static DWORD	ReadConsoleChars(HANDLE hConsole, WCHAR *lpBuffer,
		    RingSizeT nChars, RingSizeT *nCharsReadPtr);
static DWORD	WriteConsoleChars(HANDLE hConsole,
		    const WCHAR *lpBuffer, RingSizeT nChars,
		    RingSizeT *nCharsWritten);
static void	RingBufferInit(RingBuffer *ringPtr, RingSizeT capacity);
static void	RingBufferClear(RingBuffer *ringPtr);
static char *	RingBufferSegment(const RingBuffer *ringPtr, RingSizeT *lenPtr);
static RingSizeT	RingBufferIn(RingBuffer *ringPtr, const char *srcPtr,
			    RingSizeT srcLen, int partialCopyOk);
static RingSizeT	RingBufferOut(RingBuffer *ringPtr, char *dstPtr,
			    RingSizeT dstCapacity, int partialCopyOk);
static ConsoleHandleInfo *AllocateConsoleHandleInfo(HANDLE consoleHandle,
			    int permissions);
static ConsoleHandleInfo *FindConsoleInfo(const ConsoleChannelInfo *);

	ringPtr->start = 0;
    }

    RINGBUFFER_ASSERT(ringPtr);

    return dstCapacity;
}

/*
 *------------------------------------------------------------------------
 *
 * RingBufferSegment --
 *
 *    Returns a pointer to the leading data segment in the ring buffer.
 *
 * Results:
 *    Pointer to start of segment.
 *
 * Side effects:
 *    None.
 *
 *------------------------------------------------------------------------
 */
 static inline char *
 RingBufferSegment(const RingBuffer *ringPtr, RingSizeT *lengthPtr)
{
    RINGBUFFER_ASSERT(ringPtr);
    if (ringPtr->length <= (ringPtr->capacity - ringPtr->start)) {
	/* No content wrap around. */
	*lengthPtr = ringPtr->length;
    }
    else {
	/* Content wraps around so lead segment stretches to end of buffer */
	*lengthPtr = ringPtr->capacity - ringPtr->start;
    }
    return *lengthPtr == 0 ? NULL : ringPtr->start + ringPtr->bufPtr;
}

#ifndef NDEBUG
static int
RingBufferCheck(const RingBuffer *ringPtr)
{
    return (ringPtr->bufPtr != NULL && ringPtr->capacity == CONSOLE_BUFFER_SIZE
	    && ringPtr->start < ringPtr->capacity