// SPDX-License-Identifier: GPL-2.0

//

// container.c - an interface of parser/builder for formatted files.

//

// Copyright (c) 2018 Takashi Sakamoto <o-takashi@sakamocchi.jp>

//

// Licensed under the terms of the GNU General Public License, version 2.

#include "container.h"

#include "misc.h"

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <fcntl.h>

static const char *const cntr_type_labels[] = {

	[CONTAINER_TYPE_PARSER] = "parser",

	[CONTAINER_TYPE_BUILDER] = "builder",

};

static const char *const cntr_format_labels[] = {

	[CONTAINER_FORMAT_RIFF_WAVE] = "riff/wave",

	[CONTAINER_FORMAT_AU] = "au",

	[CONTAINER_FORMAT_VOC] = "voc",

	[CONTAINER_FORMAT_RAW] = "raw",

};

static const char *const suffixes[] = {

	[CONTAINER_FORMAT_RIFF_WAVE]	= ".wav",

	[CONTAINER_FORMAT_AU]		= ".au",

	[CONTAINER_FORMAT_VOC]		= ".voc",

	[CONTAINER_FORMAT_RAW]		= "",

};

const char *const container_suffix_from_format(enum container_format format)

{

	return suffixes[format];

}

int container_recursive_read(struct container_context *cntr, void *buf,

			     unsigned int byte_count)

{

	char *dst = buf;

	ssize_t result;

	size_t consumed = 0;

	while (consumed < byte_count && !cntr->interrupted) {

		result = read(cntr->fd, dst + consumed, byte_count - consumed);

		if (result < 0) {

			// This descriptor was configured with non-blocking

			// mode. EINTR is not cought when get any interrupts.

			if (cntr->interrupted)

				return -EINTR;

			if (errno == EAGAIN)

				continue;

			return -errno;

		}

		// Reach EOF.

		if (result == 0) {

			cntr->eof = true;

			return 0;

		}

		consumed += result;

	}

	return 0;

}

int container_recursive_write(struct container_context *cntr, void *buf,

			      unsigned int byte_count)

{

	char *src = buf;

	ssize_t result;

	size_t consumed = 0;

	while (consumed < byte_count && !cntr->interrupted) {

		result = write(cntr->fd, src + consumed, byte_count - consumed);

		if (result < 0) {

			// This descriptor was configured with non-blocking

			// mode. EINTR is not cought when get any interrupts.

			if (cntr->interrupted)

				return -EINTR;

			if (errno == EAGAIN)

				continue;

			return -errno;

		}

		consumed += result;

	}

	return 0;

}

enum container_format container_format_from_path(const char *path)

{

	const char *suffix;

	const char *pos;

	int i;

	for (i = 0; i < ARRAY_SIZE(suffixes); ++i) {

		suffix = suffixes[i];

		// Check last part of the string.

		pos = path + strlen(path) - strlen(suffix);

		if (!strcmp(pos, suffix))

			return i;

	}

	// Unsupported.

	return CONTAINER_FORMAT_RAW;

}

int container_seek_offset(struct container_context *cntr, off64_t offset)

{

	off64_t pos;

	pos = lseek64(cntr->fd, offset, SEEK_SET);

	if (pos < 0)

		return -errno;

	if (pos != offset)

		return -EIO;

	return 0;

}

// To avoid blocking execution at system call iteration after receiving UNIX

// signals.

static int set_nonblock_flag(int fd)

{

	int flags;

	flags = fcntl(fd, F_GETFL);

	if (flags < 0)

		return -errno;

	flags |= O_NONBLOCK;

	if (fcntl(fd, F_SETFL, flags) < 0)

		return -errno;

	return 0;

}

int container_parser_init(struct container_context *cntr,

			  const char *const path, unsigned int verbose)

{

	const struct container_parser *parsers[] = {

		[CONTAINER_FORMAT_RIFF_WAVE] = &container_parser_riff_wave,

		[CONTAINER_FORMAT_AU] = &container_parser_au,

		[CONTAINER_FORMAT_VOC] = &container_parser_voc,

	};

	const struct container_parser *parser;

	unsigned int size;

	int i;

	int err;

	assert(cntr);

	assert(path);

	assert(path[0] != '\0');

