[trunk] WIP: add a read MCO marker function (JPEG2000 part 2)
[openjpeg.git] / libopenjpeg / cio.c
index b8a7ecf8a873a7f4cf001e59334a98d4dc6ae383..85a320c8c549a8953670044e84b8ecf7d52ffa7f 100644 (file)
@@ -188,4 +188,812 @@ void cio_skip(opj_cio_t *cio, int n) {
 }
 
 
+/* ----------------------------------------------------------------------- */
+
+
+/**
+ * Write some bytes to the given data buffer, this function is used in Big Endian cpus.
+ * @param p_buffer             pointer the data buffer to write data to.
+ * @param p_value              the value to write
+ * @param p_nb_bytes   the number of bytes to write
+*/
+void opj_write_bytes_BE (OPJ_BYTE * p_buffer, OPJ_UINT32 p_value, OPJ_UINT32 p_nb_bytes)
+{
+       const OPJ_BYTE * l_data_ptr = ((const OPJ_BYTE *) &p_value) + p_nb_bytes;
+
+       assert(p_nb_bytes > 0 && p_nb_bytes <=  sizeof(OPJ_UINT32));
+
+       memcpy(p_buffer,l_data_ptr,p_nb_bytes);
+}
+
+/**
+ * Write some bytes to the given data buffer, this function is used in Little Endian cpus.
+ * @param p_buffer             pointer the data buffer to write data to.
+ * @param p_value              the value to write
+ * @param p_nb_bytes   the number of bytes to write
+ * @return                             the number of bytes written or -1 if an error occured
+*/
+void opj_write_bytes_LE (OPJ_BYTE * p_buffer, OPJ_UINT32 p_value, OPJ_UINT32 p_nb_bytes)
+{
+       const OPJ_BYTE * l_data_ptr = ((const OPJ_BYTE *) &p_value) + p_nb_bytes - 1;
+       OPJ_UINT32 i;
+
+       assert(p_nb_bytes > 0 && p_nb_bytes <= sizeof(OPJ_UINT32));
+
+       for     (i=0;i<p_nb_bytes;++i) {
+               *(p_buffer++) = *(l_data_ptr--);
+       }
+}
+
+/**
+ * Reads some bytes from the given data buffer, this function is used in Big Endian cpus.
+ * @param p_buffer             pointer the data buffer to read data from.
+ * @param p_value              pointer to the value that will store the data.
+ * @param p_nb_bytes   the nb bytes to read.
+ * @return                             the number of bytes read or -1 if an error occured.
+ */
+void opj_read_bytes_BE(const OPJ_BYTE * p_buffer, OPJ_UINT32 * p_value, OPJ_UINT32 p_nb_bytes)
+{
+       OPJ_BYTE * l_data_ptr = ((OPJ_BYTE *) p_value);
+
+       assert(p_nb_bytes > 0 && p_nb_bytes <= sizeof(OPJ_UINT32));
+
+       *p_value = 0;
+       memcpy(l_data_ptr+4-p_nb_bytes,p_buffer,p_nb_bytes);
+}
+
+/**
+ * Reads some bytes from the given data buffer, this function is used in Little Endian cpus.
+ * @param p_buffer             pointer the data buffer to read data from.
+ * @param p_value              pointer to the value that will store the data.
+ * @param p_nb_bytes   the nb bytes to read.
+ * @return                             the number of bytes read or -1 if an error occured.
+ */
+void opj_read_bytes_LE(const OPJ_BYTE * p_buffer, OPJ_UINT32 * p_value, OPJ_UINT32 p_nb_bytes)
+{
+       OPJ_BYTE * l_data_ptr = ((OPJ_BYTE *) p_value) + p_nb_bytes-1;
+       OPJ_UINT32 i;
+
+       assert(p_nb_bytes > 0 && p_nb_bytes <= sizeof(OPJ_UINT32));
+
+       *p_value = 0;
+       for (i=0;i<p_nb_bytes;++i) {
+               *(l_data_ptr--) = *(p_buffer++);
+       }
+}
+
+/**
+ * Write some bytes to the given data buffer, this function is used in Big Endian cpus.
+ * @param p_buffer             pointer the data buffer to write data to.
