src/cdata.c

   1 /*
   2  * PostRR - src/cdata.c
   3  * Copyright (C) 2012 Sebastian 'tokkee' Harl <sh@tokkee.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  17  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /*
  29  * A PostgreSQL data-type providing consolidated data points.
  30  */
  31
  32 #include "postrr.h"
  33
  34 #include <errno.h>
  35 #include <string.h>
  36
  37 #include <postgres.h>
  38 #include <fmgr.h>
  39
  40 /* Postgres utilities */
  41 #include <catalog/pg_type.h>
  42 #include <utils/array.h>
  43
  44 enum {
  45         CF_AVG = 0,
  46         CF_MIN = 1,
  47         CF_MAX = 2
  48 };
  49
  50 #define CF_TO_STR(cf) \
  51         (((cf) == CF_AVG) \
  52                 ? "AVG" \
  53                 : ((cf) == CF_MIN) \
  54                         ? "MIN" \
  55                         : ((cf) == CF_MAX) \
  56                                 ? "MAX" : "UNKNOWN")
  57
  58 /*
  59  * data type
  60  */
  61
  62 struct cdata {
  63         float8 value;
  64         int32 undef_num;
  65         int32 val_num;
  66         int32 cf;
  67 };
  68
  69 /*
  70  * prototypes for PostgreSQL functions
  71  */
  72
  73 PG_FUNCTION_INFO_V1(cdata_validate);
  74
  75 PG_FUNCTION_INFO_V1(cdata_in);
  76 PG_FUNCTION_INFO_V1(cdata_out);
  77 PG_FUNCTION_INFO_V1(cdata_typmodin);
  78 PG_FUNCTION_INFO_V1(cdata_typmodout);
  79
  80 PG_FUNCTION_INFO_V1(cdata_to_cdata);
  81 PG_FUNCTION_INFO_V1(int32_to_cdata);
  82 PG_FUNCTION_INFO_V1(cdata_to_float8);
  83
  84 PG_FUNCTION_INFO_V1(cdata_update);
  85
  86 /*
  87  * public API
  88  */
  89
  90 Datum
  91 cdata_validate(PG_FUNCTION_ARGS)
  92 {
  93         char   type_info[1024];
  94         char  *result;
  95         size_t req_len;
  96         size_t len;
  97
  98         if (PG_NARGS() != 1)
  99                 ereport(ERROR, (
 100                                         errmsg("cdata_validate() expect one argument"),
 101                                         errhint("Usage cdata_validate(expected_size)")
 102                                 ));
 103
 104         req_len = (size_t)PG_GETARG_UINT32(0);
 105         len = sizeof(cdata_t);
 106
 107         if (req_len != len)
 108                 ereport(ERROR, (
 109                                         errmsg("length of the cdata type "
 110                                                 "does not match the expected length"),
 111                                         errhint("Please report a bug against PostRR")
 112                                 ));
 113
 114         snprintf(type_info, sizeof(type_info),
 115                         "cdata validated successfully; type length = %zu", len);
 116         type_info[sizeof(type_info) - 1] = '\0';
 117
 118         result = pstrdup(type_info);
 119         PG_RETURN_CSTRING(result);
 120 } /* cdata_validate */
 121
 122 Datum
 123 cdata_in(PG_FUNCTION_ARGS)
 124 {
 125         cdata_t *data;
 126         int32 typmod;
 127
 128         char *val_str, *orig;
 129         char *endptr = NULL;
 130
 131         if (PG_NARGS() != 3)
 132                 ereport(ERROR, (
 133                                         errmsg("cdata_in() expects three arguments"),
 134                                         errhint("Usage: cdata_in(col_name, oid, typmod)")
 135                                 ));
 136
 137         data = (cdata_t *)palloc0(sizeof(*data));
 138
 139         val_str = PG_GETARG_CSTRING(0);
 140         typmod  = PG_GETARG_INT32(2);
 141
 142         orig = val_str;
 143         while ((*val_str != '\0') && isspace((int)*val_str))
 144                 ++val_str;
 145
 146         if (*val_str == '\0')
 147                 ereport(ERROR, (
 148                                         errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 149                                         errmsg("invalid input syntax for cdata: \"%s\"", orig)
 150                                 ));
 151
 152         errno = 0;
 153         data->value   = strtod(val_str, &endptr);
 154         data->val_num = 1;
 155
 156         if ((endptr == val_str) || errno)
 157                 ereport(ERROR, (
 158                                         errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 159                                         errmsg("invalid input syntax for cdata: \"%s\"", orig)
 160                                 ));
 161
 162         while ((*endptr != '\0') && isspace((int)*endptr))
 163                 ereport(ERROR, (
 164                                         errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 165                                         errmsg("invalid input syntax for cdata: \"%s\"", orig)
