src/viewer/growbuf.c

   1 /*
   2    Internal file viewer for the Midnight Commander
   3    Function for work with growing bufers
   4
   5    Copyright (C) 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003,
   6    2004, 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
   7
   8    Written by: 1994, 1995, 1998 Miguel de Icaza
   9    1994, 1995 Janne Kukonlehto
  10    1995 Jakub Jelinek
  11    1996 Joseph M. Hinkle
  12    1997 Norbert Warmuth
  13    1998 Pavel Machek
  14    2004 Roland Illig <roland.illig@gmx.de>
  15    2005 Roland Illig <roland.illig@gmx.de>
  16    2009 Slava Zanko <slavazanko@google.com>
  17    2009 Andrew Borodin <aborodin@vmail.ru>
  18    2009 Ilia Maslakov <il.smind@gmail.com>
  19
  20    This file is part of the Midnight Commander.
  21
  22    The Midnight Commander is free software; you can redistribute it
  23    and/or modify it under the terms of the GNU General Public License as
  24    published by the Free Software Foundation; either version 2 of the
  25    License, or (at your option) any later version.
  26
  27    The Midnight Commander is distributed in the hope that it will be
  28    useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  29    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  30    General Public License for more details.
  31
  32    You should have received a copy of the GNU General Public License
  33    along with this program; if not, write to the Free Software
  34    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  35    MA 02110-1301, USA.
  36  */
  37
  38 #include <config.h>
  39 #include <errno.h>
  40
  41 #include "lib/global.h"
  42 #include "lib/vfs/vfs.h"
  43 #include "lib/util.h"
  44 #include "lib/widget.h"         /* D_NORMAL */
  45
  46 #include "internal.h"
  47
  48 /* Block size for reading files in parts */
  49 #define VIEW_PAGE_SIZE ((size_t) 8192)
  50
  51 /*** global variables ****************************************************************************/
  52
  53 /*** file scope macro definitions ****************************************************************/
  54
  55 /*** file scope type declarations ****************************************************************/
  56
  57 /*** file scope variables ************************************************************************/
  58
  59 /*** file scope functions ************************************************************************/
  60 /* --------------------------------------------------------------------------------------------- */
  61
  62 /* --------------------------------------------------------------------------------------------- */
  63 /*** public functions ****************************************************************************/
  64 /* --------------------------------------------------------------------------------------------- */
  65
  66 void
  67 mcview_growbuf_init (mcview_t * view)
  68 {
  69     view->growbuf_in_use = TRUE;
  70     view->growbuf_blockptr = g_ptr_array_new ();
  71     view->growbuf_lastindex = VIEW_PAGE_SIZE;
  72     view->growbuf_finished = FALSE;
  73 }
  74
  75 /* --------------------------------------------------------------------------------------------- */
  76
  77 void
  78 mcview_growbuf_free (mcview_t * view)
  79 {
  80     assert (view->growbuf_in_use);
  81
  82     g_ptr_array_foreach (view->growbuf_blockptr, (GFunc) g_free, NULL);
  83
  84     (void) g_ptr_array_free (view->growbuf_blockptr, TRUE);
  85
  86     view->growbuf_blockptr = NULL;
  87     view->growbuf_in_use = FALSE;
  88 }
  89
  90 /* --------------------------------------------------------------------------------------------- */
  91
  92 off_t
  93 mcview_growbuf_filesize (mcview_t * view)
  94 {
  95     assert (view->growbuf_in_use);
  96
  97     if (view->growbuf_blockptr->len == 0)
  98         return 0;
  99     else
 100         return ((off_t) view->growbuf_blockptr->len - 1) * VIEW_PAGE_SIZE + view->growbuf_lastindex;
 101 }
 102
 103 /* --------------------------------------------------------------------------------------------- */
 104 /** Copies the output from the pipe to the growing buffer, until either
 105  * the end-of-pipe is reached or the interval [0..ofs) of the growing
 106  * buffer is completely filled.