+ * @param p_value              the value to write
+ * @return                             the number of bytes written or -1 if an error occured
+ */
+void opj_write_double_BE(OPJ_BYTE * p_buffer, OPJ_FLOAT64 p_value)
+{
+       const OPJ_BYTE * l_data_ptr = ((const OPJ_BYTE *) &p_value);
+       memcpy(p_buffer,l_data_ptr,sizeof(OPJ_FLOAT64));
+}
+
+/**
+ * Write some bytes to the given data buffer, this function is used in Little Endian cpus.
+ * @param p_buffer             pointer the data buffer to write data to.
+ * @param p_value              the value to write
+ */
+void opj_write_double_LE(OPJ_BYTE * p_buffer, OPJ_FLOAT64 p_value)
+{
+       const OPJ_BYTE * l_data_ptr = ((const OPJ_BYTE *) &p_value) + sizeof(OPJ_FLOAT64) - 1;
+       OPJ_UINT32 i;
+       for     (i=0;i<sizeof(OPJ_FLOAT64);++i) {
+               *(p_buffer++) = *(l_data_ptr--);
+       }
+}
+
+/**
+ * Reads some bytes from the given data buffer, this function is used in Big Endian cpus.
+ * @param p_buffer             pointer the data buffer to read data from.
+ * @param p_value              pointer to the value that will store the data.
+ */
+void opj_read_double_BE(const OPJ_BYTE * p_buffer, OPJ_FLOAT64 * p_value)
+{
+       OPJ_BYTE * l_data_ptr = ((OPJ_BYTE *) p_value);
+       memcpy(l_data_ptr,p_buffer,sizeof(OPJ_FLOAT64));
+}
+
+
+/**
+ * Reads some bytes from the given data buffer, this function is used in Little Endian cpus.
+ * @param p_buffer             pointer the data buffer to read data from.
+ * @param p_value              pointer to the value that will store the data.
+ */
+void opj_read_double_LE(const OPJ_BYTE * p_buffer, OPJ_FLOAT64 * p_value)
+{
+       OPJ_BYTE * l_data_ptr = ((OPJ_BYTE *) p_value) + sizeof(OPJ_FLOAT64)-1;
+       OPJ_UINT32 i;
+       for (i=0;i<sizeof(OPJ_FLOAT64);++i) {
+               *(l_data_ptr--) = *(p_buffer++);
+       }
+}
+
+/**
+ * Write some bytes to the given data buffer, this function is used in Big Endian cpus.
+ * @param p_buffer             pointer the data buffer to write data to.
+ * @param p_value              the value to write
+ * @return                             the number of bytes written or -1 if an error occured
+ */
+void opj_write_float_BE(OPJ_BYTE * p_buffer, OPJ_FLOAT32 p_value)
+{
+       const OPJ_BYTE * l_data_ptr = ((const OPJ_BYTE *) &p_value);
+       memcpy(p_buffer,l_data_ptr,sizeof(OPJ_FLOAT32));
+}
+
+/**
+ * Write some bytes to the given data buffer, this function is used in Little Endian cpus.
+ * @param p_buffer             pointer the data buffer to write data to.
+ * @param p_value              the value to write
+ */
+void opj_write_float_LE(OPJ_BYTE * p_buffer, OPJ_FLOAT32 p_value)
+{
+       const OPJ_BYTE * l_data_ptr = ((const OPJ_BYTE *) &p_value) + sizeof(OPJ_FLOAT32) - 1;
+       OPJ_UINT32 i;
+       for     (i=0;i<sizeof(OPJ_FLOAT32);++i) {
+               *(p_buffer++) = *(l_data_ptr--);
+       }
+}
+
+/**
+ * Reads some bytes from the given data buffer, this function is used in Big Endian cpus.
+ * @param p_buffer             pointer the data buffer to read data from.
+ * @param p_value              pointer to the value that will store the data.
+ */
+void opj_read_float_BE(const OPJ_BYTE * p_buffer, OPJ_FLOAT32 * p_value)
+{
+       OPJ_BYTE * l_data_ptr = ((OPJ_BYTE *) p_value);
+       memcpy(l_data_ptr,p_buffer,sizeof(OPJ_FLOAT32));
+}
+
+
+/**
+ * Reads some bytes from the given data buffer, this function is used in Little Endian cpus.
