control-stack: Move from language to data directory.

[pspp] / src / data / control-stack.c

diff --git a/src/data/control-stack.c b/src/data/control-stack.c
new file mode 100644 (file)
index 0000000..d8228f8
--- /dev/null
+++ b/src/data/control-stack.c
@@ -0,0 +1,98 @@
+#include <config.h>
+
+#include "data/control-stack.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "libpspp/compiler.h"
+#include "libpspp/message.h"
+
+#include "gl/xalloc.h"
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+struct ctl_struct
+  {
+    const struct ctl_class *class;    /* Class of control structure. */
+    struct ctl_struct *down;   /* Points toward the bottom of ctl_stack. */
+    void *private;              /* Private data. */
+  };
+
+static struct ctl_struct *ctl_stack;
+
+void
+ctl_stack_clear (void)
+{
+  while (ctl_stack != NULL)
+    {
+      struct ctl_struct *top = ctl_stack;
+      msg (SE, _("%s without %s."),
+           top->class->start_name, top->class->end_name);
+      ctl_stack_pop (top->private);
+    }
+}
+
+void
+ctl_stack_push (const struct ctl_class *class, void *private)
+{
+  struct ctl_struct *ctl;
+
+  assert (private != NULL);
+  ctl = xmalloc (sizeof *ctl);
+  ctl->class = class;
+  ctl->down = ctl_stack;
+  ctl->private = private;
+  ctl_stack = ctl;
+}
+
+void *
+ctl_stack_top (const struct ctl_class *class)
+{
+  struct ctl_struct *top = ctl_stack;
+  if (top != NULL && top->class == class)
+    return top->private;
+  else
+    {
+      if (ctl_stack_search (class) != NULL)
+        msg (SE, _("This command must appear inside %s...%s, "
+                   "without intermediate %s...%s."),
+             class->start_name, class->end_name,
+             top->class->start_name, top->class->end_name);
+      return NULL;
+    }
+}
+
+void *
+ctl_stack_search (const struct ctl_class *class)
+{
+  struct ctl_struct *ctl;
+
+  for (ctl = ctl_stack; ctl != NULL; ctl = ctl->down)
+    if (ctl->class == class)
+      return ctl->private;
+
+  msg (SE, _("This command cannot appear outside %s...%s."),
+       class->start_name, class->end_name);
+  return NULL;
+}
+
+void
+ctl_stack_pop (void *private)
+{
+  struct ctl_struct *top = ctl_stack;
+
+  assert (top != NULL);
+  assert (top->private == private);
+
+  top->class->close (top->private);
+  ctl_stack = top->down;
+  free (top);
+}
+
+bool
+ctl_stack_is_empty (void)
+{
+  return ctl_stack == NULL;
+}