path: root/gdb/ui-out.c

/* Output generating routines for GDB.

   Copyright (C) 1999-2015 Free Software Foundation, Inc.

   Contributed by Cygnus Solutions.
   Written by Fernando Nasser for Cygnus.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "expression.h"		/* For language.h */
#include "language.h"
#include "ui-out.h"

/* table header structures */

struct ui_out_hdr
  {
    int colno;
    int width;
    enum ui_align alignment;
    char *col_name;
    char *colhdr;
    struct ui_out_hdr *next;
  };

/* Maintain a stack so that the info applicable to the inner most list
   is always available.  Stack/nested level 0 is reserved for the
   top-level result.  */

enum { MAX_UI_OUT_LEVELS = 8 };

struct ui_out_level
  {
    /* Count each field; the first element is for non-list fields.  */
    int field_count;
    /* The type of this level.  */
    enum ui_out_type type;
  };

/* Define uiout->level vector types and operations.  */
typedef struct ui_out_level *ui_out_level_p;
DEF_VEC_P (ui_out_level_p);

/* Tables are special.  Maintain a separate structure that tracks
   their state.  At present an output can only contain a single table
   but that restriction might eventually be lifted.  */

struct ui_out_table
{
  /* If on, a table is being generated.  */
  int flag;

  /* If on, the body of a table is being generated.  If off, the table
     header is being generated.  */
  int body_flag;

  /* The level at which each entry of the table is to be found.  A row
     (a tuple) is made up of entries.  Consequently ENTRY_LEVEL is one
     above that of the table.  */
  int entry_level;

  /* Number of table columns (as specified in the table_begin call).  */
  int columns;

  /* String identifying the table (as specified in the table_begin
     call).  */
  char *id;

  /* Points to the first table header (if any).  */
  struct ui_out_hdr *header_first;

  /* Points to the last table header (if any).  */
  struct ui_out_hdr *header_last;

  /* Points to header of NEXT column to format.  */
  struct ui_out_hdr *header_next;

};


/* The ui_out structure */
/* Any change here requires a corresponding one in the initialization
   of the default uiout, which is statically initialized.  */

struct ui_out
  {
    int flags;
    /* Specific implementation of ui-out.  */
    const struct ui_out_impl *impl;
    void *data;

    /* Current level.  */
    int level;

    /* Vector to store and track the ui-out levels.  */
    VEC (ui_out_level_p) *levels;

    /* A table, if any.  At present only a single table is supported.  */
    struct ui_out_table table;
  };

/* The current (inner most) level.  */
static struct ui_out_level *
current_level (struct ui_out *uiout)
{
  return VEC_index (ui_out_level_p, uiout->levels, uiout->level);
}

/* Create a new level, of TYPE.  Return the new level's index.  */
static int
push_level (struct ui_out *uiout,
	    enum ui_out_type type,
	    const char *id)
{
  struct ui_out_level *current;

  uiout->level++;
  current = XNEW (struct ui_out_level);
  current->field_count = 0;
  current->type = type;
  VEC_safe_push (ui_out_level_p, uiout->levels, current);
  return uiout->level;
}

/* Discard the current level, return the discarded level's index.
   TYPE is the type of the level being discarded.  */
static int
pop_level (struct ui_out *uiout,
	   enum ui_out_type type)
{
  struct ui_out_level *current;

  /* We had better not underflow the buffer.  */
  gdb_assert (uiout->level > 0);
  gdb_assert (current_level (uiout)->type == type);
  current = VEC_pop (ui_out_level_p, uiout->levels);
  xfree (current);
  uiout->level--;
  return uiout->level + 1;
}


