forked from 0ad/0ad
Ykkrosh
aa118403bb
ScEd: Compilation fixes. Atlas: Screen-space to world-space conversion when editing terrain. Wireframe option. Minor wxWidgets 2.6.1 fixes. AoE3Ed. This was SVN commit r2698.
73 lines
1.9 KiB
C++
73 lines
1.9 KiB
C++
#ifndef STREAM_H__
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#define STREAM_H__
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/*
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Stream: A system for input/output of data, particularly with chained streams
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(e.g. file -> zlib decompressor -> data processor).
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Similar to wxWidget's streams, but rewritten so that code can use this without
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requiring wx.
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TODO: This concept might not actually be any good; consider alternatives.
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*/
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#include <sys/types.h>
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#include <limits>
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namespace DatafileIO
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{
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class Stream
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{
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public:
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enum whence { FROM_START, FROM_END, FROM_CURRENT };
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virtual ~Stream() {};
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virtual off_t Tell() const = 0;
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virtual bool IsOk() const = 0;
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};
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class SeekableStream
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{
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public:
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virtual void Seek(off_t pos, Stream::whence mode) = 0;
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};
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class InputStream : public Stream
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{
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public:
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// Try to read up to 'size' bytes into buffer, and return the amount
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// actually read.
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virtual size_t Read(void* buffer, size_t size) = 0;
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// Sets 'buffer' and 'size' to point to the data from the current cursor
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// position up to max_size bytes (or the end of the file, whichever is
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// reached first) and returns true if successful.
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// If a derived stream doesn't implement these, a default (which just
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// calls Read to get all the data) will be used instead. (It is implemented
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// in e.g. streams that already have a pointer to all the data, so they
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// don't need to do any memory copying.)
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virtual bool AcquireBuffer(void*& buffer, size_t& size, size_t max_size = std::numeric_limits<size_t>::max());
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virtual void ReleaseBuffer(void* buffer);
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};
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class OutputStream : public Stream
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{
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public:
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virtual void Write(const void* buffer, size_t size) = 0;
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};
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// Specialisations to indicate that a stream allows seeking.
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class SeekableInputStream : public InputStream, public SeekableStream
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{
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};
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class SeekableOutputStream : public OutputStream, public SeekableStream
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{
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};
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}
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#endif // STREAM_H__
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