[libdvdcss-devel] Add dvdcss_open_stream() API function

libdvdcss | branch: master | Thomas Guillem <[email protected]> | Tue Jan 27 15:54:44 2015 +0100| [f72b87294908e6fd28c79558bb7519e0bef1a3c9] | committer: Jean-Baptiste Kempf

Add dvdcss_open_stream() API function

This allows opening a DVD device using external read/seek callbacks.

Signed-off-by: Diego Biurrun <[email protected]>
Signed-off-by: Jean-Baptiste Kempf <[email protected]>

> http://git.videolan.org/gitweb.cgi/libdvdcss.git/?a=commit;h=f72b87294908e6fd28c79558bb7519e0bef1a3c9
---

 NEWS                |    2 +
 src/device.c        |  110 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/dvdcss/dvdcss.h |   15 +++++++
 src/libdvdcss.c     |   30 ++++++++++++++
 src/libdvdcss.h     |    3 ++
 5 files changed, 158 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 17dd7e7..01743c7 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ Changes since 1.3.0:
   * Drop support for Windows 9x and Windows NT.
     Windows 2000 is now required.
   * Replace BeOS support by Haiku support.
+  * Add dvdcss_open_stream() to public API. This allows installing custom
+    callback functions for accessing DVD, e.g. over the network.
   * dvdcss_error() now returns "const char *" instad of "char *".
   * Drop support for MSVC versions before 2010.
   * Raw device access now errors out if the device cannot be opened.
diff --git a/src/device.c b/src/device.c
index 50fc754..2b82ae1 100644
--- a/src/device.c
+++ b/src/device.c
@@ -79,6 +79,10 @@ static int libc_seek  ( dvdcss_t, int );
 static int libc_read  ( dvdcss_t, void *, int );
 static int libc_readv ( dvdcss_t, const struct iovec *, int );
 
+static int stream_seek  ( dvdcss_t, int );
+static int stream_read  ( dvdcss_t, void *, int );
+static int stream_readv ( dvdcss_t, const struct iovec *, int );
+
 #ifdef _WIN32
 static int win2k_open  ( dvdcss_t, const char * );
 static int win2k_seek  ( dvdcss_t, int );
@@ -91,6 +95,9 @@ static int os2_open ( dvdcss_t, const char * );
 
 int dvdcss_use_ioctls( dvdcss_t dvdcss )
 {
+    if( dvdcss->p_stream )
+        return 0;
+
 #if defined( _WIN32 )
     if( dvdcss->b_file )
     {
@@ -182,8 +189,8 @@ void dvdcss_check_device ( dvdcss_t dvdcss )
     int i, i_fd;
 #endif
 
-    /* If the device name is non-null, return */
-    if( dvdcss->psz_device[0] )
+    /* If the device name is non-NULL or stream is set, return. */
+    if( dvdcss->psz_device[0] || dvdcss->p_stream )
     {
         return;
     }
@@ -343,6 +350,16 @@ int dvdcss_open_device ( dvdcss_t dvdcss )
     }
     print_debug( dvdcss, "opening target `%s'", psz_device );
 
+    /* if callback functions are initialized */
+    if( dvdcss->p_stream )
+    {
+        print_debug( dvdcss, "using stream API for access" );
+        dvdcss->pf_seek  = stream_seek;
+        dvdcss->pf_read  = stream_read;
+        dvdcss->pf_readv = stream_readv;
+        return 0;
+    }
+
 #if defined( _WIN32 )
     dvdcss->b_file = 1;
     /* If device is "X:" or "X:\", we are not actually opening a file. */
@@ -527,6 +544,31 @@ static int libc_seek( dvdcss_t dvdcss, int i_blocks )
     return dvdcss->i_pos;
 }
 
