sys/src/libmp/port/mpfmt.c

   1 #include "os.h"
   2 #include <mp.h>
   3 #include "dat.h"
   4
   5 static int
   6 toencx(mpint *b, char *buf, int len, int (*enc)(char*, int, uchar*, int))
   7 {
   8         uchar *p;
   9         int n, rv;
  10
  11         p = nil;
  12         n = mptobe(b, nil, 0, &p);
  13         if(n < 0)
  14                 return -1;
  15         rv = (*enc)(buf, len, p, n);
  16         free(p);
  17         return rv;
  18 }
  19
  20 static int
  21 topow2(mpint *b, char *buf, int len, int s)
  22 {
  23         mpdigit *p, x;
  24         int i, j, sn;
  25         char *out, *eout;
  26
  27         if(len < 1)
  28                 return -1;
  29
  30         sn = 1<<s;
  31         out = buf;
  32         eout = buf+len;
  33         for(p = &b->p[b->top-1]; p >= b->p; p--){
  34                 x = *p;
  35                 for(i = Dbits-s; i >= 0; i -= s){
  36                         j = x >> i & sn - 1;
  37                         if(j != 0 || out != buf){
  38                                 if(out >= eout)
  39                                         return -1;
  40                                 *out++ = enc16chr(j);
  41                         }
  42                 }
  43         }
  44         if(out == buf)
  45                 *out++ = '0';
  46         if(out >= eout)
  47                 return -1;
  48         *out = 0;
  49         return 0;
  50 }
  51
  52 static char*
  53 modbillion(int rem, ulong r, char *out, char *buf)
  54 {
  55         ulong rr;
  56         int i;
  57
  58         for(i = 0; i < 9; i++){
  59                 rr = r%10;
  60                 r /= 10;
  61                 if(out <= buf)
  62                         return nil;
  63                 *--out = '0' + rr;
  64                 if(rem == 0 && r == 0)
  65                         break;
  66         }
  67         return out;
  68 }
  69
  70 static int
  71 to10(mpint *b, char *buf, int len)
  72 {
  73         mpint *d, *r, *billion;
  74         char *out;
  75
  76         if(len < 1)
  77                 return -1;
  78
  79         d = mpcopy(b);
  80         d->flags &= ~MPtimesafe;
  81         mpnorm(d);
  82         r = mpnew(0);
  83         billion = uitomp(1000000000, nil);
  84         out = buf+len;
  85         *--out = 0;
  86         do {
  87                 mpdiv(d, billion, d, r);
  88                 out = modbillion(d->top, r->p[0], out, buf);
  89                 if(out == nil)
  90                         break;
  91         } while(d->top != 0);
  92         mpfree(d);
  93         mpfree(r);
  94         mpfree(billion);
  95
  96         if(out == nil)
  97                 return -1;
  98         len -= out-buf;
  99         if(out != buf)
 100                 memmove(buf, out, len);
 101         return 0;
 102 }
 103
 104 static int
 105 to8(mpint *b, char *buf, int len)
 106 {
 107         mpdigit x, y;
 108         char *out;
 109         int i, j;
 110
 111         if(len < 2)
 112                 return -1;
 113
 114         out = buf+len;
 115         *--out = 0;
 116
 117         i = j = 0;
 118         x = y = 0;
 119         while(j < b->top){
 120                 y = b->p[j++];
 121                 if(i > 0)
 122                         x |= y << i;
 123                 else
 124                         x = y;
 125                 i += Dbits;
 126                 while(i >= 3){
 127 Digout:                 i -= 3;
 128                         if(out > buf)
 129                                 out--;
 130                         else if(x != 0)
 131                                 return -1;
 132                         *out = '0' + (x & 7);
 133                         x = y >> Dbits-i;
 134                 }
 135         }
 136         if(i > 0)
 137                 goto Digout;
 138
 139         while(*out == '0') out++;
 140         if(*out == '\0')
 141                 *--out = '0';
 142
 143         len -= out-buf;
 144         if(out != buf)
 145                 memmove(buf, out, len);
 146         return 0;
 147 }
 148
 149 int
 150 mpfmt(Fmt *fmt)
 151 {
 152         mpint *b;
 153         char *x, *p;
 154         int base;
 155
 156         b = va_arg(fmt->args, mpint*);
 157         if(b == nil)
 158                 return fmtstrcpy(fmt, "*");
 159
 160         base = fmt->prec;
 161         if(base == 0)
 162                 base = 16;      /* default */
 163         fmt->flags &= ~FmtPrec;
 164         p = mptoa(b, base, nil, 0);
 165         if(p == nil)
 166                 return fmtstrcpy(fmt, "*");
 167         else{
 168                 if((fmt->flags & FmtSharp) != 0){
 169                         switch(base){
 170                         case 16:
 171                                 x = "0x";
 172                                 break;
 173                         case 8:
 174                                 x = "0";
 175                                 break;
 176                         case 2:
 177                                 x = "0b";
 178                                 break;
 179                         default:
 180                                 x = "";
 181                         }
 182                         if(*p == '-')
 183                                 fmtprint(fmt, "-%s%s", x, p + 1);
 184                         else
 185                                 fmtprint(fmt, "%s%s", x, p);
 186                 }
 187                 else
 188                         fmtstrcpy(fmt, p);
 189                 free(p);
 190                 return 0;
 191         }
 192 }
 193
 194 char*
 195 mptoa(mpint *b, int base, char *buf, int len)
 196 {
 197         char *out;
 198         int rv, alloced;
 199
 200         if(base == 0)
 201                 base = 16;      /* default */
 202         alloced = 0;
 203         if(buf == nil){
 204                 /* rv <= log₂(base) */
 205                 for(rv=1; (base >> rv) > 1; rv++)
 206                         ;
 207                 len = 10 + (b->top*Dbits / rv);
 208                 buf = malloc(len);
 209                 if(buf == nil)
 210                         return nil;
 211                 alloced = 1;
 212         }
 213
 214         if(len < 2)
 215                 return nil;
 216
 217         out = buf;
 218         if(b->sign < 0){
 219                 *out++ = '-';
 220                 len--;
 221         }
 222         switch(base){
 223         case 64:
 224                 rv = toencx(b, out, len, enc64);
 225                 break;
 226         case 32:
 227                 rv = toencx(b, out, len, enc32);
 228                 break;
 229         case 16:
 230                 rv = topow2(b, out, len, 4);
 231                 break;
 232         case 10:
 233                 rv = to10(b, out, len);
 234                 break;
 235         case 8:
 236                 rv = to8(b, out, len);
 237                 break;
 238         case 4:
 239                 rv = topow2(b, out, len, 2);
 240                 break;
 241         case 2:
 242                 rv = topow2(b, out, len, 1);
 243                 break;
 244         default:
 245                 abort();
 246                 return nil;
 247         }
 248         if(rv < 0){
 249                 if(alloced)
 250                         free(buf);
 251                 return nil;
 252         }
 253         return buf;
 254 }