--- sql/oracle/parser3oracle.C	2004/10/07 09:27:02	1.65
+++ sql/oracle/parser3oracle.C	2013/05/27 20:10:14	1.78
@@ -1,21 +1,21 @@
 /** @file
 	Parser Oracle driver.
 
-	Copyright(c) 2001, 2003 ArtLebedev Group (http://www.artlebedev.com)
+	Copyright (c) 2001-2012 Art. Lebedev Studio (http://www.artlebedev.com)
 
 	Author: Alexandr Petrosian <paf@design.ru> (http://paf.design.ru)
 
 	2001.07.30 using Oracle 8.1.6 [@test tested with Oracle 7.x.x]
 */
 
-static const char *RCSId="$Id: parser3oracle.C,v 1.65 2004/10/07 09:27:02 paf Exp $"; 
-
 #include "config_includes.h"
 
 #include "pa_sql_driver.h"
 
 #include <oci.h>
 
+volatile const char * IDENT_PARSER3ORACLE_C="$Id: parser3oracle.C,v 1.78 2013/05/27 20:10:14 moko Exp $" IDENT_PA_SQL_DRIVER_H;
+
 #define MAX_COLS 500
 #define MAX_IN_LOBS 5
 #define MAX_LOB_NAME_LENGTH 100
@@ -95,24 +95,49 @@ static int pa_setenv(const char *name, c
 #endif
 }
 
-static char *lsplit(char *string, char delim) {
-    if(string) {
-		char *v=strchr(string, delim);
-		if(v) {
+static char *lsplit(char *string, char delim){
+	if(string){
+		if(char* v=strchr(string, delim)){
 			*v=0;
 			return v+1;
 		}
-    }
-    return 0;
+	}
+	return 0;
 }
 
-static char *lsplit(char **string_ref, char delim) {
-    char *result=*string_ref;
+static char *lsplit(char **string_ref, char delim){
+	char *result=*string_ref;
 	char *next=lsplit(*string_ref, delim);
-    *string_ref=next;
-    return result;
+	*string_ref=next;
+	return result;
+}
+
+static char* rsplit(char* string, char delim){
+	if(string){
+		if(char* v=strrchr(string, delim)){
+			*v=0;
+			return v+1;
+		}
+	}
+	return NULL;	
+}
+
+static void tolower_str(char *out, const char *in, size_t size) {
+	while(size--)
+		*out++=(char)tolower(*in++);
+}
+static void toupper_str(char *out, const char *in, size_t size) {
+	while(size--)
+		*out++=(char)toupper(*in++);
 }
 
+struct modified_statement {
+	const char* statement;
+	bool limit;
+	bool offset;
+	bool skip_rownum_column;
+};
+
 #ifndef DOXYGEN
 struct Connection {
 	SQL_Driver_services *services;
@@ -130,7 +155,8 @@ struct Connection {
 
 	struct Options {
 		bool bLowerCaseColumnNames;
-		const char* cstrClientCharset;
+		bool bDisableQueryModification;
+		const char* client_charset;
 	} options;
 };
 
@@ -157,7 +183,7 @@ struct Query_lobs {
 #endif
 
 // forwards
-static void faile(Connection& connection, const char *msg);
+static void fail(Connection& connection, const char *msg);
 static void check(Connection& connection, const char *step, sword status);
 static void check(Connection& connection, bool error);
 static sb4 cbf_no_data(
@@ -176,25 +202,31 @@ static sb4 cbf_get_data(dvoid *ctxp,
 						ub1 *piecep, 
 						dvoid **indpp, 
 						ub2 **rcodepp);
-static void tolower_str(char *out, const char *in, size_t size);
-static void toupper_str(char *out, const char *in, size_t size);
+
+static	bool transcode_required(Connection& connection);
 
 static const char *options2env(char *s, Connection::Options* options) {
-	while(s) {
-		if(char *key=lsplit(&s, '&')) {
-			if(*key) {
-				if(char *value=lsplit(key, '=')) {
-					if( strcmp( key, "ClientCharset" ) == 0 ) {
-						if(options) {
+	while(s){
+		if(char *key=lsplit(&s, '&')){
+			if(*key){
+				if(char *value=lsplit(key, '=')){
+					if(strcmp(key, "ClientCharset")== 0){
+						if(options){
 							toupper_str(value, value, strlen(value));
-							options->cstrClientCharset = value;
+							options->client_charset=value;
 						}
 						continue;
 					}
 
