* configure.in (RUBY_CHECK_IO_NEED): check whether fseek() and

  fflush() are needed.

* io.c (flush_before_seek): flush write stream only.

* io.c (rb_io_check_readable): seek instead of flush if the last
  operation was write.

* io.c (rb_io_check_writable): seek instead of flush if the last
  operation was read.

* bcc32/Makefile.sub, win32/Makefile.sub: needs to seek between
  R/W.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@3318 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 59 insertions, 32 deletions

diff --git a/ChangeLog b/ChangeLog
index 1c50f840ce..6286a7dbdc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+Thu Jan 09 17:05:24 2003  Nobuyoshi Nakada  <nobu.nokada@softhome.net>
+
+	* configure.in (RUBY_CHECK_IO_NEED): check whether fseek() and
+	  fflush() are needed.
+
+	* io.c (flush_before_seek): flush write stream only.
+
+	* io.c (rb_io_check_readable): seek instead of flush if the last
+	  operation was write.
+
+	* io.c (rb_io_check_writable): seek instead of flush if the last
+	  operation was read.
+
+	* bcc32/Makefile.sub, win32/Makefile.sub: needs to seek between
+	  R/W.
+
 Thu Jan  9 16:31:51 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* eval.c (rb_eval): should not discard nested NODE_BLOCK.
diff --git a/bcc32/Makefile.sub b/bcc32/Makefile.sub
index 965f564ce8..025eebbc0c 100644
--- a/bcc32/Makefile.sub
+++ b/bcc32/Makefile.sub
@@ -242,6 +242,7 @@ config.h:
 \#define HAVE_SINH 1
 \#define HAVE_TANH 1
 
+\#define NEED_IO_SEEK_BETWEEN_RW 1
 \#define RSHIFT(x,y) ((x)>>y)
 \#define FILE_COUNT level
 \#define FILE_READPTR curp
diff --git a/configure.in b/configure.in
index b6bc0a03d4..1619b798df 100644
--- a/configure.in
+++ b/configure.in
@@ -265,14 +265,14 @@ darwin*)	LIBS="-lobjc $LIBS";;
 human*)		ac_cv_func_getpgrp_void=yes;;
 beos*)		;;
 cygwin*)	rb_cv_have_daylight=no
-		rb_cv_need_io_flush_between_rw=no
+		rb_cv_need_io_seek_between_rw=no
 		rb_cv_need_io_flush_before_seek=no
 		ac_cv_var_tzname=no
 		ac_cv_func__setjmp=no
 		ac_cv_func_setitimer=no
 		;;
 mingw*)		LIBS="-lwsock32 $LIBS"
-		rb_cv_need_io_flush_between_rw=yes
+		rb_cv_need_io_seek_between_rw=yes
 		rb_cv_need_io_flush_before_seek=no
 		ac_cv_header_a_out_h=no
 		ac_cv_header_pwd_h=no
@@ -559,10 +559,19 @@ else
   fi
 fi
 
-AC_DEFUN(RUBY_CHECK_IO_NEED_FLUSH,
-[AC_CACHE_CHECK(whether need to flush [$1], [$2],
+AC_DEFUN(RUBY_CHECK_IO_NEED,
+[AC_CACHE_CHECK(whether need to [$1], [$2],
     [AC_TRY_RUN([
 #include <stdio.h>
+#ifndef SEEK_SET
+#define SEEK_SET 0
+#endif
+#ifndef SEEK_CUR
+#define SEEK_CUR 1
+#endif
+#define before_seek(f) ]ifelse(index($2,flush_before_seek),-1,[fflush(f)],[(f,0)])[
+#define reset_rw(f) ]ifelse(index($2,seek_between_rw),-1,[do_seek(f,SEEK_CUR)],[(f,0)])[
+#define do_seek(f, w) (before_seek(f), fseek(f,0,w))
 
 char *fn = "conftest.dat";
 char *wombat = "wombat\n";
@@ -576,14 +585,11 @@ int main()
 
