72 lines
2.6 KiB
C
72 lines
2.6 KiB
C
// Tencent is pleased to support the open source community by making RapidJSON available.
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//
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// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
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//
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// Licensed under the MIT License (the "License"); you may not use this file except
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// in compliance with the License. You may obtain a copy of the License at
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//
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// http://opensource.org/licenses/MIT
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//
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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#ifndef RAPIDJSON_MEMORYSTREAM_H_
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#define RAPIDJSON_MEMORYSTREAM_H_
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#include "stream.h"
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#ifdef __clang__
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RAPIDJSON_DIAG_PUSH
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RAPIDJSON_DIAG_OFF(unreachable-code)
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RAPIDJSON_DIAG_OFF(missing-noreturn)
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#endif
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RAPIDJSON_NAMESPACE_BEGIN
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//! Represents an in-memory input byte stream.
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/*!
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This class is mainly for being wrapped by EncodedInputStream or AutoUTFInputStream.
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It is similar to FileReadBuffer but the source is an in-memory buffer instead of a file.
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Differences between MemoryStream and StringStream:
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1. StringStream has encoding but MemoryStream is a byte stream.
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2. MemoryStream needs size of the source buffer and the buffer don't need to be null terminated. StringStream assume null-terminated string as source.
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3. MemoryStream supports Peek4() for encoding detection. StringStream is specified with an encoding so it should not have Peek4().
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\note implements Stream concept
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*/
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struct MemoryStream {
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typedef char Ch; // byte
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MemoryStream(const Ch *src, size_t size) : src_(src), begin_(src), end_(src + size), size_(size) {}
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Ch Peek() const { return RAPIDJSON_UNLIKELY(src_ == end_) ? '\0' : *src_; }
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Ch Take() { return RAPIDJSON_UNLIKELY(src_ == end_) ? '\0' : *src_++; }
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size_t Tell() const { return static_cast<size_t>(src_ - begin_); }
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Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
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void Put(Ch) { RAPIDJSON_ASSERT(false); }
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void Flush() { RAPIDJSON_ASSERT(false); }
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size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; }
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// For encoding detection only.
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const Ch* Peek4() const {
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return Tell() + 4 <= size_ ? src_ : 0;
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}
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const Ch* src_; //!< Current read position.
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const Ch* begin_; //!< Original head of the string.
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const Ch* end_; //!< End of stream.
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size_t size_; //!< Size of the stream.
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};
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RAPIDJSON_NAMESPACE_END
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#ifdef __clang__
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RAPIDJSON_DIAG_POP
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#endif
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#endif // RAPIDJSON_MEMORYBUFFER_H_
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