read lines and files

os/readutil.c

@@ -0,0 +1,201 @@
+/*************************************************************************
+*									 *
+*	 YAP Prolog 							 *
+*									 *
+*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
+*									 *
+* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
+*									 *
+**************************************************************************
+*									 *
+* File:		readutil.c						 *
+* Last rev:	2/8/06							 *
+* mods:									 *
+* comments:	readutil library support				 *
+*									 *
+*************************************************************************/
+#ifdef SCCS
+static char SccsId[] = "%W% %G%";
+#endif
+
+#include "Yap.h"
+#include "Yatom.h"
+#include "YapHeap.h"
+#include "yapio.h"
+#include "iopreds.h"
+#include "YapText.h"
+
+static Int
+rl_to_codes(Term TEnd, int do_as_binary, int arity USES_REGS)
+{
+  int sno = Yap_CheckStream (ARG1, Input_Stream_f, "read_line_to_codes/2");
+  Int status;
+  UInt max_inp, buf_sz, sz;
+  char *buf;
+  int  binary_stream;
+
+  if (sno < 0)
+    return FALSE;
+  status = GLOBAL_Stream[sno].status;
+  binary_stream = GLOBAL_Stream[sno].status & Binary_Stream_f;
+  if (status & Eof_Stream_f) {
+    UNLOCK(GLOBAL_Stream[sno].streamlock);
+    return Yap_unify_constant(ARG2, MkAtomTerm (AtomEof));
+  }
+  max_inp = (ASP-HR)/2-1024;
+  buf = (char *)TR;
+  buf_sz = (char *)LOCAL_TrailTop-buf;
+  while (TRUE) {
+    if ( buf_sz > max_inp ) {
+      buf_sz = max_inp;
+    }
+    if (do_as_binary && !binary_stream)
+      GLOBAL_Stream[sno].status |= Binary_Stream_f;
+    sz = GLOBAL_Stream[sno].stream_gets(sno, buf_sz, buf);
+    if (do_as_binary && !binary_stream)
+      GLOBAL_Stream[sno].status &= ~Binary_Stream_f;
+    if (sz == -1 || sz == 0) {
+      if (GLOBAL_Stream[sno].status & Eof_Stream_f) {
+	UNLOCK(GLOBAL_Stream[sno].streamlock);
+	return Yap_unify_constant(ARG2, MkAtomTerm (AtomEof));
+      }
+      UNLOCK(GLOBAL_Stream[sno].streamlock);
+      return FALSE;
+    }
+    if (GLOBAL_Stream[sno].status & Eof_Stream_f || buf[sz-1] == 10) {
+      /* we're done */
+      Term end;
+      if (!(do_as_binary || GLOBAL_Stream[sno].status & Eof_Stream_f)) {
+	UNLOCK(GLOBAL_Stream[sno].streamlock);
+	/* handle CR before NL */
+	if ((Int)sz-2 >= 0 && buf[sz-2] == 13)
+	  buf[sz-2] = '\0';
+	else
+	  buf[sz-1] = '\0';
+      } else {
+	UNLOCK(GLOBAL_Stream[sno].streamlock);
+      }
+      if (arity == 2)
+	end = TermNil;
+      else
+	end = Deref(XREGS[arity]);
+      return Yap_unify(ARG2, Yap_CharsToDiffListOfCodes((const char *)TR, end PASS_REGS)) ;
+    }
+    buf += (buf_sz-1);
+    max_inp -= (buf_sz-1);
+    if (max_inp <= 0) {
+      UNLOCK(GLOBAL_Stream[sno].streamlock);
+      Yap_Error(OUT_OF_STACK_ERROR, ARG1, "read_line_to_codes/%d", arity);
