Initial import of the CDE 2.1.30 sources from the Open Group.

cde/programs/nsgmls/RewindStorageObject.C

@@ -0,0 +1,79 @@
+/* $XConsortium: RewindStorageObject.C /main/1 1996/07/29 17:02:59 cde-hp $ */
+// Copyright (c) 1994, 1995 James Clark
+// See the file COPYING for copying permission.
+
+#ifdef __GNUG__
+#pragma implementation
+#endif
+
+#include "splib.h"
+#include "RewindStorageObject.h"
+#include "macros.h"
+
+#ifdef SP_NAMESPACE
+namespace SP_NAMESPACE {
+#endif
+
+RewindStorageObject::RewindStorageObject(Boolean mayRewind, Boolean canSeek)
+: mayRewind_(mayRewind), canSeek_(canSeek),
+  savingBytes_(mayRewind && canSeek), readingSaved_(0)
+{
+}
+
+Boolean RewindStorageObject::rewind(Messenger &mgr)
+{
+  ASSERT(mayRewind_);
+  if (canSeek_)
+    return seekToStart(mgr);
+  else {
+    readingSaved_ = 1;
+    nBytesRead_ = 0;
+    return 1;
+  }
+}
+
+void RewindStorageObject::unread(const char *s, size_t n)
+{
+  savedBytes_.append(s, n);
+  if (!readingSaved_) {
+    readingSaved_ = 1;
+    nBytesRead_ = 0;
+  }
+}
+
+void RewindStorageObject::willNotRewind()
+{
+  mayRewind_ = 0;
+  savingBytes_ = 0;
+  if (!readingSaved_) {
+    // Ensure that memory is released now.
+    String<char> tem;
+    tem.swap(savedBytes_);
+  }
+}
+
+Boolean RewindStorageObject::readSaved(char *buf, size_t bufSize,
+				       size_t &nread)
+{
+  if (!readingSaved_)
+    return 0;
+  if (nBytesRead_ >= savedBytes_.size()) {
+    if (!mayRewind_) {
+      // Ensure that memory is released now.
+      String<char> tem;
+      tem.swap(savedBytes_);
+    }
+    readingSaved_ = 0;
+    return 0;
+  }
+  nread = savedBytes_.size() - nBytesRead_;
+  if (nread > bufSize)
+    nread = bufSize;
+  memcpy(buf, savedBytes_.data() + nBytesRead_, nread);
+  nBytesRead_ += nread;
+  return 1;
+}
+
+#ifdef SP_NAMESPACE
+}
+#endif