From 08119c361d1181b3e8f1abb429236e488a664753 Mon Sep 17 00:00:00 2001 From: Hans-Christoph Steiner Date: Tue, 13 Aug 2013 15:42:54 -0400 Subject: Imported Upstream version 2.2.1 --- ext/misc/wholenumber.c | 274 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 274 insertions(+) create mode 100644 ext/misc/wholenumber.c (limited to 'ext/misc/wholenumber.c') diff --git a/ext/misc/wholenumber.c b/ext/misc/wholenumber.c new file mode 100644 index 0000000..63369c6 --- /dev/null +++ b/ext/misc/wholenumber.c @@ -0,0 +1,274 @@ +/* +** 2011 April 02 +** +** 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 implements a virtual table that returns the whole numbers +** between 1 and 4294967295, inclusive. +** +** Example: +** +** CREATE VIRTUAL TABLE nums USING wholenumber; +** SELECT value FROM nums WHERE value<10; +** +** Results in: +** +** 1 2 3 4 5 6 7 8 9 +*/ +#include "sqlite3ext.h" +SQLITE_EXTENSION_INIT1 +#include +#include + +#ifndef SQLITE_OMIT_VIRTUALTABLE + + +/* A wholenumber cursor object */ +typedef struct wholenumber_cursor wholenumber_cursor; +struct wholenumber_cursor { + sqlite3_vtab_cursor base; /* Base class - must be first */ + sqlite3_int64 iValue; /* Current value */ + sqlite3_int64 mxValue; /* Maximum value */ +}; + +/* Methods for the wholenumber module */ +static int wholenumberConnect( + sqlite3 *db, + void *pAux, + int argc, const char *const*argv, + sqlite3_vtab **ppVtab, + char **pzErr +){ + sqlite3_vtab *pNew; + pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) ); + if( pNew==0 ) return SQLITE_NOMEM; + sqlite3_declare_vtab(db, "CREATE TABLE x(value)"); + memset(pNew, 0, sizeof(*pNew)); + return SQLITE_OK; +} +/* Note that for this virtual table, the xCreate and xConnect +** methods are identical. */ + +static int wholenumberDisconnect(sqlite3_vtab *pVtab){ + sqlite3_free(pVtab); + return SQLITE_OK; +} +/* The xDisconnect and xDestroy methods are also the same */ + + +/* +** Open a new wholenumber cursor. +*/ +static int wholenumberOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){ + wholenumber_cursor *pCur; + pCur = sqlite3_malloc( sizeof(*pCur) ); + if( pCur==0 ) return SQLITE_NOMEM; + memset(pCur, 0, sizeof(*pCur)); + *ppCursor = &pCur->base; + return SQLITE_OK; +} + +/* +** Close a wholenumber cursor. +*/ +static int wholenumberClose(sqlite3_vtab_cursor *cur){ + sqlite3_free(cur); + return SQLITE_OK; +} + + +/* +** Advance a cursor to its next row of output +*/ +static int wholenumberNext(sqlite3_vtab_cursor *cur){ + wholenumber_cursor *pCur = (wholenumber_cursor*)cur; + pCur->iValue++; + return SQLITE_OK; +} + +/* +** Return the value associated with a wholenumber. +*/ +static int wholenumberColumn( + sqlite3_vtab_cursor *cur, + sqlite3_context *ctx, + int i +){ + wholenumber_cursor *pCur = (wholenumber_cursor*)cur; + sqlite3_result_int64(ctx, pCur->iValue); + return SQLITE_OK; +} + +/* +** The rowid. +*/ +static int wholenumberRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ + wholenumber_cursor *pCur = (wholenumber_cursor*)cur; + *pRowid = pCur->iValue; + return SQLITE_OK; +} + +/* +** When the wholenumber_cursor.rLimit value is 0 or less, that is a signal +** that the cursor has nothing more to output. +*/ +static int wholenumberEof(sqlite3_vtab_cursor *cur){ + wholenumber_cursor *pCur = (wholenumber_cursor*)cur; + return pCur->iValue>pCur->mxValue || pCur->iValue==0; +} + +/* +** Called to "rewind" a cursor back to the beginning so that +** it starts its output over again. Always called at least once +** prior to any wholenumberColumn, wholenumberRowid, or wholenumberEof call. +** +** idxNum Constraints +** ------ --------------------- +** 