+      return FALSE;      
+    }
+  }
+}
+
+static Int
+p_rl_to_codes(USES_REGS1)
+{
+  return rl_to_codes(TermNil, FALSE, 2 PASS_REGS);
+}
+
+static Int
+p_rl_to_codes2(USES_REGS1)
+{
+  return rl_to_codes(TermNil, TRUE, 3 PASS_REGS);
+}
+
+static Int
+p_stream_to_codes(USES_REGS1)
+{
+  int sno = Yap_CheckStream (ARG1, Input_Stream_f, "reaMkAtomTerm (AtomEofd_line_to_codes/2");
+  CELL *HBASE = HR;
+  CELL *h0 = &ARG4;
+
+  if (sno < 0)
+    return FALSE;
+  while (!(GLOBAL_Stream[sno].status & Eof_Stream_f)) {
+    /* skip errors */
+    Int ch = GLOBAL_Stream[sno].stream_getc(sno);
+    Term t;
+    if (ch == EOFCHAR)
+      break;
+    t = MkIntegerTerm(ch);
+    h0[0] = AbsPair(HR);
+    *HR = t;
+    HR+=2;
+    h0 = HR-1;
+    if (HR >= ASP-1024) {
+      RESET_VARIABLE(h0);
+      ARG4 = AbsPair(HBASE);
+      ARG5 = (CELL)h0;
+      if (!Yap_gcl((ASP-HBASE)*sizeof(CELL), 5, ENV, gc_P(P,CP))) {
+	Yap_Error(OUT_OF_STACK_ERROR, ARG1, "read_stream_to_codes/3");
+	return FALSE;
+      }
+      /* build a legal term again */
+      h0 = (CELL *)ARG5;
+      HBASE = RepPair(ARG4);
+    }
+  }
+  UNLOCK(GLOBAL_Stream[sno].streamlock);
+  if (HR == HBASE)
+    return Yap_unify(ARG2,ARG3);
+  RESET_VARIABLE(HR-1);
+  Yap_unify(HR[-1],ARG3);
+  return Yap_unify(AbsPair(HBASE),ARG2);
+    
+}
+
+static Int
+p_stream_to_terms(USES_REGS1)
+{
+  int sno = Yap_CheckStream (ARG1, Input_Stream_f, "read_line_to_codes/2");
+  Term t, hd;
+  yhandle_t tails, outs, news;
+
+  if (sno < 0)
+    return FALSE;
+
+  t = AbsPair(HR);
+  RESET_VARIABLE(HR);
+  outs = Yap_InitSlot( (CELL)(HR) );
+  tails = Yap_InitSlot( (CELL)(HR) );
+  news = Yap_InitSlot( (CELL)(HR) );
+  HR++;
+    
+  while (!(GLOBAL_Stream[sno].status & Eof_Stream_f)) {
+    RESET_VARIABLE(HR);
+    RESET_VARIABLE(HR+1);
+    hd = (CELL)HR;
+    Yap_PutInSlot(news, (CELL)(HR+1) PASS_REGS);
+    HR += 2;
+    while ((hd=Yap_read_term(sno, TermNil, 2)) == 0L)
+      ;
+    // just ignore failure
+    CELL *pt = VarOfTerm(Yap_GetFromSlot(tails));
+    if (Deref(hd) == TermEOfCode) {
+      *pt = Deref(ARG3);
+      break;
+    } else {
+      CELL *newpt = (CELL*)Yap_GetFromSlot(news);
+      *pt =AbsPair(newpt-1);
+     Yap_PutInSlot(tails, (CELL)newpt PASS_REGS);
+    }
+  }
+  UNLOCK(GLOBAL_Stream[sno].streamlock);
+  return Yap_unify(t,ARG2);
+}
+
+void
+Yap_InitReadUtil(void)
+{
+    CACHE_REGS
+
+  Term cm = CurrentModule;
+  CurrentModule = READUTIL_MODULE;
+  Yap_InitCPred("read_line_to_codes", 2, p_rl_to_codes, SyncPredFlag);
+  Yap_InitCPred("read_line_to_codes", 3, p_rl_to_codes2, SyncPredFlag);
+  Yap_InitCPred("read_stream_to_codes", 3, p_stream_to_codes, SyncPredFlag);
+  Yap_InitCPred("read_stream_to_terms", 3, p_stream_to_terms, SyncPredFlag);
+  CurrentModule = cm;
+}
+