Import changeset

1 files changed, 137 insertions, 0 deletions

diff --git a/mysys/my_pread.c b/mysys/my_pread.c
new file mode 100644
index 00000000000..1190f2cc81b
--- /dev/null
+++ b/mysys/my_pread.c
@@ -0,0 +1,137 @@
+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+   
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+   
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+   MA 02111-1307, USA */
+
+#include "mysys_priv.h"
+#include "mysys_err.h"
+#include <errno.h>
+#ifdef HAVE_PREAD
+#include <unistd.h>
+#endif
+
+	/* Read a chunk of bytes from a file  */
+
+uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
+	      myf MyFlags)
+{
+  uint readbytes;
+  DBUG_ENTER("my_pread");
+  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: %lx  Count: %u  MyFlags: %d",
+		   Filedes, (ulong) offset, Buffer, Count, MyFlags));
+
+  for (;;)
+  {
+#ifndef __WIN__
+    errno=0;					/* Linux doesn't reset this */
+#endif
+#ifndef HAVE_PREAD
+    readbytes= (uint) -1;
+    if (lseek(Filedes, offset, MY_SEEK_SET) == -1L ||
+	(readbytes = (uint) read(Filedes, Buffer, Count)) != Count)
+#else
+      if ((readbytes = (uint) pread(Filedes, Buffer, Count, offset)) != Count)
+#endif
+      {
+	my_errno=errno;
+	DBUG_PRINT("warning",("Read only %ld bytes off %ld from %d, errno: %d",
+			      readbytes,Count,Filedes,my_errno));
+#ifdef THREAD
+	if (readbytes == 0 && errno == EINTR)
+	  continue;				/* Interrupted */
+#endif
+	if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
+	{
+	  if ((int) readbytes == -1)
+	    my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
+		     my_filename(Filedes),my_errno);
+	  else if (MyFlags & (MY_NABP | MY_FNABP))
+	    my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
+		     my_filename(Filedes),my_errno);
+	}
+	if ((int) readbytes == -1 || (MyFlags & (MY_FNABP | MY_NABP)))
+	  DBUG_RETURN(MY_FILE_ERROR);	/* Return with error */
+      }
+    if (MyFlags & (MY_NABP | MY_FNABP))
+      DBUG_RETURN(0);			/* Ok vid l{sning */
+    DBUG_RETURN(readbytes); /* purecov: inspected */
+  }
+} /* my_pread */
+
+
+	/* Write a chunk of bytes to a file */
+
+uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset,
+	       myf MyFlags)
+{
+  uint writenbytes,errors;
+  ulong written;
+  DBUG_ENTER("my_pwrite");
+  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: %lx  Count: %d  MyFlags: %d",
+		   Filedes, (ulong) offset,Buffer, Count, MyFlags));
+  errors=0; written=0L;
+
+  for (;;)
+  {
+#ifndef HAVE_PREAD
+    writenbytes= (uint) -1;
+    if (lseek(Filedes, offset, MY_SEEK_SET) != -1L &&
+	(writenbytes = (uint) write(Filedes, Buffer, Count)) == Count)
+#else
+    if ((writenbytes = (uint) pwrite(Filedes, Buffer, Count,offset)) == Count)
+#endif
+      break;
+    if ((int) writenbytes != -1)
+    {					/* Safegueard */
+      written+=writenbytes;
+      Buffer+=writenbytes;
+      Count-=writenbytes;
+      offset+=writenbytes;
+    }
+    my_errno=errno;
+    DBUG_PRINT("error",("Write only %d bytes",writenbytes));
+#ifndef NO_BACKGROUND
+#ifdef THREAD
+    if (my_thread_var->abort)
+      MyFlags&= ~ MY_WAIT_IF_FULL;		/* End if aborted by user */
+#endif
+    if (my_errno == ENOSPC && (MyFlags & MY_WAIT_IF_FULL))
+    {
+      if (!(errors++ % MY_WAIT_GIVE_USER_A_MESSAGE))
+	my_error(EE_DISK_FULL,MYF(ME_BELL | ME_NOREFRESH),
+		 my_filename(Filedes));
+      VOID(sleep(MY_WAIT_FOR_USER_TO_FIX_PANIC));
+      continue;
+    }
+    if ((writenbytes == 0 && my_errno == EINTR) ||
+	(writenbytes > 0 && (uint) writenbytes != (uint) -1))
+      continue;					/* Retry */
+#endif
+    if (MyFlags & (MY_NABP | MY_FNABP))
+    {
+      if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
+      {
+	my_error(EE_WRITE, MYF(ME_BELL+ME_WAITTANG),
+		 my_filename(Filedes),my_errno);
+      }
+      DBUG_RETURN(MY_FILE_ERROR);		/* Error on read */
+    }
+    else
+      break;					/* Return bytes written */
+  }
+  if (MyFlags & (MY_NABP | MY_FNABP))
+    DBUG_RETURN(0);			/* Want only errors */
+  DBUG_RETURN(writenbytes+written); /* purecov: inspected */
+} /* my_write */