+static int stream_seek( dvdcss_t dvdcss, int i_blocks )
+{
+    off_t i_seek = i_blocks * DVDCSS_BLOCK_SIZE;
+
+    if( !dvdcss->p_stream_cb->pf_seek )
+        return -1;
+
+    if( dvdcss->i_pos == i_blocks )
+    {
+        /* We are already in position */
+        return i_blocks;
+    }
+
+    if( dvdcss->p_stream_cb->pf_seek( dvdcss->p_stream, i_seek ) != 0 )
+    {
+        print_error( dvdcss, "seek error" );
+        dvdcss->i_pos = -1;
+        return -1;
+    }
+
+    dvdcss->i_pos = i_blocks;
+
+    return dvdcss->i_pos;
+}
+
 #if defined( _WIN32 )
 static int win2k_seek( dvdcss_t dvdcss, int i_blocks )
 {
@@ -596,6 +638,46 @@ static int libc_read ( dvdcss_t dvdcss, void *p_buffer, int i_blocks )
     return i_ret_blocks;
 }
 
+static int stream_read ( dvdcss_t dvdcss, void *p_buffer, int i_blocks )
+{
+    off_t i_size, i_ret, i_ret_blocks;
+
+    i_size = i_blocks * DVDCSS_BLOCK_SIZE;
+
+    if( !dvdcss->p_stream_cb->pf_read )
+        return -1;
+
+    i_ret = dvdcss->p_stream_cb->pf_read( dvdcss->p_stream, p_buffer, i_size );
+
+    if( i_ret < 0 )
+    {
+        print_error( dvdcss, "read error" );
+        dvdcss->i_pos = -1;
+        return i_ret;
+    }
+
+    i_ret_blocks = i_ret / DVDCSS_BLOCK_SIZE;
+
+    /* Handle partial reads */
+    if( i_ret != i_size )
+    {
+        int i_seek;
+
+        dvdcss->i_pos = -1;
+        i_seek = stream_seek( dvdcss, i_ret_blocks );
+        if( i_seek < 0 )
+        {
+            return i_seek;
+        }
+
+        /* We have to return now so that i_pos isn't clobbered */
+        return i_ret_blocks;
+    }
+
+    dvdcss->i_pos += i_ret_blocks;
+    return i_ret_blocks;
+}
+
 #if defined( _WIN32 )
 static int win2k_read ( dvdcss_t dvdcss, void *p_buffer, int i_blocks )
 {
@@ -688,6 +770,30 @@ static int libc_readv ( dvdcss_t dvdcss, const struct iovec *p_iovec,
 #endif
 }
 
+/*****************************************************************************
+ * stream_readv: vectored read
+ *****************************************************************************/
+static int stream_readv ( dvdcss_t dvdcss, const struct iovec *p_iovec,
+                          int i_blocks )
+{
+    int i_read;
+
+    if( !dvdcss->p_stream_cb->pf_readv )
+        return -1;
+
+    i_read = dvdcss->p_stream_cb->pf_readv( dvdcss->p_stream, p_iovec,
+                                            i_blocks );
+
+    if( i_read < 0 )
+    {
+        dvdcss->i_pos = -1;
+        return i_read;
+    }
+
+    dvdcss->i_pos += i_read / DVDCSS_BLOCK_SIZE;
+    return i_read / DVDCSS_BLOCK_SIZE;
+}
+
 #if defined( _WIN32 )
 /*****************************************************************************
  * win2k_readv: vectored read using ReadFile for Win2K
diff --git a/src/dvdcss/dvdcss.h b/src/dvdcss/dvdcss.h
index ea62b8b..a630107 100644
--- a/src/dvdcss/dvdcss.h
+++ b/src/dvdcss/dvdcss.h
@@ -31,6 +31,8 @@
 #define DVDCSS_DVDCSS_H 1
 #endif
 
+#include <stdint.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -38,6 +40,17 @@ extern "C" {
 /** Library instance handle, to be used for each library call. */
 typedef struct dvdcss_s* dvdcss_t;
 
