mirror of
https://github.com/sqlite/sqlite.git
synced 2025-11-03 16:53:36 +03:00
115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
/*
|
|
** 2013-05-15
|
|
**
|
|
** 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 SQLite extension implements a rot13() function and a rot13
|
|
** collating sequence.
|
|
*/
|
|
#include "sqlite3ext.h"
|
|
SQLITE_EXTENSION_INIT1
|
|
#include <assert.h>
|
|
#include <string.h>
|
|
|
|
/*
|
|
** Perform rot13 encoding on a single ASCII character.
|
|
*/
|
|
static unsigned char rot13(unsigned char c){
|
|
if( c>='a' && c<='z' ){
|
|
c += 13;
|
|
if( c>'z' ) c -= 26;
|
|
}else if( c>='A' && c<='Z' ){
|
|
c += 13;
|
|
if( c>'Z' ) c -= 26;
|
|
}
|
|
return c;
|
|
}
|
|
|
|
/*
|
|
** Implementation of the rot13() function.
|
|
**
|
|
** Rotate ASCII alphabetic characters by 13 character positions.
|
|
** Non-ASCII characters are unchanged. rot13(rot13(X)) should always
|
|
** equal X.
|
|
*/
|
|
static void rot13func(
|
|
sqlite3_context *context,
|
|
int argc,
|
|
sqlite3_value **argv
|
|
){
|
|
const unsigned char *zIn;
|
|
int nIn;
|
|
unsigned char *zOut;
|
|
unsigned char *zToFree = 0;
|
|
int i;
|
|
unsigned char zTemp[100];
|
|
assert( argc==1 );
|
|
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
|
|
zIn = (const unsigned char*)sqlite3_value_text(argv[0]);
|
|
nIn = sqlite3_value_bytes(argv[0]);
|
|
if( nIn<sizeof(zTemp)-1 ){
|
|
zOut = zTemp;
|
|
}else{
|
|
zOut = zToFree = (unsigned char*)sqlite3_malloc64( nIn+1 );
|
|
if( zOut==0 ){
|
|
sqlite3_result_error_nomem(context);
|
|
return;
|
|
}
|
|
}
|
|
for(i=0; i<nIn; i++) zOut[i] = rot13(zIn[i]);
|
|
zOut[i] = 0;
|
|
sqlite3_result_text(context, (char*)zOut, i, SQLITE_TRANSIENT);
|
|
sqlite3_free(zToFree);
|
|
}
|
|
|
|
/*
|
|
** Implement the rot13 collating sequence so that if
|
|
**
|
|
** x=y COLLATE rot13
|
|
**
|
|
** Then
|
|
**
|
|
** rot13(x)=rot13(y) COLLATE binary
|
|
*/
|
|
static int rot13CollFunc(
|
|
void *notUsed,
|
|
int nKey1, const void *pKey1,
|
|
int nKey2, const void *pKey2
|
|
){
|
|
const char *zA = (const char*)pKey1;
|
|
const char *zB = (const char*)pKey2;
|
|
int i, x;
|
|
for(i=0; i<nKey1 && i<nKey2; i++){
|
|
x = (int)rot13(zA[i]) - (int)rot13(zB[i]);
|
|
if( x!=0 ) return x;
|
|
}
|
|
return nKey1 - nKey2;
|
|
}
|
|
|
|
|
|
#ifdef _WIN32
|
|
__declspec(dllexport)
|
|
#endif
|
|
int sqlite3_rot_init(
|
|
sqlite3 *db,
|
|
char **pzErrMsg,
|
|
const sqlite3_api_routines *pApi
|
|
){
|
|
int rc = SQLITE_OK;
|
|
SQLITE_EXTENSION_INIT2(pApi);
|
|
(void)pzErrMsg; /* Unused parameter */
|
|
rc = sqlite3_create_function(db, "rot13", 1, SQLITE_UTF8, 0,
|
|
rot13func, 0, 0);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3_create_collation(db, "rot13", SQLITE_UTF8, 0, rot13CollFunc);
|
|
}
|
|
return rc;
|
|
}
|