sbgSplitBuffer.h

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#ifndef SBG_SPLIT_BUFFER_H
#define SBG_SPLIT_BUFFER_H
 
#include <sbgCommon.h>
 
//----------------------------------------------------------------------//
//- Header (open extern C block)                                       -//
//----------------------------------------------------------------------//
#ifdef __cplusplus
extern "C" {
#endif
 
//----------------------------------------------------------------------//
//- Structs definitions                                                -//
//----------------------------------------------------------------------//

typedef struct _SbgSplitBuffer
{
    uint8_t *pLinkedBuffer;                    
    size_t   linkedBufferSize;              
    size_t   subBufferSize;                    
    size_t   subBufferNbr;                  
} SbgSplitBuffer;
 
//----------------------------------------------------------------------//
//- Public methods definitions                                         -//
//----------------------------------------------------------------------//

SBG_INLINE void sbgSplitBufferInitForRead(SbgSplitBuffer *pSplitBuffer, const void *pBuffer, size_t bufferSize, size_t subBufferSize)
{
    //
    //  Test input arguments
    //
    assert(pSplitBuffer);
 
    //
    // Initialize split buffer parameters
    //
    pSplitBuffer->pLinkedBuffer = (uint8_t*)pBuffer;
    pSplitBuffer->linkedBufferSize = bufferSize;
    pSplitBuffer->subBufferSize = subBufferSize;
 
    //
    // Compute sub buffer number
    //
    pSplitBuffer->subBufferNbr = (bufferSize + (subBufferSize - 1)) / subBufferSize;
}

SBG_INLINE void sbgSplitBufferInitForWrite(SbgSplitBuffer *pSplitBuffer, void *pBuffer, size_t bufferSize, size_t subBufferSize)
{
    //
    //  Test input arguments
    //
    assert(pSplitBuffer);
 
    //
    // Initialize split buffer parameters
    //
    pSplitBuffer->pLinkedBuffer = (uint8_t*)pBuffer;
    pSplitBuffer->linkedBufferSize = bufferSize;
    pSplitBuffer->subBufferSize = subBufferSize;
 
    //
    // Compute sub buffer number
    //
    pSplitBuffer->subBufferNbr = (bufferSize + (subBufferSize - 1)) / subBufferSize;
}

SBG_INLINE size_t sbgSplitBufferGetSubBufferNbr(const SbgSplitBuffer *pSplitBuffer)
{
    //
    //  Test input arguments
    //
    assert(pSplitBuffer);
 
    //
    // Return subBufferNbr parameter
    //
    return pSplitBuffer->subBufferNbr;
}

SBG_INLINE void *sbgSplitBufferGetSubBuffer(const SbgSplitBuffer *pSplitBuffer, size_t subBufferIdx)
{
    //
    //  Test input arguments
    //
    assert(pSplitBuffer);
 
    //
    // Test input parameters
    //
    if (subBufferIdx < pSplitBuffer->subBufferNbr)
    {
        //
        // Return pointer to buffer
        //
        return ((uint8_t*)pSplitBuffer->pLinkedBuffer + pSplitBuffer->subBufferSize*subBufferIdx);
    }
    else
    {
        //
        // Invalid index
        //
        return NULL;
    }
}

SBG_INLINE size_t sbgSplitBufferGetSubBufferOffset(const SbgSplitBuffer *pSplitBuffer, size_t subBufferIdx)
{
    //
    //  Test input arguments
    //
    assert(pSplitBuffer);
 
    //
    // Test input parameters
    //
    if (subBufferIdx < pSplitBuffer->subBufferNbr)
    {
        //
        // Return pointer to buffer
        //
        return (pSplitBuffer->subBufferSize * subBufferIdx);
    }
    else
    {
        //
        // Invalid index
        //
        return 0;
    }
}

SBG_INLINE size_t sbgSplitBufferGetSubBufferSize(const SbgSplitBuffer *pSplitBuffer, size_t subBufferIdx)
{
    size_t subBufferSize = 0;
 
    //
    //  Test input arguments
    //
    assert(pSplitBuffer);
 
    //
    // Test input parameters
    //
    if (pSplitBuffer->subBufferNbr > 0)
    {
        //
        // Test that the sub buffer index is not the last one
        //
        if (subBufferIdx < (pSplitBuffer->subBufferNbr-1))
        {
            //
            // We can just return the sub buffer size because it's not the last sub buffer
            //
            subBufferSize =  pSplitBuffer->subBufferSize;
        }
        else if (subBufferIdx == (pSplitBuffer->subBufferNbr-1) )
        {
            //
            // It's the last sub buffer so return the remaining size
            //
            subBufferSize = pSplitBuffer->linkedBufferSize - (subBufferIdx * pSplitBuffer->subBufferSize);
        }
    }
 
    //
    // Return computed size
    //
    return subBufferSize;
}
 
//----------------------------------------------------------------------//
//- Footer (close extern C block)                                      -//
//----------------------------------------------------------------------//
#ifdef __cplusplus
}
#endif
 
#endif // SBG_SPLIT_BUFFER_H