/* These are the default implementation functions.  */

static void default_table_begin (struct ui_out *uiout, int nbrofcols,
				 int nr_rows, const char *tblid);
static void default_table_body (struct ui_out *uiout);
static void default_table_end (struct ui_out *uiout);
static void default_table_header (struct ui_out *uiout, int width,
				  enum ui_align alig, const char *col_name,
				  const char *colhdr);
static void default_begin (struct ui_out *uiout,
			   enum ui_out_type type,
			   int level, const char *id);
static void default_end (struct ui_out *uiout,
			 enum ui_out_type type,
			 int level);
static void default_field_int (struct ui_out *uiout, int fldno, int width,
			       enum ui_align alig,
			       const char *fldname,
			       int value);
static void default_field_skip (struct ui_out *uiout, int fldno, int width,
				enum ui_align alig,
				const char *fldname);
static void default_field_string (struct ui_out *uiout, int fldno, int width,
				  enum ui_align align,
				  const char *fldname,
				  const char *string);
static void default_field_fmt (struct ui_out *uiout, int fldno,
			       int width, enum ui_align align,
			       const char *fldname,
			       const char *format,
			       va_list args) ATTRIBUTE_PRINTF (6, 0);
static void default_spaces (struct ui_out *uiout, int numspaces);
static void default_text (struct ui_out *uiout, const char *string);
static void default_message (struct ui_out *uiout, int verbosity,
			     const char *format,
			     va_list args) ATTRIBUTE_PRINTF (3, 0);
static void default_wrap_hint (struct ui_out *uiout, char *identstring);
static void default_flush (struct ui_out *uiout);
static void default_data_destroy (struct ui_out *uiout);

/* This is the default ui-out implementation functions vector.  */

const struct ui_out_impl default_ui_out_impl =
{
  default_table_begin,
  default_table_body,
  default_table_end,
  default_table_header,
  default_begin,
  default_end,
  default_field_int,
  default_field_skip,
  default_field_string,
  default_field_fmt,
  default_spaces,
  default_text,
  default_message,
  default_wrap_hint,
  default_flush,
  NULL, /* redirect */
  default_data_destroy,
  0, /* Does not need MI hacks.  */
};

/* The default ui_out */

struct ui_out def_uiout =
{
  0,				/* flags */
  &default_ui_out_impl,		/* impl */
};

/* Pointer to current ui_out */
/* FIXME: This should not be a global, but something passed down from main.c
   or top.c.  */

struct ui_out *current_uiout = &def_uiout;

/* These are the interfaces to implementation functions.  */

static void uo_table_begin (struct ui_out *uiout, int nbrofcols,
			    int nr_rows, const char *tblid);
static void uo_table_body (struct ui_out *uiout);
static void uo_table_end (struct ui_out *uiout);
static void uo_table_header (struct ui_out *uiout, int width,
			     enum ui_align align, const char *col_name,
			     const char *colhdr);
static void uo_begin (struct ui_out *uiout,
		      enum ui_out_type type,
		      int level, const char *id);
static void uo_end (struct ui_out *uiout,
		    enum ui_out_type type,
		    int level);
static void uo_field_int (struct ui_out *uiout, int fldno, int width,
			  enum ui_align align, const char *fldname, int value);
static void uo_field_skip (struct ui_out *uiout, int fldno, int width,
			   enum ui_align align, const char *fldname);
static void uo_field_fmt (struct ui_out *uiout, int fldno, int width,
			  enum ui_align align, const char *fldname,
			  const char *format, va_list args)
     ATTRIBUTE_PRINTF (6, 0);
static void uo_spaces (struct ui_out *uiout, int numspaces);
static void uo_text (struct ui_out *uiout, const char *string);
static void uo_message (struct ui_out *uiout, int verbosity,
			const char *format, va_list args)
     ATTRIBUTE_PRINTF (3, 0);
static void uo_wrap_hint (struct ui_out *uiout, char *identstring);
static void uo_flush (struct ui_out *uiout);
static int uo_redirect (struct ui_out *uiout, struct ui_file *outstream);
static void uo_data_destroy (struct ui_out *uiout);

/* Prototypes for local functions */

extern void _initialize_ui_out (void);
static void append_header_to_list (struct ui_out *uiout, int width,
				   enum ui_align alignment, const char *col_name,
				   const char *colhdr);
static int get_next_header (struct ui_out *uiout, int *colno, int *width,
			    enum ui_align *alignment, char **colhdr);
static void clear_header_list (struct ui_out *uiout);
static void clear_table (struct ui_out *uiout);
static void verify_field (struct ui_out *uiout, int *fldno, int *width,
			  enum ui_align *align);