	// Detect forgotten to destruct.

	assert(cntr->fd == 0);

	assert(cntr->private_data == NULL);

	memset(cntr, 0, sizeof(*cntr));

	// Open a target descriptor.

	if (!strcmp(path, "-")) {

		cntr->fd = fileno(stdin);

		if (isatty(cntr->fd)) {

			fprintf(stderr,

				"A terminal is referred for standard input. "

				"Output from any process or shell redirection "

				"should be referred instead.\n");

			return -EIO;

		}

		err = set_nonblock_flag(cntr->fd);

		if (err < 0)

			return err;

		cntr->stdio = true;

	} else {

		cntr->fd = open(path, O_RDONLY | O_NONBLOCK);

		if (cntr->fd < 0)

			return -errno;

	}

	// 4 bytes are enough to detect supported containers.

	err = container_recursive_read(cntr, cntr->magic, sizeof(cntr->magic));

	if (err < 0)

		return err;

	for (i = 0; i < ARRAY_SIZE(parsers); ++i) {

		parser = parsers[i];

		size = strlen(parser->magic);

		if (size > 4)

			size = 4;

		if (!strncmp(cntr->magic, parser->magic, size))

			break;

	}

	// Don't forget that the first 4 bytes were already read for magic

	// bytes.

	cntr->magic_handled = false;

	// Unless detected, use raw container.

	if (i == ARRAY_SIZE(parsers))

		parser = &container_parser_raw;

	// Allocate private data for the parser.

	if (parser->private_size > 0) {

		cntr->private_data = malloc(parser->private_size);

		if (cntr->private_data == NULL)

			return -ENOMEM;

		memset(cntr->private_data, 0, parser->private_size);

	}

	cntr->type = CONTAINER_TYPE_PARSER;

	cntr->process_bytes = container_recursive_read;

	cntr->format = parser->format;

	cntr->ops = &parser->ops;

	cntr->max_size = parser->max_size;

	cntr->verbose = verbose;

	return 0;

}

int container_builder_init(struct container_context *cntr,

			   const char *const path, enum container_format format,

			   unsigned int verbose)

{

	const struct container_builder *builders[] = {

		[CONTAINER_FORMAT_RIFF_WAVE] = &container_builder_riff_wave,

		[CONTAINER_FORMAT_AU] = &container_builder_au,

		[CONTAINER_FORMAT_VOC] = &container_builder_voc,

		[CONTAINER_FORMAT_RAW] = &container_builder_raw,

	};

	const struct container_builder *builder;

	int err;

	assert(cntr);

	assert(path);

	assert(path[0] != '\0');

	// Detect forgotten to destruct.

	assert(cntr->fd == 0);

	assert(cntr->private_data == NULL);

	memset(cntr, 0, sizeof(*cntr));

	// Open a target descriptor.

	if (path == NULL || *path == '\0')

		return -EINVAL;

	if (!strcmp(path, "-")) {

		cntr->fd = fileno(stdout);

		if (isatty(cntr->fd)) {

			fprintf(stderr,

				"A terminal is referred for standard output. "

				"Input to any process or shell redirection "

				"should be referred instead.\n");

			return -EIO;

		}

		err = set_nonblock_flag(cntr->fd);

		if (err < 0)

			return err;

		cntr->stdio = true;

	} else {

		cntr->fd = open(path, O_RDWR | O_NONBLOCK | O_CREAT | O_TRUNC,

				0644);

		if (cntr->fd < 0)

			return -errno;

	}

	builder = builders[format];

	// Allocate private data for the builder.

	if (builder->private_size > 0) {

		cntr->private_data = malloc(builder->private_size);

		if (cntr->private_data == NULL)

			return -ENOMEM;

		memset(cntr->private_data, 0, builder->private_size);

	}

	cntr->type = CONTAINER_TYPE_BUILDER;

	cntr->process_bytes = container_recursive_write;

	cntr->format = builder->format;

	cntr->ops = &builder->ops;

	cntr->max_size = builder->max_size;

	cntr->verbose = verbose;

	return 0;

