package org.jcodec.scale;

import java.nio.ByteBuffer;

public class ImageConvert {
  private static final int SCALEBITS = 10;
  
  private static final int ONE_HALF = 512;
  
  private static final int FIX(double x) {
    return (int)(x * 1024.0D + 0.5D);
  }
  
  private static final int FIX_0_71414 = FIX(0.71414D);
  
  private static final int FIX_1_772 = FIX(1.772D);
  
  private static final int _FIX_0_34414 = -FIX(0.34414D);
  
  private static final int FIX_1_402 = FIX(1.402D);
  
  private static final int CROP = 1024;
  
  public static final int ycbcr_to_rgb24(int y, int cb, int cr) {
    y <<= 10;
    cb -= 128;
    cr -= 128;
    int add_r = FIX_1_402 * cr + 512;
    int add_g = _FIX_0_34414 * cb - FIX_0_71414 * cr + 512;
    int add_b = FIX_1_772 * cb + 512;
    int r = y + add_r >> 10;
    int g = y + add_g >> 10;
    int b = y + add_b >> 10;
    r = crop(r);
    g = crop(g);
    b = crop(b);
    return (r & 0xFF) << 16 | (g & 0xFF) << 8 | b & 0xFF;
  }
  
  static final int Y_JPEG_TO_CCIR(int y) {
    return y * FIX(0.8588235294117647D) + 16896 >> 10;
  }
  
  static final int Y_CCIR_TO_JPEG(int y) {
    return y * FIX(1.1643835616438356D) + 512 - 16 * FIX(1.1643835616438356D) >> 10;
  }
  
  private static final byte[] cropTable = new byte[2304];
  
  private static final int[] intCropTable = new int[2304];
  
  private static final byte[] _y_ccir_to_jpeg = new byte[256];
  
  private static final byte[] _y_jpeg_to_ccir = new byte[256];
  
  static {
    for (int m = -1024; m < 0; m++) {
      cropTable[m + 1024] = 0;
      intCropTable[m + 1024] = 0;
    } 
    for (int k = 0; k < 256; k++) {
      cropTable[k + 1024] = (byte)k;
      intCropTable[k + 1024] = k;
    } 
    for (int j = 256; j < 1024; j++) {
      cropTable[j + 1024] = -1;
      intCropTable[j + 1024] = 255;
    } 
    for (int i = 0; i < 256; i++) {
      _y_ccir_to_jpeg[i] = crop(Y_CCIR_TO_JPEG(i));
      _y_jpeg_to_ccir[i] = crop(Y_JPEG_TO_CCIR(i));
    } 
  }
  
  public static final int icrop(int i) {
    return intCropTable[i + 1024];
  }
  
  public static final byte crop(int i) {
    return cropTable[i + 1024];
  }
  
  public static final byte y_ccir_to_jpeg(byte y) {
    return _y_ccir_to_jpeg[y & 0xFF];
  }
  
  public static final byte y_jpeg_to_ccir(byte y) {
    return _y_jpeg_to_ccir[y & 0xFF];
  }
  
  public static void YUV444toRGB888(int y, int u, int v, ByteBuffer rgb) {
    int c = y - 16;
    int d = u - 128;
    int e = v - 128;
    int r = 298 * c + 409 * e + 128 >> 8;
    int g = 298 * c - 100 * d - 208 * e + 128 >> 8;
    int b = 298 * c + 516 * d + 128 >> 8;
    rgb.put(crop(r));
    rgb.put(crop(g));
    rgb.put(crop(b));
  }
  
  public static void RGB888toYUV444(ByteBuffer rgb, ByteBuffer Y, ByteBuffer U, ByteBuffer V) {
    int r = rgb.get() & 0xFF;
    int g = rgb.get() & 0xFF;
    int b = rgb.get() & 0xFF;
    int y = 66 * r + 129 * g + 25 * b;
    int u = -38 * r - 74 * g + 112 * b;
    int v = 112 * r - 94 * g - 18 * b;
    y = y + 128 >> 8;
    u = u + 128 >> 8;
    v = v + 128 >> 8;
    Y.put(crop(y + 16));
    U.put(crop(u + 128));
    V.put(crop(v + 128));
  }
  
  public static byte RGB888toY4(int r, int g, int b) {
    int y = 66 * r + 129 * g + 25 * b;
    y = y + 128 >> 8;
    return crop(y + 16);
  }
  
  public static byte RGB888toU4(int r, int g, int b) {
    int u = -38 * r - 74 * g + 112 * b;
    u = u + 128 >> 8;
    return crop(u + 128);
  }
  
  public static byte RGB888toV4(int r, int g, int b) {
    int v = 112 * r - 94 * g - 18 * b;
    v = v + 128 >> 8;
    return crop(v + 128);
  }
}