45 lines
1.5 KiB
C++
45 lines
1.5 KiB
C++
// Copyright 2021-present StarRocks, Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "cache/disk_cache/io_buffer.h"
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#include "gutil/strings/fastmem.h"
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namespace starrocks {
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size_t IOBuffer::copy_to(void* data, ssize_t size, size_t pos) const {
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size_t bytes_to_copy = size > 0 ? size : _buf.size();
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size_t bytes_copied = 0;
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size_t skip = pos;
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for (size_t i = 0; i < _buf.backing_block_num(); ++i) {
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auto sp = _buf.backing_block(i);
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if (!sp.empty()) {
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if (sp.size() <= skip) {
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skip -= sp.size();
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continue;
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}
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size_t to_cp = std::min(sp.size() - skip, bytes_to_copy - bytes_copied);
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strings::memcpy_inlined((char*)data + bytes_copied, sp.data() + skip, to_cp);
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bytes_copied += to_cp;
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if (bytes_copied >= size) {
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break;
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}
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skip = 0;
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}
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}
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return bytes_copied;
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}
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} // namespace starrocks
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