-					if( strcmp( key, "LowerCaseColumnNames" ) == 0 ) {
+					if(strcmp(key, "LowerCaseColumnNames")==0){
+						if(options)
+							options->bLowerCaseColumnNames=atoi(value)!=0;
+						continue;
+					}
+
+					if(strcmp(key, "DisableQueryModification")==0){
 						if(options)
-							options->bLowerCaseColumnNames = atoi(value)!=0;
+							options->bDisableQueryModification=atoi(value)!=0;
 						continue;
 					}
 
@@ -229,21 +261,22 @@ public:
 
 	/// get api version
 	int api_version() { return SQL_DRIVER_API_VERSION; }
+
 	/** initialize driver by loading sql dynamic link library
 		@todo ?objects=1 which would turn on OCI_OBJECT init flag
 	*/
 	const char *initialize(char *dlopen_file_spec) {
 		char *options=lsplit(dlopen_file_spec, '?');
 
-		const char *error=dlopen_file_spec?
-			dlink(dlopen_file_spec):"client library column is empty";
+		const char *error=options2env(options, 0);
+	    
 		if(!error) {
-			error=options2env(options, 0);
+			error=dlopen_file_spec ? dlink(dlopen_file_spec) : "client library column is empty";
 
 			if(!error)
 				OCIInitialize((ub4)OCI_THREADED/*| OCI_OBJECT*/, (dvoid *)0, 
-					(dvoid * (*)(void *, unsigned int))0, 
-					(dvoid * (*)(void*, void*, unsigned int))0,  
+					(dvoid * (*)(void *, size_t))0, 
+					(dvoid * (*)(void*, void*, size_t))0,  
 					(void (*)(void*, void*))0 
 				);
 		}
@@ -254,28 +287,31 @@ public:
 	/**	connect
 		@param url
 			format: @b user:pass@service?
-			   ORACLE_HOME=/u01/app/oracle/product/8.1.5&
-			   ORA_NLS33=/u01/app/oracle/product/8.1.5/ocommon/nls/admin/data&
-			   NLS_LANG=RUSSIAN_AMERICA.CL8MSWIN1251&
-			   ORA_ENCRYPT_LOGIN=TRUE
+				ORACLE_HOME=/u01/app/oracle/product/8.1.5&
+				ORA_NLS33=/u01/app/oracle/product/8.1.5/ocommon/nls/admin/data&
+				NLS_LANG=RUSSIAN_AMERICA.CL8MSWIN1251&
+				ORA_ENCRYPT_LOGIN=TRUE&
+				ClientCharset=charset&
+				LowerCaseColumnNames=0
 
 		@todo environment manupulation doesnt look thread safe
 		@todo allocate 'aused_only_in_connect_url' on gc heap, so it can be manipulated directly
 	*/
 	void connect(
-		char *url, 
-		SQL_Driver_services& services, 
-		void **connection_ref ///< output: Connection *
+			char *url, 
+			SQL_Driver_services& services, 
+			void **connection_ref ///< output: Connection *
 		) 
 	{
 		// connections are cross-request, do not use services._alloc [linked with request]
-		Connection& connection=*(Connection  *)services.malloc(sizeof(Connection));
+		Connection& connection=*(Connection *)services.malloc(sizeof(Connection));
 		connection.services=&services;
-		connection.options.bLowerCaseColumnNames = true;
+		connection.options.bLowerCaseColumnNames=true;
+		connection.options.bDisableQueryModification=false;
 		*connection_ref=&connection;
 
 		char *user=url;
-		char *service=lsplit(user, '@');
+		char *service=rsplit(user, '@');
 		char *pwd=lsplit(user, ':');
 		char *options=lsplit(service, '?');
 
@@ -348,6 +384,7 @@ public:
 			(dvoid *)connection.usrhp, (ub4)0, 
 			OCI_ATTR_SESSION, connection.errhp));
 	}
+
 	void disconnect(void *aconnection) {
 	    Connection& connection=*static_cast<Connection *>(aconnection);
 
