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, "fma")) {
  84                 a->a = A__FLT_FLT_FLT__FLT;
  85                 a->f32.f32_f32_f32__f32 = fmaf;
  86                 a->f64.f64_f64_f64__f64 = fma;
  87         } else if (!strcmp(f, "exp")) {
  88                 a->a = A__FLT__FLT;
  89                 a->f32.f32__f32 = expf;
  90                 a->f64.f64__f64 = exp;
  91         } else if (!strcmp(f, "expm1")) {
  92                 a->a = A__FLT__FLT;
  93                 a->f32.f32__f32 = expm1f;
  94                 a->f64.f64__f64 = expm1;
  95         } else if (!strcmp(f, "log")) {
  96                 a->a = A__FLT__FLT;
  97                 a->f32.f32__f32 = logf;
  98                 a->f64.f64__f64 = log;
  99         } else if (!strcmp(f, "log1p")) {
 100                 a->a = A__FLT__FLT;
 101                 a->f32.f32__f32 = log1pf;
 102                 a->f64.f64__f64 = log1p;
 103         } else if (!strcmp(f, "sin")) {
 104                 a->a = A__FLT__FLT;
 105                 a->f32.f32__f32 = sinf;
 106                 a->f64.f64__f64 = sin;
 107         } else if (!strcmp(f, "sqrt")) {
 108                 a->a = A__FLT__FLT;
 109                 a->f32.f32__f32 = sqrtf;
 110                 a->f64.f64__f64 = sqrt;
 111         } else if (!strcmp(f, "trunc")) {
 112                 a->a = A__FLT__FLT;
 113                 a->f32.f32__f32 = truncf;
 114                 a->f64.f64__f64 = trunc;
 115         } else {
 116                 fprintf(stderr, "impl-libc: unknown function \"%s\"\n", f);
 117                 _exit(1);
 118         }
 119 }
 120
 121 void read_buf(char *b, ssize_t len)
 122 {
 123         ssize_t r;
 124         ssize_t total = 0;
 125
 126         while (total < len) {
 127                 r = read(0, (b + total), (len - total));
 128
 129                 if (!r) {
 130                         /* EOF */
 131                         _exit(0);
 132                 } else if (r == -1) {
 133                         perror("impl-libc: read");
 134                         _exit(1);
 135                 } else {
 136                         total += r;
 137                 }
 138         }
 139 }
 140
 141 void write_buf(const char *b, ssize_t len)
 142 {
 143         ssize_t r;
 144         ssize_t total = 0;
 145
 146         while (total < len) {
 147                 r = write(1, (b + total), (len - total));
 148
 149                 if (r == -1) {
 150                         perror("impl-libc: write");
 151                         _exit(1);
 152                 } else {
 153                         total += r;
 154                 }
 155         }
 156 }
 157
 158 size_t input_width(argtype a, precision p)
 159 {
 160         size_t w = (p == P_SINGLE) ? 4 : 8;
 161
 162         switch (a) {
 163         case A_UNKNOWN:
 164                 break;
 165         case A__FLT__FLT:
 166
 167                 return 1 * w;
 168         case A__FLT_FLT_FLT__FLT:
 169
 170                 return 3 * w;
 171         }
 172
 173         return (size_t) -1;
 174 }
 175
 176 size_t output_width(argtype a, precision p)
 177 {
 178         size_t w = (p == P_SINGLE) ? 4 : 8;
 179
 180         switch (a) {
 181         case A_UNKNOWN:
 182                 break;
 183         case A__FLT__FLT:
 184
 185                 return 1 * w;
 186         case A__FLT_FLT_FLT__FLT:
 187
 188                 return 1 * w;
 189         }
 190
 191         return (size_t) -1;
 192 }
 193
 194 void io_loop(action a, size_t n)
 195 {
 196         char *in_buf = 0;
 197         char *out_buf = 0;
 198         size_t in_sz = input_width(a.a, a.p);
 199         size_t out_sz = output_width(a.a, a.p);
 200
 201         if ((in_sz * n) / n != in_sz) {
 202                 fprintf(stderr, "impl-libc: input length overflow\n");
 203                 _exit(1);
 204         }
 205
 206         if ((out_sz * n) / n != out_sz) {
 207                 fprintf(stderr, "impl-libc: output length overflow\n");
 208                 _exit(1);
 209         }
 210
 211         if (!(in_buf = malloc(in_sz * n))) {
 212                 perror("impl-libc: malloc");
 213                 _exit(1);
 214         }
 215
 216         if (!(out_buf = malloc(out_sz * n))) {
 217                 perror("impl-libc: malloc");
 218                 _exit(1);
 219         }
 220
 221         while (1) {
 222                 read_buf(in_buf, in_sz * n);
 223
 224                 switch (a.a) {
 225                 case A_UNKNOWN:
 226                         fprintf(stderr, "impl-libc: impossible\n");
 227                         _exit(1);
 228                         break;
 229                 case A__FLT__FLT:
 230
 231                         switch (a.p) {
 232                         case P_SINGLE:
 233
 234                                 for (size_t j = 0; j < n; ++j) {
 235                                         float *x = (float *) (in_buf + (in_sz *