 107  */
 108
 109 void
 110 mcview_growbuf_read_until (mcview_t * view, off_t ofs)
 111 {
 112     ssize_t nread;
 113     byte *p;
 114     size_t bytesfree;
 115     gboolean short_read;
 116
 117     assert (view->growbuf_in_use);
 118
 119     if (view->growbuf_finished)
 120         return;
 121
 122     short_read = FALSE;
 123     while (mcview_growbuf_filesize (view) < ofs || short_read)
 124     {
 125         if (view->growbuf_lastindex == VIEW_PAGE_SIZE)
 126         {
 127             /* Append a new block to the growing buffer */
 128             byte *newblock = g_try_malloc (VIEW_PAGE_SIZE);
 129             if (newblock == NULL)
 130                 return;
 131
 132             g_ptr_array_add (view->growbuf_blockptr, newblock);
 133             view->growbuf_lastindex = 0;
 134         }
 135         p = g_ptr_array_index (view->growbuf_blockptr,
 136                                view->growbuf_blockptr->len - 1) + view->growbuf_lastindex;
 137
 138         bytesfree = VIEW_PAGE_SIZE - view->growbuf_lastindex;
 139
 140         if (view->datasource == DS_STDIO_PIPE)
 141         {
 142             nread = fread (p, 1, bytesfree, view->ds_stdio_pipe);
 143             if (nread == 0)
 144             {
 145                 view->growbuf_finished = TRUE;
 146                 (void) pclose (view->ds_stdio_pipe);
 147                 mcview_display (view);
 148                 close_error_pipe (D_NORMAL, NULL);
 149                 view->ds_stdio_pipe = NULL;
 150                 return;
 151             }
 152         }
 153         else
 154         {
 155             assert (view->datasource == DS_VFS_PIPE);
 156             do
 157             {
 158                 nread = mc_read (view->ds_vfs_pipe, p, bytesfree);
 159             }
 160             while (nread == -1 && errno == EINTR);
 161             if (nread == -1 || nread == 0)
 162             {
 163                 view->growbuf_finished = TRUE;
 164                 (void) mc_close (view->ds_vfs_pipe);
 165                 view->ds_vfs_pipe = -1;
 166                 return;
 167             }
 168         }
 169         short_read = ((size_t) nread < bytesfree);
 170         view->growbuf_lastindex += nread;
 171     }
 172 }
 173
 174 /* --------------------------------------------------------------------------------------------- */
 175
 176 gboolean
 177 mcview_get_byte_growing_buffer (mcview_t * view, off_t byte_index, int *retval)
 178 {
 179     off_t pageno;
 180     off_t pageindex;
 181
 182     if (retval != NULL)
 183         *retval = -1;
 184
 185     pageno = byte_index / VIEW_PAGE_SIZE;
 186     pageindex = byte_index % VIEW_PAGE_SIZE;
 187
 188     assert (view->growbuf_in_use);
 189
 190     if (pageno < 0)
 191         return FALSE;
 192
 193     mcview_growbuf_read_until (view, byte_index + 1);
 194     if (view->growbuf_blockptr->len == 0)
 195         return FALSE;
 196     if (pageno < (off_t) view->growbuf_blockptr->len - 1)
 197     {
 198         if (retval != NULL)
 199             *retval = *((byte *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex));
 200         return TRUE;
 201     }
 202     if (pageno == (off_t) view->growbuf_blockptr->len - 1
 203         && pageindex < (off_t) view->growbuf_lastindex)
 204     {
 205         if (retval != NULL)
 206             *retval = *((byte *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex));
 207         return TRUE;
 208     }
 209     return FALSE;
 210 }
 211
 212 /* --------------------------------------------------------------------------------------------- */
 213
 214 char *
 215 mcview_get_ptr_growing_buffer (mcview_t * view, off_t byte_index)
 216 {
 217     off_t pageno = byte_index / VIEW_PAGE_SIZE;
 218     off_t pageindex = byte_index % VIEW_PAGE_SIZE;
 219
 220     assert (view->growbuf_in_use);
 221
 222     if (pageno < 0)
 223         return NULL;
 224
 225     mcview_growbuf_read_until (view, byte_index + 1);
 226     if (view->growbuf_blockptr->len == 0)
 227         return NULL;
 228     if (pageno < (off_t) view->growbuf_blockptr->len - 1)
 229         return (char *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex);
 230     if (pageno == (off_t) view->growbuf_blockptr->len - 1
 231         && pageindex < (off_t) view->growbuf_lastindex)
 232         return (char *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex);
 233     return NULL;
 234 }
 235
 236 /* --------------------------------------------------------------------------------------------- */