@@ -383,6 +420,7 @@ public:
 		// free connection. leave that to GC [no such services func. yet?]
 		// connection.services->free(&connection);
 	}
+
 	void commit(void *aconnection) {
 	    Connection& connection=*static_cast<Connection *>(aconnection);
 		if(setjmp(connection.mark))
@@ -390,6 +428,7 @@ public:
 
 		check(connection, "commit", OCITransCommit(connection.svchp, connection.errhp, 0));
 	}
+
 	void rollback(void *aconnection) {
 	    Connection& connection=*static_cast<Connection *>(aconnection);
 		if(setjmp(connection.mark))
@@ -406,46 +445,50 @@ public:
 		return true;
 	}
 
-	const char* quote(void *aconnection,
-		const char *from, unsigned int length) 
+	// charset here is services.request_charset(), not connection.client_charset
+	// thus we can't use the sql server quoting support
+	const char* quote(void *aconnection, const char *str, unsigned int length) 
 	{
-		Connection& connection=*static_cast<Connection *>(aconnection);
-		char *result=(char*)connection.services->malloc_atomic(length*2+1);
-		char *to=result;
-		while(length--) {
-			switch(*from) {
-			case '\'': // "'" -> "''"
-				*to++='\'';
-				break;
-			}
-			*to++=*from++;
+		const char* from;
+		const char* from_end=str+length;
+
+		size_t quoted=0;
+
+		for(from=str; from<from_end; from++){
+			if(*from=='\'')
+				quoted++;
+		}
+
+		if(!quoted)
+			return str;
+
+		Connection& connection=*static_cast<Connection*>(aconnection);
+		char *result=(char*)connection.services->malloc_atomic(length + quoted + 1);
+		char *to = result;
+
+		for(from=str; from<from_end; from++){
+			if(*from=='\'')
+				*to++= '\''; // ' -> ''
+			*to++=*from;
 		}
+		
 		*to=0;
 		return result;
 	}
+
 	void query(void* aconnection, 
-		const char* astatement, 
-		size_t placeholders_count, Placeholder* placeholders, 
-		unsigned long offset, unsigned long limit,
-		SQL_Driver_query_event_handlers& handlers) 
-	{
+			const char* astatement, 
+			size_t placeholders_count, Placeholder* placeholders, 
+			unsigned long offset, unsigned long limit,
+			SQL_Driver_query_event_handlers& handlers
+	){
 
 		Connection& connection=*static_cast<Connection *>(aconnection);
-		const char* cstrClientCharset=connection.options.cstrClientCharset;
 		Query_lobs lobs={{0}, 0};
 		OCIStmt *stmthp=0;
 
 		SQL_Driver_services& services=*connection.services;
 
-		// transcode from $request:charset to connect-string?client_charset
-		if(cstrClientCharset) {
-			size_t transcoded_xxx_size;
-			services.transcode(astatement, strlen(astatement),
-				astatement, transcoded_xxx_size,
-				services.request_charset(),
-				cstrClientCharset);
-		}
-
 		bool failed=false;
 		if(setjmp(connection.mark)) {
 			failed=true;
@@ -453,8 +496,32 @@ public:
 		} else {
 			if(placeholders_count>MAX_BINDS)
 				fail(connection, "too many bind variables");
+			
+			while(isspace((unsigned char)*astatement)) 
+				astatement++;
 
-			const char *statement=preprocess_statement(connection, astatement, lobs);
+			const char* client_charset=connection.options.client_charset;
+			const char* request_charset=services.request_charset();
+			bool transcode_needed=transcode_required(connection);
+
+			if(transcode_needed){
+				// transcode query from $request:charset to ?ClientCharset
+				size_t transcoded_xxx_size;
+				services.transcode(astatement, strlen(astatement),
+					astatement, transcoded_xxx_size,
+					request_charset,
+					client_charset);
+			}
+
+			const char *statement=_preprocess_statement_lobs(connection, astatement, lobs);
+
+			modified_statement mstatement=_preprocess_statement_limit(connection, statement, offset, limit);
+			statement=mstatement.statement;
+
+			if(mstatement.limit) // limit was added in statement
+				limit=SQL_NO_LIMIT;
+			if(mstatement.offset) // limit was added in statement
+				offset=0;
 
 			check(connection, "HandleAlloc STMT", OCIHandleAlloc( 
 				(dvoid *)connection.envhp, (dvoid **) &stmthp, (ub4)OCI_HTYPE_STMT, 0, 0));
@@ -483,18 +550,19 @@ public:
 
 					size_t value_length;
 