 236                                                                         j));
 237                                         float *y = (float *) (out_buf +
 238                                                               (out_sz * j));
 239
 240                                         *y = a.f32.f32__f32(*x);
 241                                 }
 242
 243                                 break;
 244                         case P_DOUBLE:
 245
 246                                 for (size_t j = 0; j < n; ++j) {
 247                                         double *x = (double *) (in_buf +
 248                                                                 (in_sz * j));
 249                                         double *y = (double *) (out_buf +
 250                                                                 (out_sz * j));
 251
 252                                         *y = a.f64.f64__f64(*x);
 253                                 }
 254
 255                                 break;
 256                         }
 257
 258                         break;
 259                 case A__FLT_FLT_FLT__FLT:
 260
 261                         switch (a.p) {
 262                         case P_SINGLE:
 263
 264                                 for (size_t j = 0; j < n; ++j) {
 265                                         float *x1 = (float *) (in_buf + (in_sz *
 266                                                                          j));
 267                                         float *x2 = (float *) (in_buf + (in_sz *
 268                                                                          j +
 269                                                                          4));
 270                                         float *x3 = (float *) (in_buf + (in_sz *
 271                                                                          j +
 272                                                                          8));
 273                                         float *y = (float *) (out_buf +
 274                                                               (out_sz * j));
 275
 276                                         *y = a.f32.f32_f32_f32__f32(*x1, *x2,
 277                                                                     *x3);
 278                                 }
 279
 280                                 break;
 281                         case P_DOUBLE:
 282
 283                                 for (size_t j = 0; j < n; ++j) {
 284                                         double *x1 = (double *) (in_buf +
 285                                                                  (in_sz * j));
 286                                         double *x2 = (double *) (in_buf +
 287                                                                  (in_sz * j) +
 288                                                                  8);
 289                                         double *x3 = (double *) (in_buf +
 290                                                                  (in_sz * j) +
 291                                                                  16);
 292                                         double *y = (double *) (out_buf +
 293                                                                 (out_sz * j));
 294
 295                                         *y = a.f64.f64_f64_f64__f64(*x1, *x2,
 296                                                                     *x3);
 297                                 }
 298
 299                                 break;
 300                         }
 301
 302                         break;
 303                 }
 304
 305                 write_buf(out_buf, out_sz * n);
 306         }
 307 }
 308
 309 int main(int argc, char **argv)
 310 {
 311         int c = 0;
 312         action a = { .p = P_SINGLE };
 313         long long n = 0;
 314
 315         while ((c = getopt(argc, argv, "sdf:n:")) != -1) {
 316                 switch (c) {
 317                 case 's':
 318                         a.p = P_SINGLE;
 319                         break;
 320                 case 'd':
 321                         a.p = P_DOUBLE;
 322                         break;
 323                 case 'f':
 324                         determine_function(optarg, &a);
 325                         break;
 326                 case 'n':
 327                         errno = 0;
 328                         n = strtoll(optarg, 0, 0);
 329
 330                         if (errno) {
 331                                 perror("impl-libc: unparsable");
 332
 333                                 return 1;
 334                         }
 335
 336                         break;
 337                 default:
 338                         usage();
 339                         break;
 340                 }
 341         }
 342
 343         if (a.a == A_UNKNOWN) {
 344                 usage();
 345         }
 346
 347         io_loop(a, n);
 348 }