/********************************************************************************/
/*										*/
/*			    I/O Buffers		 				*/
/*			     Written by Ken Goldman				*/
/*		       IBM Thomas J. Watson Research Center			*/
/*            $Id: IoBuffers.c 1311 2018-08-23 21:39:29Z kgoldman $		*/
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/********************************************************************************/

/* 9.7	IoBuffers.c */
/* 9.7.1	Includes and Data Definitions */
/* This definition allows this module to see the values that are private to this module but kept in
   Global.c for ease of state migration. */
#define IO_BUFFER_C
#include "Tpm.h"
#include "IoBuffers_fp.h"
/* 9.7.2	Buffers and Functions */
/* These buffers are set aside to hold command and response values. In this implementation, it is
   not guaranteed that the code will stop accessing the s_actionInputBuffer before starting to put
   values in the s_actionOutputBuffer so different buffers are required. */
/*     9.7.2.1 MemoryIoBufferAllocationReset() */
/*     This function is used to reset the allocation of buffers. */
void
MemoryIoBufferAllocationReset(
			      void
			      )
{
    s_actionIoAllocation = 0;
}
/* 9.7.2.2	MemoryIoBufferZero() */
/* Function zeros the action I/O buffer at the end of a command. Calling this is not mandatory for
   proper functionality. */
void
MemoryIoBufferZero(
		   void
		   )
{
    memset(s_actionIoBuffer, 0, s_actionIoAllocation);
}
/* 9.7.2.3	MemoryGetInBuffer() */
/* This function returns the address of the buffer into which the command parameters will be
   unmarshaled in preparation for calling the command actions. */
BYTE *
MemoryGetInBuffer(
		  UINT32           size           // Size, in bytes, required for the input
		  // unmarshaling
		  )
{
    pAssert(size <= sizeof(s_actionIoBuffer));
    // In this implementation, a static buffer is set aside for the command action
    // buffers. The buffer is shared between input and output. This is because
    // there is no need to allocate for the worst case input and worst case output
    // at the same time.
    // Round size up
#define UoM  (sizeof(s_actionIoBuffer[0]))
    size = (size + (UoM - 1)) & (UINT32_MAX - (UoM - 1));
    memset(s_actionIoBuffer, 0, size);
    s_actionIoAllocation = size;
    return (BYTE *)&s_actionIoBuffer[0];
}
/* 9.7.2.4	MemoryGetOutBuffer() */
/* This function returns the address of the buffer into which the command action code places its
   output values. */
BYTE *
MemoryGetOutBuffer(
		   UINT32           size           // required size of the buffer
		   )
{
    BYTE        *retVal = (BYTE *)(&s_actionIoBuffer[s_actionIoAllocation / UoM]);
    pAssert((size + s_actionIoAllocation) < (sizeof(s_actionIoBuffer)));
    // In this implementation, a static buffer is set aside for the command action
    // output buffer.
    memset(retVal, 0, size);
    s_actionIoAllocation += size;
    return retVal;
}
/* 9.7.2.5	IsLabelProperlyFormatted() */
/* This function checks that a label is a null-terminated string. */
/* NOTE:	this function is here because there was no better place for it. */
/* Return Value	Meaning */
/* FALSE	string is not null terminated */
/* TRUE	string is null terminated */

BOOL
IsLabelProperlyFormatted(
			 TPM2B           *x
			 )
{
    return (((x)->size == 0) || ((x)->buffer[(x)->size - 1] == 0));
}