/* exported functions (ui_out API) */

/* Mark beginning of a table.  */

static void
ui_out_table_begin (struct ui_out *uiout, int nbrofcols,
		    int nr_rows,
		    const char *tblid)
{
  if (uiout->table.flag)
    internal_error (__FILE__, __LINE__,
		    _("tables cannot be nested; table_begin found before \
previous table_end."));

  uiout->table.flag = 1;
  uiout->table.body_flag = 0;
  uiout->table.entry_level = uiout->level + 1;
  uiout->table.columns = nbrofcols;
  if (tblid != NULL)
    uiout->table.id = xstrdup (tblid);
  else
    uiout->table.id = NULL;
  clear_header_list (uiout);

  uo_table_begin (uiout, nbrofcols, nr_rows, uiout->table.id);
}

void
ui_out_table_body (struct ui_out *uiout)
{
  if (!uiout->table.flag)
    internal_error (__FILE__, __LINE__,
		    _("table_body outside a table is not valid; it must be \
after a table_begin and before a table_end."));
  if (uiout->table.body_flag)
    internal_error (__FILE__, __LINE__,
		    _("extra table_body call not allowed; there must be \
only one table_body after a table_begin and before a table_end."));
  if (uiout->table.header_next->colno != uiout->table.columns)
    internal_error (__FILE__, __LINE__,
		    _("number of headers differ from number of table \
columns."));

  uiout->table.body_flag = 1;
  uiout->table.header_next = uiout->table.header_first;

  uo_table_body (uiout);
}

static void
ui_out_table_end (struct ui_out *uiout)
{
  if (!uiout->table.flag)
    internal_error (__FILE__, __LINE__,
		    _("misplaced table_end or missing table_begin."));

  uiout->table.entry_level = 0;
  uiout->table.body_flag = 0;
  uiout->table.flag = 0;

  uo_table_end (uiout);
  clear_table (uiout);
}

void
ui_out_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
		     const char *col_name,
		     const char *colhdr)
{
  if (!uiout->table.flag || uiout->table.body_flag)
    internal_error (__FILE__, __LINE__,
		    _("table header must be specified after table_begin \
and before table_body."));

  append_header_to_list (uiout, width, alignment, col_name, colhdr);

  uo_table_header (uiout, width, alignment, col_name, colhdr);
}

static void
do_cleanup_table_end (void *data)
{
  struct ui_out *ui_out = data;

  ui_out_table_end (ui_out);
}

struct cleanup *
make_cleanup_ui_out_table_begin_end (struct ui_out *ui_out, int nr_cols,
                                     int nr_rows, const char *tblid)
{
  ui_out_table_begin (ui_out, nr_cols, nr_rows, tblid);
  return make_cleanup (do_cleanup_table_end, ui_out);
}

void
ui_out_begin (struct ui_out *uiout,
	      enum ui_out_type type,
	      const char *id)
{
  int new_level;

  if (uiout->table.flag && !uiout->table.body_flag)
    internal_error (__FILE__, __LINE__,
		    _("table header or table_body expected; lists must be \
specified after table_body."));

  /* Be careful to verify the ``field'' before the new tuple/list is
     pushed onto the stack.  That way the containing list/table/row is
     verified and not the newly created tuple/list.  This verification
     is needed (at least) for the case where a table row entry
     contains either a tuple/list.  For that case bookkeeping such as
     updating the column count or advancing to the next heading still
     needs to be performed.  */
  {
    int fldno;
    int width;
    enum ui_align align;

    verify_field (uiout, &fldno, &width, &align);
  }

  new_level = push_level (uiout, type, id);

  /* If the push puts us at the same level as a table row entry, we've
     got a new table row.  Put the header pointer back to the start.  */
  if (uiout->table.body_flag
      && uiout->table.entry_level == new_level)
    uiout->table.header_next = uiout->table.header_first;

  uo_begin (uiout, type, new_level, id);
}

void
ui_out_end (struct ui_out *uiout,
	    enum ui_out_type type)
{
  int old_level = pop_level (uiout, type);

  uo_end (uiout, type, old_level);
}

struct ui_out_end_cleanup_data
{
  struct ui_out *uiout;
  enum ui_out_type type;
};

static void
do_cleanup_end (void *data)
{
  struct ui_out_end_cleanup_data *end_cleanup_data = data;

  ui_out_end (end_cleanup_data->uiout, end_cleanup_data->type);
  xfree (end_cleanup_data);
}