+ * @param p_buffer             pointer the data buffer to read data from.
+ * @param p_value              pointer to the value that will store the data.
+ */
+void opj_read_float_LE(const OPJ_BYTE * p_buffer, OPJ_FLOAT32 * p_value)
+{
+       OPJ_BYTE * l_data_ptr = ((OPJ_BYTE *) p_value) + sizeof(OPJ_FLOAT32)-1;
+       OPJ_UINT32 i;
+       for     (i=0;i<sizeof(OPJ_FLOAT32);++i) {
+               *(l_data_ptr--) = *(p_buffer++);
+       }
+}
+
+
+/**
+ * Creates an abstract stream. This function does nothing except allocating memory and initializing the abstract stream.
+ * @return a stream object.
+*/
+opj_stream_t* OPJ_CALLCONV opj_stream_create(OPJ_UINT32 p_size,opj_bool l_is_input)
+{
+       opj_stream_private_t * l_stream = 00;
+       l_stream = (opj_stream_private_t*) opj_malloc(sizeof(opj_stream_private_t));
+       if (! l_stream) {
+               return 00;
+       }
+
+       memset(l_stream,0,sizeof(opj_stream_private_t));
+       l_stream->m_buffer_size = p_size;
+       l_stream->m_stored_data = (OPJ_BYTE *) opj_malloc(p_size);
+       if (! l_stream->m_stored_data) {
+               opj_free(l_stream);
+               return 00;
+       }
+
+       l_stream->m_current_data = l_stream->m_stored_data;
+
+       if (l_is_input) {
+               l_stream->m_status |= opj_stream_e_input;
+               l_stream->m_opj_skip = opj_stream_read_skip;
+               l_stream->m_opj_seek = opj_stream_read_seek;
+       }
+       else {
+               l_stream->m_status |= opj_stream_e_output;
+               l_stream->m_opj_skip = opj_stream_write_skip;
+               l_stream->m_opj_seek = opj_stream_write_seek;
+       }
+
+       l_stream->m_read_fn = opj_stream_default_read;
+       l_stream->m_write_fn = opj_stream_default_write;
+       l_stream->m_skip_fn = opj_stream_default_skip;
+       l_stream->m_seek_fn = opj_stream_default_seek;
+
+       return (opj_stream_t *) l_stream;
+}
+
+/**
+ * Creates an abstract stream. This function does nothing except allocating memory and initializing the abstract stream.
+ * @return a stream object.
+*/
+opj_stream_t* OPJ_CALLCONV opj_stream_default_create(opj_bool l_is_input)
+{
+       return opj_stream_create(J2K_STREAM_CHUNK_SIZE,l_is_input);
+}
+
+/**
+ * Destroys a stream created by opj_create_stream. This function does NOT close the abstract stream. If needed the user must
+ * close its own implementation of the stream.
+ */
+OPJ_API void OPJ_CALLCONV opj_stream_destroy(opj_stream_t* p_stream)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+       if (l_stream) {
+               opj_free(l_stream->m_stored_data);
+               l_stream->m_stored_data = 00;
+               opj_free(l_stream);
+       }
+}
+
+/**
+ * Sets the given function to be used as a read function.
+ * @param              p_stream        the stream to modify
+ * @param              p_function      the function to use a read function.
+*/
+OPJ_API void OPJ_CALLCONV opj_stream_set_read_function(opj_stream_t* p_stream, opj_stream_read_fn p_function)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+
+       if ((!l_stream) || (! (l_stream->m_status & opj_stream_e_input))) {
+               return;
+       }
+
+       l_stream->m_read_fn = p_function;
+}
+
+OPJ_API void OPJ_CALLCONV opj_stream_set_seek_function(opj_stream_t* p_stream, opj_stream_seek_fn p_function)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+       if
+               (!l_stream)
+       {
+               return;
+       }
+       l_stream->m_seek_fn = p_function;
+}
+
+/**
+ * Sets the given function to be used as a write function.
+ * @param              p_stream        the stream to modify
+ * @param              p_function      the function to use a write function.