-					if(cstrClientCharset) {
+					if(transcode_needed){
+						// transcode bind variables names and their values from $request:charset to ?ClientCharset
 						size_t name_length;
 						services.transcode(ph.name, strlen(ph.name),
 							ph.name, name_length,
-							services.request_charset(),
-							cstrClientCharset);
+							request_charset,
+							client_charset);
 
 						if(ph.value)
 							services.transcode(ph.value, strlen(ph.value),
 								ph.value, value_length,
-								services.request_charset(),
-								cstrClientCharset);
+								request_charset,
+								client_charset);
 					} else {
 						value_length=ph.value? strlen(ph.value): 0;
 					}
@@ -506,6 +574,8 @@ public:
 						value_buf=(char *)services.malloc_atomic(MAX_OUT_STRING_LENGTH+1/*terminator*/);
 					if(value_length)
 						memcpy(value_buf, ph.value, value_length+1);
+					else
+						value_buf[0]=0;
 
 					char name_buf[MAX_STRING];
 					sb4 placeh_len=snprintf(name_buf, sizeof(name_buf), ":%s", ph.name);
@@ -544,7 +614,7 @@ public:
 
 			execute_prepared(connection, 
 				statement, stmthp, lobs, 
-				offset, limit, handlers);
+				offset, limit, handlers, mstatement.skip_rownum_column);
 
 			{
 				for(size_t i=0; i<placeholders_count; i++) {
@@ -570,11 +640,12 @@ public:
 						memcpy(returned_value, bind_buffer, value_length+1 );
 						ph.value=returned_value;
 
-						if(cstrClientCharset) {
+						if(transcode_needed){
+							// transcode bind variable output from ?ClientCharset to $request:charset
 							services.transcode(ph.value, value_length,
 								ph.value, value_length/*<this new value is not used afterwards, actually*/,
-								cstrClientCharset,
-								services.request_charset());
+								client_charset,
+								request_charset);
 						}
 					} else {
 						ph.value=0;
@@ -607,16 +678,19 @@ cleanup: // no check call after this poi
 
 private: // private funcs
 
-	const char *preprocess_statement(Connection& connection, 
-		const char *astatement, Query_lobs &lobs) {
-		size_t statement_size=strlen(astatement);
+	const char* _preprocess_statement_lobs(
+			Connection& connection, 
+			const char* statement,
+			Query_lobs &lobs
+	){
+		size_t statement_size=strlen(statement);
 		SQL_Driver_services& services=*connection.services;
-
+		
 		char *result=(char *)services.malloc_atomic(statement_size
 			+MAX_STRING // in case of short 'strings'
 			+11/* returning */+6/* into */+(MAX_LOB_NAME_LENGTH+2/*:, */)*2/*ret into*/*MAX_IN_LOBS
 			+1);
-		const char *o=astatement;
+		const char *o=statement;
 
 		// /**xxx**/'literal' -> EMPTY_CLOB_FUNC_CALL
 		char *n=result;
@@ -644,7 +718,7 @@ private: // private funcs
 						const char *start=o;
 						bool escaped=false;
 						while(*o && !(o[0]=='\'' && o[1]!='\'' && !escaped)) {
-							escaped=o[0]=='\'' && o[1]=='\'';
+							escaped=!escaped && (o[0]=='\'' && o[1]=='\'');
 							if(escaped) {
 								// write pending, skip "\" or "'"
 								if(size_t size=o-start) {
@@ -696,9 +770,9 @@ private: // private funcs
 
 	void execute_prepared(
 		Connection& connection, 
-		const char *statement, OCIStmt *stmthp, Query_lobs &lobs, 
-		unsigned long offset, unsigned long limit, 
-		SQL_Driver_query_event_handlers& handlers) {
+		const char* astatement, OCIStmt *stmthp, Query_lobs &lobs, 
+		unsigned long offset, unsigned long limit,
+		SQL_Driver_query_event_handlers& handlers, bool skip_rownum_column) {
 
 		ub2 stmt_type=0; // UNKNOWN
 	/*
@@ -709,13 +783,11 @@ private: // private funcs
 			(ub4 *)0, OCI_ATTR_STMT_TYPE, connection.errhp));
 	*/
 