static struct cleanup *
make_cleanup_ui_out_end (struct ui_out *uiout,
			 enum ui_out_type type)
{
  struct ui_out_end_cleanup_data *end_cleanup_data;

  end_cleanup_data = XNEW (struct ui_out_end_cleanup_data);
  end_cleanup_data->uiout = uiout;
  end_cleanup_data->type = type;
  return make_cleanup (do_cleanup_end, end_cleanup_data);
}

struct cleanup *
make_cleanup_ui_out_tuple_begin_end (struct ui_out *uiout,
				     const char *id)
{
  ui_out_begin (uiout, ui_out_type_tuple, id);
  return make_cleanup_ui_out_end (uiout, ui_out_type_tuple);
}

struct cleanup *
make_cleanup_ui_out_list_begin_end (struct ui_out *uiout,
				    const char *id)
{
  ui_out_begin (uiout, ui_out_type_list, id);
  return make_cleanup_ui_out_end (uiout, ui_out_type_list);
}

void
ui_out_field_int (struct ui_out *uiout,
		  const char *fldname,
		  int value)
{
  int fldno;
  int width;
  enum ui_align align;

  verify_field (uiout, &fldno, &width, &align);

  uo_field_int (uiout, fldno, width, align, fldname, value);
}

void
ui_out_field_fmt_int (struct ui_out *uiout,
                      int input_width,
                      enum ui_align input_align,
		      const char *fldname,
		      int value)
{
  int fldno;
  int width;
  enum ui_align align;

  verify_field (uiout, &fldno, &width, &align);

  uo_field_int (uiout, fldno, input_width, input_align, fldname, value);
}

/* Documented in ui-out.h.  */

void
ui_out_field_core_addr (struct ui_out *uiout,
			const char *fldname,
			struct gdbarch *gdbarch,
			CORE_ADDR address)
{
  ui_out_field_string (uiout, fldname,
		       print_core_address (gdbarch, address));
}

void
ui_out_field_stream (struct ui_out *uiout,
		     const char *fldname,
		     struct ui_file *stream)
{
  long length;
  char *buffer = ui_file_xstrdup (stream, &length);
  struct cleanup *old_cleanup = make_cleanup (xfree, buffer);

  if (length > 0)
    ui_out_field_string (uiout, fldname, buffer);
  else
    ui_out_field_skip (uiout, fldname);
  ui_file_rewind (stream);
  do_cleanups (old_cleanup);
}

/* Used to omit a field.  */

void
ui_out_field_skip (struct ui_out *uiout,
		   const char *fldname)
{
  int fldno;
  int width;
  enum ui_align align;

  verify_field (uiout, &fldno, &width, &align);

  uo_field_skip (uiout, fldno, width, align, fldname);
}

void
ui_out_field_string (struct ui_out *uiout,
		     const char *fldname,
		     const char *string)
{
  int fldno;
  int width;
  enum ui_align align;

  verify_field (uiout, &fldno, &width, &align);

  uo_field_string (uiout, fldno, width, align, fldname, string);
}

/* VARARGS */
void
ui_out_field_fmt (struct ui_out *uiout,
		  const char *fldname,
		  const char *format, ...)
{
  va_list args;
  int fldno;
  int width;
  enum ui_align align;

  /* Will not align, but has to call anyway.  */
  verify_field (uiout, &fldno, &width, &align);

  va_start (args, format);

  uo_field_fmt (uiout, fldno, width, align, fldname, format, args);

  va_end (args);
}

void
ui_out_spaces (struct ui_out *uiout, int numspaces)
{
  uo_spaces (uiout, numspaces);
}

void
ui_out_text (struct ui_out *uiout,
	     const char *string)
{
  uo_text (uiout, string);
}

void
ui_out_message (struct ui_out *uiout, int verbosity,
		const char *format,...)
{
  va_list args;

  va_start (args, format);
  uo_message (uiout, verbosity, format, args);
  va_end (args);
}

void
ui_out_wrap_hint (struct ui_out *uiout, char *identstring)
{
  uo_wrap_hint (uiout, identstring);
}

void
ui_out_flush (struct ui_out *uiout)
{
  uo_flush (uiout);
}

int
ui_out_redirect (struct ui_out *uiout, struct ui_file *outstream)
{
  return uo_redirect (uiout, outstream);
}

