[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/ext/misc/wholenumber.c

+/*
+** 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 <assert.h>
+#include <string.h>
+
+#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 && v<pCur->mxValue ) 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; i<pIdxInfo->nConstraint; 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;
+}