gEDA-cvs: CVS update: s_textbuffer.c

[cvspsrv@xxxxxxxx]

  User: peterb  
  Date: 07/05/28 03:31:36

  Added:       .        s_textbuffer.c
  Log:
  Add new file omitted in previous commit.
  
  
  
  
  Revision  Changes    Path
  1.1                  eda/geda/gaf/libgeda/src/s_textbuffer.c
  
  Index: s_textbuffer.c
  ===================================================================
  /* gEDA - GPL Electronic Design Automation
   * libgeda - gEDA's library
   * Copyright (C) 1998-2000 Ales V. Hvezda
   *
   * 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 2 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, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA
   */
  
  #include <config.h>
  
  #include <glib.h>
  
  #ifdef HAVE_STRING_H
  #include <string.h>
  #endif
  
  #ifdef HAVE_LIBDMALLOC
  #include <dmalloc.h>
  #endif
  
  #include <gtk/gtk.h>
  #include <libguile.h>
  
  #include "defines.h"
  #include "struct.h"
  #include "globals.h"
  #include "o_types.h"
  #include "colors.h"
  #include "i_vars.h"
  #include "prototype.h"
  
  struct _TextBuffer
  {
    gchar *buffer;
    gsize size;
  
    gchar *line;
    gsize linesize;
  
    gsize offset;
  };
  
  #define TEXT_BUFFER_LINE_SIZE 1024
  
  /*! \brief Create a new managed text buffer.
   *
   *  \par Function description 
   *  Allocates and initialises a new TextBuffer to manage the given data
   *  buffer.
   *
   *  If the size argument is negative, assumes that data is
   *  null-terminated.
   *
   *  \param data The address of the buffer to be managed.
   *  \param size The length of the buffer.
   *  \retval Pointer to a new TextBuffer struct.
   */
  TextBuffer *s_textbuffer_new (gchar *data, const gint size)
  {
    TextBuffer *result;
    gsize realsize;
  
    g_assert (data != NULL);
  
    if (size < 0)
      realsize = strlen(data);
    else
      realsize = size;
  
    result = g_new0(TextBuffer, 1);
  
    result->buffer = data;
    result->size = realsize;
  
    result->linesize = TEXT_BUFFER_LINE_SIZE;
    result->line = g_malloc(result->linesize);
  
    return result;
  }
  
  /*! \brief Clean up a managed text buffer
   *
   *  \par Function description
   *  Cleans up all of the resources associated with a given TextBuffer.
   *
   *  Should be called thus:
   *
   *  \code
   *  tb = s_textbuffer_free (tb);
   *  \endcode
   */
  TextBuffer *s_textbuffer_free (TextBuffer *tb)
  {
    if (tb == NULL) return NULL;
  
    g_free (tb->line);
    tb->line = NULL;
    g_free (tb);
    return NULL;
  }
  
  /*! \brief Change the current position within a text buffer
   *
   *  \par Function description
   *  Changes where the next call to s_textbuffer_next() will start
   *  reading.  If offset is negative, it is considered as a distance
   *  from the end of the buffer.
   *
   *  \param tb     A TextBuffer to seek within.
   *  \param offset A new position within the buffer.
   */
  void s_textbuffer_seek (TextBuffer *tb, const gint offset)
  {
    gint ofs;
    gsize realoffset;
  
    if (tb == NULL) return;
  
    ofs = offset;
    if (ofs > tb->size)
      ofs = tb->size;
  
    if (ofs < -tb->size)
      ofs = 0;
  
    if (ofs < 0)
      realoffset = tb->size - ofs;
    else
      realoffset = ofs;
  
    tb->offset = realoffset;
  }
  
  /*! \brief Fetch a number of characters from a text buffer
   *
   *  \par Function description
   *  Get some number of characters from a TextBuffer, starting at the
   *  current position.  If the end of the buffer has been reached (and
   *  thus no more characters remain) returns null.
   *
   *  The returned character array should be considered highly volatile,
   *  and is only valid until the next call to s_textbuffer_next() or
   *  s_textbuffer_next_line().
   *
   *  \param tb    TextBuffer to read from.
   *  \param count Maximum number of characters to read.
   *  \retval      Character array, or NULL if no characters left.
   */
  gchar *s_textbuffer_next (TextBuffer *tb, const gsize count)
  {
    gsize len = count;
    gsize maxlen = tb->size - tb->offset;
  
    if (tb == NULL) return NULL;
  
    if (count == 0) return NULL;
  
    if (tb->offset >= tb->size) 
      return NULL;
  
    if (len > maxlen) 
      len = maxlen;
  
    if (tb->linesize < len + 1) {
      tb->line = g_realloc(tb->line, len + 1);
      tb->linesize = len + 1;
    }
  
    strncpy (tb->line, tb->buffer + tb->offset, len);
  
    tb->line[len] = 0;
    tb->offset += len;
  
    return tb->line;
  }
  /*! \brief Fetch the next line from a text buffer
   *
   *  \par Function description
   *  Get the next line of characters from a TextBuffer, starting from
   *  the current position.  If the end of the buffer has been reached
   *  (and thus no more characters remain) returns null.
   *
   *  The returned character array should be considered highly volatile,
   *  and is only valid until the next call to s_textbuffer_next() or
   *  s_textbuffer_next_line().
   *
   *  \param tb    TextBuffer to read from.
   *  \retval      Character array, or NULL if no characters left.
   */
  gchar *s_textbuffer_next_line (TextBuffer *tb)
  {
    int len = 0;
  
    if (tb == NULL) return NULL;
  
    if (tb->offset >= tb->size) 
      return NULL;
  
    while ((tb->buffer[tb->offset + len] != '\n')
  	 && (len < tb->size - tb->offset - 1)) {
      len++;
    }
  
    len++;
  
    return s_textbuffer_next (tb, len);
  }
  
  
  


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