/* Set the flags specified by the mask given.  */
int
ui_out_set_flags (struct ui_out *uiout, int mask)
{
  int oldflags = uiout->flags;

  uiout->flags |= mask;
  return oldflags;
}

/* Clear the flags specified by the mask given.  */
int
ui_out_clear_flags (struct ui_out *uiout, int mask)
{
  int oldflags = uiout->flags;

  uiout->flags &= ~mask;
  return oldflags;
}

/* Test the flags against the mask given.  */
int
ui_out_test_flags (struct ui_out *uiout, int mask)
{
  return (uiout->flags & mask);
}

/* Obtain the current verbosity level (as stablished by the
   'set verbositylevel' command.  */

int
ui_out_get_verblvl (struct ui_out *uiout)
{
  /* FIXME: not implemented yet.  */
  return 0;
}

int
ui_out_is_mi_like_p (struct ui_out *uiout)
{
  return uiout->impl->is_mi_like_p;
}

/* Default gdb-out hook functions.  */

static void
default_table_begin (struct ui_out *uiout, int nbrofcols,
		     int nr_rows,
		     const char *tblid)
{
}

static void
default_table_body (struct ui_out *uiout)
{
}

static void
default_table_end (struct ui_out *uiout)
{
}

static void
default_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
		      const char *col_name,
		      const char *colhdr)
{
}

static void
default_begin (struct ui_out *uiout,
	       enum ui_out_type type,
	       int level,
	       const char *id)
{
}

static void
default_end (struct ui_out *uiout,
	     enum ui_out_type type,
	     int level)
{
}

static void
default_field_int (struct ui_out *uiout, int fldno, int width,
		   enum ui_align align,
		   const char *fldname, int value)
{
}

static void
default_field_skip (struct ui_out *uiout, int fldno, int width,
		    enum ui_align align, const char *fldname)
{
}

static void
default_field_string (struct ui_out *uiout,
		      int fldno,
		      int width,
		      enum ui_align align,
		      const char *fldname,
		      const char *string)
{
}

static void
default_field_fmt (struct ui_out *uiout, int fldno, int width,
		   enum ui_align align,
		   const char *fldname,
		   const char *format,
		   va_list args)
{
}

static void
default_spaces (struct ui_out *uiout, int numspaces)
{
}

static void
default_text (struct ui_out *uiout, const char *string)
{
}

static void
default_message (struct ui_out *uiout, int verbosity,
		 const char *format,
		 va_list args)
{
}

static void
default_wrap_hint (struct ui_out *uiout, char *identstring)
{
}

static void
default_flush (struct ui_out *uiout)
{
}

static void
default_data_destroy (struct ui_out *uiout)
{
}

/* Interface to the implementation functions.  */

void
uo_table_begin (struct ui_out *uiout, int nbrofcols,
		int nr_rows,
		const char *tblid)
{
  if (!uiout->impl->table_begin)
    return;
  uiout->impl->table_begin (uiout, nbrofcols, nr_rows, tblid);
}

void
uo_table_body (struct ui_out *uiout)
{
  if (!uiout->impl->table_body)
    return;
  uiout->impl->table_body (uiout);
}

void
uo_table_end (struct ui_out *uiout)
{
  if (!uiout->impl->table_end)
    return;
  uiout->impl->table_end (uiout);
}

void
uo_table_header (struct ui_out *uiout, int width, enum ui_align align,
		 const char *col_name,
		 const char *colhdr)
{
  if (!uiout->impl->table_header)
    return;
  uiout->impl->table_header (uiout, width, align, col_name, colhdr);
}