+/** Set of callbacks to access DVDs in custom ways. */
+typedef struct dvdcss_stream_cb
+{
+    /** custom seek callback */
+    int ( *pf_seek )  ( void *p_stream, uint64_t i_pos);
+    /** custom read callback */
+    int ( *pf_read )  ( void *p_stream, void *buffer, int i_read);
+    /** custom vectored read callback */
+    int ( *pf_readv ) ( void *p_stream, const void *p_iovec, int i_blocks);
+} dvdcss_stream_cb;
+
 
 /** The block size of a DVD. */
 #define DVDCSS_BLOCK_SIZE      2048
@@ -73,6 +86,8 @@ typedef struct dvdcss_s* dvdcss_t;
  * Exported prototypes.
  */
 LIBDVDCSS_EXPORT dvdcss_t dvdcss_open  ( const char *psz_target );
+LIBDVDCSS_EXPORT dvdcss_t dvdcss_open_stream( void *p_stream,
+                                              dvdcss_stream_cb *p_stream_cb );
 LIBDVDCSS_EXPORT int      dvdcss_close ( dvdcss_t );
 LIBDVDCSS_EXPORT int      dvdcss_seek  ( dvdcss_t,
                                int i_blocks,
diff --git a/src/libdvdcss.c b/src/libdvdcss.c
index 73a91e8..1b4c680 100644
--- a/src/libdvdcss.c
+++ b/src/libdvdcss.c
@@ -143,6 +143,8 @@
 #define MANUFACTURING_DATE_LENGTH  16
 
 
+static dvdcss_t dvdcss_open_common ( const char *psz_target, void *p_stream,
+                                     dvdcss_stream_cb *p_stream_cb );
 static void set_verbosity( dvdcss_t dvdcss )
 {
     const char *psz_verbose = getenv( "DVDCSS_VERBOSE" );
@@ -456,6 +458,27 @@ static void init_cache( dvdcss_t dvdcss )
  */
 LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char *psz_target )
 {
+    return dvdcss_open_common( psz_target, NULL, NULL );
+}
+
+/**
+ * \brief Open a DVD device using dvdcss_stream_cb.
+ *
+ * \param p_stream a private handle used by p_stream_cb
+ * \param p_stream_cb a struct containing seek and read functions
+ * \return a handle to a dvdcss instance or NULL on error.
+ *
+ * \see dvdcss_open()
+ */
+LIBDVDCSS_EXPORT dvdcss_t dvdcss_open_stream ( void *p_stream,
+                                               dvdcss_stream_cb *p_stream_cb )
+{
+    return dvdcss_open_common( NULL, p_stream, p_stream_cb );
+}
+
+static dvdcss_t dvdcss_open_common ( const char *psz_target, void *p_stream,
+                                     dvdcss_stream_cb *p_stream_cb )
+{
     int i_ret;
 
     /* Allocate the library structure. */
@@ -465,6 +488,10 @@ LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char *psz_target )
         return NULL;
     }
 
+    if( psz_target == NULL &&
+      ( p_stream == NULL || p_stream_cb == NULL ) )
+        return NULL;
+
     /* Initialize structure with default values. */
     dvdcss->i_pos = 0;
     dvdcss->p_titles = NULL;
@@ -473,6 +500,9 @@ LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char *psz_target )
     dvdcss->i_method = DVDCSS_METHOD_KEY;
     dvdcss->psz_cachefile[0] = '\0';
 
+    dvdcss->p_stream = p_stream;
+    dvdcss->p_stream_cb = p_stream_cb;
+
     /* Set library verbosity from DVDCSS_VERBOSE environment variable. */
     set_verbosity( dvdcss );
 
diff --git a/src/libdvdcss.h b/src/libdvdcss.h
index 881bb45..93668e0 100644
--- a/src/libdvdcss.h
+++ b/src/libdvdcss.h
@@ -74,6 +74,9 @@ struct dvdcss_s
     char * p_readv_buffer;
     int    i_readv_buf_size;
 #endif /* _WIN32 */
+
+    void                *p_stream;
+    dvdcss_stream_cb    *p_stream_cb;
 };
 
 /*****************************************************************************

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