103 lines
2.3 KiB
C++
103 lines
2.3 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 1998, Microsoft Corp. All rights reserved.
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//
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// FILE
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//
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// outbuf.cpp
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//
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// SYNOPSIS
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//
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// Defines the class OutputBuffer.
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//
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// MODIFICATION HISTORY
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//
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// 08/04/1998 Original version.
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// 11/17/1998 Streamline resize().
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <ias.h>
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#include <outbuf.h>
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OutputBuffer::OutputBuffer() throw ()
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: start(scratch),
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next(scratch),
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end(scratch + sizeof(scratch))
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{ }
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OutputBuffer::~OutputBuffer() throw ()
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{
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// Delete the buffer if necessary.
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if (start != scratch) { delete[] start; }
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}
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//////////
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// I defined this as a macro to force the compiler to inline it.
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//////////
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#define QUICK_RESERVE(p, nbyte) \
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p = next; if ((next += nbyte) > end) { resize(p); }
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// Append an octet string.
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void OutputBuffer::append(const BYTE* buf, DWORD buflen)
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{
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PBYTE p;
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QUICK_RESERVE(p, buflen);
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memcpy(p, buf, buflen);
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}
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// Append a null-terminated ANSI string.
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void OutputBuffer::append(PCSTR sz)
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{
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DWORD len = strlen(sz);
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PBYTE p;
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QUICK_RESERVE(p, len);
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memcpy(p, sz, len);
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}
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// Append a single ANSI character.
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void OutputBuffer::append(CHAR ch)
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{
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PBYTE p;
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QUICK_RESERVE(p, 1);
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*p = (BYTE)ch;
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}
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// Reserves 'nbyte' bytes in the buffer and returns a pointer to the
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// reserved bytes.
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PBYTE OutputBuffer::reserve(DWORD nbyte)
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{
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PBYTE p;
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QUICK_RESERVE(p, nbyte);
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return p;
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}
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void OutputBuffer::resize(PBYTE& cursor)
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{
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// Convert everything to relative offsets.
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ptrdiff_t cursorOffset = cursor - start;
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ptrdiff_t nextOffset = next - start;
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ptrdiff_t endOffset = end - start;
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// We always at least double the buffer.
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endOffset *= 2;
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// Make sure it's big enough to hold the next chunk.
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if (endOffset < nextOffset) { endOffset = nextOffset; }
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// Allocate the new buffer and copy in the existing bytes.
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PBYTE newBuffer = new BYTE[(size_t)endOffset];
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memcpy(newBuffer, start, (size_t)cursorOffset);
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// Release the old buffer if necessary.
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if (start != scratch) { delete[] start; }
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// Save the new buffer.
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start = newBuffer;
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// Convert from offsets back to absolutes.
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next = start + nextOffset;
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cursor = start + cursorOffset;
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end = start + endOffset;
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}
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