Add capability to libFLAC to seek in chained streams

include/FLAC/stream_decoder.h

@@ -806,10 +806,8 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_ogg_serial_number(FLAC__StreamDecod
  *  by using FLAC__STREAM_DECODER_READ_STATUS_END_OF_LINK
  *  appropriately.
  *
- *  Note that seeking is not yet supported when this flag is set to
- *  true. Also, when this flag is set to true, the serial number set
- *  with FLAC__stream_decoder_set_ogg_serial_number is ignored when
- *  decoding chained ogg streams.
+ *  Note that when this flag is set to true, the serial number set
+ *  with FLAC__stream_decoder_set_ogg_serial_number is ignored.
  *
  * \note
  * This function has no effect with native FLAC decoding.
@@ -856,7 +854,7 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_md5_checking(FLAC__StreamDecoder *d
  *    \code decoder != NULL \endcode
  *    \a type is valid
  * \retval FLAC__bool
- *    \c false if the decoder is already initialized, else \c true.
+ *    \c false if type is invalid, else \c true.
  */
 FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond(FLAC__StreamDecoder *decoder, FLAC__MetadataType type);
 
@@ -871,7 +869,7 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond(FLAC__StreamDecode
  *    \code decoder != NULL \endcode
  *    \code id != NULL \endcode
  * \retval FLAC__bool
- *    \c false if the decoder is already initialized, else \c true.
+ *    \c false when memory allocation fails, else \c true.
  */
 FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_application(FLAC__StreamDecoder *decoder, const FLAC__byte id[4]);
 
@@ -883,7 +881,7 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_application(FLAC__
  * \assert
  *    \code decoder != NULL \endcode
  * \retval FLAC__bool
- *    \c false if the decoder is already initialized, else \c true.
+ *    \c always \c true.
  */
 FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_all(FLAC__StreamDecoder *decoder);
 
@@ -897,7 +895,7 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_all(FLAC__StreamDe
  *    \code decoder != NULL \endcode
  *    \a type is valid
  * \retval FLAC__bool
- *    \c false if the decoder is already initialized, else \c true.
+ *    \c false if type is invalid, else \c true.
  */
 FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore(FLAC__StreamDecoder *decoder, FLAC__MetadataType type);
 
@@ -912,7 +910,7 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore(FLAC__StreamDecoder
  *    \code decoder != NULL \endcode
  *    \code id != NULL \endcode
  * \retval FLAC__bool
- *    \c false if the decoder is already initialized, else \c true.
+ *    \c false if memory allocation fails, else \c true.
  */
 FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_application(FLAC__StreamDecoder *decoder, const FLAC__byte id[4]);
 
@@ -924,7 +922,7 @@ FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_application(FLAC__S
  * \assert
  *    \code decoder != NULL \endcode
  * \retval FLAC__bool
- *    \c false if the decoder is already initialized, else \c true.
+ *    \c always \c true.
  */
 FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_all(FLAC__StreamDecoder *decoder);
 
@@ -1661,6 +1659,14 @@ FLAC_API FLAC__bool FLAC__stream_decoder_skip_single_frame(FLAC__StreamDecoder *
  *  with FLAC__stream_decoder_flush() or reset with
  *  FLAC__stream_decoder_reset() before decoding can continue.
  *
+ *  When seeking in a chained stream with decoding of such streams
+ *  enabled with FLAC__stream_decoder_set_decode_chained_stream(),
+ *  this function seeks in the whole stream, over all links. When
+ *  a seek to another link is performed, the decoder will also
+ *  return metadata blocks of that link. If this is not desired,
+ *  use FLAC__stream_decoder_set_metadata_ignore_all() before
+ *  seeking.
+ *
  * \param  decoder  A decoder instance.
  * \param  sample   The target sample number to seek to.
  * \assert

oss-fuzz/seek.cc

@@ -42,7 +42,7 @@ int write_abort_check_counter = -1;
 #define FPRINTF_DEBUG_ONLY(...)
 #endif
 
-#define CONFIG_LENGTH 2
+#define CONFIG_LENGTH 3
 
 static FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 *const buffer[], void *client_data)
 {
@@ -70,8 +70,11 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 	uint8_t command_length;
 	FLAC__bool init_bools[16], ogg;
 