-		while(isspace((unsigned char)*statement)) 
-			statement++;
-		if(strncasecmp(statement, "select", 6)==0) 
+		if(strncasecmp(astatement, "select", 6)==0) 
 			stmt_type=OCI_STMT_SELECT;
-		else if(strncasecmp(statement, "insert", 6)==0)
+		else if(strncasecmp(astatement, "insert", 6)==0)
 			stmt_type=OCI_STMT_INSERT;
-		else if(strncasecmp(statement, "update", 6)==0)
+		else if(strncasecmp(astatement, "update", 6)==0)
 			stmt_type=OCI_STMT_UPDATE;
 
 		sword status=OCIStmtExecute(connection.svchp, stmthp, connection.errhp, 
@@ -746,7 +818,7 @@ private: // private funcs
 		case OCI_STMT_SELECT:
 			fetch_table(connection,
 				stmthp, offset, limit, 
-				handlers);
+				handlers, skip_rownum_column);
 			break;
 		default:
 		/*
@@ -758,10 +830,9 @@ private: // private funcs
 	}
 
 	void fetch_table(Connection& connection, 
-		OCIStmt *stmthp, unsigned long offset, unsigned long limit, 
-		SQL_Driver_query_event_handlers& handlers) 
+		OCIStmt *stmthp, unsigned long offset, unsigned long limit,
+		SQL_Driver_query_event_handlers& handlers, bool skip_rownum_column) 
 	{
-		const char* cstrClientCharset=connection.options.cstrClientCharset;
 		SQL_Driver_services& services=*connection.services;
 
 		ub4 prefetch_rows=100;
@@ -776,9 +847,9 @@ private: // private funcs
 			(dvoid *)&prefetch_mem_size, (ub4)0, 
 			(ub4)OCI_ATTR_PREFETCH_MEMORY, (OCIError *)connection.errhp));
 
-		OCIParam          *mypard;
-		ub2                    dtype;
-		const char*           col_name;
+		OCIParam		*mypard;
+		ub2				dtype;
+		const char*		col_name;
 
 		struct Col {
 			ub2 type;
@@ -795,6 +866,10 @@ private: // private funcs
 			failed=true;
 			goto cleanup;
 		} else {
+			bool transcode_needed=transcode_required(connection);
+			const char* client_charset=connection.options.client_charset;
+			const char* request_charset=services.request_charset();
+
 			// idea of preincrementing is that at error time all handles would free up
 			while(++column_count<=MAX_COLS) {
 				/* get next descriptor, if there is one */
@@ -803,7 +878,10 @@ private: // private funcs
 					--column_count;
 					break;
 				}
-				
+
+				if(skip_rownum_column && column_count==1)
+					continue;
+
 				/* Retrieve the data type attribute */
 				check(connection, "get type", OCIAttrGet(
 					(dvoid*) mypard, (ub4)OCI_DTYPE_PARAM, 
@@ -816,17 +894,18 @@ private: // private funcs
 					(dvoid*) mypard, (ub4)OCI_DTYPE_PARAM, 
 					(dvoid**) &col_name, (ub4 *) &col_name_len, (ub4)OCI_ATTR_NAME, 
 					(OCIError *)connection.errhp));
-				// transcode to $request:charset from connect-string?client_charset
-				if(cstrClientCharset) {
+
+				size_t length=(size_t)col_name_len;
+				if(transcode_needed){
+					// transcode column name from ?ClientCharset to $request:charset
 					services.transcode(col_name, col_name_len,
-						col_name, col_name_len,
-						cstrClientCharset,
-						services.request_charset());
+						col_name, length,
+						client_charset,
+						request_charset);
 				}
 