 166                                 ));
 167
 168         if (typmod > 0)
 169                 data->cf = typmod;
 170         else
 171                 data->cf = 0;
 172
 173         PG_RETURN_CDATA_P(data);
 174 } /* cdata_in */
 175
 176 Datum
 177 cdata_out(PG_FUNCTION_ARGS)
 178 {
 179         cdata_t *data;
 180
 181         char  cd_str[1024];
 182         char *result;
 183
 184         if (PG_NARGS() != 1)
 185                 ereport(ERROR, (
 186                                         errmsg("cdata_out() expects one argument"),
 187                                         errhint("Usage: cdata_out(cdata)")
 188                                 ));
 189
 190         data = PG_GETARG_CDATA_P(0);
 191
 192         snprintf(cd_str, sizeof(cd_str), "%g (U:%i/%i)",
 193                         data->value, data->undef_num, data->val_num);
 194
 195         result = pstrdup(cd_str);
 196         PG_RETURN_CSTRING(result);
 197 } /* cdata_out */
 198
 199 Datum
 200 cdata_typmodin(PG_FUNCTION_ARGS)
 201 {
 202         ArrayType *tm_array;
 203
 204         Datum *elem_values;
 205         int    n;
 206         char  *cf_str;
 207         int32  typmod = CF_AVG;
 208
 209         if (PG_NARGS() != 1)
 210                 ereport(ERROR, (
 211                                         errmsg("cdata_typmodin() expects one argument"),
 212                                         errhint("Usage: cdata_typmodin(array)")
 213                                 ));
 214
 215         tm_array = PG_GETARG_ARRAYTYPE_P(0);
 216
 217         if (ARR_ELEMTYPE(tm_array) != CSTRINGOID)
 218                 ereport(ERROR, (
 219                                         errcode(ERRCODE_ARRAY_ELEMENT_ERROR),
 220                                         errmsg("typmod array must be type cstring[]")
 221                                 ));
 222
 223         if (ARR_NDIM(tm_array) != 1)
 224                 ereport(ERROR, (
 225                                         errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
 226                                         errmsg("typmod array must be one-dimensional")
 227                                 ));
 228
 229         deconstruct_array(tm_array, CSTRINGOID,
 230                         /* elmlen = */ -2, /* elmbyval = */ false, /* elmalign = */ 'c',
 231                         &elem_values, /* nullsp = */ NULL, &n);
 232
 233         if (n != 1)
 234                 ereport(ERROR, (
 235                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 236                                         errmsg("cdata typmod array must have one element")
 237                                 ));
 238
 239         cf_str = DatumGetCString(elem_values[0]);
 240         if (! strcasecmp(cf_str, "AVG"))
 241                 typmod = CF_AVG;
 242         else if (! strcasecmp(cf_str, "MIN"))
 243                 typmod = CF_MIN;
 244         else if (! strcasecmp(cf_str, "MAX"))
 245                 typmod = CF_MAX;
 246         else
 247                 ereport(ERROR, (
 248                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 249                                         errmsg("invalid cdata typmod: %s", cf_str)
 250                                 ));
 251
 252         PG_RETURN_INT32(typmod);
 253 } /* cdata_typmodin */
 254
 255 Datum
 256 cdata_typmodout(PG_FUNCTION_ARGS)
 257 {
 258         int32 typmod;
 259         char  tm_str[32];
 260         char *result;
 261
 262         if (PG_NARGS() != 1)
 263                 ereport(ERROR, (
 264                                         errmsg("cdata_typmodout() expects one argument"),
 265                                         errhint("Usage: cdata_typmodout(typmod)")
 266                                 ));
 267
 268         typmod = PG_GETARG_INT32(0);
 269         snprintf(tm_str, sizeof(tm_str), "('%s')", CF_TO_STR(typmod));
 270         tm_str[sizeof(tm_str) - 1] = '\0';
 271         result = pstrdup(tm_str);
 272         PG_RETURN_CSTRING(result);
 273 } /* cdata_typmodout */
 274
 275 Datum
 276 cdata_to_cdata(PG_FUNCTION_ARGS)
 277 {
 278         cdata_t *data;
 279         int32 typmod;
 280
 281         if (PG_NARGS() != 3)
 282                 ereport(ERROR, (
 283                                         errmsg("cdata_to_cdata() "
 284                                                 "expects three arguments"),
 285                                         errhint("Usage: cdata_to_cdata"
 286                                                 "(cdata, typmod, is_explicit)")