+*/
+OPJ_API void OPJ_CALLCONV opj_stream_set_write_function(opj_stream_t* p_stream, opj_stream_write_fn p_function)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+       if
+               ((!l_stream )|| (! (l_stream->m_status & opj_stream_e_output)))
+       {
+               return;
+       }
+       l_stream->m_write_fn = p_function;
+}
+
+/**
+ * Sets the given function to be used as a skip function.
+ * @param              p_stream        the stream to modify
+ * @param              p_function      the function to use a skip function.
+*/
+OPJ_API void OPJ_CALLCONV opj_stream_set_skip_function(opj_stream_t* p_stream, opj_stream_skip_fn p_function)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+       if
+               (! l_stream)
+       {
+               return;
+       }
+       l_stream->m_skip_fn = p_function;
+}
+
+/**
+ * Sets the given data to be used as a user data for the stream.
+ * @param              p_stream        the stream to modify
+ * @param              p_data          the data to set.
+*/
+OPJ_API void OPJ_CALLCONV opj_stream_set_user_data(opj_stream_t* p_stream, void * p_data)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+       l_stream->m_user_data = p_data;
+}
+
+/**
+ * Sets the given data to be used as a user data for the stream.
+ * @param              p_stream        the stream to modify
+ * @param              p_data          the data to set.
+*/
+OPJ_API void OPJ_CALLCONV opj_stream_set_user_data_length(opj_stream_t* p_stream, OPJ_UINT32 data_length)
+{
+       opj_stream_private_t* l_stream = (opj_stream_private_t*) p_stream;
+
+       l_stream->m_user_data_length = data_length;
+}
+
+/**
+ * Reads some bytes from the stream.
+ * @param              p_stream        the stream to read data from.
+ * @param              p_buffer        pointer to the data buffer that will receive the data.
+ * @param              p_size          number of bytes to read.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes read, or -1 if an error occured or if the stream is at the end.
+ */
+OPJ_UINT32 opj_stream_read_data (opj_stream_private_t * p_stream,OPJ_BYTE * p_buffer, OPJ_UINT32 p_size, opj_event_mgr_t * p_event_mgr)
+{
+       OPJ_UINT32 l_read_nb_bytes = 0;
+       if
+               (p_stream->m_bytes_in_buffer >= p_size)
+       {
+               memcpy(p_buffer,p_stream->m_current_data,p_size);
+               p_stream->m_current_data += p_size;
+               p_stream->m_bytes_in_buffer -= p_size;
+               l_read_nb_bytes += p_size;
+               p_stream->m_byte_offset += p_size;
+               return l_read_nb_bytes;
+       }
+
+       // we are now in the case when the remaining data if not sufficient
+       if
+               (p_stream->m_status & opj_stream_e_end)
+       {
+               l_read_nb_bytes += p_stream->m_bytes_in_buffer;
+               memcpy(p_buffer,p_stream->m_current_data,p_stream->m_bytes_in_buffer);
+               p_stream->m_current_data += p_stream->m_bytes_in_buffer;
+               p_stream->m_byte_offset += p_stream->m_bytes_in_buffer;
+               p_stream->m_bytes_in_buffer = 0;
+               return l_read_nb_bytes ? l_read_nb_bytes : -1;
+       }
+
+       // the flag is not set, we copy data and then do an actual read on the stream
+       if
+               (p_stream->m_bytes_in_buffer)
+       {
+               l_read_nb_bytes += p_stream->m_bytes_in_buffer;
+               memcpy(p_buffer,p_stream->m_current_data,p_stream->m_bytes_in_buffer);
+               p_stream->m_current_data = p_stream->m_stored_data;
+               p_buffer += p_stream->m_bytes_in_buffer;
+               p_size -= p_stream->m_bytes_in_buffer;
+               p_stream->m_byte_offset += p_stream->m_bytes_in_buffer;
+               p_stream->m_bytes_in_buffer = 0;
+       }
+  else
+  {
+    /* case where we are already at the end of the buffer
+       so reset the m_current_data to point to the start of the
+       stored buffer to get ready to read from disk*/
+    p_stream->m_current_data = p_stream->m_stored_data;
+  }
+
+
+       while(1){
+               // we should read less than a chunk -> read a chunk
+               if
+                       (p_size < p_stream->m_buffer_size)
+               {
+                       // we should do an actual read on the media
