/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2001-2002 NaN Holding BV. All rights reserved. */

/** \file
 * \ingroup avi
 *
 * This is external code. Converts RGB-type AVI files.
 */

#include <stdlib.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "AVI_avi.h"
#include "avi_rgb.h"

#include "IMB_imbuf.h"

#include "BLI_utildefines.h"

/* implementation */

void *avi_converter_from_avi_rgb(AviMovie *movie, int stream, uchar *buffer, const size_t *size)
{
  uchar *buf;
  AviBitmapInfoHeader *bi;
  short bits = 32;

  (void)size; /* unused */

  bi = (AviBitmapInfoHeader *)movie->streams[stream].sf;
  if (bi) {
    bits = bi->BitCount;
  }

  if (bits == 16) {
    ushort *pxl;
    uchar *to;
#ifdef __BIG_ENDIAN__
    uchar *pxla;
#endif

    buf = imb_alloc_pixels(
        movie->header->Height, movie->header->Width, 3, sizeof(uchar), "fromavirgbbuf");

    if (buf) {
      size_t y = movie->header->Height;
      to = buf;

      while (y--) {
        pxl = (ushort *)(buffer + y * movie->header->Width * 2);

#ifdef __BIG_ENDIAN__
        pxla = (uchar *)pxl;
#endif

        size_t x = movie->header->Width;
        while (x--) {
#ifdef __BIG_ENDIAN__
          int i = pxla[0];
          pxla[0] = pxla[1];
          pxla[1] = i;

          pxla += 2;
#endif

          *(to++) = ((*pxl >> 10) & 0x1f) * 8;
          *(to++) = ((*pxl >> 5) & 0x1f) * 8;
          *(to++) = (*pxl & 0x1f) * 8;
          pxl++;
        }
      }
    }

    MEM_freeN(buffer);

    return buf;
  }

  buf = imb_alloc_pixels(
      movie->header->Height, movie->header->Width, 3, sizeof(uchar), "fromavirgbbuf");

  if (buf) {
    size_t rowstride = movie->header->Width * 3;
    BLI_assert(bits != 16);
    if (movie->header->Width % 2) {
      rowstride++;
    }

    for (size_t y = 0; y < movie->header->Height; y++) {
      memcpy(&buf[y * movie->header->Width * 3],
             &buffer[((movie->header->Height - 1) - y) * rowstride],
             movie->header->Width * 3);
    }

    for (size_t y = 0; y < (size_t)movie->header->Height * (size_t)movie->header->Width * 3;
         y += 3) {
      int i = buf[y];
      buf[y] = buf[y + 2];
      buf[y + 2] = i;
    }
  }

  MEM_freeN(buffer);

  return buf;
}

void *avi_converter_to_avi_rgb(AviMovie *movie, int stream, uchar *buffer, size_t *size)
{
  uchar *buf;

  (void)stream; /* unused */

  size_t rowstride = movie->header->Width * 3;
  /* AVI files has uncompressed lines 4-byte aligned */
  rowstride = (rowstride + 3) & ~3;

  *size = movie->header->Height * rowstride;
  buf = MEM_mallocN(*size, "toavirgbbuf");

  for (size_t y = 0; y < movie->header->Height; y++) {
    memcpy(&buf[y * rowstride],
           &buffer[((movie->header->Height - 1) - y) * movie->header->Width * 3],
           movie->header->Width * 3);
  }

  for (size_t y = 0; y < movie->header->Height; y++) {
    for (size_t x = 0; x < movie->header->Width * 3; x += 3) {
      int i = buf[y * rowstride + x];
      buf[y * rowstride + x] = buf[y * rowstride + x + 2];
      buf[y * rowstride + x + 2] = i;
    }
  }

  MEM_freeN(buffer);

  return buf;
}