytes, 0u);
RawSharedBuffer* rv = new RawSharedBuffer(num_bytes);
// No need to take the lock since we haven't given the object to anyone yet.
if (!rv->InitNoLock())
return NULL;
return rv;
}
scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::Map(size_t offset,
size_t length) {
if (!IsValidMap(offset, length))
return scoped_ptr<RawSharedBufferMapping>();
return MapNoCheck(offset, length);
}
bool RawSharedBuffer::IsValidMap(size_t offset, size_t length) {
if (offset > num_bytes_ || length == 0)
return false;
// Note: This is an overflow-safe check of |offset + length > num_bytes_|
// (that |num_bytes >= offset| is verified above).
if (length > num_bytes_ - offset)
return false;
return true;
}
scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::MapNoCheck(size_t offset,
size_t length) {
DCHECK(IsValidMap(offset, length));
base::AutoLock locker(lock_);
return MapImplNoLock(offset, length);
}
RawSharedBuffer::RawSharedBuffer(size_t num_bytes) : num_bytes_(num_bytes) {
}
RawSharedBuffer::~RawSharedBuffer() {
}
} // namespace system
} // namespace mojo
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