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
  83 PG_FUNCTION_INFO_V1(cdata_update);
  84
  85 /*
  86  * public API
  87  */
  88
  89 Datum
  90 cdata_validate(PG_FUNCTION_ARGS)
  91 {
  92         char   type_info[1024];
  93         char  *result;
  94         size_t req_len;
  95         size_t len;
  96
  97         if (PG_NARGS() != 1)
  98                 ereport(ERROR, (
  99                                         errmsg("cdata_validate() expect one argument"),
 100                                         errhint("Usage cdata_validate(expected_size)")
 101                                 ));
 102
 103         req_len = (size_t)PG_GETARG_UINT32(0);
 104         len = sizeof(cdata_t);
 105
 106         if (req_len != len)
 107                 ereport(ERROR, (
 108                                         errmsg("length of the cdata type "
 109                                                 "does not match the expected length"),
 110                                         errhint("Please report a bug against PostRR")
 111                                 ));
 112
 113         snprintf(type_info, sizeof(type_info),
 114                         "cdata validated successfully; type length = %zu", len);
 115         type_info[sizeof(type_info) - 1] = '\0';
 116
 117         result = pstrdup(type_info);
 118         PG_RETURN_CSTRING(result);
 119 } /* cdata_validate */
 120
 121 Datum
 122 cdata_in(PG_FUNCTION_ARGS)
 123 {
 124         cdata_t *data;
 125         int32 typmod;
 126
 127         char *val_str, *orig;
 128         char *endptr = NULL;
 129
 130         if (PG_NARGS() != 3)
 131                 ereport(ERROR, (
 132                                         errmsg("cdata_in() expects three arguments"),
 133                                         errhint("Usage: cdata_in(col_name, oid, typmod)")
 134                                 ));
 135
 136         data = (cdata_t *)palloc0(sizeof(*data));
 137
 138         val_str = PG_GETARG_CSTRING(0);
 139         typmod  = PG_GETARG_INT32(2);
 140
 141         orig = val_str;
 142         while ((*val_str != '\0') && isspace((int)*val_str))
 143                 ++val_str;
 144
 145         if (*val_str == '\0')
 146                 ereport(ERROR, (
 147                                         errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 148                                         errmsg("invalid input syntax for cdata: \"%s\"", orig)
 149                                 ));
 150
 151         errno = 0;
 152         data->value   = strtod(val_str, &endptr);
 153         data->val_num = 1;
 154
 155         if ((endptr == val_str) || errno)
 156                 ereport(ERROR, (
 157                                         errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 158                                         errmsg("invalid input syntax for cdata: \"%s\"", orig)
 159                                 ));
 160
 161         while ((*endptr != '\0') && isspace((int)*endptr))
 162                 ereport(ERROR, (
 163                                         errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 164                                         errmsg("invalid input syntax for cdata: \"%s\"", orig)
 165                                 ));
 166
 167         if (typmod > 0)
 168                 data->cf = typmod;
 169         else
 170                 data->cf = 0;
 171
 172         PG_RETURN_CDATA_P(data);
 173 } /* cdata_in */
 174
 175 Datum
 176 cdata_out(PG_FUNCTION_ARGS)
 177 {
 178         cdata_t *data;
 179
 180         char  cd_str[1024];
 181         char *result;
 182
 183         if (PG_NARGS() != 1)
 184                 ereport(ERROR, (
 185                                         errmsg("cdata_out() expects one argument"),
 186                                         errhint("Usage: cdata_out(cdata)")
 187                                 ));
 188
 189         data = PG_GETARG_CDATA_P(0);
 190
 191         snprintf(cd_str, sizeof(cd_str), "%g (U:%i/%i)",
 192                         data->value, data->undef_num, data->val_num);
 193
 194         result = pstrdup(cd_str);
 195         PG_RETURN_CSTRING(result);
 196 } /* cdata_out */
 197
 198 Datum
 199 cdata_typmodin(PG_FUNCTION_ARGS)
 200 {
 201         ArrayType *tm_array;
 202
 203         Datum *elem_values;
 204         int    n;
 205         char  *cf_str;
 206         int32  typmod = CF_AVG;
 207
 208         if (PG_NARGS() != 1)
 209                 ereport(ERROR, (
 210                                         errmsg("cdata_typmodin() expects one argument"),
 211                                         errhint("Usage: cdata_typmodin(array)")
 212                                 ));
 213
 214         tm_array = PG_GETARG_ARRAYTYPE_P(0);
 215
 216         if (ARR_ELEMTYPE(tm_array) != CSTRINGOID)
 217                 ereport(ERROR, (
 218                                         errcode(ERRCODE_ARRAY_ELEMENT_ERROR),
 219                                         errmsg("typmod array must be type cstring[]")
 220                                 ));
 221
 222         if (ARR_NDIM(tm_array) != 1)
 223                 ereport(ERROR, (
 224                                         errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
 225                                         errmsg("typmod array must be one-dimensional")
 226                                 ));
 227
 228         deconstruct_array(tm_array, CSTRINGOID,
 229                         /* elmlen = */ -2, /* elmbyval = */ false, /* elmalign = */ 'c',
 230                         &elem_values, /* nullsp = */ NULL, &n);
 231
 232         if (n != 1)
 233                 ereport(ERROR, (
 234                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 235                                         errmsg("cdata typmod array must have one element")
 236                                 ));
 237
 238         cf_str = DatumGetCString(elem_values[0]);
