/* Copyright (C) 2004  David Decotigny (with INSA Rennes for vsnprintf)
    Copyright (C) 2003  The KOS Team
    Copyright (C) 1999  Free Software Foundation
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    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 General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    USA. 
 */
 #include <string.h>
 
 #include "stdarg.h"
 
 
 /* I (d2) borrowed and rewrote this for Nachos/INSA Rennes. Thanks to
    them for having kindly allowed me to do so. */
 int vsnprintf(char *buff, size_t len, const char * format, va_list ap)
 {
   int i, result;
   int fmt_modifiers = 0;
   int prefix_long   = 0;
   int prefix_long_long = 0;
  
   if (!buff || !format || (len < 0))
     return -1;
   
 #define PUTCHAR(thechar) \
   do { \
     if (result < len-1) \
       *buff++ = (thechar);  \
     result++; \
   } while (0)
   
   result = 0;
   for(i=0 ; format[i] != '\0' ; i++)
     {
       if (!fmt_modifiers && (format[i] != '%'))
         {
           PUTCHAR(format[i]);
           continue;
         }
         
       switch (format[i])
         {
         case '%':
           if (fmt_modifiers)
             {
               PUTCHAR('%');
               fmt_modifiers = 0;
               break;
             }
           
           fmt_modifiers    = 1;
           prefix_long      = 0;
           prefix_long_long = 0;
           break;
           
         case 'l':
           if (prefix_long)
             prefix_long_long = 1;
           else
             prefix_long = 1;
           break;
           
         case 'u':
           {
             if (! prefix_long_long)
               {
                 unsigned int integer = va_arg(ap,unsigned int);
                 int cpt2 = 0;
                 char buff_int[16];
                 
                 do {
                   int m10 = integer%10;
                   buff_int[cpt2++]=(char)('0'+ m10);
                   integer=integer/10;
                 } while(integer!=0);
             
                 for(cpt2 = cpt2 - 1 ; cpt2 >= 0 ; cpt2--)
                   PUTCHAR(buff_int[cpt2]);
               }
             else
               {
                 unsigned long long int integer
                   = va_arg(ap,unsigned long long int);
                 int cpt2 = 0;
                 char buff_int[32];
                 
                 do {
                   int m10 = integer%10;
                   buff_int[cpt2++]=(char)('0'+ m10);
                   integer=integer/10;
                 } while(integer!=0);
             
                 for(cpt2 = cpt2 - 1 ; cpt2 >= 0 ; cpt2--)
                   PUTCHAR(buff_int[cpt2]);
               }
           }
           fmt_modifiers = 0;
           break;
 
         case 'i':
         case 'd':
           {
             if (! prefix_long_long)
               {
                 int integer = va_arg(ap,int);
                 int cpt2 = 0;
                 char buff_int[16];
                 
                 if (integer<0)
                   PUTCHAR('-');
                 /* Ne fait pas integer = -integer ici parce que INT_MIN
                    n'a pas d'equivalent positif (int = [-2^31, 2^31-1]) */
                 
                 do {
                   int m10 = integer%10;
                   m10 = (m10 < 0)? -m10:m10;
                   buff_int[cpt2++]=(char)('0'+ m10);
                   integer=integer/10;
                 } while(integer!=0);
             
                 for(cpt2 = cpt2 - 1 ; cpt2 >= 0 ; cpt2--)
                   PUTCHAR(buff_int[cpt2]);
               }
             else
               {
                 long long int integer = va_arg(ap,long long int);
                 int cpt2 = 0;
                 char buff_int[32];
                 
                 if (integer<0)
                   PUTCHAR('-');
                 /* Ne fait pas integer = -integer ici parce que INT_MIN
                    n'a pas d'equivalent positif (int = [-2^63, 2^63-1]) */
                 
                 do {
                   int m10 = integer%10;
                   m10 = (m10 < 0)? -m10:m10;
                   buff_int[cpt2++]=(char)('0'+ m10);
                   integer=integer/10;
                 } while(integer!=0);
             
                 for(cpt2 = cpt2 - 1 ; cpt2 >= 0 ; cpt2--)
                   PUTCHAR(buff_int[cpt2]);
               }
           }
           fmt_modifiers = 0;
           break;
           
         case 'c':
           {
             int value = va_arg(ap,int);
             PUTCHAR((char)value);
             fmt_modifiers = 0;
             break;
           }
           
         case 's':
           {
             char *string = va_arg(ap,char *);
             if (! string)
               string = "(null)";
             for( ; *string != '\0' ; string++)
               PUTCHAR(*string);
             fmt_modifiers = 0;
             break;
           }
           
         case 'p':
           PUTCHAR('0');
           PUTCHAR('x');
         case 'x':
           {
             unsigned long long int hexa;
             unsigned long long int nb;
             int i, had_nonzero = 0;
             
             if (prefix_long_long)
               hexa = va_arg(ap,unsigned long long int);
             else
               hexa = va_arg(ap,unsigned int);
             
             for(i=0 ; i < 16 ; i++)
               {
                 nb = (unsigned long long int)(hexa << (i*4));
                 nb = (nb >> 60) & 0xf;
                 // Skip the leading zeros
                 if (nb == 0)
                   {
                     if (had_nonzero)
                       PUTCHAR('0');
                   }
                 else
                   {
                     had_nonzero = 1;
                     if (nb < 10)
                       PUTCHAR('0'+nb);
                     else
                       PUTCHAR('a'+(nb-10));
                   }
               }
             if (! had_nonzero)
               PUTCHAR('0');
           }
           fmt_modifiers = 0;
           break;
           
         default:
           PUTCHAR('%');
           if (prefix_long)
             PUTCHAR('l');
           if (prefix_long_long)
             PUTCHAR('l');
           PUTCHAR(format[i]);
           fmt_modifiers = 0;
         }
     }
 
   *buff = '\0';
   return result;
 }
 
 
 int snprintf(char * buff, size_t len, const char *format, ...)
 {
   va_list ap;
  
   va_start(ap, format);
   len = vsnprintf(buff, len, format, ap);
   va_end(ap);
  
   return len;
 }