impl-libc/impl-libc.c

   1 #include <errno.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6
   7 #include <unistd.h>
   8
   9 /* Whether we're looking at 32-bit or 64-bit floats */
  10 typedef enum { P_SINGLE, P_DOUBLE } precision;
  11
  12 /* What type of arguments we expect, and what we'll give back. */
  13 typedef enum {
  14         /* */
  15         A_UNKNOWN,
  16         A__FLT__FLT,
  17         A__FLT_FLT_FLT__FLT,
  18 } argtype;
  19
  20 /* Types of functions we could call */
  21 typedef float (*f__f32__f32)(float);
  22 typedef float (*f__f32_f32_f32__f32)(float, float, float);
  23 typedef double (*f__f64__f64)(double);
  24 typedef double (*f__f64_f64_f64__f64)(double, double, double);
  25
  26 /* Wrapper around a function pointer */
  27 typedef struct {
  28         /* */
  29         precision p;
  30         argtype a;
  31
  32         union {
  33                 /* */
  34                 f__f32__f32 f32__f32;
  35                 f__f32_f32_f32__f32 f32_f32_f32__f32;
  36         } f32;
  37
  38         union {
  39                 /* */
  40                 f__f64__f64 f64__f64;
  41                 f__f64_f64_f64__f64 f64_f64_f64__f64;
  42         } f64;
  43
  44 } action;
  45
  46 void usage(void)
  47 {
  48         fprintf(stderr,
  49                 "usage: impl-libc [-s|-d] -f <function_name> -n <num_inputs>\n");
  50         _exit(1);
  51 }
  52
  53 float idf(float f)
  54 {
  55         return f;
  56 }
  57
  58 double idd(double d)
  59 {
  60         return d;
  61 }
  62
  63 void determine_function(const char *f, action *a)
  64 {
  65         if (!strcmp(f, "zzzzzz")) {
  66                 a->a = A_UNKNOWN;
  67         } else if (!strcmp(f, "id")) {
  68                 a->a = A__FLT__FLT;
  69                 a->f32.f32__f32 = idf;
  70                 a->f64.f64__f64 = idd;
  71         } else if (!strcmp(f, "ceil")) {
  72                 a->a = A__FLT__FLT;
  73                 a->f32.f32__f32 = ceilf;
  74                 a->f64.f64__f64 = ceil;
  75         } else if (!strcmp(f, "cos")) {
  76                 a->a = A__FLT__FLT;
  77                 a->f32.f32__f32 = cosf;
  78                 a->f64.f64__f64 = cos;
  79         } else if (!strcmp(f, "floor")) {
  80                 a->a = A__FLT__FLT;
  81                 a->f32.f32__f32 = floorf;
  82                 a->f64.f64__f64 = floor;
  83         } else if (!strcmp(f, "sin")) {
  84                 a->a = A__FLT__FLT;
  85                 a->f32.f32__f32 = sinf;
  86                 a->f64.f64__f64 = sin;
  87         } else if (!strcmp(f, "trunc")) {
  88                 a->a = A__FLT__FLT;
  89                 a->f32.f32__f32 = truncf;
  90                 a->f64.f64__f64 = trunc;
  91         } else if (!strcmp(f, "fma")) {
  92                 a->a = A__FLT_FLT_FLT__FLT;
  93                 a->f32.f32_f32_f32__f32 = fmaf;
  94                 a->f64.f64_f64_f64__f64 = fma;
  95         } else if (!strcmp(f, "sqrt")) {
  96                 a->a = A__FLT__FLT;
  97                 a->f32.f32__f32 = sqrtf;
  98                 a->f64.f64__f64 = sqrt;
  99         } else {
 100                 fprintf(stderr, "impl-libc: unknown function \"%s\"\n", f);
 101                 _exit(1);
 102         }
 103 }
 104
 105 void read_buf(char *b, ssize_t len)
 106 {
 107         ssize_t r;
 108         ssize_t total = 0;
 109
 110         while (total < len) {
 111                 r = read(0, (b + total), (len - total));
 112
 113                 if (!r) {
 114                         /* EOF */
 115                         _exit(0);
 116                 } else if (r == -1) {
 117                         perror("impl-libc: read");
 118                         _exit(1);
 119                 } else {
 120                         total += r;
 121                 }
 122         }
 123 }
 124
 125 void write_buf(const char *b, ssize_t len)
 126 {
 127         ssize_t r;
 128         ssize_t total = 0;
 129
 130         while (total < len) {
 131                 r = write(1, (b + total), (len - total));
 132
 133                 if (r == -1) {
 134                         perror("impl-libc: write");
 135                         _exit(1);
 136                 } else {
 137                         total += r;
 138                 }
 139         }
 140 }
 141
 142 size_t input_width(argtype a, precision p)
 143 {
 144         size_t w = (p == P_SINGLE) ? 4 : 8;
 145
 146         switch (a) {
 147         case A_UNKNOWN:
 148                 break;
 149         case A__FLT__FLT:
 150
 151                 return 1 * w;
 152         case A__FLT_FLT_FLT__FLT:
 153
 154                 return 3 * w;
 155         }
 156
 157         return (size_t) -1;
 158 }
 159
 160 size_t output_width(argtype a, precision p)
 161 {
 162         size_t w = (p == P_SINGLE) ? 4 : 8;
 163
 164         switch (a) {
 165         case A_UNKNOWN:
 166                 break;
 167         case A__FLT__FLT:
 168
 169                 return 1 * w;
 170         case A__FLT_FLT_FLT__FLT:
 171
 172                 return 1 * w;
 173         }
 174
 175         return (size_t) -1;
 176 }
 177
 178 void io_loop(action a, size_t n)
 179 {
 180         char *in_buf = 0;
 181         char *out_buf = 0;
 182         size_t in_sz = input_width(a.a, a.p);
 183         size_t out_sz = output_width(a.a, a.p);
 184
 185         if ((in_sz * n) / n != in_sz) {
 186                 fprintf(stderr, "impl-libc: input length overflow\n");
 187                 _exit(1);
 188         }
 189
 190         if ((out_sz * n) / n != out_sz) {
 191                 fprintf(stderr, "impl-libc: output length overflow\n");
 192                 _exit(1);
 193         }
 194
 195         if (!(in_buf = malloc(in_sz * n))) {