0 (none) +** 1 value > $argv0 +** 2 value >= $argv0 +** 4 value < $argv0 +** 8 value <= $argv0 +** +** 5 value > $argv0 AND value < $argv1 +** 6 value >= $argv0 AND value < $argv1 +** 9 value > $argv0 AND value <= $argv1 +** 10 value >= $argv0 AND value <= $argv1 +*/ +static int wholenumberFilter( + sqlite3_vtab_cursor *pVtabCursor, + int idxNum, const char *idxStr, + int argc, sqlite3_value **argv +){ + wholenumber_cursor *pCur = (wholenumber_cursor *)pVtabCursor; + sqlite3_int64 v; + int i = 0; + pCur->iValue = 1; + pCur->mxValue = 0xffffffff; /* 4294967295 */ + if( idxNum & 3 ){ + v = sqlite3_value_int64(argv[0]) + (idxNum&1); + if( v>pCur->iValue && v<=pCur->mxValue ) pCur->iValue = v; + i++; + } + if( idxNum & 12 ){ + v = sqlite3_value_int64(argv[i]) - ((idxNum>>2)&1); + if( v>=pCur->iValue && vmxValue ) pCur->mxValue = v; + } + return SQLITE_OK; +} + +/* +** Search for terms of these forms: +** +** (1) value > $value +** (2) value >= $value +** (4) value < $value +** (8) value <= $value +** +** idxNum is an ORed combination of 1 or 2 with 4 or 8. +*/ +static int wholenumberBestIndex( + sqlite3_vtab *tab, + sqlite3_index_info *pIdxInfo +){ + int i; + int idxNum = 0; + int argvIdx = 1; + int ltIdx = -1; + int gtIdx = -1; + const struct sqlite3_index_constraint *pConstraint; + pConstraint = pIdxInfo->aConstraint; + for(i=0; inConstraint; i++, pConstraint++){ + if( pConstraint->usable==0 ) continue; + if( (idxNum & 3)==0 && pConstraint->op==SQLITE_INDEX_CONSTRAINT_GT ){ + idxNum |= 1; + ltIdx = i; + } + if( (idxNum & 3)==0 && pConstraint->op==SQLITE_INDEX_CONSTRAINT_GE ){ + idxNum |= 2; + ltIdx = i; + } + if( (idxNum & 12)==0 && pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT ){ + idxNum |= 4; + gtIdx = i; + } + if( (idxNum & 12)==0 && pConstraint->op==SQLITE_INDEX_CONSTRAINT_LE ){ + idxNum |= 8; + gtIdx = i; + } + } + pIdxInfo->idxNum = idxNum; + if( ltIdx>=0 ){ + pIdxInfo->aConstraintUsage[ltIdx].argvIndex = argvIdx++; + pIdxInfo->aConstraintUsage[ltIdx].omit = 1; + } + if( gtIdx>=0 ){ + pIdxInfo->aConstraintUsage[gtIdx].argvIndex = argvIdx; + pIdxInfo->aConstraintUsage[gtIdx].omit = 1; + } + if( pIdxInfo->nOrderBy==1 + && pIdxInfo->aOrderBy[0].desc==0 + ){ + pIdxInfo->orderByConsumed = 1; + } + if( (idxNum & 12)==0 ){ + pIdxInfo->estimatedCost = (double)100000000; + }else if( (idxNum & 3)==0 ){ + pIdxInfo->estimatedCost = (double)5; + }else{ + pIdxInfo->estimatedCost = (double)1; + } + return SQLITE_OK; +} + +/* +** A virtual table module that provides read-only access to a +** Tcl global variable namespace. +*/ +static sqlite3_module wholenumberModule = { + 0, /* iVersion */ + wholenumberConnect, + wholenumberConnect, + wholenumberBestIndex, + wholenumberDisconnect, + wholenumberDisconnect, + wholenumberOpen, /* xOpen - open a cursor */ + wholenumberClose, /* xClose - close a cursor */ + wholenumberFilter, /* xFilter - configure scan constraints */ + wholenumberNext, /* xNext - advance a cursor */ + wholenumberEof, /* xEof - check for end of scan */ + wholenumberColumn, /* xColumn - read data */ + wholenumberRowid, /* xRowid - read data */ + 0, /* xUpdate */ + 0, /* xBegin */ + 0, /* xSync */ + 0, /* xCommit */ + 0, /* xRollback */ + 0, /* xFindMethod */ + 0, /* xRename */ +}; + +#endif /* SQLITE_OMIT_VIRTUALTABLE */ + +#ifdef _WIN32 +__declspec(dllexport) +#endif +int sqlite3_wholenumber_init( + sqlite3 *db, + char **pzErrMsg, + const sqlite3_api_routines *pApi +){ + int rc = SQLITE_OK; + SQLITE_EXTENSION_INIT2(pApi); +#ifndef SQLITE_OMIT_VIRTUALTABLE + rc = sqlite3_create_module(db, "wholenumber", &wholenumberModule, 0); +#endif + return rc; +} -- cgit v1.2.3