Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
Comment: | Add the "csv" virtual table for reading CSV files, as an extension in the ext/misc/ subfolder. |
---|---|
Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
00d3570c8bb96469c984903e20de589e |
User & Date: | drh 2016-05-31 16:22:48.849 |
Context
2016-05-31
| ||
18:08 | Add the testflags parameter to the csv extension. (check-in: b93fb2fe0d user: drh tags: trunk) | |
16:22 | Add the "csv" virtual table for reading CSV files, as an extension in the ext/misc/ subfolder. (check-in: 00d3570c8b user: drh tags: trunk) | |
2016-05-30
| ||
08:28 | Fix an FTS5 problem (segfault or incorrect query results) with "... MATCH 'x OR y' ORDER BY rank" queries when either token 'x' or 'y' is completely absent from the dataset. (check-in: 64ca1a835a user: dan tags: trunk) | |
Changes
Added ext/misc/csv.c.
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 | /* ** 2016-05-28 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ****************************************************************************** ** ** This file contains the implementation of an SQLite virtual table for ** reading CSV files. ** ** Usage: ** ** .load ./csv ** CREATE VIRTUAL TABLE temp.csv USING csv(filename=FILENAME); ** SELECT * FROM csv; ** ** The columns are named "c1", "c2", "c3", ... by default. But the ** application can define its own CREATE TABLE statement as an additional ** parameter. For example: ** ** CREATE VIRTUAL TABLE temp.csv2 USING csv( ** filename = "../http.log", ** schema = "CREATE TABLE x(date,ipaddr,url,referrer,userAgent)" ** ); */ #include <sqlite3ext.h> SQLITE_EXTENSION_INIT1 #include <string.h> #include <stdlib.h> #include <assert.h> #include <stdarg.h> #include <ctype.h> #include <stdio.h> /* ** A macro to hint to the compiler that a function should not be ** inlined. */ #if defined(__GNUC__) # define CSV_NOINLINE __attribute__((noinline)) #elif defined(_MSC_VER) && _MSC_VER>=1310 # define CSV_NOINLINE __declspec(noinline) #else # define CSV_NOINLINE #endif /* Max size of the error message in a CsvReader */ #define CSV_MXERR 200 /* A context object used when read a CSV file. */ typedef struct CsvReader CsvReader; struct CsvReader { FILE *in; /* Read the CSV text from this input stream */ char *z; /* Accumulated text for a field */ int n; /* Number of bytes in z */ int nAlloc; /* Space allocated for z[] */ int nLine; /* Current line number */ int cTerm; /* Character that terminated the most recent field */ char zErr[CSV_MXERR]; /* Error message */ }; /* Initialize a CsvReader object */ static void csv_reader_init(CsvReader *p){ memset(p, 0, sizeof(*p)); } /* Close and reset a CsvReader object */ static void csv_reader_reset(CsvReader *p){ if( p->in ) fclose(p->in); sqlite3_free(p->z); csv_reader_init(p); } /* Report an error on a CsvReader */ static void csv_errmsg(CsvReader *p, const char *zFormat, ...){ va_list ap; va_start(ap, zFormat); sqlite3_vsnprintf(CSV_MXERR, p->zErr, zFormat, ap); va_end(ap); } /* Open the file associated with a CsvReader ** Return the number of errors. */ static int csv_reader_open(CsvReader *p, const char *zFilename){ p->in = fopen(zFilename, "rb"); if( p->in==0 ){ csv_errmsg(p, "cannot open '%s' for reading", zFilename); return 1; } return 0; } /* Increase the size of p->z and append character c to the end. ** Return 0 on success and non-zero if there is an OOM error */ static CSV_NOINLINE int csv_resize_and_append(CsvReader *p, char c){ char *zNew; int nNew = p->nAlloc*2 + 100; zNew = sqlite3_realloc64(p->z, nNew); if( zNew ){ p->z = zNew; p->nAlloc = nNew; p->z[p->n++] = c; return 0; }else{ csv_errmsg(p, "out of memory"); return 1; } } /* Append a single character to the CsvReader.z[] array. ** Return 0 on success and non-zero if there is an OOM error */ static int csv_append(CsvReader *p, char c){ if( p->n>=p->nAlloc-1 ) return csv_resize_and_append(p, c); p->z[p->n++] = c; return 0; } /* Read a single field of CSV text. Compatible with rfc4180 and extended ** with the option of having a separator other than ",". ** ** + Input comes from p->in. ** + Store results in p->z of length p->n. Space to hold p->z comes ** from sqlite3_malloc64(). ** + Keep track of the line number in p->nLine. ** + Store the character that terminates the field in p->cTerm. Store ** EOF on end-of-file. ** ** Return "" at EOF. Return 0 on an OOM error. */ static char *csv_read_one_field(CsvReader *p){ int c; p->n = 0; c = fgetc(p->in); if( c==EOF ){ p->cTerm = EOF; return ""; } if( c=='"' ){ int pc, ppc; int startLine = p->nLine; int cQuote = c; pc = ppc = 0; while( 1 ){ c = fgetc(p->in); if( c=='\n' ) p->nLine++; if( c==cQuote ){ if( pc==cQuote ){ pc = 0; continue; } } if( (c==',' && pc==cQuote) || (c=='\n' && pc==cQuote) || (c=='\n' && pc=='\r' && ppc==cQuote) || (c==EOF && pc==cQuote) ){ do{ p->n--; }while( p->z[p->n]!=cQuote ); p->cTerm = c; break; } if( pc==cQuote && c!='\r' ){ csv_errmsg(p, "line %d: unescaped %c character", p->nLine, cQuote); break; } if( c==EOF ){ csv_errmsg(p, "line %d: unterminated %c-quoted field\n", startLine, cQuote); p->cTerm = c; break; } if( csv_append(p, (char)c) ) return 0; ppc = pc; pc = c; } }else{ while( c!=EOF && c!=',' && c!='\n' ){ if( csv_append(p, (char)c) ) return 0; c = fgetc(p->in); } if( c=='\n' ){ p->nLine++; if( p->n>0 && p->z[p->n-1]=='\r' ) p->n--; } p->cTerm = c; } if( p->z ) p->z[p->n] = 0; return p->z; } /* Forward references to the various virtual table methods implemented ** in this file. */ static int csvtabCreate(sqlite3*, void*, int, const char*const*, sqlite3_vtab**,char**); static int csvtabConnect(sqlite3*, void*, int, const char*const*, sqlite3_vtab**,char**); static int csvtabBestIndex(sqlite3_vtab*,sqlite3_index_info*); static int csvtabDisconnect(sqlite3_vtab*); static int csvtabOpen(sqlite3_vtab*, sqlite3_vtab_cursor**); static int csvtabClose(sqlite3_vtab_cursor*); static int csvtabFilter(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, int argc, sqlite3_value **argv); static int csvtabNext(sqlite3_vtab_cursor*); static int csvtabEof(sqlite3_vtab_cursor*); static int csvtabColumn(sqlite3_vtab_cursor*,sqlite3_context*,int); static int csvtabRowid(sqlite3_vtab_cursor*,sqlite3_int64*); /* An instance of the CSV virtual table */ typedef struct CsvTable { sqlite3_vtab base; /* Base class. Must be first */ char *zFilename; /* Name of the CSV file */ long iStart; /* Offset to start of data in zFilename */ int nCol; /* Number