 196                 perror("impl-libc: malloc");
 197                 _exit(1);
 198         }
 199
 200         if (!(out_buf = malloc(out_sz * n))) {
 201                 perror("impl-libc: malloc");
 202                 _exit(1);
 203         }
 204
 205         while (1) {
 206                 read_buf(in_buf, in_sz * n);
 207
 208                 switch (a.a) {
 209                 case A_UNKNOWN:
 210                         fprintf(stderr, "impl-libc: impossible\n");
 211                         _exit(1);
 212                         break;
 213                 case A__FLT__FLT:
 214
 215                         switch (a.p) {
 216                         case P_SINGLE:
 217
 218                                 for (size_t j = 0; j < n; ++j) {
 219                                         float *x = (float *) (in_buf + (in_sz *
 220                                                                         j));
 221                                         float *y = (float *) (out_buf +
 222                                                               (out_sz * j));
 223
 224                                         *y = a.f32.f32__f32(*x);
 225                                 }
 226
 227                                 break;
 228                         case P_DOUBLE:
 229
 230                                 for (size_t j = 0; j < n; ++j) {
 231                                         double *x = (double *) (in_buf +
 232                                                                 (in_sz * j));
 233                                         double *y = (double *) (out_buf +
 234                                                                 (out_sz * j));
 235
 236                                         *y = a.f64.f64__f64(*x);
 237                                 }
 238
 239                                 break;
 240                         }
 241
 242                         break;
 243                 case A__FLT_FLT_FLT__FLT:
 244
 245                         switch (a.p) {
 246                         case P_SINGLE:
 247
 248                                 for (size_t j = 0; j < n; ++j) {
 249                                         float *x1 = (float *) (in_buf + (in_sz *
 250                                                                          j));
 251                                         float *x2 = (float *) (in_buf + (in_sz *
 252                                                                          j +
 253                                                                          4));
 254                                         float *x3 = (float *) (in_buf + (in_sz *
 255                                                                          j +
 256                                                                          8));
 257                                         float *y = (float *) (out_buf +
 258                                                               (out_sz * j));
 259
 260                                         *y = a.f32.f32_f32_f32__f32(*x1, *x2,
 261                                                                     *x3);
 262                                 }
 263
 264                                 break;
 265                         case P_DOUBLE:
 266
 267                                 for (size_t j = 0; j < n; ++j) {
 268                                         double *x1 = (double *) (in_buf +
 269                                                                  (in_sz * j));
 270                                         double *x2 = (double *) (in_buf +
 271                                                                  (in_sz * j) +
 272                                                                  8);
 273                                         double *x3 = (double *) (in_buf +
 274                                                                  (in_sz * j) +
 275                                                                  16);
 276                                         double *y = (double *) (out_buf +
 277                                                                 (out_sz * j));
 278
 279                                         *y = a.f64.f64_f64_f64__f64(*x1, *x2,
 280                                                                     *x3);
 281                                 }
 282
 283                                 break;
 284                         }
 285
 286                         break;
 287                 }
 288
 289                 write_buf(out_buf, out_sz * n);
 290         }
 291 }
 292
 293 int main(int argc, char **argv)
 294 {
 295         int c = 0;
 296         action a = { .p = P_SINGLE };
 297         long long n = 0;
 298
 299         while ((c = getopt(argc, argv, "sdf:n:")) != -1) {
 300                 switch (c) {
 301                 case 's':
 302                         a.p = P_SINGLE;
 303                         break;
 304                 case 'd':
 305                         a.p = P_DOUBLE;
 306                         break;
 307                 case 'f':
 308                         determine_function(optarg, &a);
 309                         break;
 310                 case 'n':
 311                         errno = 0;
 312                         n = strtoll(optarg, 0, 0);
 313
 314                         if (errno) {
 315                                 perror("impl-libc: unparsable");
 316
 317                                 return 1;
 318                         }
 319
 320                         break;
 321                 default:
 322                         usage();
 323                         break;
 324                 }
 325         }
 326
 327         if (a.a == A_UNKNOWN) {
 328                 usage();
 329         }
 330
 331         io_loop(a, n);
 332 }