From bd1985eb89916da6815e4f3f6afa5f4f7a2070ff Mon Sep 17 00:00:00 2001
From: massiot <massiot@271ca591-50e6-457e-a4d7-9fbfa1de8f49>
Date: Thu, 7 Jan 2010 23:30:42 +0000
Subject:  * Initial import.

git-svn-id: svn://svn.videolan.org/multicat/trunk@1 271ca591-50e6-457e-a4d7-9fbfa1de8f49
---
 offsets.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 offsets.c

(limited to 'offsets.c')

diff --git a/offsets.c b/offsets.c
new file mode 100644
index 0000000..364eb7d
--- /dev/null
+++ b/offsets.c
@@ -0,0 +1,129 @@
+/*****************************************************************************
+ * offsets.c: find position in an aux file
+ *****************************************************************************
+ * Copyright (C) 2009 VideoLAN
+ * $Id: offsets.c 10 2005-11-16 18:09:00Z cmassiot $
+ *
+ * Authors: Christophe Massiot <massiot@via.ecp.fr>
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+/*****************************************************************************
+ * Entry point
+ *****************************************************************************/
+int main( int i_argc, char **pp_argv )
+{
+    uint8_t *p_aux;
+    uint64_t i_wanted;
+    off_t i_offset1 = 0, i_offset2;
+    int i_stc_fd;
+    struct stat stc_stat;
+    uint64_t i_stc0;
+
+    if ( i_argc != 3 )
+    {
+        fprintf( stderr, "Usage: offsets <aux file> <27 MHz timestamp>\n" );
+        exit(EXIT_FAILURE);
+    }
+
+    i_wanted = strtoull( pp_argv[2], NULL, 0 );
+    if ( !i_wanted )
+    {
+        printf( "0\n" );
+        exit(EXIT_SUCCESS);
+    }
+
+    if ( (i_stc_fd = open( pp_argv[1], O_RDONLY )) == -1 )
+    {
+        fprintf( stderr, "unable to open %s (%s)\n", pp_argv[1],
+                 strerror(errno) );
+        exit(EXIT_FAILURE);
+    }
+
+    if ( fstat( i_stc_fd, &stc_stat ) == -1 )
+    {
+        fprintf( stderr, "unable to stat %s (%s)\n", pp_argv[1],
+                 strerror(errno) );
+        exit(EXIT_FAILURE);
+    }
+
+    p_aux = mmap( NULL, stc_stat.st_size, PROT_READ, MAP_SHARED,
+                  i_stc_fd, 0 );
+    if ( p_aux == MAP_FAILED )
+    {
+        fprintf( stderr, "unable to mmap %s (%s)\n", pp_argv[1],
+                 strerror(errno) );
+        exit(EXIT_FAILURE);
+    }
+
+    if ( p_aux[0] == 0x47 && p_aux[188] == 0x47 && p_aux[376] == 0x47 )
+    {
+        fprintf( stderr, "this is a TS file, not an aux file\n" );
+        exit(EXIT_FAILURE);
+    }
+
+    i_offset2 = stc_stat.st_size / sizeof(uint64_t);
+    i_stc0 = ((uint64_t)p_aux[0] << 56)
+              | ((uint64_t)p_aux[1] << 48)
+              | ((uint64_t)p_aux[2] << 40)
+              | ((uint64_t)p_aux[3] << 32)
+              | ((uint64_t)p_aux[4] << 24)
+              | ((uint64_t)p_aux[5] << 16)
+              | ((uint64_t)p_aux[6] << 8)
+              | ((uint64_t)p_aux[7] << 0);
+
+    for ( ; ; )
+    {
+        off_t i_mid_offset = (i_offset1 + i_offset2) / 2;
+        uint8_t *p_mid_aux = p_aux + i_mid_offset * sizeof(uint64_t);
+        uint64_t i_mid_stc = ((uint64_t)p_mid_aux[0] << 56)
+                              | ((uint64_t)p_mid_aux[1] << 48)
+                              | ((uint64_t)p_mid_aux[2] << 40)
+                              | ((uint64_t)p_mid_aux[3] << 32)
+                              | ((uint64_t)p_mid_aux[4] << 24)
+                              | ((uint64_t)p_mid_aux[5] << 16)
+                              | ((uint64_t)p_mid_aux[6] << 8)
+                              | ((uint64_t)p_mid_aux[7] << 0);
+
+
+        if ( i_offset1 == i_mid_offset )
+            break;
+
+        if ( i_mid_stc - i_stc0 >= i_wanted )
+            i_offset2 = i_mid_offset;
+        else
+            i_offset1 = i_mid_offset;
+    }
+
+    munmap( p_aux, stc_stat.st_size );
+    close( i_stc_fd );
+
+    printf( "%jd\n", (intmax_t)i_offset2 );
+
+    exit(EXIT_SUCCESS);
+}
+
-- 
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