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 "src/wtools.h"
  43
  44 #include "lib/vfs/mc-vfs/vfs.h"
  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 /*** public functions ****************************************************************************/
  62
  63 /* --------------------------------------------------------------------------------------------- */
  64
  65 void
  66 mcview_growbuf_init (mcview_t * view)
  67 {
  68     view->growbuf_in_use = TRUE;
  69     view->growbuf_blockptr = g_ptr_array_new ();
  70     view->growbuf_lastindex = VIEW_PAGE_SIZE;
  71     view->growbuf_finished = FALSE;
  72 }
  73
  74 /* --------------------------------------------------------------------------------------------- */
  75
  76 void
  77 mcview_growbuf_free (mcview_t * view)
  78 {
  79     assert (view->growbuf_in_use);
  80
  81     g_ptr_array_foreach (view->growbuf_blockptr, (GFunc) g_free, NULL);
  82
  83     (void) g_ptr_array_free (view->growbuf_blockptr, TRUE);
  84
  85     view->growbuf_blockptr = NULL;
  86     view->growbuf_in_use = FALSE;
  87 }
  88
  89 /* --------------------------------------------------------------------------------------------- */
  90
  91 off_t
  92 mcview_growbuf_filesize (mcview_t * view)
  93 {
  94     assert (view->growbuf_in_use);
  95
  96     if (view->growbuf_blockptr->len == 0)
  97         return 0;
  98     else
  99         return ((off_t) view->growbuf_blockptr->len - 1) * VIEW_PAGE_SIZE + view->growbuf_lastindex;
 100 }
 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 void
 108 mcview_growbuf_read_until (mcview_t * view, off_t ofs)
 109 {
 110     ssize_t nread;
 111     byte *p;
 112     size_t bytesfree;
 113     gboolean short_read;
 114
 115     assert (view->growbuf_in_use);
 116
 117     if (view->growbuf_finished)
 118         return;
 119
 120     short_read = FALSE;
 121     while (mcview_growbuf_filesize (view) < ofs || short_read) {
 122         if (view->growbuf_lastindex == VIEW_PAGE_SIZE) {
 123             /* Append a new block to the growing buffer */
 124             byte *newblock = g_try_malloc (VIEW_PAGE_SIZE);
 125             if (newblock == NULL)
 126                 return;
 127
 128             g_ptr_array_add (view->growbuf_blockptr, newblock);
 129             view->growbuf_lastindex = 0;
 130         }
 131         p = g_ptr_array_index(
 132                             view->growbuf_blockptr,
 133                             view->growbuf_blockptr->len - 1)
 134             + view->growbuf_lastindex;
 135
 136         bytesfree = VIEW_PAGE_SIZE - view->growbuf_lastindex;
 137
 138         if (view->datasource == DS_STDIO_PIPE) {
 139             nread = fread (p, 1, bytesfree, view->ds_stdio_pipe);
 140             if (nread == 0) {
 141                 view->growbuf_finished = TRUE;
 142                 (void) pclose (view->ds_stdio_pipe);
 143                 mcview_display (view);
 144                 close_error_pipe (D_NORMAL, NULL);
 145                 view->ds_stdio_pipe = NULL;
 146                 return;
 147             }
 148         } else {
 149                 assert (view->datasource == DS_VFS_PIPE);
 150             do {
 151                 nread = mc_read (view->ds_vfs_pipe, p, bytesfree);
 152             } while (nread == -1 && errno == EINTR);
 153             if (nread == -1 || nread == 0) {
 154                 view->growbuf_finished = TRUE;
 155                 (void) mc_close (view->ds_vfs_pipe);
 156                 view->ds_vfs_pipe = -1;
 157                 return;
 158             }
 159         }
 160         short_read = ((size_t) nread < bytesfree);
 161         view->growbuf_lastindex += nread;
 162     }
 163 }
 164
 165 /* --------------------------------------------------------------------------------------------- */
 166
 167 gboolean
 168 mcview_get_byte_growing_buffer (mcview_t * view, off_t byte_index, int *retval)
 169 {
 170     off_t pageno;
 171     off_t pageindex;
 172
 173     if (retval)
 174         *retval = -1;
 175
 176     pageno = byte_index / VIEW_PAGE_SIZE;
 177     pageindex = byte_index % VIEW_PAGE_SIZE;
 178
 179     assert (view->growbuf_in_use);
 180
 181     if (pageno < 0)
 182         return FALSE;
 183
 184     mcview_growbuf_read_until (view, byte_index + 1);
 185     if (view->growbuf_blockptr->len == 0)
 186         return FALSE;
 187     if (pageno < view->growbuf_blockptr->len - 1) {
 188         if (retval)
 189             *retval = *((byte *) (g_ptr_array_index(view->growbuf_blockptr, pageno) + pageindex));
 190         return TRUE;
 191     }
 192     if (pageno == view->growbuf_blockptr->len - 1 && pageindex < (off_t) view->growbuf_lastindex) {
 193         if (retval)
 194             *retval = *((byte *) (g_ptr_array_index(view->growbuf_blockptr, pageno) + pageindex));
 195         return TRUE;
 196     }
 197     return FALSE;
 198 }
 199
 200 /* --------------------------------------------------------------------------------------------- */
 201
 202 char *
 203 mcview_get_ptr_growing_buffer (mcview_t * view, off_t byte_index)
 204 {
 205     off_t pageno = byte_index / VIEW_PAGE_SIZE;
 206     off_t pageindex = byte_index % VIEW_PAGE_SIZE;
 207
 208     assert (view->growbuf_in_use);
 209
 210     if (pageno < 0)
 211         return NULL;
 212
 213     mcview_growbuf_read_until (view, byte_index + 1);
 214     if (view->growbuf_blockptr->len == 0)
 215         return NULL;
 216     if (pageno < view->growbuf_blockptr->len - 1)
 217         return (char *) (g_ptr_array_index(view->growbuf_blockptr, pageno) + pageindex);
 218     if (pageno == view->growbuf_blockptr->len - 1 && pageindex < (off_t) view->growbuf_lastindex)
 219         return (char *) (g_ptr_array_index(view->growbuf_blockptr, pageno) + pageindex);
 220     return NULL;
 221 }
 222
 223 /* --------------------------------------------------------------------------------------------- */