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119 lines
4.4 KiB
C++
119 lines
4.4 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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//=============================================================================
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//
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// MemoryStream does reading and writing over the buffer of bytes stored in
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// memory. Currently has rather trivial implementation. Does not own a buffer
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// itself, but works with the provided C-buffer pointer, which means that the
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// buffer object *must* persist until stream is closed.
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//
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// VectorStream is a specialized implementation that works with std::vector.
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// Unlike base MemoryStream provides continiously resizing buffer for writing.
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// TODO: separate StringStream for reading & writing String object?
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//
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//=============================================================================
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#ifndef AGS_SHARED_UTIL_MEMORY_STREAM_H
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#define AGS_SHARED_UTIL_MEMORY_STREAM_H
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#include "ags/lib/std/vector.h"
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#include "ags/shared/util/data_stream.h"
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#include "ags/shared/util/string.h"
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namespace AGS3 {
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namespace AGS {
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namespace Shared {
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class MemoryStream : public DataStream {
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public:
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// Construct memory stream in the read-only mode over a const C-buffer;
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// reading will never exceed buf_sz bytes;
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// buffer must persist in memory until the stream is closed.
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MemoryStream(const uint8_t *cbuf, size_t buf_sz, DataEndianess stream_endianess = kLittleEndian);
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// Construct memory stream in the chosen mode over a given C-buffer;
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// neither reading nor writing will ever exceed buf_sz bytes;
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// buffer must persist in memory until the stream is closed.
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MemoryStream(uint8_t *buf, size_t buf_sz, StreamWorkMode mode, DataEndianess stream_endianess = kLittleEndian);
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~MemoryStream() override {}
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void Close() override;
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bool Flush() override;
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// Is stream valid (underlying data initialized properly)
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bool IsValid() const override;
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// Is end of stream
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bool EOS() const override;
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// Total length of stream (if known)
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soff_t GetLength() const override;
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// Current position (if known)
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soff_t GetPosition() const override;
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bool CanRead() const override;
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bool CanWrite() const override;
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bool CanSeek() const override;
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size_t Read(void *buffer, size_t size) override;
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int32_t ReadByte() override;
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size_t Write(const void *buffer, size_t size) override;
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int32_t WriteByte(uint8_t b) override;
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bool Seek(soff_t offset, StreamSeek origin) override;
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protected:
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const uint8_t *_cbuf = nullptr; // readonly buffer ptr
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size_t _buf_sz = 0u; // hard buffer limit
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size_t _len = 0u; // calculated length of stream
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const StreamWorkMode _mode;
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size_t _pos = 0u; // current stream pos
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private:
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uint8_t *_buf = nullptr; // writeable buffer ptr
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};
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class VectorStream : public MemoryStream {
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public:
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// Construct memory stream in the read-only mode over a const std::vector;
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// vector must persist in memory until the stream is closed.
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VectorStream(const std::vector<uint8_t> &cbuf, DataEndianess stream_endianess = kLittleEndian);
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// Construct memory stream in the chosen mode over a given std::vector;
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// vector must persist in memory until the stream is closed.
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VectorStream(std::vector<uint8_t> &buf, StreamWorkMode mode, DataEndianess stream_endianess = kLittleEndian);
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~VectorStream() override {}
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void Close() override;
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bool CanRead() const override;
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bool CanWrite() const override;
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size_t Write(const void *buffer, size_t size) override;
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int32_t WriteByte(uint8_t b) override;
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private:
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std::vector<uint8_t> *_vec = nullptr; // writeable vector (may be null)
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};
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} // namespace Shared
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} // namespace AGS
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} // namespace AGS3
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#endif
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