path: root/ogg_afh_common.c

/* SPDX-License-Identifier: GPL-2.0 */

/** \file ogg_afh_common.c Functions common to all ogg/ codecs. */

#include <ogg/ogg.h>

#include "para.h"
#include "afh.h"
#include "error.h"
#include "string.h"
#include "ogg_afh_common.h"
#include "fd.h"

/* Taken from decoder_example.c of libvorbis-1.2.3. */
static int process_packets_2_and_3(ogg_sync_state *oss,
		ogg_stream_state *stream, struct afh_info *afhi,
		struct oac_callback_info *ci)
{
	ogg_page page;
	ogg_packet packet;
	int i = 0;

	while (i < 2) {
		while (i < 2) {
			int ret = ogg_sync_pageout(oss, &page);
			if (ret == 0)
				break; /* Need more data */
			if (ret != 1)
				continue;
			/*
			 * We can ignore any errors here as they'll also become
			 * apparent at packetout.
			 */
			ogg_stream_pagein(stream, &page);
			PARA_INFO_LOG("ogg page serial: %d\n",
				ogg_page_serialno(&page));
			while (i < 2) {
				ret = ogg_stream_packetout(stream, &packet);
				if (ret == 0)
					break;
				if (ret < 0)
					return -E_STREAM_PACKETOUT;
				ret = ci->packet_callback(&packet, i + 1,
					ogg_page_serialno(&page), afhi,
					ci->private_data);
				if (ret < 0)
					return ret;
				if (ret == 0) /* header complete */
					return 1;
				i++;
			}
		}
	}
	return 1;
}

static int process_ogg_packets(ogg_sync_state *oss, struct afh_info *afhi,
		struct oac_callback_info *ci)
{
	ogg_packet packet;
	ogg_stream_state stream;
	ogg_page page;
	int ret;

	if (ogg_sync_pageout(oss, &page) != 1)
		return -E_SYNC_PAGEOUT;

	ret = ogg_page_serialno(&page);
	ogg_stream_init(&stream, ret);

	ret = -E_STREAM_PAGEIN;
	if (ogg_stream_pagein(&stream, &page) < 0)
		goto out;

	ret = -E_STREAM_PACKETOUT;
	if (ogg_stream_packetout(&stream, &packet) != 1)
		goto out;
	ret = ci->packet_callback(&packet, 0, ogg_page_serialno(&page),
		afhi, ci->private_data);
	if (ret < 0)
		goto out;
	ret = process_packets_2_and_3(oss, &stream, afhi, ci);
	if (ret < 0)
		goto out;
	ret = 1;
out:
	ogg_stream_clear(&stream);
	return ret;
}

static void set_chunk_tv(int frames_per_chunk, int frequency,
		struct timeval *result)
{
	uint64_t x = (uint64_t)frames_per_chunk * 1000 * 1000 / frequency;

	result->tv_sec = x / 1000 / 1000;
	result->tv_usec = x % (1000 * 1000);
	PARA_INFO_LOG("%d frames per chunk, chunk time: %lums\n",
		frames_per_chunk, tv2ms(result));
}

/**
 * Pass first three ogg packets to callback and build the chunk table.
 *
 * This function extracts the first three ogg packets of the audio data
 * given by \a map and \a numbytes and passes each packet to the callback
 * defined by \a ci.
 *
 * If the packet callback indicates success and \a afhi is not \p NULL, the
 * chunk table is built. Chunk zero contains the first three ogg packets while
 * all other chunks consist of exactly one ogg page.
 *
 * \param map Audio file data.
 * \param numbytes The length of \a map.
 * \param afhi Passed to the packet callback, contains chunk table.
 * \param ci The callback structure.
 *
 * \return Standard.
 */
int oac_get_file_info(char *map, size_t numbytes, struct afh_info *afhi,
		struct oac_callback_info *ci)
{
	ogg_sync_state oss;
	ogg_page op;
	char *buf;
	int ret, i, j, frames_per_chunk, ct_size, prev_pageno = 0;
	long long unsigned granule_skip = 0, num_frames = 0;
	int64_t granule = 0, prev_granule = 0;

