add read callback to OggFLAC__SeekableStreamEncoder, necessary for metadata rewriting
diff --git a/src/libOggFLAC/ogg_helper.c b/src/libOggFLAC/ogg_helper.c
new file mode 100644
index 0000000..fea73a5
--- /dev/null
+++ b/src/libOggFLAC/ogg_helper.c
@@ -0,0 +1,189 @@
+/* libOggFLAC - Free Lossless Audio Codec + Ogg library
+ * Copyright (C) 2002,2003 Josh Coalson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the Xiph.org Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdlib.h> /* for malloc() */
+#include <string.h> /* for memcmp(), memcpy() */
+#include "FLAC/assert.h"
+#include "private/ogg_helper.h"
+#include "protected/seekable_stream_encoder.h"
+
+
+static FLAC__bool full_read_(OggFLAC__SeekableStreamEncoder *encoder, FLAC__byte *buffer, unsigned bytes, OggFLAC__SeekableStreamEncoderReadCallback read_callback, void *client_data)
+{
+ while(bytes > 0) {
+ unsigned bytes_read = bytes;
+ switch(read_callback(encoder, buffer, &bytes_read, client_data)) {
+ case OggFLAC__SEEKABLE_STREAM_ENCODER_READ_STATUS_CONTINUE:
+ bytes -= bytes_read;
+ buffer += bytes_read;
+ break;
+ case OggFLAC__SEEKABLE_STREAM_ENCODER_READ_STATUS_END_OF_STREAM:
+ if(bytes_read == 0) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_OGG_ERROR;
+ return false;
+ }
+ bytes -= bytes_read;
+ buffer += bytes_read;
+ break;
+ case OggFLAC__SEEKABLE_STREAM_ENCODER_READ_STATUS_ABORT:
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_READ_ERROR;
+ return false;
+ default:
+ /* double protection: */
+ FLAC__ASSERT(0);
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_READ_ERROR;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+void simple_ogg_page__init(ogg_page *page)
+{
+ page->header = 0;
+ page->header_len = 0;
+ page->body = 0;
+ page->body_len = 0;
+}
+
+void simple_ogg_page__clear(ogg_page *page)
+{
+ if(page->header)
+ free(page->header);
+ if(page->body)
+ free(page->body);
+ simple_ogg_page__init(page);
+}
+
+FLAC__bool simple_ogg_page__get_at(OggFLAC__SeekableStreamEncoder *encoder, FLAC__uint64 position, ogg_page *page, OggFLAC__SeekableStreamEncoderSeekCallback seek_callback, OggFLAC__SeekableStreamEncoderReadCallback read_callback, void *client_data)
+{
+ static const unsigned OGG_HEADER_FIXED_PORTION_LEN = 27;
+ static const unsigned OGG_MAX_HEADER_LEN = 27/*OGG_HEADER_FIXED_PORTION_LEN*/ + 255;
+ FLAC__byte crc[4];
+
+ FLAC__ASSERT(page->header = 0);
+ FLAC__ASSERT(page->header_len = 0);
+ FLAC__ASSERT(page->body = 0);
+ FLAC__ASSERT(page->body_len = 0);
+
+ /* move the stream pointer to the supposed beginning of the page */
+ if(seek_callback(encoder, position, client_data) != FLAC__SEEKABLE_STREAM_ENCODER_SEEK_STATUS_OK) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_SEEK_ERROR;
+ return false;
+ }
+
+ /* allocate space for the page header */
+ if(0 == (page->header = malloc(OGG_MAX_HEADER_LEN))) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_MEMORY_ALLOCATION_ERROR;
+ return false;
+ }
+
+ /* read in the fixed part of the page header (up to but not including
+ * the segment table */
+ if(!full_read_(encoder, page->header, OGG_HEADER_FIXED_PORTION_LEN, read_callback, client_data))
+ return false;
+
+ page->header_len = OGG_HEADER_FIXED_PORTION_LEN + page->header[26];
+
+ /* check to see if it's a correct, "simple" page (one packet only) */
+ if(
+ memcmp(page->header, "OggS", 4) || /* doesn't start with OggS */
+ (page->header[5] & 0x01) || /* continued packet */
+ memcmp(page->header+6, "\0\0\0\0\0\0\0\0", 8) || /* granulepos is non-zero */
+ page->header[26] == 0 /* packet is 0-size */
+ ) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_OGG_ERROR;
+ return false;
+ }
+
+ /* read in the segment table */
+ if(!full_read_(encoder, page->header + OGG_HEADER_FIXED_PORTION_LEN, page->header[26], read_callback, client_data))
+ return false;
+
+ {
+ unsigned i;
+
+ /* check to see that it specifies a single packet */
+ for(i = 0; i < (unsigned)page->header[26] - 1; i++) {
+ if(page->header[i + OGG_HEADER_FIXED_PORTION_LEN] != 255) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_OGG_ERROR;
+ return false;
+ }
+ }
+
+ page->body_len = 255 * i + page->header[i];
+ }
+
+ /* allocate space for the page body */
+ if(0 == (page->body = malloc(page->body_len))) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_MEMORY_ALLOCATION_ERROR;
+ return false;
+ }
+
+ /* read in the page body */
+ if(!full_read_(encoder, page->body, page->body_len, read_callback, client_data))
+ return false;
+
+ /* check the CRC */
+ memcpy(crc, page->header+22, 4);
+ ogg_page_checksum_set(page);
+ if(memcmp(crc, page->header+22, 4)) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_OGG_ERROR;
+ return false;
+ }
+
+ return true;
+}
+
+FLAC__bool simple_ogg_page__set_at(OggFLAC__SeekableStreamEncoder *encoder, FLAC__uint64 position, ogg_page *page, OggFLAC__SeekableStreamEncoderSeekCallback seek_callback, OggFLAC__SeekableStreamEncoderWriteCallback write_callback, void *client_data)
+{
+ FLAC__ASSERT(page->header != 0);
+ FLAC__ASSERT(page->header_len != 0);
+ FLAC__ASSERT(page->body != 0);
+ FLAC__ASSERT(page->body_len != 0);
+
+ /* move the stream pointer to the supposed beginning of the page */
+ if(seek_callback(encoder, position, client_data) != FLAC__SEEKABLE_STREAM_ENCODER_SEEK_STATUS_OK) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_SEEK_ERROR;
+ return false;
+ }
+
+ ogg_page_checksum_set(page);
+
+ /* re-write the page */
+ if(write_callback(encoder, page->header, page->header_len, 0, 0, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK) {
+ encoder->protected_->state = OggFLAC__SEEKABLE_STREAM_ENCODER_WRITE_ERROR;
+ return false;
+ }
+
+ return true;
+}