 				Col& col=cols[column_count-1];
 				{
-					size_t length=(size_t)col_name_len;
 					char *ptr=(char *)services.malloc_atomic(length+1);
 					if( connection.options.bLowerCaseColumnNames ) 
 						tolower_str(ptr, col_name, length);
@@ -841,25 +920,25 @@ private: // private funcs
 				void *ptr;
 				
 				switch(dtype) {
-				case SQLT_CLOB: 
-					{
-						check(connection, "alloc output var desc", OCIDescriptorAlloc(
-							(dvoid *)connection.envhp, (dvoid **)(ptr=&col.var), 
-							(ub4)OCI_DTYPE_LOB, 
-							0, (dvoid **)0));
-						
-						size=0;
+					case SQLT_CLOB: 
+						{
+							check(connection, "alloc output var desc", OCIDescriptorAlloc(
+								(dvoid *)connection.envhp, (dvoid **)(ptr=&col.var), 
+								(ub4)OCI_DTYPE_LOB, 
+								0, (dvoid **)0));
+							
+							size=0;
+							break;
+						}
+					default:
+						coerce_type=SQLT_STR;
+						char*& buf=connection.fetch_buffers[column_count-1];
+						ptr=buf; // get cached buffer
+						if(!ptr) // allocate if needed, caching it
+							ptr=buf=(char *)services.malloc_atomic(MAX_OUT_STRING_LENGTH+1/*terminator*/);
+						col.str=(char*)ptr;
+						size=MAX_OUT_STRING_LENGTH;
 						break;
-					}
-				default:
-					coerce_type=SQLT_STR;
-					char*& buf=connection.fetch_buffers[column_count-1];
-					ptr=buf; // get cached buffer
-					if(!ptr) // allocate if needed, caching it
-						ptr=buf=(char *)services.malloc_atomic(MAX_OUT_STRING_LENGTH+1/*terminator*/);
-					col.str=(char*)ptr;
-					size=MAX_OUT_STRING_LENGTH;
-					break;
 				}
 				
 				col.type=coerce_type;
@@ -878,7 +957,7 @@ private: // private funcs
 			
 			check(connection, handlers.before_rows(connection.sql_error));
 			
-			for(unsigned long row=0; !limit||row<offset+limit; row++) {
+			for(unsigned long row=0; limit==SQL_NO_LIMIT || row<offset+limit; row++) {
 				sword status=OCIStmtFetch(stmthp, connection.errhp, (ub4)1,  (ub4)OCI_FETCH_NEXT, 
 					(ub4)OCI_DEFAULT);
 				if(status==OCI_NO_DATA)
@@ -888,8 +967,12 @@ private: // private funcs
 				if(row>=offset) {
 					check(connection, handlers.add_row(connection.sql_error));
 					for(int i=0; i<column_count; i++) {
+						if(skip_rownum_column && i==0)
+							continue;
+
 						size_t length=0;
 						char* strm=0;
+						bool transcode_value=transcode_needed;
 