/* Clear the table associated with UIOUT.  */

static void
clear_table (struct ui_out *uiout)
{
  xfree (uiout->table.id);
  uiout->table.id = NULL;
  clear_header_list (uiout);
}

void
uo_begin (struct ui_out *uiout,
	  enum ui_out_type type,
	  int level,
	  const char *id)
{
  if (uiout->impl->begin == NULL)
    return;
  uiout->impl->begin (uiout, type, level, id);
}

void
uo_end (struct ui_out *uiout,
	enum ui_out_type type,
	int level)
{
  if (uiout->impl->end == NULL)
    return;
  uiout->impl->end (uiout, type, level);
}

void
uo_field_int (struct ui_out *uiout, int fldno, int width, enum ui_align align,
	      const char *fldname,
	      int value)
{
  if (!uiout->impl->field_int)
    return;
  uiout->impl->field_int (uiout, fldno, width, align, fldname, value);
}

void
uo_field_skip (struct ui_out *uiout, int fldno, int width, enum ui_align align,
	       const char *fldname)
{
  if (!uiout->impl->field_skip)
    return;
  uiout->impl->field_skip (uiout, fldno, width, align, fldname);
}

void
uo_field_string (struct ui_out *uiout, int fldno, int width,
		 enum ui_align align,
		 const char *fldname,
		 const char *string)
{
  if (!uiout->impl->field_string)
    return;
  uiout->impl->field_string (uiout, fldno, width, align, fldname, string);
}

void
uo_field_fmt (struct ui_out *uiout, int fldno, int width, enum ui_align align,
	      const char *fldname,
	      const char *format,
	      va_list args)
{
  if (!uiout->impl->field_fmt)
    return;
  uiout->impl->field_fmt (uiout, fldno, width, align, fldname, format, args);
}

void
uo_spaces (struct ui_out *uiout, int numspaces)
{
  if (!uiout->impl->spaces)
    return;
  uiout->impl->spaces (uiout, numspaces);
}

void
uo_text (struct ui_out *uiout,
	 const char *string)
{
  if (!uiout->impl->text)
    return;
  uiout->impl->text (uiout, string);
}

void
uo_message (struct ui_out *uiout, int verbosity,
	    const char *format,
	    va_list args)
{
  if (!uiout->impl->message)
    return;
  uiout->impl->message (uiout, verbosity, format, args);
}

void
uo_wrap_hint (struct ui_out *uiout, char *identstring)
{
  if (!uiout->impl->wrap_hint)
    return;
  uiout->impl->wrap_hint (uiout, identstring);
}

void
uo_flush (struct ui_out *uiout)
{
  if (!uiout->impl->flush)
    return;
  uiout->impl->flush (uiout);
}

int
uo_redirect (struct ui_out *uiout, struct ui_file *outstream)
{
  if (!uiout->impl->redirect)
    return -1;
  uiout->impl->redirect (uiout, outstream);
  return 0;
}

void
uo_data_destroy (struct ui_out *uiout)
{
  if (!uiout->impl->data_destroy)
    return;

  uiout->impl->data_destroy (uiout);
}

/* local functions */

/* List of column headers manipulation routines.  */

static void
clear_header_list (struct ui_out *uiout)
{
  while (uiout->table.header_first != NULL)
    {
      uiout->table.header_next = uiout->table.header_first;
      uiout->table.header_first = uiout->table.header_first->next;
      xfree (uiout->table.header_next->colhdr);
      xfree (uiout->table.header_next->col_name);
      xfree (uiout->table.header_next);
    }
  gdb_assert (uiout->table.header_first == NULL);
  uiout->table.header_last = NULL;
  uiout->table.header_next = NULL;
}

static void
append_header_to_list (struct ui_out *uiout,
		       int width,
		       enum ui_align alignment,
		       const char *col_name,
		       const char *colhdr)
{
  struct ui_out_hdr *temphdr;

  temphdr = XNEW (struct ui_out_hdr);
  temphdr->width = width;
  temphdr->alignment = alignment;
  /* We have to copy the column title as the original may be an
     automatic.  */
  if (colhdr != NULL)
    temphdr->colhdr = xstrdup (colhdr);
  else
    temphdr->colhdr = NULL;

  if (col_name != NULL)
    temphdr->col_name = xstrdup (col_name);
  else if (colhdr != NULL)
    temphdr->col_name = xstrdup (colhdr);
  else
    temphdr->col_name = NULL;

  temphdr->next = NULL;
  if (uiout->table.header_first == NULL)
    {
      temphdr->colno = 1;
      uiout->table.header_first = temphdr;
      uiout->table.header_last = temphdr;
    }
  else
    {
      temphdr->colno = uiout->table.header_last->colno + 1;
      uiout->table.header_last->next = temphdr;
      uiout->table.header_last = temphdr;
    }
  uiout->table.header_next = uiout->table.header_last;
}

