/*
 * PSPLINK
 * -----------------------------------------------------------------------
 * Licensed under the BSD license, see LICENSE in PSPLINK root for details.
 *
 * util.c - util functions for psplink
 *
 * Copyright (c) 2005 James F <tyranid@gmail.com>
 * Copyright (c) 2005 Julian T <lovely@crm114.net>
 *
 * $HeadURL: svn://svn.ps2dev.org/psp/trunk/psplink/psplink/util.c $
 * $Id: util.c 1981 2006-07-24 21:51:41Z tyranid $
 */
 
#define MODE_GENERIC 0
#define MODE_EXP 1
#define MODE_FLOAT_ONLY 2

static int is_inf(unsigned int val)
{
  unsigned int conv;
  int sign;
  int exp;
  int mantissa;

  conv = *((unsigned int *) val);
  sign = (conv >> 31) & 1;

  exp = (conv >> 23) & 0xff;
  mantissa = conv & 0x7fffff;

  if((exp == 255) && (mantissa == 0))
  {
    if(sign)
    {
      return -1;
    }
    else
    {
      return 1;
    }
  }
  if(exp == 255)
  {
    return 2;
  }
  if(exp > 180)
  {
    return 3;
  }

  return 0;
}


static char get_num(float *val, int *exp)
{
  int digit;
  float tmp;
  char ret = '0';

  if((*exp)++ < 16)
  {
    digit = (int) *val;
    if((digit >= 0) && (digit < 10))
    {
      ret = digit + '0';
      tmp = (float) digit;
      *val = (*val - digit)*10.0f;
    }
  }

  return ret;
}

void f_cvt(unsigned int addr, char *buf, int bufsize, int precision, int mode)
{

  addr&=0xFFFFFFFC;
  char conv_buf[128];
  char *conv_p = conv_buf;
  float normval;
  int digits = 0;//桁数
  int exp = 0;//指数
  int exp_pos = 0;//指数の位置
  int inf=0;//無限大
  int sign = 0;//符号
  float round;
  int rndpos = 0;
  float val=*((float*)(addr));
  char   zero=0;
    
  /* check for nan and +/- infinity */  
  inf = is_inf(addr);
  if(inf != 0)
  {
	if(inf < 0)
    {
     strncpy(buf,"-INF", bufsize);
    }
    if(inf==2)
    {
    strncpy(buf, "NAN", bufsize);
    }
    if(inf==3)
	{
    strncpy(buf, "HUGE", bufsize);
	}
    if(inf==1)
    {
    strncpy(buf,"INF", bufsize);
    }
    buf[bufsize-1] = 0;
    return;
  }

  if(val < 0.0f)
  {
    sign = 1;
    normval -= val;
  }
  else
  {
    sign = 0;
    normval = val;
  }

  if(precision < 0)
  {
    precision = 6;
  }

  // normalise value 10べき乗指数化
  if(normval > 0.0f)
  {
    while((normval >= 1e8f) && (digits++ < 100))
    {
      normval *= 1e-8f;//0.00000001倍
      exp += 8;
    }
    while((normval >= 10.0f) && (digits++ < 100))
    {
      normval *= 0.1f;//0.1倍
      exp++;
    }
    while((normval < 1e-8f) && (digits++ < 100))
    {
      normval *= 1e8f;//100000000倍
      exp -= 8;
    }
    while((normval < 1.0f) && (digits++ < 100))
    {
      normval *= 10.0f;//10倍
      exp--;
    }
  }


  for(rndpos = precision, round = 0.49999f; rndpos > 0; rndpos--, round *= 0.1f);

  if(sign)
  {
    *conv_p++ = '-';
    }
    else{
    *conv_p++ = '+';
  }

  normval += round;

   
 	float   x=0.0f;
	float   y=1.0f;
	float   z=0.0f;
		
    if(exp >= 0)
    {

		/*
	float   w=0.0f;
	float   v=val;
	char   c='0';
      while (y <= val){
      y*= 10.0f;
      }
		
      for(; (y == 1.0f);exp--){
		x=v/y;
		z=v-y*x;
		while (x==w){
		w+=1.0f;
		c+=1;
		}
		y/=10.0f;
		v=z;
		*conv_p++ = c;
		c ='0';
		zero++;
      }*/
      
      while (y <= val){
      y*= 10.0f;
      }
      
      for (;exp>=0;exp--){
      x=0.9999998f*y;
      z=1.000000f*y;
      y/=10.0f;
      	if (val>x && val<z && zero==0){
      *conv_p++= '1';
      *conv_p++=get_num(&normval, &exp_pos);
      zero=1;
      	}
      else{
      *conv_p++=get_num(&normval, &exp_pos);
      }
      }
      zero=0;
    }
    else
    {
      *conv_p++ = '0';
    }

    exp++;
    if(precision > 0)
    {
      *conv_p++ = '.';
    }
    
    
    x=0.0f;
    y=1.0f;
    for( ; (exp < 0) && (precision > 0); exp++, precision--)
    {
    
      y/=10.0f;
      x= 0.999999f*y;
		if(val > x && zero==0){
        *conv_p++ = '1';
        zero=1;
    	}
        else{
        *conv_p++ = '0';
        }
    }
    
    while(precision > 0)
    {
    	if(zero){
      *conv_p++ = 0x30;
    	}
    	else{
      *conv_p++ = get_num(&normval, &exp_pos);
      }
      precision--;
    }

  *conv_p = 0;

  strncpy(buf, conv_buf, bufsize);
  buf[bufsize-1] = 0;

  return;
}