SQLite

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.131 2006/06/17 14:12:48 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
/* #include <math.h> */
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"

    zResult[j] = 0;
    sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
  }else{
    sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
  }
}
#endif

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** A function that loads a shared-library extension then returns NULL.
*/
static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
  const char *zFile = sqlite3_value_text(argv[0]);
  const char *zProc = 0;
  sqlite3 *db = sqlite3_user_data(context);
  char *zErrMsg = 0;

  if( argc==2 ){
    zProc = sqlite3_value_text(argv[1]);
  }
  if( sqlite3_load_extension(db, zFile, zProc, &zErrMsg) ){
    sqlite3_result_error(context, zErrMsg, -1);
    sqlite3_free(zErrMsg);
  }
}
#endif

#ifdef SQLITE_TEST
/*
** This function generates a string of random characters.  Used for
** generating test data.
*/
static void randStr(sqlite3_context *context, int argc, sqlite3_value **argv){

    { "last_insert_rowid",  0, 1, SQLITE_UTF8,    0, last_insert_rowid },
    { "changes",            0, 1, SQLITE_UTF8,    0, changes    },
    { "total_changes",      0, 1, SQLITE_UTF8,    0, total_changes },
    { "match",              2, 0, SQLITE_UTF8,    0, matchStub },
#ifdef SQLITE_SOUNDEX
    { "soundex",            1, 0, SQLITE_UTF8, 0, soundexFunc},
#endif
#ifndef SQLITE_OMIT_LOAD_EXTENSION
    { "load_extension",     1, 1, SQLITE_UTF8,    0, loadExt },
    { "load_extension",     2, 1, SQLITE_UTF8,    0, loadExt },
#endif
#ifdef SQLITE_TEST
    { "randstr",               2, 0, SQLITE_UTF8, 0, randStr    },
    { "test_destructor",       1, 1, SQLITE_UTF8, 0, test_destructor},
    { "test_destructor_count", 0, 0, SQLITE_UTF8, 0, test_destructor_count},
    { "test_auxdata",         -1, 0, SQLITE_UTF8, 0, test_auxdata},
    { "test_error",            1, 0, SQLITE_UTF8, 0, test_error},
#endif

# 2006 July 14
#
# 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 regression tests for SQLite library.  The
# focus of this script is in-memory database backend.
#
# $Id: loadext.test,v 1.3 2006/06/17 14:12:48 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# The name of the test extension varies by operating system.
#
if {$::tcl_platform(platform) eq "windows"} {

#
do_test loadext-2.4 {
  set rc [catch {
    sqlite3_load_extension db $testextension testbrokenext_init
  } msg]
  list $rc $msg
} {1 {error during initialization: broken!}}

############################################################################
# Tests for the load_extension() SQL function
#

db close
sqlite3 db test.db
do_test loadext-3.1 {
  catchsql {
    SELECT half(5);
  }
} {1 {no such function: half}}
do_test loadext-3.2 {
  catchsql {
    SELECT load_extension($::testextension)
  }
} [list 1 "no entry point \[sqlite3_extension_init\]\
           in shared library \[$testextension\]"]
do_test loadext-3.3 {
  catchsql {
    SELECT load_extension($::testextension,'testloadext_init')
  }
} {0 {{}}}
do_test loadext-3.4 {
  catchsql {
    SELECT half(5);
  }
} {0 2.5}

finish_test

#
# Run this Tcl script to generate the lang-*.html files.
#
set rcsid {$Id: lang.tcl,v 1.113 2006/06/17 14:12:48 drh Exp $}
source common.tcl

if {[llength $argv]>0} {
  set outputdir [lindex $argv 0]
} else {
  set outputdir ""
}

<expr> [NOT] IN ( <value-list> ) |
<expr> [NOT] IN ( <select-statement> ) |
<expr> [NOT] IN [<database-name> .] <table-name> |
[EXISTS] ( <select-statement> ) |
CASE [<expr>] LP WHEN <expr> THEN <expr> RPPLUS [ELSE <expr>] END |
CAST ( <expr> AS <type> )
} {like-op} {
LIKE | GLOB | REGEXP | MATCH
}

puts {
<p>This section is different from the others.  Most other sections of
this document talks about a particular SQL command.  This section does
not talk about a standalone command but about "expressions" which are 
subcomponents of most other commands.</p>