+                       p_stream->m_bytes_in_buffer = p_stream->m_read_fn(p_stream->m_stored_data,p_stream->m_buffer_size,p_stream->m_user_data);
+                       if
+                               (p_stream->m_bytes_in_buffer == -1)
+                       {
+                               // end of stream
+                               opj_event_msg_v2(p_event_mgr, EVT_INFO, "Stream reached its end !\n");
+
+                               p_stream->m_bytes_in_buffer = 0;
+                               p_stream->m_status |= opj_stream_e_end;
+                               // end of stream
+                               return l_read_nb_bytes ? l_read_nb_bytes : -1;
+                       }
+                       else if
+                               (p_stream->m_bytes_in_buffer < p_size)
+                       {
+                               // not enough data
+                               l_read_nb_bytes += p_stream->m_bytes_in_buffer;
+                               memcpy(p_buffer,p_stream->m_current_data,p_stream->m_bytes_in_buffer);
+                               p_stream->m_current_data = p_stream->m_stored_data;
+                               p_buffer += p_stream->m_bytes_in_buffer;
+                               p_size -= p_stream->m_bytes_in_buffer;
+                               p_stream->m_byte_offset += p_stream->m_bytes_in_buffer;
+                               p_stream->m_bytes_in_buffer = 0;
+                       }
+                       else
+                       {
+                               l_read_nb_bytes += p_size;
+                               memcpy(p_buffer,p_stream->m_current_data,p_size);
+                               p_stream->m_current_data += p_size;
+                               p_stream->m_bytes_in_buffer -= p_size;
+                               p_stream->m_byte_offset += p_size;
+                               return l_read_nb_bytes;
+                       }
+               }
+               else
+               {
+                       // direct read on the dest buffer
+                       p_stream->m_bytes_in_buffer = p_stream->m_read_fn(p_buffer,p_size,p_stream->m_user_data);
+                       if
+                               (p_stream->m_bytes_in_buffer == -1)
+                       {
+                               // end of stream
+                               opj_event_msg_v2(p_event_mgr, EVT_INFO, "Stream reached its end !\n");
+
+                               p_stream->m_bytes_in_buffer = 0;
+                               p_stream->m_status |= opj_stream_e_end;
+                               // end of stream
+                               return l_read_nb_bytes ? l_read_nb_bytes : -1;
+                       }
+                       else if
+                               (p_stream->m_bytes_in_buffer < p_size)
+                       {
+                               // not enough data
+                               l_read_nb_bytes += p_stream->m_bytes_in_buffer;
+                               p_stream->m_current_data = p_stream->m_stored_data;
+                               p_buffer += p_stream->m_bytes_in_buffer;
+                               p_size -= p_stream->m_bytes_in_buffer;
+                               p_stream->m_byte_offset += p_stream->m_bytes_in_buffer;
+                               p_stream->m_bytes_in_buffer = 0;
+                       }
+                       else
+                       {
+                               // we have read the exact size
+                               l_read_nb_bytes += p_stream->m_bytes_in_buffer;
+                               p_stream->m_byte_offset += p_stream->m_bytes_in_buffer;
+                               p_stream->m_current_data = p_stream->m_stored_data;
+                               p_stream->m_bytes_in_buffer = 0;
+                               return l_read_nb_bytes;
+                       }
+               }
+       }
+}
+
+/**
+ * Writes some bytes from the stream.
+ * @param              p_stream        the stream to write data to.
+ * @param              p_buffer        pointer to the data buffer holds the data to be writtent.
+ * @param              p_size          number of bytes to write.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes writtent, or -1 if an error occured.