of columns in the CSV file */ } CsvTable; /* A cursor for the CSV virtual table */ typedef struct CsvCursor { sqlite3_vtab_cursor base; /* Base class. Must be first */ CsvReader rdr; /* The CsvReader object */ char **azVal; /* Value of the current row */ sqlite3_int64 iRowid; /* The current rowid. Negative for EOF */ } CsvCursor; /* Transfer error message text from a reader into a CsvTable */ static void csv_xfer_error(CsvTable *pTab, CsvReader *pRdr){ sqlite3_free(pTab->base.zErrMsg); pTab->base.zErrMsg = sqlite3_mprintf("%s", pRdr->zErr); } /* ** This method is the destructor fo a CsvTable object. */ static int csvtabDisconnect(sqlite3_vtab *pVtab){ CsvTable *p = (CsvTable*)pVtab; sqlite3_free(p->zFilename); sqlite3_free(p); return SQLITE_OK; } /* Skip leading whitespace. Return a pointer to the first non-whitespace ** character, or to the zero terminator if the string has only whitespace */ static const char *csv_skip_whitespace(const char *z){ while( isspace((unsigned char)z[0]) ) z++; return z; } /* Remove trailing whitespace from the end of string z[] */ static void csv_trim_whitespace(char *z){ size_t n = strlen(z); while( n>0 && isspace((unsigned char)z[n]) ) n--; z[n] = 0; } /* Dequote the string */ static void csv_dequote(char *z){ int i, j; char cQuote = z[0]; size_t n; if( cQuote!='\'' && cQuote!='"' ) return; n = strlen(z); if( n<2 || z[n-1]!=z[0] ) return; for(i=1, j=0; i<n-1; i++){ if( z[i]==cQuote && z[i+1]==cQuote ) i++; z[j++] = z[i]; } z[j] = 0; } /* Check to see if the string is of the form: "TAG = VALUE" with optional ** whitespace before and around tokens. If it is, return a pointer to the ** first character of VALUE. If it is not, return NULL. */ static const char *csv_parameter(const char *zTag, int nTag, const char *z){ z = csv_skip_whitespace(z); if( strncmp(zTag, z, nTag)!=0 ) return 0; z = csv_skip_whitespace(z+nTag); if( z[0]!='=' ) return 0; return csv_skip_whitespace(z+1); } /* Return 0 if the argument is false and 1 if it is true. Return -1 if ** we cannot really tell. */ static int csv_boolean(const char *z){ if( sqlite3_stricmp("yes",z)==0 || sqlite3_stricmp("on",z)==0 || sqlite3_stricmp("true",z)==0 || (z[0]=='1' && z[0]==0) ){ return 1; } if( sqlite3_stricmp("no",z)==0 || sqlite3_stricmp("off",z)==0 || sqlite3_stricmp("false",z)==0 || (z[0]=='0' && z[1]==0) ){ return 0; } return -1; } /* ** Parameters: ** filename=FILENAME Required ** schema=SCHEMA Optional ** header=YES|NO First row of CSV defines the names of ** columns if "yes". Default "no". ** ** If header=no and not columns are listed, then the columns are named ** "c0", "c1", "c2", and so forth. */ static int csvtabConnect( sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVtab, char **pzErr ){ CsvTable *pNew = 0; int bHeader = -1; int rc = SQLITE_OK; int i; char *zFilename = 0; char *zSchema = 0; CsvReader sRdr; memset(&sRdr, 0, sizeof(sRdr)); for(i=3; i<argc; i++){ const char *z = argv[i]; const char *zValue; if( (zValue = csv_parameter("filename",8,z))!=0 ){ if( zFilename ){ csv_errmsg(&sRdr, "more than one 'filename' parameter"); goto csvtab_connect_error; } zFilename = sqlite3_mprintf("%s", zValue); if( zFilename==0 ) goto csvtab_connect_oom; csv_trim_whitespace(zFilename); csv_dequote(zFilename); }else if( (zValue = csv_parameter("schema",6,z))!