Robust/src/Tests/ssJava/mp3decoder/SideInfoBuffer.java

   1 public class SideInfoBuffer {
   2
   3         /**
   4          * The frame buffer that holds the data for the current frame.
   5          */
   6         private final int[] framebuffer = new int[BUFFER_INT_SIZE];
   7
   8         /**
   9          * Maximum size of the frame buffer.
  10          */
  11         private static final int BUFFER_INT_SIZE = 433;
  12
  13         /**
  14          * Index into <code>framebuffer</code> where the next bits are retrieved.
  15          */
  16         private int wordpointer;
  17
  18         /**
  19          * Number (0-31, from MSB to LSB) of next bit for get_bits()
  20          */
  21         private int bitindex;
  22
  23         private int main_data_begin;
  24
  25         public int getMain_data_begin() {
  26                 return main_data_begin;
  27         }
  28
  29         public void setMain_data_begin(int main_data_begin) {
  30                 this.main_data_begin = main_data_begin;
  31         }
  32
  33         private final int bitmask[] = {
  34                         0, // dummy
  35                         0x00000001, 0x00000003, 0x00000007, 0x0000000F, 0x0000001F,
  36                         0x0000003F, 0x0000007F, 0x000000FF, 0x000001FF, 0x000003FF,
  37                         0x000007FF, 0x00000FFF, 0x00001FFF, 0x00003FFF, 0x00007FFF,
  38                         0x0000FFFF, 0x0001FFFF };
  39
  40         public int get_bits(int number_of_bits) {
  41                 int returnvalue = 0;
  42                 int sum = bitindex + number_of_bits;
  43                 // System.out.println("bitindex=" + bitindex + " wordpointer="
  44                 // + wordpointer);
  45                 // E.B
  46                 // There is a problem here, wordpointer could be -1 ?!
  47                 if (wordpointer < 0)
  48                         wordpointer = 0;
  49                 // E.B : End.
  50
  51                 if (sum <= 32) {
  52                         // all bits contained in *wordpointer
  53                         returnvalue = (framebuffer[wordpointer] >>> (32 - sum))
  54                                         & bitmask[number_of_bits];
  55                         // returnvalue = (wordpointer[0] >> (32 - sum)) &
  56                         // bitmask[number_of_bits];
  57                         if ((bitindex += number_of_bits) == 32) {
  58                                 bitindex = 0;
  59                                 wordpointer++; // added by me!
  60                         }
  61                         return returnvalue;
  62                 }
  63
  64                 // E.B : Check that ?
  65                 // ((short[])&returnvalue)[0] = ((short[])wordpointer + 1)[0];
  66                 // wordpointer++; // Added by me!
  67                 // ((short[])&returnvalue + 1)[0] = ((short[])wordpointer)[0];
  68                 int Right = (framebuffer[wordpointer] & 0x0000FFFF);
  69                 wordpointer++;
  70                 int Left = (framebuffer[wordpointer] & 0xFFFF0000);
  71                 returnvalue = ((Right << 16) & 0xFFFF0000)
  72                                 | ((Left >>> 16) & 0x0000FFFF);
  73
  74                 returnvalue >>>= 48 - sum; // returnvalue >>= 16 - (number_of_bits - (32
  75                                                                         // - bitindex))
  76                 returnvalue &= bitmask[number_of_bits];
  77                 bitindex = sum - 32;
  78                 return returnvalue;
  79         }
  80
  81         public void setBuffer(int idx, int value) {
  82                 framebuffer[idx] = value;
  83         }
  84
  85 }