	ogg_sync_init(&oss);
	ret = -E_OGG_SYNC;
	buf = ogg_sync_buffer(&oss, numbytes);
	if (!buf)
		goto out;
	memcpy(buf, map, numbytes);
	ret = -E_OGG_SYNC;
	if (ogg_sync_wrote(&oss, numbytes) < 0)
		goto out;
	ret = process_ogg_packets(&oss, afhi, ci);
	if (ret < 0)
		goto out;
	if (!afhi)
		goto out;
	afhi->header_len = oss.returned;
	oss.returned = 0;
	oss.fill = numbytes;
	/* count ogg pages and get duration of the file */
	for (i = 0; ogg_sync_pageseek(&oss, &op) > 0; i++) {
		int this_pageno = ogg_page_pageno(&op);
		int64_t this_granule = ogg_page_granulepos(&op);
		if (this_granule >= 0)
			granule = this_granule;
		if (i > 0 && this_pageno != prev_pageno + 1) /* hole */
			granule_skip += granule - prev_granule;
		prev_pageno = this_pageno;
		prev_granule = granule;
	}
	num_frames = granule - granule_skip;
	PARA_INFO_LOG("%d pages, %llu frames\n", i, num_frames);
	ret = -E_OGG_EMPTY;
	if (i == 0)
		goto out;
	afhi->seconds_total = num_frames / afhi->frequency;
	/* use roughly one page per chunk */
	frames_per_chunk = num_frames / i;
	PARA_INFO_LOG("%" PRIu32 " seconds, %d frames/chunk\n",
		afhi->seconds_total, frames_per_chunk);
	ct_size = 250;
	afhi->chunk_table = arr_alloc(ct_size, sizeof(uint32_t));
	afhi->chunk_table[0] = 0;
	afhi->chunk_table[1] = afhi->header_len;
	oss.returned = afhi->header_len;
	oss.fill = numbytes;
	for (j = 1; ogg_sync_pageseek(&oss, &op) > 0; /* nothing */) {
		granule = ogg_page_granulepos(&op);

		while (granule >= (j + 1) * frames_per_chunk) {
			j++;
			if (j >= ct_size) {
				ct_size *= 2;
				afhi->chunk_table = arr_realloc(
					afhi->chunk_table,
					ct_size, sizeof(uint32_t));
			}
			afhi->chunk_table[j] = oss.returned;
		}
	}
	afhi->chunks_total = j;
	set_max_chunk_size(afhi);
	set_chunk_tv(frames_per_chunk, afhi->frequency, &afhi->chunk_tv);
	ret = 0;
out:
	ogg_sync_clear(&oss);
	return ret;
}

static int write_ogg_page(int fd, const ogg_page *op)
{
	int ret;

	PARA_DEBUG_LOG("header/body: %li/%li\n", op->header_len, op->body_len);
	ret = xwrite(fd, (const char *)op->header, op->header_len);
	if (ret < 0)
		return ret;
	return xwrite(fd, (const char *)op->body, op->body_len);
}

/**
 * Change meta tags of ogg files.
 *
 * \param map The (read-only) memory map of the input file.
 * \param map_sz The size of the input file in bytes.
 * \param fd The output file descriptor.
 * \param meta_packet Codec-specific packet containing modified tags.
 * \param meta_sz Size of the metadata packet.
 *
 * This function writes a new ogg file content using file descriptor \a fd,
 * which must correspond to a file which has been opened for writing.  The
 * second packet is supposed to contain the metadata, and is replaced by \a
 * meta_packet. This output file has to be closed by the caller.
 *
 * \return Standard.
 */
int oac_rewrite_tags(const char *map, size_t map_sz, int fd,
		char *meta_packet, size_t meta_sz)
{
	ogg_sync_state oss_in, oss_out;
	ogg_stream_state stream_in, stream_out, *si = NULL, *so = NULL;
	ogg_packet packet;
	ogg_page op;
	char *buf;
	int serial, ret;
	long len = map_sz;

	ogg_sync_init(&oss_in);
	ogg_sync_init(&oss_out);

	ret = -E_OGG_SYNC;
	buf = ogg_sync_buffer(&oss_in, len);
	if (!buf)
		goto out;
	memcpy(buf, map, len);
	ret = -E_OGG_SYNC;
	if (ogg_sync_wrote(&oss_in, len) < 0)
		goto out;
	if (ogg_sync_pageout(&oss_in, &op) != 1)
		goto out;
	ret = ogg_page_serialno(&op);
	serial = ret;