+ */
+OPJ_UINT32 opj_stream_write_data (opj_stream_private_t * p_stream,const OPJ_BYTE * p_buffer,OPJ_UINT32 p_size, opj_event_mgr_t * p_event_mgr)
+{
+       OPJ_UINT32 l_remaining_bytes = 0;
+       OPJ_UINT32 l_write_nb_bytes = 0;
+
+       if
+               (p_stream->m_status & opj_stream_e_error)
+       {
+               return -1;
+       }
+
+       while(1)
+       {
+               l_remaining_bytes = p_stream->m_buffer_size - p_stream->m_bytes_in_buffer;
+               // we have more memory than required
+               if
+                       (l_remaining_bytes >= p_size)
+               {
+                       memcpy(p_stream->m_current_data,p_buffer,p_size);
+                       p_stream->m_current_data += p_size;
+                       p_stream->m_bytes_in_buffer += p_size;
+                       l_write_nb_bytes += p_size;
+                       p_stream->m_byte_offset += p_size;
+                       return l_write_nb_bytes;
+               }
+
+               // we copy data and then do an actual read on the stream
+               if
+                       (l_remaining_bytes)
+               {
+                       l_write_nb_bytes += l_remaining_bytes;
+                       memcpy(p_stream->m_current_data,p_buffer,l_remaining_bytes);
+                       p_stream->m_current_data = p_stream->m_stored_data;
+                       p_buffer += l_remaining_bytes;
+                       p_size -= l_remaining_bytes;
+                       p_stream->m_bytes_in_buffer += l_remaining_bytes;
+                       p_stream->m_byte_offset += l_remaining_bytes;
+               }
+               if
+                       (! opj_stream_flush(p_stream, p_event_mgr))
+               {
+                       return -1;
+               }
+       }
+
+}
+
+/**
+ * Writes the content of the stream buffer to the stream.
+ * @param              p_stream        the stream to write data to.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes written, or -1 if an error occured.
+ */
+opj_bool opj_stream_flush (opj_stream_private_t * p_stream, opj_event_mgr_t * p_event_mgr)
+{
+       // the number of bytes written on the media.
+       OPJ_UINT32 l_current_write_nb_bytes = 0;
+       p_stream->m_current_data = p_stream->m_stored_data;
+
+       while
+               (p_stream->m_bytes_in_buffer)
+       {
+               // we should do an actual write on the media
+               l_current_write_nb_bytes = p_stream->m_write_fn(p_stream->m_current_data,p_stream->m_bytes_in_buffer,p_stream->m_user_data);
+               if
+                       (l_current_write_nb_bytes == -1)
+               {
+                       p_stream->m_status |= opj_stream_e_error;
+                       opj_event_msg_v2(p_event_mgr, EVT_INFO, "Error on writting stream!\n");
+
+                       return EXIT_FAILURE;
+               }
+               p_stream->m_current_data += l_current_write_nb_bytes;
+               p_stream->m_bytes_in_buffer -= l_current_write_nb_bytes;
+       }
+       p_stream->m_current_data = p_stream->m_stored_data;
+       return EXIT_SUCCESS;
+}
+
+/**
+ * Skips a number of bytes from the stream.
+ * @param              p_stream        the stream to skip data from.
+ * @param              p_size          the number of bytes to skip.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes skipped, or -1 if an error occured.
+ */
+OPJ_SIZE_T opj_stream_read_skip (opj_stream_private_t * p_stream, OPJ_SIZE_T p_size, opj_event_mgr_t * p_event_mgr)
+{
+       OPJ_SIZE_T l_skip_nb_bytes = 0;
+       OPJ_SIZE_T l_current_skip_nb_bytes = 0;
+
+       if
+               (p_stream->m_bytes_in_buffer >= p_size)
+       {
+               p_stream->m_current_data += p_size;
+               p_stream->m_bytes_in_buffer -= p_size;
+               l_skip_nb_bytes += p_size;
+               p_stream->m_byte_offset += l_skip_nb_bytes;
+               return l_skip_nb_bytes;
+       }
+
+       // we are now in the case when the remaining data if not sufficient
+       if
+               (p_stream->m_status & opj_stream_e_end)
+       {
+               l_skip_nb_bytes += p_stream->m_bytes_in_buffer;