     if (!(f = fopen(fn, "w+"))) return 1;
     fputs(wombat, f);
-    fflush(f);
-    fseek(f, 0, 0);
+    do_seek(f, SEEK_SET);
     if (!fgets(buf, BUFSIZ, f) || strcmp(buf, wombat)) goto fail;
-    ]ifelse(index($2,between_rw),-1,fflush(f);)[
+    reset_rw(f);
     fputs(koara, f);
-    ]ifelse(index($2,before_seek),-1,fflush(f);)[
-    fseek(f, 0, 0);
-    ]ifelse(index($2,between_rw),-1,fflush(f);)[
+    do_seek(f, SEEK_SET);
     if (!fgets(buf, BUFSIZ, f) || strcmp(buf, wombat)) goto fail;
     if (!fgets(buf, BUFSIZ, f) || strcmp(buf, koara)) goto fail;
     r = 0;
@@ -593,14 +599,22 @@ int main()
     return r;
 }
 ], [$2]=no, [$2]=yes, [$2]=yes)])])
-
-RUBY_CHECK_IO_NEED_FLUSH(between R/W, rb_cv_need_io_flush_between_rw)
-RUBY_CHECK_IO_NEED_FLUSH(before seek, rb_cv_need_io_flush_before_seek)
-if test "$rb_cv_need_io_flush_between_rw" = yes; then
-  AC_DEFINE(NEED_IO_FLUSH_BETWEEN_RW, 1)
+RUBY_CHECK_IO_NEED(seek between R/W, rb_cv_need_io_seek_between_rw)
+RUBY_CHECK_IO_NEED(flush before seek, rb_cv_need_io_flush_before_seek)
+check_to_do_something_else=no
+if test "$rb_cv_need_io_seek_between_rw" = yes; then
+  AC_DEFINE(NEED_IO_SEEK_BETWEEN_RW, 1)
+  check_to_do_something_else=yes
 fi
 if test "$rb_cv_need_io_flush_before_seek" = yes; then
   AC_DEFINE(NEED_IO_FLUSH_BEFORE_SEEK, 1)
+  check_to_do_something_else=yes
+fi
+if test "$cross_compiling" = no -a "$check_to_do_something_else" = yes; then
+  RUBY_CHECK_IO_NEED(do something else, unexpected_stdio_behavior)
+  if test "$unexpected_stdio_behavior" = yes; then
+    AC_MSG_FAILURE([unexpected stdio behavior])
+  fi
 fi
 
 dnl default value for $KANJI
diff --git a/io.c b/io.c
index 0c2ba4d0af..fd612ddcce 100644
--- a/io.c
+++ b/io.c
@@ -195,12 +195,8 @@ static OpenFile *
 flush_before_seek(fptr)
     OpenFile *fptr;
 {
-    int mode = fptr->mode;
-    if (mode & FMODE_RBUF) {
-	if (!fptr->f2) io_fflush(fptr->f, fptr);
-    }
-    if (mode & FMODE_WBUF) {
-	io_fflush((fptr->f2 ? fptr->f2 : fptr->f), fptr);
+    if (fptr->mode & FMODE_WBUF) {
+	io_fflush(GetWriteFile(fptr), fptr);
     }
     return fptr;
 }
@@ -211,6 +207,12 @@ flush_before_seek(fptr)
 #define io_seek(fptr, ofs, whence) fseeko(flush_before_seek(fptr)->f, ofs, whence)
 #define io_tell(fptr) ftello(flush_before_seek(fptr)->f)
 
+#ifndef SEEK_CUR
+# define SEEK_SET 0
+# define SEEK_CUR 1
+# define SEEK_END 2
+#endif
+
 void
 rb_io_check_readable(fptr)
     OpenFile *fptr;
@@ -218,9 +220,9 @@ rb_io_check_readable(fptr)
     if (!(fptr->mode & FMODE_READABLE)) {
 	rb_raise(rb_eIOError, "not opened for reading");
     }
-#if NEED_IO_FLUSH_BETWEEN_RW
+#if NEED_IO_SEEK_BETWEEN_RW
     if ((fptr->mode & FMODE_WBUF) && !fptr->f2) {
-	io_fflush(fptr->f, fptr);
+	io_seek(fptr, 0, SEEK_CUR);
     }
     fptr->mode |= FMODE_RBUF;
 #endif
@@ -233,9 +235,9 @@ rb_io_check_writable(fptr)
     if (!(fptr->mode & FMODE_WRITABLE)) {
 	rb_raise(rb_eIOError, "not opened for writing");
     }
-#if NEED_IO_FLUSH_BETWEEN_RW
+#if NEED_IO_SEEK_BETWEEN_RW
     if ((fptr->mode & FMODE_RBUF) && !fptr->f2) {
-	io_fflush(fptr->f, fptr);
+	io_seek(fptr, 0, SEEK_CUR);
     }
 #endif
 }
@@ -472,12 +474,6 @@ rb_io_tell(io)
     return OFFT2NUM(pos);
 }
 
-#ifndef SEEK_CUR
-# define SEEK_SET 0
-# define SEEK_CUR 1
-# define SEEK_END 2
-#endif
-
 static VALUE
 rb_io_seek(io, offset, whence)
     VALUE io, offset;
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 57add88df7..5ba33b1830 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -260,7 +260,7 @@ config.h:
 #define HAVE_DAYLIGHT 1
 #define SETPGRP_VOID 1
 #define inline __inline
-#define NEED_IO_FLUSH_BETWEEN_RW 1
+#define NEED_IO_SEEK_BETWEEN_RW 1
 #define RSHIFT(x,y) ((x)>>(int)y)
 #define FILE_COUNT _cnt
 #define FILE_READPTR _ptr