-	if(size > 2 && data[1] < 128) /* Use MSB as on/off */
-		alloc_check_threshold = data[1];
+	if(size < 1)
+		return 1;
+
+	if(data[0] < 128) /* Use MSB as on/off */
+		alloc_check_threshold = data[0];
 	else
 		alloc_check_threshold = INT32_MAX;
 	alloc_check_counter = 0;
@@ -83,17 +86,17 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 		return 1;
 	}
 
-	/* Use first byte for configuration, leave at least one byte of input */
+	/* Use first CONFIG_LENGTH bytes for configuration, leave at least one byte of input */
 	if(size < 1 + CONFIG_LENGTH){
 		FLAC__stream_decoder_delete(decoder);
 		return 0;
 	}
 
-	/* First 4 bits for configuration bools, next 4 for length of command section */
-	for(int i = 0; i < 4; i++)
-		init_bools[i] = data[i/8] & (1 << (i % 8));
+	/* bit 8 to 19 bits for configuration bools, bit 20 to 23 for length of command section */
+	for(int i = 0; i < 12; i++)
+		init_bools[i] = data[1+i/8] & (1 << (i % 8));
 
-	command_length = data[0] >> 4;
+	command_length = data[CONFIG_LENGTH-1] >> 4;
 
 	/* Leave at least one byte as input */
 	if(command_length >= size - 1 - CONFIG_LENGTH)
@@ -106,13 +109,15 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 		fclose(file_to_decode);
 	}
 
-	ogg =  init_bools[0];
+	ogg = init_bools[0];
 
 	FLAC__stream_decoder_set_md5_checking(decoder,init_bools[1]);
 	if(init_bools[2])
 		FLAC__stream_decoder_set_metadata_respond_all(decoder);
 	if(init_bools[3])
 		FLAC__stream_decoder_set_metadata_ignore_all(decoder);
+	if(init_bools[4])
+		FLAC__stream_decoder_set_decode_chained_stream(decoder, true);
 
 	/* initialize decoder */
 	if(decoder_valid) {
@@ -182,6 +187,15 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 				/* Set abort on write callback */
 				write_abort_check_counter = (command[0] >> 4) + 1;
 				break;
+			case 9:
+				FPRINTF_DEBUG_ONLY(stderr,"end_of_link\n");
+				decoder_valid = FLAC__stream_decoder_process_until_end_of_link(decoder);
+				break;
+			case 10:
+				FPRINTF_DEBUG_ONLY(stderr,"finish_link\n");
+				if(FLAC__stream_decoder_get_state(decoder) == FLAC__STREAM_DECODER_END_OF_LINK)
+					FLAC__stream_decoder_finish_link(decoder);
+
 		}
 	}
 

src/libFLAC/include/private/ogg_decoder_aspect.h

@@ -37,6 +37,22 @@
 
 #include "FLAC/ordinals.h"
 #include "FLAC/stream_decoder.h" /* for FLAC__StreamDecoderReadStatus */
+#include "share/compat.h"
+
+typedef struct FLAC__OggDecoderAspect_LinkDetails {
+	long serial_number;
+	FLAC__off_t size;
+	uint64_t samples;
+} FLAC__OggDecoderAspect_LinkDetails;
+
+typedef struct FLAC__OggDecoderAspect_TargetLink {
+	long serial_number;
+	FLAC__off_t start_byte;
+	FLAC__off_t end_byte;
+	uint64_t samples_in_preceding_links;
+	uint64_t samples_this_link;
+	uint32_t linknumber;
+} FLAC__OggDecoderAspect_TargetLink;
 
 typedef struct FLAC__OggDecoderAspect {
 	/* these are storage for values that can be set through the API */
@@ -55,6 +71,12 @@ typedef struct FLAC__OggDecoderAspect {
 	ogg_page working_page;
 	FLAC__bool have_working_packet; /* only if true will the following vars be valid */
 	ogg_packet working_packet; /* as we work through the packet we will move working_packet.packet forward and working_packet.bytes down */
+	FLAC__OggDecoderAspect_LinkDetails *linkdetails;
+	FLAC__OggDecoderAspect_TargetLink target_link; /* to pass data to the seek routine */
+	uint32_t number_of_links_detected;
+	uint32_t number_of_links_indexed;
+	uint32_t current_linknumber;
+	FLAC__bool is_seeking;
 } FLAC__OggDecoderAspect;
 