+               p_stream->m_current_data += p_stream->m_bytes_in_buffer;
+               p_stream->m_bytes_in_buffer = 0;
+               p_stream->m_byte_offset += l_skip_nb_bytes;
+               return l_skip_nb_bytes ? l_skip_nb_bytes : (OPJ_SIZE_T) -1;
+       }
+
+       // the flag is not set, we copy data and then do an actual skip on the stream
+       if
+               (p_stream->m_bytes_in_buffer)
+       {
+               l_skip_nb_bytes += p_stream->m_bytes_in_buffer;
+               p_stream->m_current_data = p_stream->m_stored_data;
+               p_size -= p_stream->m_bytes_in_buffer;
+               p_stream->m_bytes_in_buffer = 0;
+       }
+
+       while
+               (p_size > 0)
+       {
+               // we should do an actual skip on the media
+               l_current_skip_nb_bytes = p_stream->m_skip_fn(p_size, p_stream->m_user_data);
+               if
+                       (l_current_skip_nb_bytes == (OPJ_SIZE_T) -1)
+               {
+                       opj_event_msg_v2(p_event_mgr, EVT_INFO, "Stream reached its end !\n");
+
+                       p_stream->m_status |= opj_stream_e_end;
+                       p_stream->m_byte_offset += l_skip_nb_bytes;
+                       // end if stream
+                       return l_skip_nb_bytes ? l_skip_nb_bytes : (OPJ_SIZE_T) -1;
+               }
+               p_size -= l_current_skip_nb_bytes;
+               l_skip_nb_bytes += l_current_skip_nb_bytes;
+       }
+       p_stream->m_byte_offset += l_skip_nb_bytes;
+       return l_skip_nb_bytes;
+}
+
+/**
+ * Skips a number of bytes from the stream.
+ * @param              p_stream        the stream to skip data from.
+ * @param              p_size          the number of bytes to skip.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes skipped, or -1 if an error occured.
+ */
+OPJ_SIZE_T opj_stream_write_skip (opj_stream_private_t * p_stream, OPJ_SIZE_T p_size, opj_event_mgr_t * p_event_mgr)
+{
+       opj_bool l_is_written = 0;
+       OPJ_SIZE_T l_current_skip_nb_bytes = 0;
+       OPJ_SIZE_T l_skip_nb_bytes = 0;
+
+       if
+               (p_stream->m_status & opj_stream_e_error)
+       {
+               return (OPJ_SIZE_T) -1;
+       }
+
+       // we should flush data
+       l_is_written = opj_stream_flush (p_stream, p_event_mgr);
+       if
+               (! l_is_written)
+       {
+               p_stream->m_status |= opj_stream_e_error;
+               p_stream->m_bytes_in_buffer = 0;
+               p_stream->m_current_data = p_stream->m_current_data;
+               return (OPJ_SIZE_T) -1;
+       }
+       // then skip
+
+       while
+               (p_size > 0)
+       {
+               // we should do an actual skip on the media
+               l_current_skip_nb_bytes = p_stream->m_skip_fn(p_size, p_stream->m_user_data);
+               if
+                       (l_current_skip_nb_bytes == (OPJ_SIZE_T)-1)
+               {
+                       opj_event_msg_v2(p_event_mgr, EVT_INFO, "Stream error!\n");
+
+                       p_stream->m_status |= opj_stream_e_error;
+                       p_stream->m_byte_offset += l_skip_nb_bytes;
+                       // end if stream
+                       return l_skip_nb_bytes ? l_skip_nb_bytes : (OPJ_SIZE_T)-1;
+               }
+               p_size -= l_current_skip_nb_bytes;
+               l_skip_nb_bytes += l_current_skip_nb_bytes;
+       }
+       p_stream->m_byte_offset += l_skip_nb_bytes;
+       return l_skip_nb_bytes;
+}
+
+/**
+ * Tells the byte offset on the stream (similar to ftell).
+ *
+ * @param              p_stream        the stream to get the information from.
+ *
+ * @return             the current position of the stream.
+ */
+OPJ_SIZE_T opj_stream_tell (const opj_stream_private_t * p_stream)
+{
+       return p_stream->m_byte_offset;
+}
+
+
+/**
+ * Get the number of bytes left before the end of the stream (similar to cio_numbytesleft).
+ *
+ * @param              p_stream        the stream to get the information from.
+ *
+ * @return             Number of bytes left before the end of the stream.
+ */
+OPJ_SIZE_T opj_stream_get_number_byte_left (const opj_stream_private_t * p_stream)
+{
+       return p_stream->m_user_data_length ?
