/*
	A basic helper library for bit-manipulation in streams
	Preliminary version 3

        Copyright (C) 2005 Oivind Gylver (oivindg@gmail.com)

        This library is free software; you can redistribute it and/or modify
        it under the terms of the GNU Lesser General Public License as
        published by the Free Software Foundation; either version 2.1 of
        the License, or (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU Lesser General Public License for more details.

        You should have received a copy of the GNU Lesser General Public
        License along with this library; if not, write to the Free Software
        Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
*/

#ifndef __TOOLBOX_H__
#define __TOOLBOX_H__
 

/*

  General information

  All bits are numbered as in a stream,
  MSB->LSB, 0->n. 

  As in,  
    bit positions         0123 4567 .... ..15
    8-bit word      (MSB) xxxx xxxx (LSB)   |
    16-bit word     (MSB) xxxx xxxx .... ...x (LSB)



  Get bits from a stream

  GETBITS_Sx_Ly_zB(word)
    x    = start bit
    y    = bitlength
    z    = bitsize of word

    word = 1010 1110
    n    = GETBITS_S0_L3_8B(word);
            (get bits 0,1,2 and right-shift them to the lsb edge of n)
    n   -> 0000 0101
  


  Replace bits in a stream
  
  PUTBITS_Sx_Ly_zB(dst,src)
    x = start bit
    y = bitlength
    z = bitsize of operation

  Example pseudo code #1;
    src =  0000 0001
    dst =  0110 1100
    PUTBITS_S0_L1_8B(dst,src);
    dst -> 1110 1100
           ^ this bit (number 0) was set

  Example pseudo code #2;
    src =  0001 0000 0000 1111   (16 bit)
    msb =  0110 1111
    lsb =            0100 1000
    PUTBITS_S3_L13_16B(msb,lsb,src);
    msb -> 0111 1100
              ^ ^^^^ these bits (3-7) were set
    lsb ->           0000 1111
                     ^^^^ ^^^^ all bits updated

*/


#define GETBITS_S0_L1_8B(b) (b >> 7)
#define GETBITS_S0_L2_8B(b) (b >> 6)
#define GETBITS_S0_L3_8B(b) (b >> 5)
#define GETBITS_S0_L4_8B(b) (b >> 4)
#define GETBITS_S0_L8_8B(b) (b)
#define GETBITS_S1_L1_8B(b) ((b & 0x40) >> 6)
#define GETBITS_S1_L2_8B(b) ((b & 0x60) >> 5)
#define GETBITS_S2_L2_8B(b) ((b & 0x30) >> 4)
#define GETBITS_S2_L5_8B(b) ((b & 0x3e) >> 1)
#define GETBITS_S2_L6_8B(b) (b & 0x3f)
#define GETBITS_S3_L5_8B(b) (b & 0x1f)
#define GETBITS_S7_L1_8B(b) (b & 0x01)

#define GETBITS_S3_L13_16B(msb,lsb) (((msb & 0x1f) << 8) | lsb)
#define GETBITS_S4_L12_16B(msb,lsb) (((msb & 0x0f) << 8) | lsb)
#define GETBITS_S0_L16_16B(msb,lsb) ((msb << 8) | lsb)


#define PUTBITS_S0_L1_8B(dst,src) { dst &= ~0x80; dst |= (src << 7) & 0x80; }
#define PUTBITS_S0_L2_8B(dst,src) { dst &= ~0xc0; dst |= (src << 6) & 0xc0; }
#define PUTBITS_S0_L3_8B(dst,src) { dst &= ~0xe0; dst |= (src << 5) & 0xe0; }
#define PUTBITS_S0_L4_8B(dst,src) { dst &= ~0xf0; dst |= (src << 4) & 0xf0; }
#define PUTBITS_S0_L8_8B(dst,src) { dst = src & 0xff; }
#define PUTBITS_S1_L1_8B(dst,src) { dst &= ~0x40; dst |= (src << 6) & 0x40; }
#define PUTBITS_S1_L2_8B(dst,src) { dst &= ~0x60; dst |= (src << 5) & 0x60; }
#define PUTBITS_S2_L6_8B(dst,src) { dst &= ~0x3f; dst |= src & 0x3f; }
#define PUTBITS_S2_L2_8B(dst,src) { dst &= ~0x30; dst |= (src << 4) & 0x30; }
#define PUTBITS_S2_L5_8B(dst,src) { dst &= ~0x3e; dst |= (src << 1) & 0x3e; }
#define PUTBITS_S3_L5_8B(dst,src) { dst &= ~0x1f; dst |= src & 0x1f; }
#define PUTBITS_S7_L1_8B(dst,src) { dst &= ~0x01; dst |= src & 0x01; }

#define PUTBITS_S3_L13_16B(msb,lsb,src) \
	{ msb &= ~0x1f; msb |= (src & 0x1f00) >> 8; lsb = src & 0xff; }
#define PUTBITS_S4_L12_16B(msb,lsb,src) \
	{ msb &= ~0x0f; msb |= (src & 0x0f00) >> 8; lsb = src & 0xff; }
#define PUTBITS_S0_L16_16B(msb,lsb,src) \
	{ msb = (src & 0xff00) >> 8; lsb = src & 0xff; } 


#endif