rfx_differential.h

 
#ifndef FREERDP_LIB_CODEC_RFX_DIFFERENTIAL_H
#define FREERDP_LIB_CODEC_RFX_DIFFERENTIAL_H
 
#include <freerdp/codec/rfx.h>
#include <freerdp/api.h>
#include "rfx_types.h"
 
WINPR_ATTR_NODISCARD
static inline BOOL rfx_differential_decode(INT16* WINPR_RESTRICT buffer, size_t size)
{
  INT16* ptr = buffer;
  INT16* end = &buffer[size - 1];
 
  while (ptr != end)
  {
    const int tmp = ptr[0] + ptr[1];
    if ((tmp > INT16_MAX) || (tmp < INT16_MIN))
    {
      WLog_ERR(RFX_TAG, "differental: %d <= %d <= %d\n", INT16_MIN, tmp, INT16_MAX);
      return FALSE;
    }
    ptr[1] = WINPR_ASSERTING_INT_CAST(INT16, tmp);
    ptr++;
  }
  return TRUE;
}
 
static inline void rfx_differential_encode(INT16* WINPR_RESTRICT buffer, size_t size)
{
  INT16 n1 = buffer[0];
  for (size_t x = 0; x < size - 1; x++)
  {
    INT16* dst = &buffer[x + 1];
    const INT16 n2 = *dst;
    const int tmp = n2 - n1;
    *dst = WINPR_ASSERTING_INT_CAST(INT16, tmp);
    n1 = n2;
  }
}
 
#endif /* FREERDP_LIB_CODEC_RFX_DIFFERENTIAL_H */