	si = &stream_in;
	ogg_stream_init(si, serial);
	/* Packet #0 goes to an own page */
	ret = -E_STREAM_PAGEIN;
	if (ogg_stream_pagein(si, &op) < 0)
		goto out;
	ret = -E_STREAM_PACKETOUT;
	if (ogg_stream_packetout(si, &packet) != 1)
		goto out;
	ret = -E_STREAM_PACKETIN;
	so = &stream_out;
	ogg_stream_init(so, serial);
	if (ogg_stream_packetin(so, &packet) != 0)
		goto out;
	ret = ogg_stream_flush(so, &op);
	assert(ret != 0);
	/* packets have been flushed into the page. */
	ret = write_ogg_page(fd, &op);
	if (ret < 0)
		goto out;
	/*
	 * For all supported ogg/xxx audio formats the meta data packet is
	 * packet #1. Write out our modified version of this packet.
	 */
	packet.packetno = 1;
	packet.b_o_s = packet.e_o_s = 0;
	packet.packet = (typeof(packet.packet))meta_packet;
	packet.bytes = meta_sz;
	ret = -E_STREAM_PACKETIN;
	if (ogg_stream_packetin(so, &packet) != 0)
		goto out;
	/* Copy ogg packets, ignoring the meta data packet. */
	for (;;) {
		ret = ogg_stream_packetout(si, &packet);
		if (ret == -1)
			break;
		if (ret != 1) {
			ret = -E_STREAM_PAGEOUT;
			if (ogg_sync_pageout(&oss_in, &op) < 0)
				goto out;
			ret = -E_STREAM_PAGEIN;
			if (ogg_stream_pagein(si, &op))
				goto out;
			continue;
		}
		PARA_DEBUG_LOG("packet: bytes: %d, granule: %d, packetno: %d\n",
			(int)packet.bytes, (int)packet.granulepos,
			(int)packet.packetno);
		/* ignore meta data packet which we replaced */
		if (packet.packetno == 1)
			continue;
		ret = -E_STREAM_PACKETIN;
		if (ogg_stream_packetin(so, &packet) != 0)
			goto out;
		/* only create a new ogg page if granulepos is valid */
		if (packet.granulepos == -1)
			continue;
		/* force remaining packets into a page */
		for (;;) {
#ifdef HAVE_OGG_STREAM_FLUSH_FILL
			ret = ogg_stream_flush_fill(so, &op, INT_MAX);
#else
			ret = ogg_stream_flush(so, &op);
#endif
			if (ret <= 0)
				break;
			PARA_DEBUG_LOG("writing page (%li bytes)\n",
				op.header_len + op.body_len);
			ret = write_ogg_page(fd, &op);
			if (ret < 0)
				goto out;
		}
	}
	if (ogg_stream_flush(so, &op)) {
		/* write remaining data */
		ret = write_ogg_page(fd, &op);
		if (ret < 0)
			goto out;
	}
	ret = 1;
out:
	ogg_sync_clear(&oss_in);
	ogg_sync_clear(&oss_out);
	if (si)
		ogg_stream_clear(si);
	if (so)
		ogg_stream_clear(so);
	return ret;
}

/* Structure for providing custom headers for streaming. */
struct oac_custom_header {
	char *buf;
	size_t len;
	ogg_stream_state oss;
};

/**
 * Allocate and return a custom header structure.
 *
 * For some audio codecs which employ the ogg container format, the server side
 * wants to replace the meta tags at the beginning of the file because they are
 * not needed for streaming and can be arbitrary large. The structure returned
 * by this function is typically used as the ->private field of struct \ref
 * oac_callback_info for \ref oac_get_file_info(). This allows the audio format
 * handler to set up a custom header which is identical to the original header,
 * but with the meta data part replaced by fixed length dummy contents.
 *
 * \return The returned memory must be initialized with the serial number of
 * the ogg stream before ogg packets can be submitted to it. This is not done
 * here because the header structure is allocated before \ref
 * oac_get_file_info() is called, and the serial number is not known at this
 * point.
 *
 * \sa \ref oac_custom_header_init().
 */
__malloc struct oac_custom_header *oac_custom_header_new(void)
{
	return zalloc(sizeof(struct oac_custom_header));
}

/**
 * Set the serial number of an allocated header structure.
 *
 * \param serial Passed to the callback function.
 * \param h As returned from \ref oac_custom_header_new().
 *
 * This function must be called before any packets are submitted.
 */
void oac_custom_header_init(int serial, struct oac_custom_header *h)
{
	ogg_stream_init(&h->oss, serial);
}

/**
 * Submit an ogg packet to a custom header structure.
 *
 * \param op The packet to append.
 * \param h Must be initialized.
 *
 * The packet may be the one which was passed to the callback, or a completely
 * different one, like a dummy metadata packet.
 *
 * \return Standard.
 */
int oac_custom_header_append(ogg_packet *op, struct oac_custom_header *h)
{
	return ogg_stream_packetin(&h->oss, op) < 0? -E_OGG_PACKET_IN : 1;
}

/**
 * Force remaining packets into an ogg page.
 *
 * \param h Should contain submitted but not yet flushed packets.
 *
 * This is called after the first packet has been submitted with \ref
 * oac_custom_header_append() to make sure the first ogg page contains only
 * this packet. Also when header processing is complete, the callbacks call
 * this to force the previously submitted packets into a page.
 */
void oac_custom_header_flush(struct oac_custom_header *h)
{
	ogg_page og;

	while (ogg_stream_flush(&h->oss, &og)) {
		size_t len = og.header_len + og.body_len;
		h->buf = para_realloc(h->buf, h->len + len);
		memcpy(h->buf + h->len, og.header, og.header_len);
		memcpy(h->buf + h->len + og.header_len, og.body, og.body_len);
		h->len += len;
	}
}

/**
 * Return the custom header buffer and deallocate resources.
 *
 * This is called after the ogg packets which comprise the header have been
 * submitted and flushed.
 *
 * \param buf Result pointer.
 * \param h Must not be used any more after the call.
 *
 * \return The size of the header. This is the sum of the sizes of all ogg
 * pages that have been flushed out.
 */
size_t oac_custom_header_get(char **buf, struct oac_custom_header *h)
{
	size_t ret = h->len;

	*buf = h->buf;
	ogg_stream_clear(&h->oss);
	free(h);
	return ret;
}