 						sb2 indicator=cols[i].indicator;
 						if(indicator!=-1) { // not NULL
@@ -897,58 +980,66 @@ private: // private funcs
 								fail(connection, indicator<0?
 									"column return buffer overflow, additionally size too big to be returned in 'indicator'"
 									: "column return buffer overflow");
-
-							switch(cols[i].type) {
-							case SQLT_CLOB: 
-								{
-									ub4   offset=1;
-									OCILobLocator *var=(OCILobLocator *)cols[i].var;
-									size_t read_size=0;
-									strm=(char*)services.malloc_atomic(1/*for terminator*/); // set type of memory block
-									do {
-										char buf[MAX_STRING*10];
-										ub4   amtp=0/*to be read in stream mode*/;
-										// http://i/docs/oracle/server.804/a58234/oci_func.htm#427818
-										status=OCILobRead(connection.svchp, connection.errhp, 
-											var, &amtp, offset, (dvoid *)buf, 
-											sizeof(buf), 
-											(dvoid *)0, 0, 
-											(ub2)0, (ub1)SQLCS_IMPLICIT);
-                                        if(status!=OCI_SUCCESS && status!=OCI_NEED_DATA)
-											check(connection, "lobread", status);
-
-										strm=(char*)services.realloc(strm, read_size+amtp+1/*for termintator*/);
-										memcpy(strm+read_size, buf, amtp);
-										read_size+=amtp;
-										offset+=amtp;
-									} while(status==OCI_NEED_DATA);
-
-									length=(size_t)read_size;
-									strm[length]=0;
+							
+							switch(cols[i].type){
+								case SQLT_CLOB: 
+									{
+										ub4   offset=1;
+										OCILobLocator *var=(OCILobLocator *)cols[i].var;
+										size_t read_size=0;
+										strm=(char*)services.malloc_atomic(1/*for terminator*/); // set type of memory block
+										do {
+											char buf[MAX_STRING*10];
+											ub4   amtp=0/*to be read in stream mode*/;
+											// http://i/docs/oracle/server.804/a58234/oci_func.htm#427818
+											status=OCILobRead(connection.svchp, connection.errhp, 
+												var, &amtp, offset, (dvoid *)buf, 
+												sizeof(buf), 
+												(dvoid *)0, 0, 
+												(ub2)0, (ub1)SQLCS_IMPLICIT);
+											if(status!=OCI_SUCCESS && status!=OCI_NEED_DATA)
+												check(connection, "lobread", status);
+
+											strm=(char*)services.realloc(strm, read_size+amtp+1/*for termintator*/);
+											memcpy(strm+read_size, buf, amtp);
+											read_size+=amtp;
+											offset+=amtp;
+										} while(status==OCI_NEED_DATA);
+
+										length=(size_t)read_size;
+										strm[length]=0;
+										break;
+									}
+								case SQLT_NUM:
+								case SQLT_INT:
+								case SQLT_FLT:
+								case SQLT_LNG:
+								case SQLT_RID:
+								case SQLT_UIN:
+								case SQLT_DATE:
+								case SQLT_TIME:
+								case SQLT_TIMESTAMP:
+									transcode_value=false; // transcode calls not needed for numbers and dates
+								default:
+									if(const char *value=cols[i].str) {
+										length=strlen(value);
+										strm=(char*)services.malloc_atomic(length+1);
+										memcpy(strm, value, length+1);
+									} else {
+										length=0;
+										strm=0;
+									}
 									break;
-								}
-							default:
-								if(const char *value=cols[i].str) {
-									length=strlen(value);
-									strm=(char*)services.malloc_atomic(length+1);
-									memcpy(strm, value, length+1);
-								} else {
-									length=0;
-									strm=0;
-								}
-								break;
 							}
 						}
 
 						const char* str=strm;
-						if(str && length)
-						{
-							// transcode to $request:charset from connect-string?client_charset
-							if(cstrClientCharset)
-								services.transcode(str, length,
-									str, length,
-									cstrClientCharset,
-									services.request_charset());
+						if(transcode_value && str && length){
+							// transcode cell value from ?ClientCharset to $request:charset
+							services.transcode(str, length,
+								str, length,
+								client_charset,
+								request_charset);
 						}
 
 						check(connection, handlers.add_row_cell(connection.sql_error, str, length));
@@ -973,6 +1064,72 @@ cleanup: // no check call after this poi
 			longjmp(saved_mark, 1);
 	}
 