 void FLAC__ogg_decoder_aspect_set_serial_number(FLAC__OggDecoderAspect *aspect, long value);
@@ -64,8 +86,10 @@ void FLAC__ogg_decoder_aspect_finish(FLAC__OggDecoderAspect *aspect);
 void FLAC__ogg_decoder_aspect_flush(FLAC__OggDecoderAspect *aspect);
 void FLAC__ogg_decoder_aspect_reset(FLAC__OggDecoderAspect* aspect);
 void FLAC__ogg_decoder_aspect_next_link(FLAC__OggDecoderAspect* aspect);
+FLAC__OggDecoderAspect_TargetLink * FLAC__ogg_decoder_aspect_get_target_link(FLAC__OggDecoderAspect* aspect, FLAC__uint64 target_sample);
 void FLAC__ogg_decoder_aspect_set_decode_chained_stream(FLAC__OggDecoderAspect* aspect, FLAC__bool value);
 FLAC__bool FLAC__ogg_decoder_aspect_get_decode_chained_stream(FLAC__OggDecoderAspect* aspect);
+void FLAC__ogg_decoder_aspect_set_seek_parameters(FLAC__OggDecoderAspect *aspect, FLAC__OggDecoderAspect_TargetLink *target_link);
 
 typedef enum {
 	FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK = 0,

src/libFLAC/ogg_decoder_aspect.c

@@ -36,11 +36,11 @@
 
 #include <string.h> /* for memcpy() */
 #include "FLAC/assert.h"
+#include "share/alloc.h" /* for free() */
 #include "private/ogg_decoder_aspect.h"
 #include "private/ogg_mapping.h"
 #include "private/macros.h"
 
-
 /***********************************************************************
  *
  * Public class methods
@@ -65,13 +65,22 @@ FLAC__bool FLAC__ogg_decoder_aspect_init(FLAC__OggDecoderAspect *aspect)
 	aspect->have_working_page = false;
 	aspect->end_of_link = false;
 
+	aspect->current_linknumber = 0;
+	aspect->number_of_links_indexed = 0;
+	aspect->number_of_links_detected = 0;
+
+	if(NULL == (aspect->linkdetails = safe_realloc_mul_2op_(NULL,4,sizeof(FLAC__OggDecoderAspect_LinkDetails))))
+		return false;
+	memset(aspect->linkdetails, 0, 4 * sizeof(FLAC__OggDecoderAspect_LinkDetails));
+
 	return true;
 }
 
 void FLAC__ogg_decoder_aspect_finish(FLAC__OggDecoderAspect *aspect)
 {
 	(void)ogg_sync_clear(&aspect->sync_state);
 	(void)ogg_stream_clear(&aspect->stream_state);
+	free(aspect->linkdetails);
 }
 
 void FLAC__ogg_decoder_aspect_set_serial_number(FLAC__OggDecoderAspect *aspect, long value)
@@ -98,6 +107,7 @@ void FLAC__ogg_decoder_aspect_flush(FLAC__OggDecoderAspect *aspect)
 void FLAC__ogg_decoder_aspect_reset(FLAC__OggDecoderAspect *aspect)
 {
 	FLAC__ogg_decoder_aspect_flush(aspect);
+	aspect->current_linknumber = 0;
 
 	if(aspect->use_first_serial_number || aspect->decode_chained_stream)
 		aspect->need_serial_number = true;
@@ -106,6 +116,7 @@ void FLAC__ogg_decoder_aspect_reset(FLAC__OggDecoderAspect *aspect)
 void FLAC__ogg_decoder_aspect_next_link(FLAC__OggDecoderAspect* aspect)
 {
 	aspect->end_of_link = false;
+	aspect->current_linknumber++;
 }
 
 void FLAC__ogg_decoder_aspect_set_decode_chained_stream(FLAC__OggDecoderAspect* aspect, FLAC__bool value)
@@ -118,6 +129,48 @@ FLAC__bool FLAC__ogg_decoder_aspect_get_decode_chained_stream(FLAC__OggDecoderAs
 	return aspect->decode_chained_stream;
 }
 