/* Extract the format information for the NEXT header and advance
   the header pointer.  Return 0 if there was no next header.  */

static int
get_next_header (struct ui_out *uiout,
		 int *colno,
		 int *width,
		 enum ui_align *alignment,
		 char **colhdr)
{
  /* There may be no headers at all or we may have used all columns.  */
  if (uiout->table.header_next == NULL)
    return 0;
  *colno = uiout->table.header_next->colno;
  *width = uiout->table.header_next->width;
  *alignment = uiout->table.header_next->alignment;
  *colhdr = uiout->table.header_next->colhdr;
  /* Advance the header pointer to the next entry.  */
  uiout->table.header_next = uiout->table.header_next->next;
  return 1;
}


/* Verify that the field/tuple/list is correctly positioned.  Return
   the field number and corresponding alignment (if
   available/applicable).  */

static void
verify_field (struct ui_out *uiout, int *fldno, int *width,
	      enum ui_align *align)
{
  struct ui_out_level *current = current_level (uiout);
  char *text;

  if (uiout->table.flag)
    {
      if (!uiout->table.body_flag)
	internal_error (__FILE__, __LINE__,
			_("table_body missing; table fields must be \
specified after table_body and inside a list."));
      /* NOTE: cagney/2001-12-08: There was a check here to ensure
	 that this code was only executed when uiout->level was
	 greater than zero.  That no longer applies - this code is run
	 before each table row tuple is started and at that point the
	 level is zero.  */
    }

  current->field_count += 1;

  if (uiout->table.body_flag
      && uiout->table.entry_level == uiout->level
      && get_next_header (uiout, fldno, width, align, &text))
    {
      if (*fldno != current->field_count)
	internal_error (__FILE__, __LINE__,
			_("ui-out internal error in handling headers."));
    }
  else
    {
      *width = 0;
      *align = ui_noalign;
      *fldno = current->field_count;
    }
}


/* Access to ui-out members data.  */

void *
ui_out_data (struct ui_out *uiout)
{
  return uiout->data;
}

/* Access table field parameters.  */
int
ui_out_query_field (struct ui_out *uiout, int colno,
		    int *width, int *alignment, char **col_name)
{
  struct ui_out_hdr *hdr;

  if (!uiout->table.flag)
    return 0;

  for (hdr = uiout->table.header_first; hdr; hdr = hdr->next)
    if (hdr->colno == colno)
      {
	*width = hdr->width;
	*alignment = hdr->alignment;
	*col_name = hdr->col_name;
	return 1;
      }

  return 0;
}

/* Initalize private members at startup.  */

struct ui_out *
ui_out_new (const struct ui_out_impl *impl, void *data,
	    int flags)
{
  struct ui_out *uiout = XNEW (struct ui_out);
  struct ui_out_level *current = XNEW (struct ui_out_level);

  uiout->data = data;
  uiout->impl = impl;
  uiout->flags = flags;
  uiout->table.flag = 0;
  uiout->table.body_flag = 0;
  uiout->level = 0;
  uiout->levels = NULL;

  /* Create uiout->level 0, the default level.  */
  current->type = ui_out_type_tuple;
  current->field_count = 0;
  VEC_safe_push (ui_out_level_p, uiout->levels, current);

  uiout->table.id = NULL;
  uiout->table.header_first = NULL;
  uiout->table.header_last = NULL;
  uiout->table.header_next = NULL;
  return uiout;
}

/* Free  UIOUT and the memory areas it references.  */

void
ui_out_destroy (struct ui_out *uiout)
{
  int i;
  struct ui_out_level *current;

  /* Make sure that all levels are freed in the case where levels have
     been pushed, but not popped before the ui_out object is
     destroyed.  */
  for (i = 0;
       VEC_iterate (ui_out_level_p, uiout->levels, i, current);
       ++i)
    xfree (current);

  VEC_free (ui_out_level_p, uiout->levels);
  uo_data_destroy (uiout);
  clear_table (uiout);
  xfree (uiout);
}

/* Standard gdb initialization hook.  */

void
_initialize_ui_out (void)
{
  /* nothing needs to be done */
}