+	modified_statement _preprocess_statement_limit(
+		Connection& connection, 
+		const char* astatement,
+		unsigned long offset,
+		unsigned long limit
+	){
+		modified_statement result={astatement, false, false, false};
+
+		if(!connection.options.bDisableQueryModification && limit!=SQL_NO_LIMIT && strncasecmp(astatement, "select", 6)==0){
+			result.limit=true;
+
+			size_t statement_size=strlen(astatement);
+			char* statement_limited;
+			
+			if(offset && limit/* throwing offset away if limit==0 */){
+				
+				result.skip_rownum_column=true;
+				result.offset=true;
+
+				// SELECT * FROM (SELECT ROWNUM r__, z__.* FROM (user_query) z__) WHERE r__<=limit+offset AND r__>offset
+				statement_limited=(char *)connection.services->malloc_atomic(
+						statement_size
+						+64/*SELECT * FROM (SELECT ROWNUM r__, z__.* FROM () z__) WHERE r__<=*/
+						+MAX_NUMBER
+						+9/* AND r__>*/
+						+MAX_NUMBER
+						+1/*terminator*/
+					);
+
+				result.statement=statement_limited;
+
+				strcpy(statement_limited, "SELECT * FROM (SELECT ROWNUM r__, z__.* FROM (");
+				strcat(statement_limited, astatement);
+
+				statement_limited+=46+statement_size;
+				statement_limited+=snprintf(statement_limited, 18+MAX_NUMBER, ") z__) WHERE r__<=%lu", limit+offset);
+				statement_limited+=snprintf(statement_limited, 9+MAX_NUMBER, " AND r__>%lu", offset);
+
+			} else {
+
+				// SELECT * FROM (user_query) WHERE ROWNUM<=limit
+				// this statement can be easy for the sql server but we can't use it with offset
+
+				statement_limited=(char *)connection.services->malloc_atomic(
+						statement_size
+						+31/*SELECT * FROM () WHERE ROWNUM<=*/
+						+MAX_NUMBER
+						+1/*terminator*/
+					);
+
+				result.statement=statement_limited;
+
+				strcpy(statement_limited, "SELECT * FROM (");
+				strcat(statement_limited, astatement);
+
+				statement_limited+=15+statement_size;
+				statement_limited+=snprintf(statement_limited, 16+MAX_NUMBER, ") WHERE ROWNUM<=%lu", limit);
+
+			}
+			*statement_limited=0;
+
+			//connection.services->_throw(result.statement);
+		}
+		return result;
+	}
+
 private: // conn client library funcs
 	
 	friend void fail(Connection& connection, const char *msg);
@@ -1090,11 +1247,19 @@ private: // conn client library funcs
 private: // conn client library funcs linking
 
 	const char *dlink(const char *dlopen_file_spec) {
-		if(lt_dlinit())
-			return lt_dlerror();
-        lt_dlhandle handle=lt_dlopen(dlopen_file_spec);
-        if(!handle)
-			return lt_dlerror(); //"can not open the dynamic link module";
+		if(lt_dlinit()){
+			if(const char* result=lt_dlerror())
+				return result;
+			return "can not prepare to dynamic loading";
+		}
+
+		lt_dlhandle handle=lt_dlopen(dlopen_file_spec);
+
+		if(!handle){
+			if(const char* result=lt_dlerror())
+				return result;
+			return "can not open the dynamic link module";
+		}
 
 		#define DSLINK(name, action) \
 			name=(t_##name)lt_dlsym(handle, #name); \
@@ -1141,15 +1306,13 @@ void check(Connection& connection, const
 				(text *)reason, (ub4)sizeof(reason), OCI_HTYPE_ERROR)==OCI_SUCCESS) {
 				msg=reason;
 
-				// transcode to $request:charset from connect-string?client_charset
-				if(const char* cstrClientCharset=connection.options.cstrClientCharset) {
-					if(msg) {
-						if(size_t msg_length=strlen(msg)) {
-							connection.services->transcode(msg, msg_length,
-								msg, msg_length,
-								cstrClientCharset,
-								connection.services->request_charset());
-						}
+				if(msg && transcode_required(connection)){
+					// transcode server error message from ?ClientCharset to $request:charset
+					if(size_t msg_length=strlen(msg)){
+						connection.services->transcode(msg, msg_length,
+							msg, msg_length,
+							connection.options.client_charset,
+							connection.services->request_charset());
 					}
 				}
 			} else
@@ -1175,6 +1338,10 @@ void check(Connection& connection, const
 	longjmp(connection.mark, 1);
 }
 
+bool transcode_required(Connection& connection){
+	return (connection.options.client_charset && strcmp(connection.options.client_charset, connection.services->request_charset())!=0);
+}
+
 void fail(Connection& connection, const char* msg) {
 	snprintf(connection.error, sizeof(connection.error), "%s", msg);
 	longjmp(connection.mark, 1);
@@ -1245,16 +1412,6 @@ static sb4 cbf_get_data(dvoid *ctxp,
 	return OCI_CONTINUE;
 }
 
-static void tolower_str(char *out, const char *in, size_t size) {
-	while(size--)
-		*out++=(char)tolower(*in++);
-}
-static void toupper_str(char *out, const char *in, size_t size) {
-	while(size--)
-		*out++=(char)toupper(*in++);
-}
-
-
 extern "C" SQL_Driver *SQL_DRIVER_CREATE() {
 	return OracleSQL_driver=new OracleSQL_Driver();
 }