enable obtaining current stream_position from SWI.y

C/iopreds.c

@@ -4765,6 +4765,9 @@ StreamPosition(int sno)
   Term sargs[5];
   Int cpos;
   cpos = Stream[sno].charcount;
+  if (Stream[sno].status & SWI_Stream_f) {
+    return Yap_get_stream_position(Stream[sno].u.swi_stream.swi_ptr);
+  }
   if (Stream[sno].stream_getc == PlUnGetc) {
     cpos--;
   }

H/YapHeap.h

@@ -29,6 +29,7 @@ typedef int (*SWI_GetWideFunction)(void *);
 typedef int (*SWI_CloseFunction)(void *);
 typedef int (*SWI_FlushFunction)(void *);
 typedef int (*SWI_PLGetStreamFunction)(void *);
+typedef int (*SWI_PLGetStreamPositionFunction)(void *);
 
 #include "../include/dswiatoms.h"
 

H/Yapproto.h

@@ -462,6 +462,7 @@ void    STD_PROTO(Yap_InitMYDDAS_TopLevelPreds,(void));
 void	STD_PROTO(Yap_swi_install,(void));
 void    STD_PROTO(Yap_InitSWIHash,(void));
 int     STD_PROTO(Yap_get_stream_handle,(Term, int, int, void *));
+Term    STD_PROTO(Yap_get_stream_position,(void *));
 
 /* ypsocks.c */
 void	STD_PROTO(Yap_InitSockets,(void));

H/dglobals.h

@@ -188,6 +188,7 @@
 #define SWIClose Yap_global->swi_close
 #define SWIFlush Yap_global->swi_flush
 #define SWIGetStream Yap_global->swi_get_stream_f
+#define SWIGetStreamPosition Yap_global->swi_get_stream_position_f
 
 #define Yap_AllowLocalExpansion Yap_global->allow_local_expansion
 #define Yap_AllowGlobalExpansion Yap_global->allow_global_expansion

H/hglobals.h

@@ -190,6 +190,7 @@ typedef struct worker_shared {
   SWI_CloseFunction  swi_close;
   SWI_FlushFunction  swi_flush;
   SWI_PLGetStreamFunction  swi_get_stream_f;
+  SWI_PLGetStreamPositionFunction  swi_get_stream_position_f;
 
   int  allow_local_expansion;
   int  allow_global_expansion;

H/iglobals.h

@@ -188,6 +188,7 @@ static void InitGlobal(void) {
   Yap_global->swi_close = NULL;
   Yap_global->swi_flush = NULL;
   Yap_global->swi_get_stream_f = NULL;
+  Yap_global->swi_get_stream_position_f = NULL;
 
   Yap_global->allow_local_expansion = TRUE;
   Yap_global->allow_global_expansion = TRUE;

H/rglobals.h

@@ -199,6 +199,7 @@ static void RestoreGlobal(void) {
 
 
 
+
 #if HAVE_LIBREADLINE
 
 

include/SWI-Prolog.h

@@ -699,6 +699,7 @@ typedef struct SWI_IO {
   void *flush_s;
   void *close_s;
   void *get_stream_handle;
+  void *get_stream_position;
 } swi_io_struct;
 
 /*  SWI stream info */

library/dialect/swi/fli/swi.c

@@ -3096,6 +3096,7 @@ PL_YAP_InitSWIIO(struct SWI_IO *swio)
   SWIFlush = swio->flush_s;
   SWIClose = swio->close_s;
   SWIGetStream = swio->get_stream_handle;
+  SWIGetStreamPosition = swio->get_stream_position;
 }
 
 typedef int     (*GetStreamF)(term_t, int, int, IOSTREAM **s);
@@ -3115,6 +3116,23 @@ Yap_get_stream_handle(Term t0, int read_mode, int write_mode, void *s){
 }
 
 
+typedef int     (*GetStreamPosF)(IOSTREAM *s, term_t);
+
+Term 
+Yap_get_stream_position(void *s){
+  term_t t;
+  Term t0;
+  GetStreamPosF f = (GetStreamPosF)SWIGetStreamPosition;
+
+  t = (term_t)Yap_NewSlots(1);
+  if (!(*f)(s, t))
+    return 0L;
+  t0 = Yap_GetFromSlot((Int)t);
+  Yap_RecoverSlots(1);
+  return t0;
+}
+
+
 X_API void (*PL_signal(int sig, void (*func)(int)))(int)
 {
   //  return Yap_signal2(sig,func);

misc/GLOBALS

@@ -211,6 +211,7 @@ SWI_PutWideFunction	swi_wputc		SWIWidePutc	=NULL
 SWI_CloseFunction	swi_close		SWIClose	=NULL
 SWI_FlushFunction	swi_flush		SWIFlush	=NULL
 SWI_PLGetStreamFunction	swi_get_stream_f	SWIGetStream	=NULL
+SWI_PLGetStreamPositionFunction swi_get_stream_position_f	SWIGetStreamPosition	=NULL
 
 // stack overflow expansion/gc control
 int		allow_local_expansion	Yap_AllowLocalExpansion =TRUE

packages/PLStream/pl-file.c

@@ -4350,6 +4350,12 @@ get_stream_handle_no_errors(term_t t, int read, int write, IOSTREAM **s)
   return get_stream_handle(t, s, SH_ALIAS);
 }
 
+static int
+get_stream_position(IOSTREAM *s, term_t t)
+{ GET_LD
+    return stream_position_prop(s, t);
+}
+
 static void
 init_yap_extras(void)
 {
@@ -4363,6 +4369,7 @@ init_yap_extras(void)
   swiio.flush_s = Sflush;
   swiio.close_s = closeStream;
   swiio.get_stream_handle = get_stream_handle_no_errors;
+  swiio.get_stream_position = get_stream_position;
   PL_YAP_InitSWIIO(&swiio);
   initCharTypes();
   initFiles();