+                               p_stream->m_user_data_length - p_stream->m_byte_offset :
+                               0;
+}
+
+/**
+ * Skips a number of bytes from the stream.
+ * @param              p_stream        the stream to skip data from.
+ * @param              p_size          the number of bytes to skip.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes skipped, or -1 if an error occured.
+ */
+OPJ_SIZE_T opj_stream_skip (opj_stream_private_t * p_stream, OPJ_SIZE_T p_size, opj_event_mgr_t * p_event_mgr)
+{
+       return p_stream->m_opj_skip(p_stream,p_size,p_event_mgr);
+}
+
+
+/**
+ * Skips a number of bytes from the stream.
+ * @param              p_stream        the stream to skip data from.
+ * @param              p_size          the number of bytes to skip.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes skipped, or -1 if an error occured.
+ */
+opj_bool opj_stream_read_seek (opj_stream_private_t * p_stream, OPJ_SIZE_T p_size, opj_event_mgr_t * p_event_mgr)
+{
+       p_stream->m_current_data = p_stream->m_stored_data;
+       p_stream->m_bytes_in_buffer = 0;
+       if
+               (! p_stream->m_seek_fn(p_size,p_stream->m_user_data))
+       {
+               p_stream->m_status |= opj_stream_e_end;
+               return EXIT_FAILURE;
+       }
+       else
+       {
+               // reset stream status
+               p_stream->m_status &= (~opj_stream_e_end);
+               p_stream->m_byte_offset = p_size;
+
+       }
+       return EXIT_SUCCESS;
+}
+
+/**
+ * Skips a number of bytes from the stream.
+ * @param              p_stream        the stream to skip data from.
+ * @param              p_size          the number of bytes to skip.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             the number of bytes skipped, or -1 if an error occured.
+ */
+opj_bool opj_stream_write_seek (opj_stream_private_t * p_stream, OPJ_SIZE_T p_size, opj_event_mgr_t * p_event_mgr)
+{
+       if
+               (! opj_stream_flush(p_stream,p_event_mgr))
+       {
+               p_stream->m_status |= opj_stream_e_error;
+               return EXIT_FAILURE;
+       }
+
+       p_stream->m_current_data = p_stream->m_stored_data;
+       p_stream->m_bytes_in_buffer = 0;
+
+       if
+               (! p_stream->m_seek_fn(p_size,p_stream->m_user_data))
+       {
+               p_stream->m_status |= opj_stream_e_error;
+               return EXIT_FAILURE;
+       }
+       else
+       {
+               p_stream->m_byte_offset = p_size;
+       }
+       return EXIT_SUCCESS;
+}
+
+
+/**
+ * Seeks a number of bytes from the stream.
+ * @param              p_stream        the stream to skip data from.
+ * @param              p_size          the number of bytes to skip.
+ * @param              p_event_mgr     the user event manager to be notified of special events.
+ * @return             true if the stream is seekable.
+ */
+opj_bool opj_stream_seek (opj_stream_private_t * p_stream, OPJ_SIZE_T p_size, struct opj_event_mgr * p_event_mgr)
+{
+       return p_stream->m_opj_seek(p_stream,p_size,p_event_mgr);
+}
+
+/**
+ * Tells if the given stream is seekable.
+ */
+opj_bool opj_stream_has_seek (const opj_stream_private_t * p_stream)
+{
+       return p_stream->m_seek_fn != opj_stream_default_seek;
+}
+
+
+
+
+
+OPJ_UINT32 opj_stream_default_read (void * p_buffer, OPJ_UINT32 p_nb_bytes, void * p_user_data)
+{
+       return (OPJ_UINT32) -1;
+}
+OPJ_UINT32 opj_stream_default_write (void * p_buffer, OPJ_UINT32 p_nb_bytes, void * p_user_data)
+{
+       return (OPJ_UINT32) -1;
+}
+OPJ_SIZE_T opj_stream_default_skip (OPJ_SIZE_T p_nb_bytes, void * p_user_data)
+{
+       return (OPJ_SIZE_T) -1;
+}
+
+opj_bool opj_stream_default_seek (OPJ_SIZE_T p_nb_bytes, void * p_user_data)
+{
+       return EXIT_FAILURE;
+}
+
+
+