 239         if (! strcasecmp(cf_str, "AVG"))
 240                 typmod = CF_AVG;
 241         else if (! strcasecmp(cf_str, "MIN"))
 242                 typmod = CF_MIN;
 243         else if (! strcasecmp(cf_str, "MAX"))
 244                 typmod = CF_MAX;
 245         else
 246                 ereport(ERROR, (
 247                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 248                                         errmsg("invalid cdata typmod: %s", cf_str)
 249                                 ));
 250
 251         PG_RETURN_INT32(typmod);
 252 } /* cdata_typmodin */
 253
 254 Datum
 255 cdata_typmodout(PG_FUNCTION_ARGS)
 256 {
 257         int32 typmod;
 258         char  tm_str[32];
 259         char *result;
 260
 261         if (PG_NARGS() != 1)
 262                 ereport(ERROR, (
 263                                         errmsg("cdata_typmodout() expects one argument"),
 264                                         errhint("Usage: cdata_typmodout(typmod)")
 265                                 ));
 266
 267         typmod = PG_GETARG_INT32(0);
 268         snprintf(tm_str, sizeof(tm_str), "('%s')", CF_TO_STR(typmod));
 269         tm_str[sizeof(tm_str) - 1] = '\0';
 270         result = pstrdup(tm_str);
 271         PG_RETURN_CSTRING(result);
 272 } /* cdata_typmodout */
 273
 274 Datum
 275 cdata_to_cdata(PG_FUNCTION_ARGS)
 276 {
 277         cdata_t *data;
 278         int32 typmod;
 279
 280         if (PG_NARGS() != 3)
 281                 ereport(ERROR, (
 282                                         errmsg("cdata_to_cdata() "
 283                                                 "expects three arguments"),
 284                                         errhint("Usage: cdata_to_cdata"
 285                                                 "(cdata, typmod, is_explicit)")
 286                                 ));
 287
 288         data   = PG_GETARG_CDATA_P(0);
 289         typmod = PG_GETARG_INT32(1);
 290
 291         if ((data->cf >= 0) && (data->cf != typmod) && (data->val_num > 1))
 292                 ereport(ERROR, (
 293                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 294                                         errmsg("invalid cast: cannot cast cdata "
 295                                                 "with different typmod (yet)")
 296                                 ));
 297
 298         data->cf = typmod;
 299         PG_RETURN_CDATA_P(data);
 300 } /* cdata_to_cdata */
 301
 302 Datum
 303 int32_to_cdata(PG_FUNCTION_ARGS)
 304 {
 305         int32 i_val;
 306         int32 typmod;
 307
 308         cdata_t *data;
 309
 310         if (PG_NARGS() != 3)
 311                 ereport(ERROR, (
 312                                         errmsg("int32_to_cdata() expects three arguments"),
 313                                         errhint("Usage: int32_to_cdata"
 314                                                 "(integer, typmod, is_explicit)")
 315                                 ));
 316
 317         i_val  = PG_GETARG_INT32(0);
 318         typmod = PG_GETARG_INT32(1);
 319
 320         data = (cdata_t *)palloc0(sizeof(*data));
 321
 322         data->value     = (float8)i_val;
 323         data->undef_num = 0;
 324         data->val_num   = 1;
 325
 326         if (typmod >= 0)
 327                 data->cf = typmod;
 328         else
 329                 data->cf = CF_AVG;
 330
 331         PG_RETURN_CDATA_P(data);
 332 } /* int32_to_cdata */
 333
 334 Datum
 335 cdata_update(PG_FUNCTION_ARGS)
 336 {
 337         cdata_t *data;
 338         cdata_t *update;
 339
 340         if (PG_NARGS() != 2)
 341                 ereport(ERROR, (
 342                                         errmsg("cdata_update() expects two arguments"),
 343                                         errhint("Usage: cdata_update(cdata, cdata)")
 344                                 ));
 345
 346         data   = PG_GETARG_CDATA_P(0);
 347         update = PG_GETARG_CDATA_P(1);
 348
 349         if ((data->cf != update->cf) && (update->val_num > 1))
 350                 ereport(ERROR, (
 351                                         errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 352                                         errmsg("invalid update value: incompatible "
 353                                                 "consolidation function")
 354                                 ));
 355
 356         switch (data->cf) {
 357                 case CF_AVG:
 358                         data->value = (data->value * (data->val_num - data->undef_num))
 359                                 + (update->value * (update->val_num - update->undef_num));
 360                         data->value /= (data->val_num - data->undef_num)
 361                                         +  (update->val_num - update->undef_num);
 362                         break;
 363                 case CF_MIN:
 364                         data->value = (data->value <= update->value)
 365                                 ? data->value : update->value;
 366                         break;
 367                 case CF_MAX:
 368                         data->value = (data->value >= update->value)
 369                                 ? data->value : update->value;
 370                         break;
 371                 default:
 372                         ereport(ERROR, (
 373                                                 errcode(ERRCODE_DATA_CORRUPTED),
 374                                                 errmsg("unknown consolidation function %d",
 375                                                         data->cf)
 376                                         ));
 377                         break;
 378         }
 379
 380         data->undef_num += update->undef_num;
 381         data->val_num   += update->val_num;
 382         PG_RETURN_CDATA_P(data);
 383 } /* cdata_update */
 384
 385 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 386