+FLAC__OggDecoderAspect_TargetLink * FLAC__ogg_decoder_aspect_get_target_link(FLAC__OggDecoderAspect* aspect, FLAC__uint64 target_sample)
+{
+	/* This returns the link containing the seek target if known. In
+	 * effect, this function always returns NULL if no links have been
+	 * indexed */
+
+	uint32_t current_link = 0;
+	uint32_t total_samples = 0;
+	uint32_t position = 0;
+
+	while(current_link < aspect->number_of_links_indexed) {
+		total_samples += aspect->linkdetails[current_link].samples;
+		if(target_sample < total_samples) {
+			aspect->target_link.serial_number = aspect->linkdetails[current_link].serial_number;
+			aspect->target_link.start_byte = position;
+			aspect->target_link.samples_in_preceding_links = total_samples - aspect->linkdetails[current_link].samples;
+			aspect->target_link.end_byte = position + aspect->linkdetails[current_link].size;
+			aspect->target_link.samples_this_link = aspect->linkdetails[current_link].samples;
+			aspect->target_link.linknumber = current_link;
+			return &aspect->target_link;
+		}
+		position += aspect->linkdetails[current_link].size;
+		current_link++;
+	}
+	return NULL;
+}
+
+void FLAC__ogg_decoder_aspect_set_seek_parameters(FLAC__OggDecoderAspect *aspect, FLAC__OggDecoderAspect_TargetLink *target_link)
+{
+	if(target_link == 0) {
+		aspect->is_seeking = false;
+	}
+	else {
+		aspect->need_serial_number = false;
+		aspect->current_linknumber = target_link->linknumber;
+		aspect->serial_number = target_link->serial_number;
+		ogg_stream_reset_serialno(&aspect->stream_state, aspect->serial_number);
+		aspect->is_seeking = true;
+	}
+}
+
+
 FLAC__OggDecoderAspectReadStatus FLAC__ogg_decoder_aspect_read_callback_wrapper(FLAC__OggDecoderAspect *aspect, FLAC__byte buffer[], size_t *bytes, FLAC__OggDecoderAspectReadCallbackProxy read_callback, const FLAC__StreamDecoder *decoder, void *client_data)
 {
 	static const size_t OGG_BYTES_CHUNK = 8192;
@@ -173,7 +226,13 @@ FLAC__OggDecoderAspectReadStatus FLAC__ogg_decoder_aspect_read_callback_wrapper(
 							aspect->end_of_stream = true;
 						else {
 							aspect->end_of_link = true;
-							aspect->need_serial_number = true;
+							if(aspect->current_linknumber >= aspect->number_of_links_indexed) {
+								aspect->linkdetails[aspect->current_linknumber].samples = aspect->working_packet.granulepos;
+								aspect->linkdetails[aspect->current_linknumber].serial_number = aspect->serial_number;
+								aspect->number_of_links_indexed++;
+							}
+							if(!aspect->is_seeking)
+								aspect->need_serial_number = true;
 							aspect->have_working_page = false; /* e-o-s packet ends page */
 						}
 					}
@@ -234,10 +293,31 @@ FLAC__OggDecoderAspectReadStatus FLAC__ogg_decoder_aspect_read_callback_wrapper(
 					aspect->serial_number = ogg_page_serialno(&aspect->working_page);
 					ogg_stream_reset_serialno(&aspect->stream_state, aspect->serial_number);
 					aspect->need_serial_number = false;
+
+					/* current_linknumber lags a bit: it is only increased after processing
+					 * of the whole links is done, while this code does advance processing */
+					if(aspect->current_linknumber >= aspect->number_of_links_detected) {
+						FLAC__OggDecoderAspect_LinkDetails * tmpptr = NULL;
+						aspect->number_of_links_detected = aspect->current_linknumber + 1;
+
+						/* reallocate in chunks of 4 */
+						if((aspect->current_linknumber + 1) % 4 == 0) {
+							if(NULL == (tmpptr = safe_realloc_nofree_mul_2op_(aspect->linkdetails,5+aspect->current_linknumber,sizeof(FLAC__OggDecoderAspect_LinkDetails)))) {
+								return FLAC__OGG_DECODER_ASPECT_READ_STATUS_MEMORY_ALLOCATION_ERROR;
+							}
+							aspect->linkdetails = tmpptr;
+						}
+						memset(&aspect->linkdetails[aspect->current_linknumber], 0, sizeof(FLAC__OggDecoderAspect_LinkDetails));
+					}
+
+
 				}
 				if(ogg_stream_pagein(&aspect->stream_state, &aspect->working_page) == 0) {
 					aspect->have_working_page = true;
 					aspect->have_working_packet = false;
+					if(aspect->current_linknumber >= aspect->number_of_links_indexed) {
+						aspect->linkdetails[aspect->current_linknumber].size += aspect->working_page.header_len + aspect->working_page.body_len;
+					}
 				}
 				/* else do nothing, could be a page from another stream */
 			}