 287                                 ));
 288
 289         data   = PG_GETARG_CDATA_P(0);
 290         typmod = PG_GETARG_INT32(1);
 291
 292         if ((data->cf >= 0) && (data->cf != typmod) && (data->val_num > 1))
 293                 ereport(ERROR, (
 294                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 295                                         errmsg("invalid cast: cannot cast cdata "
 296                                                 "with different typmod (yet)")
 297                                 ));
 298
 299         data->cf = typmod;
 300         PG_RETURN_CDATA_P(data);
 301 } /* cdata_to_cdata */
 302
 303 Datum
 304 int32_to_cdata(PG_FUNCTION_ARGS)
 305 {
 306         int32 i_val;
 307         int32 typmod;
 308
 309         cdata_t *data;
 310
 311         if (PG_NARGS() != 3)
 312                 ereport(ERROR, (
 313                                         errmsg("int32_to_cdata() expects three arguments"),
 314                                         errhint("Usage: int32_to_cdata"
 315                                                 "(integer, typmod, is_explicit)")
 316                                 ));
 317
 318         i_val  = PG_GETARG_INT32(0);
 319         typmod = PG_GETARG_INT32(1);
 320
 321         data = (cdata_t *)palloc0(sizeof(*data));
 322
 323         data->value     = (float8)i_val;
 324         data->undef_num = 0;
 325         data->val_num   = 1;
 326
 327         if (typmod >= 0)
 328                 data->cf = typmod;
 329         else
 330                 data->cf = CF_AVG;
 331
 332         PG_RETURN_CDATA_P(data);
 333 } /* int32_to_cdata */
 334
 335 Datum
 336 cdata_to_float8(PG_FUNCTION_ARGS)
 337 {
 338         cdata_t *data;
 339
 340         if (PG_NARGS() != 1)
 341                 ereport(ERROR, (
 342                                         errmsg("cdata_to_float8() expects one argument"),
 343                                         errhint("Usage: cdata_to_float8(cdata)")
 344                                 ));
 345
 346         data = PG_GETARG_CDATA_P(0);
 347         PG_RETURN_FLOAT8(data->value);
 348 } /* cdata_to_float8 */
 349
 350 Datum
 351 cdata_update(PG_FUNCTION_ARGS)
 352 {
 353         cdata_t *data;
 354         cdata_t *update;
 355
 356         if (PG_NARGS() != 2)
 357                 ereport(ERROR, (
 358                                         errmsg("cdata_update() expects two arguments"),
 359                                         errhint("Usage: cdata_update(cdata, cdata)")
 360                                 ));
 361
 362         data   = PG_GETARG_CDATA_P(0);
 363         update = PG_GETARG_CDATA_P(1);
 364
 365         if ((data->cf != update->cf) && (update->val_num > 1))
 366                 ereport(ERROR, (
 367                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 368                                         errmsg("invalid update value: incompatible "
 369                                                 "consolidation function")
 370                                 ));
 371
 372         switch (data->cf) {
 373                 case CF_AVG:
 374                         data->value = (data->value * (data->val_num - data->undef_num))
 375                                 + (update->value * (update->val_num - update->undef_num));
 376                         data->value /= (data->val_num - data->undef_num)
 377                                         +  (update->val_num - update->undef_num);
 378                         break;
 379                 case CF_MIN:
 380                         data->value = (data->value <= update->value)
 381                                 ? data->value : update->value;
 382                         break;
 383                 case CF_MAX:
 384                         data->value = (data->value >= update->value)
 385                                 ? data->value : update->value;
 386                         break;
 387                 default:
 388                         ereport(ERROR, (
 389                                                 errcode(ERRCODE_DATA_CORRUPTED),
 390                                                 errmsg("unknown consolidation function %d",
 391                                                         data->cf)
 392                                         ));
 393                         break;
 394         }
 395
 396         data->undef_num += update->undef_num;
 397         data->val_num   += update->val_num;
 398         PG_RETURN_CDATA_P(data);
 399 } /* cdata_update */
 400
 401 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 402