</pre></blockquote>

<p>Supported unary operators are these:</p>

<blockquote><pre>
<font color="#2c2cf0"><big>-    +    !    ~    NOT</big></font>
</pre></blockquote>

<p>The unary operator [Operator +] is a no-op.  It can be applied
to strings, numbers, or blobs and it always gives as its result the
value of the operand.</p>

<p>Note that there are two variations of the equals and not equals
operators.  Equals can be either}
puts "[Operator =] or [Operator ==].
The non-equals operator can be either
[Operator !=] or [Operator {&lt;&gt;}].
The [Operator ||] operator is \"concatenate\" - it joins together

<tr>
<td align="right" valign="top"><b>:</b><i>AAAA</i></td><td width="20"></td>
<td>A colon followed by an identifier name holds a spot for a named
parameter with the name AAAA.  Named parameters are also numbered.
The number assigned is the next unused number.  To avoid confusion,
it is best to avoid mixing named and numbered parameters.</td>
</tr>
<tr>
<td align="right" valign="top"><b>@</b><i>AAAA</i></td><td width="20"></td>
<td>An "at" sign works exactly like a colon.</td>
</tr>
<tr>
<td align="right" valign="top"><b>$</b><i>AAAA</i></td><td width="20"></td>
<td>A dollar-sign followed by an identifier name also holds a spot for a named
parameter with the name AAAA.  The identifier name in this case can include
one or more occurances of "::" and a suffix enclosed in "(...)" containing
any text at all.  This syntax is the form of a variable name in the Tcl
programming language.</td>

that function.</p>

<a name="regexp"></a>
<p>The REGEXP operator is a special syntax for the regexp()
user function.  No regexp() user function is defined by default
and so use of the REGEXP operator will normally result in an
error message.  If a user-defined function named "regexp"
is added at run-time, that function will be called in order
to implement the REGEXP operator.</p>

<a name="match"></a>
<p>The MATCH operator is a special syntax for the match()
user function.  The default match() function implementation
raises and exception and is not really useful for anything.
But extensions can override the match() function with more
helpful logic.</p>

<p>A column name can be any of the names defined in the CREATE TABLE
statement or one of the following special identifiers: "<b>ROWID</b>",
"<b>OID</b>", or "<b>_ROWID_</b>".
These special identifiers all describe the
unique random integer key (the "row key") associated with every 
row of every table.

href= "#like">LIKE</a> operator. When doing this, it may be important
to override both the two and three argument versions of the like() 
function. Otherwise, different code may be called to implement the
LIKE operator depending on whether or not an ESCAPE clause was 
specified.</td>
</tr>

<tr>
<td valign="top" align="right">load_extension(<i>X</i>)<br>
load_extension(<i>X</i>,<i>Y</i>)</td>
<td valign="top">Load SQLite extensions out of the shared library
file named <i>X</i> using the entry point <i>Y</i>.  The result
is a NULL.  If <i>Y</i> is omitted then the default entry point
of <b>sqlite3_extension_init</b> is used.  This function raises
an exception if the extension fails to load or initialize correctly.
</tr>

<tr>
<td valign="top" align="right">lower(<i>X</i>)</td>
<td valign="top">Return a copy of string <i>X</i> will all characters
converted to lower case.  The C library <b>tolower()</b> routine is used
for the conversion, which means that this function might not
work correctly on UTF-8 characters.</td>
</tr>

The current implementation of VACUUM uses this function.  The function
is also useful when writing triggers to implement undo/redo functionality.
</td>
</tr>

<tr>
<td valign="top" align="right">random(*)</td>
<td valign="top">Return a pseudo-random integer
between -9223372036854775808 and +9223372036854775807.</td>
</tr>

<tr>
<td valign="top" align="right">round(<i>X</i>)<br>round(<i>X</i>,<i>Y</i>)</td>
<td valign="top">Round off the number <i>X</i> to <i>Y</i> digits to the
right of the decimal point.  If the <i>Y</i> argument is omitted, 0 is 
assumed.</td>