guile/guile-core/libguile ChangeLog fports.c

[Gary Houston]

CVSROOT:        /cvs
Module name:    guile
Changes by:     Gary Houston <address@hidden>   01/01/01 16:38:42

Modified files:
        guile-core/libguile: ChangeLog fports.c 

Log message:
        * fports.c (fport_write): bugfix: handle short writes for
        unbuffered ports too.  optimize the buffered case by minimizing
        the number of write/flush calls.
        (write_all): new helper procedure.

CVSWeb URLs:
http://subversions.gnu.org/cgi-bin/cvsweb/guile/guile-core/libguile/ChangeLog.diff?r1=1.1226&r2=1.1227
http://subversions.gnu.org/cgi-bin/cvsweb/guile/guile-core/libguile/fports.c.diff?r1=1.86&r2=1.87

Patches:
Index: guile/guile-core/libguile/ChangeLog
diff -u guile/guile-core/libguile/ChangeLog:1.1226 
guile/guile-core/libguile/ChangeLog:1.1227
--- guile/guile-core/libguile/ChangeLog:1.1226  Sat Dec 30 11:26:37 2000
+++ guile/guile-core/libguile/ChangeLog Mon Jan  1 16:38:41 2001
@@ -1,3 +1,10 @@
+2001-01-01  Gary Houston  <address@hidden>
+
+       * fports.c (fport_write): bugfix: handle short writes for
+       unbuffered ports too.  optimize the buffered case by minimizing
+       the number of write/flush calls.
+       (write_all): new helper procedure.
+
 2000-12-30  Michael Livshin  <address@hidden>
 
        * guardians.c (guardian_print): for sharing guardians, print that
Index: guile/guile-core/libguile/fports.c
diff -u guile/guile-core/libguile/fports.c:1.86 
guile/guile-core/libguile/fports.c:1.87
--- guile/guile-core/libguile/fports.c:1.86     Fri Dec  8 09:32:56 2000
+++ guile/guile-core/libguile/fports.c  Mon Jan  1 16:38:41 2001
@@ -573,41 +573,83 @@
     scm_syserror ("ftruncate");
 }
 
+/* helper for fport_write: try to write data, using multiple system
+   calls if required.  */
+#define FUNC_NAME "write_all"
+static void write_all (SCM port, const void *data, size_t remaining)
+{
+  int fdes = SCM_FSTREAM (port)->fdes;
+
+  while (remaining > 0)
+    {
+      ssize_t done;
+
+      SCM_SYSCALL (done = write (fdes, data, remaining));
+
+      if (done == -1)
+       SCM_SYSERROR;
+      remaining -= done;
+      data = ((const char *) data) + done;
+    }
+}
+#undef FUNC_NAME
+
 static void
 fport_write (SCM port, const void *data, size_t size)
 {
+  /* this procedure tries to minimize the number of writes/flushes.  */
   scm_port *pt = SCM_PTAB_ENTRY (port);
 
-  if (pt->write_buf == &pt->shortbuf)
+  if (pt->write_buf == &pt->shortbuf
+      || (pt->write_pos == pt->write_buf && size >= pt->write_buf_size))
     {
-      /* "unbuffered" port.  */
-      int fdes = SCM_FSTREAM (port)->fdes;
-
-      if (write (fdes, data, size) == -1)
-       scm_syserror ("fport_write");
+      /* "unbuffered" port, or
+        port with empty buffer and data won't fit in buffer. */
+      write_all (port, data, size);
+      return;
     }
-  else 
-    {
-      const char *input = (char *) data;
-      size_t remaining = size;
 
-      while (remaining > 0)
-       {
-         int space = pt->write_end - pt->write_pos;
-         int write_len = (remaining > space) ? space : remaining;
+  {
+    off_t space = pt->write_end - pt->write_pos;
 
-         memcpy (pt->write_pos, input, write_len);
-         pt->write_pos += write_len;
-         remaining -= write_len;
-         input += write_len;
-         if (write_len == space)
+    if (size <= space)
+      {
+       /* data fits in buffer.  */
+       memcpy (pt->write_pos, data, size);
+       pt->write_pos += size;
+       if (pt->write_pos == pt->write_end)
+         {
            fport_flush (port);
+           /* we can skip the line-buffering check if nothing's buffered. */
+           return;
+         }
+      }
+    else
+      {
+       memcpy (pt->write_pos, data, space);
+       pt->write_pos = pt->write_end;
+       fport_flush (port);
+       {
+         const void *ptr = ((const char *) data) + space;
+         size_t remaining = size - space;
+
+         if (size >= pt->write_buf_size)
+           {
+             write_all (port, ptr, remaining);
+             return;
+           }
+         else
+           {
+             memcpy (pt->write_pos, ptr, remaining);
+             pt->write_pos += remaining;
+           }
        }
+      }
 
-      /* handle line buffering.  */
-      if ((SCM_CELL_WORD_0 (port) & SCM_BUFLINE) && memchr (data, '\n', size))
-       fport_flush (port);
-    }
+    /* handle line buffering.  */     
+    if ((SCM_CELL_WORD_0 (port) & SCM_BUFLINE) && memchr (data, '\n', size))
+      fport_flush (port);
+  }
 }
 
 /* becomes 1 when process is exiting: normal exception handling won't