/*
  * Copyright (c) 2016 Umair Khan <omerjerk@gmail.com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef AVUTIL_SOFTFLOAT_IEEE754_H
 #define AVUTIL_SOFTFLOAT_IEEE754_H
 
 #include <stdint.h>
 
 #define EXP_BIAS 127
 #define MANT_BITS 23
 
 typedef struct SoftFloat_IEEE754 {
     int32_t sign;
     uint64_t mant;
     int32_t  exp;
 } SoftFloat_IEEE754;
 
 static const SoftFloat_IEEE754 FLOAT_0 = {0, 0, -126};
 static const SoftFloat_IEEE754 FLOAT_1 = {0, 0,    0};
 
 /** Normalize the softfloat as defined by IEEE 754 single-recision floating
  *  point specification
  */

 static inline SoftFloat_IEEE754 av_normalize_sf_ieee754(SoftFloat_IEEE754 sf) {

     while( sf.mant >= 0x1000000UL ) {
         sf.exp++;
         sf.mant >>= 1;
     }
     sf.mant &= 0x007fffffUL;
     return sf;
 }
 
 /** Convert integer to softfloat.
  *  @return softfloat with value n * 2^e
  */

 static inline SoftFloat_IEEE754 av_int2sf_ieee754(int64_t n, int e) {

     int sign = 0;
 
     if (n < 0) {
         sign = 1;
         n    *= -1;
     }
     return av_normalize_sf_ieee754((SoftFloat_IEEE754) {sign, n << MANT_BITS, 0 + e});
 }
 
 /** Make a softfloat out of the bitstream. Assumes the bits are in the form as defined
  *  by the IEEE 754 spec.
  */

 static inline SoftFloat_IEEE754 av_bits2sf_ieee754(uint32_t n) {

     return ((SoftFloat_IEEE754) { (n & 0x80000000UL), (n & 0x7FFFFFUL), (n & 0x7F800000UL) });
 }
 
 /** Convert the softfloat to integer
  */

 static inline int av_sf2int_ieee754(SoftFloat_IEEE754 a) {

     if(a.exp >= 0) return a.mant <<  a.exp ;
     else           return a.mant >>(-a.exp);
 }
 
 /** Divide a by b. b should not be zero.
  *  @return normalized result
  */

 static inline SoftFloat_IEEE754 av_div_sf_ieee754(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {

     int32_t mant, exp, sign;
     a    = av_normalize_sf_ieee754(a);
     b    = av_normalize_sf_ieee754(b);
     sign = a.sign ^ b.sign;
     mant = ((((uint64_t) (a.mant | 0x00800000UL)) << MANT_BITS) / (b.mant| 0x00800000UL));
     exp  = a.exp - b.exp;
     return av_normalize_sf_ieee754((SoftFloat_IEEE754) {sign, mant, exp});
 }
 
 /** Multiply a with b
  *  #return normalized result
  */

 static inline SoftFloat_IEEE754 av_mul_sf_ieee754(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {

     int32_t sign, mant, exp;
     a    = av_normalize_sf_ieee754(a);
     b    = av_normalize_sf_ieee754(b);
     sign = a.sign ^ b.sign;
     mant = (((uint64_t)(a.mant|0x00800000UL) * (uint64_t)(b.mant|0x00800000UL))>>MANT_BITS);
     exp  = a.exp + b.exp;
     return av_normalize_sf_ieee754((SoftFloat_IEEE754) {sign, mant, exp});
 }
 
 /** Compare a with b strictly
  *  @returns 1 if the a and b are equal, 0 otherwise.
  */

 static inline int av_cmp_sf_ieee754(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {

     a = av_normalize_sf_ieee754(a);
     b = av_normalize_sf_ieee754(b);
     if (a.sign != b.sign) return 0;
     if (a.mant != b.mant) return 0;
     if (a.exp  != b.exp ) return 0;
     return 1;
 }
 
 #endif /*AVUTIL_SOFTFLOAT_IEEE754_H*/