=0 ){ if( zSchema ){ csv_errmsg(&sRdr, "more than one 'schema' parameter"); goto csvtab_connect_error; } zSchema = sqlite3_mprintf("%s", zValue); if( zSchema==0 ) goto csvtab_connect_oom; csv_trim_whitespace(zSchema); csv_dequote(zSchema); }else if( (zValue = csv_parameter("header",6,z))!=0 ){ int x; if( bHeader>=0 ){ csv_errmsg(&sRdr, "more than one 'header' parameter"); goto csvtab_connect_error; } x = csv_boolean(zValue); if( x==1 ){ bHeader = 1; }else if( x==0 ){ bHeader = 0; }else{ csv_errmsg(&sRdr, "unrecognized argument to 'header': %s", zValue); goto csvtab_connect_error; } }else { csv_errmsg(&sRdr, "unrecognized parameter '%s'", z); goto csvtab_connect_error; } } if( zFilename==0 ){ csv_errmsg(&sRdr, "missing 'filename' parameter"); goto csvtab_connect_error; } if( csv_reader_open(&sRdr, zFilename) ){ goto csvtab_connect_error; } pNew = sqlite3_malloc( sizeof(*pNew) ); *ppVtab = (sqlite3_vtab*)pNew; if( pNew==0 ) goto csvtab_connect_oom; memset(pNew, 0, sizeof(*pNew)); do{ const char *z = csv_read_one_field(&sRdr); if( z==0 ) goto csvtab_connect_oom; pNew->nCol++; }while( sRdr.cTerm==',' ); pNew->zFilename = zFilename; zFilename = 0; pNew->iStart = bHeader==1 ? ftell(sRdr.in) : 0; csv_reader_reset(&sRdr); if( zSchema==0 ){ char *zSep = ""; zSchema = sqlite3_mprintf("CREATE TABLE x("); if( zSchema==0 ) goto csvtab_connect_oom; for(i=0; i<pNew->nCol; i++){ zSchema = sqlite3_mprintf("%z%sc%d TEXT",zSchema, zSep, i); zSep = ","; } zSchema = sqlite3_mprintf("%z);", zSchema); } rc = sqlite3_declare_vtab(db, zSchema); if( rc ) goto csvtab_connect_error; sqlite3_free(zSchema); return SQLITE_OK; csvtab_connect_oom: rc = SQLITE_NOMEM; csv_errmsg(&sRdr, "out of memory"); csvtab_connect_error: if( pNew ) csvtabDisconnect(&pNew->base); sqlite3_free(zFilename); sqlite3_free(zSchema); if( sRdr.zErr[0] ){ sqlite3_free(*pzErr); *pzErr = sqlite3_mprintf("%s", sRdr.zErr); } csv_reader_reset(&sRdr); return rc; } /* ** Reset the current row content held by a CsvCursor. */ static void csvtabCursorRowReset(CsvCursor *pCur){ CsvTable *pTab = (CsvTable*)pCur->base.pVtab; int i; for(i=0; i<pTab->nCol; i++){ sqlite3_free(pCur->azVal[i]); pCur->azVal[i] = 0; } } /* ** The xConnect and xCreate methods do the same thing, but they must be ** different so that the virtual table is not an eponymous virtual table. */ static int csvtabCreate( sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVtab, char **pzErr ){ return csvtabConnect(db, pAux, argc, argv, ppVtab, pzErr); } /* ** Destructor for a CsvCursor. */ static int csvtabClose(sqlite3_vtab_cursor *cur){ CsvCursor *pCur = (CsvCursor*)cur; csvtabCursorRowReset(pCur); csv_reader_reset(&pCur->rdr); sqlite3_free(cur); return SQLITE_OK; } /* ** Constructor for a new CsvTable cursor object. */ static int csvtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){ CsvTable *pTab = (CsvTable*)p; CsvCursor *pCur; pCur = sqlite3_malloc( sizeof(*pCur) * sizeof(char*)*pTab->nCol ); if( pCur==0 ) return SQLITE_NOMEM; memset(pCur, 0, sizeof(*pCur) + sizeof(char*)*pTab->nCol ); pCur->azVal = (char**)&pCur[1]; *ppCursor = &pCur->base; if( csv_reader_open(&pCur->rdr, pTab->zFilename) ){ csv_xfer_error(pTab, &pCur->rdr); return SQLITE_ERROR; } return SQLITE_OK; } /* ** Advance a CsvCursor to its next row of input. ** Set the EOF marker if we reach the end of input. */ static int csvtabNext(sqlite3_vtab_cursor *cur){ CsvCursor *pCur = (CsvCursor*)cur; CsvTable *pTab = (CsvTable*)cur->pVtab; int i = 0; char *z; csvtabCursorRowReset(pCur); do{ z = csv_read_one_field(&pCur->rdr); if( z==0 ){ csv_xfer_error(pTab, &pCur->rdr); break; } z = sqlite3_mprintf("%s", z); if( z==0 ){ csv_errmsg(&pCur->rdr, "out of memory"); csv_xfer_error(pTab, &pCur->rdr); break; } if( i<pTab->nCol ){ pCur->azVal[i++] = z; } }while( z!=0 && pCur->rdr.cTerm==',' ); if( z==0 || pCur->rdr.cTerm==EOF ){ pCur->iRowid = -1; }else{ pCur->iRowid++; } return SQLITE_OK; } /* ** Return values of columns for the row at which the CsvCursor ** is currently pointing. */ static int csvtabColumn( sqlite3_vtab_cursor *cur, /* The cursor */ sqlite3_context *ctx, /* First argument to sqlite3_result_...() */ int i /* Which column to return */ ){ CsvCursor *pCur = (CsvCursor*)cur; CsvTable *pTab = (CsvTable*)cur->pVtab; if( i>=0 && i<pTab->nCol && pCur->azVal[i]!=0 ){ sqlite3_result_text(ctx, pCur->azVal[i], -1, SQLITE_STATIC); } return SQLITE_OK; } /* ** Return the rowid for the current row. */ static int csvtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ CsvCursor *pCur = (CsvCursor*)cur; *pRowid = pCur->iRowid; return SQLITE_OK; } /* ** Return TRUE if the cursor has been moved off of the last ** row of output. */ static int csvtabEof(sqlite3_vtab_cursor *cur){ CsvCursor *pCur = (CsvCursor*)cur; return pCur->iRowid<0; } /* ** Only a full table scan is supported. So xFilter simply rewinds to ** the beginning. */ static int csvtabFilter( sqlite3_vtab_cursor *pVtabCursor, int idxNum, const char *idxStr, int argc, sqlite3_value **argv ){ CsvCursor *pCur = (CsvCursor*)pVtabCursor; CsvTable *pTab = (CsvTable*)pVtabCursor->pVtab; pCur->iRowid = 0; fseek(pCur->rdr.in, pTab->iStart, SEEK_SET); return csvtabNext(pVtabCursor); } /* ** Only a forwards full table scan is supported. xBestIndex is a no-op. */ static int csvtabBestIndex( sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo ){ return SQLITE_OK; } static sqlite3_module CsvModule = { 0, /* iVersion */ csvtabCreate, /* xCreate */ csvtabConnect, /* xConnect */ csvtabBestIndex, /* xBestIndex */ csvtabDisconnect, /* xDisconnect */ csvtabDisconnect, /* xDestroy */ csvtabOpen, /* xOpen - open a cursor */ csvtabClose, /* xClose - close a cursor */ csvtabFilter, /* xFilter - configure scan constraints */ csvtabNext, /* xNext - advance a cursor */ csvtabEof, /* xEof - check for end of scan */ csvtabColumn, /* xColumn - read data */ csvtabRowid, /* xRowid - read data */ 0, /* xUpdate */ 0, /* xBegin */ 0, /* xSync */ 0, /* xCommit */ 0, /* xRollback */ 0, /* xFindMethod */ 0, /* xRename */ }; #ifdef _WIN32 __declspec(dllexport) #endif /* ** This routine is called when the extension is loaded. The new ** CSV virtual table module is registered with the calling database ** connection. */ int sqlite3_csv_init( sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi ){ SQLITE_EXTENSION_INIT2(pApi); return sqlite3_create_module(db, "csv", &CsvModule, 0); } |