}

int container_context_pre_process(struct container_context *cntr,

				  snd_pcm_format_t *format,

				  unsigned int *samples_per_frame,

				  unsigned int *frames_per_second,

				  uint64_t *frame_count)

{

	uint64_t byte_count = 0;

	unsigned int bytes_per_frame;

	int err;

	assert(cntr);

	assert(format);

	assert(samples_per_frame);

	assert(frames_per_second);

	assert(frame_count);

	if (cntr->type == CONTAINER_TYPE_BUILDER)

		byte_count = cntr->max_size;

	if (cntr->ops->pre_process) {

		err = cntr->ops->pre_process(cntr, format, samples_per_frame,

					     frames_per_second, &byte_count);

		if (err < 0)

			return err;

		if (cntr->eof)

			return 0;

	}

	if (cntr->format == CONTAINER_FORMAT_RAW) {

		if (*format == SND_PCM_FORMAT_UNKNOWN ||

		    *samples_per_frame == 0 || *frames_per_second == 0) {

			fprintf(stderr,

				"Any file format is not detected. Need to "

				"indicate all of sample format, channels and "

				"rate explicitly.\n");

			return -EINVAL;

		}

	}

	assert(*format >= SND_PCM_FORMAT_S8);

	assert(*format <= SND_PCM_FORMAT_LAST);

	assert(*samples_per_frame > 0);

	assert(*frames_per_second > 0);

	assert(byte_count > 0);

	cntr->bytes_per_sample = snd_pcm_format_physical_width(*format) / 8;

	cntr->samples_per_frame = *samples_per_frame;

	cntr->frames_per_second = *frames_per_second;

	bytes_per_frame = cntr->bytes_per_sample * *samples_per_frame;

	*frame_count = byte_count / bytes_per_frame;

	cntr->max_size -= cntr->max_size / bytes_per_frame;

	if (cntr->verbose > 0) {

		fprintf(stderr, "Container: %s\n",

			cntr_type_labels[cntr->type]);

		fprintf(stderr, "  format: %s\n",

			cntr_format_labels[cntr->format]);

		fprintf(stderr, "  sample format: %s\n",

			snd_pcm_format_name(*format));

		fprintf(stderr, "  bytes/sample: %u\n",

			cntr->bytes_per_sample);

		fprintf(stderr, "  samples/frame: %u\n",

			cntr->samples_per_frame);

		fprintf(stderr, "  frames/second: %u\n",

			cntr->frames_per_second);

		if (cntr->type == CONTAINER_TYPE_PARSER) {

			fprintf(stderr, "  frames: %lu\n",

				*frame_count);

		} else {

			fprintf(stderr, "  max frames: %lu\n",

				*frame_count);

		}

	}

	return 0;

}

int container_context_process_frames(struct container_context *cntr,

				     void *frame_buffer,

				     unsigned int *frame_count)

{

	char *buf = frame_buffer;

	unsigned int bytes_per_frame;

	unsigned int byte_count;

	unsigned int target_byte_count;

	int err;

	assert(cntr);

	assert(!cntr->eof);

	assert(frame_buffer);

	assert(frame_count);

	bytes_per_frame = cntr->bytes_per_sample * cntr->samples_per_frame;

	target_byte_count = *frame_count * bytes_per_frame;

	// A parser of cotainers already read first 4 bytes to detect format

	// of container, however they includes PCM frames when any format was

	// undetected. Surely to write out them.

	byte_count = target_byte_count;

	if (cntr->format == CONTAINER_FORMAT_RAW &&

	    cntr->type == CONTAINER_TYPE_PARSER && !cntr->magic_handled) {

		memcpy(buf, cntr->magic, sizeof(cntr->magic));

		buf += sizeof(cntr->magic);

		byte_count -= sizeof(cntr->magic);

		cntr->magic_handled = true;

	}

	// Each container has limitation for its volume for sample data.

	if (cntr->handled_byte_count > cntr->max_size - byte_count)

		byte_count = cntr->max_size - cntr->handled_byte_count;

	// All of supported containers include interleaved PCM frames.

	// TODO: process frames for truncate case.

	err = cntr->process_bytes(cntr, buf, byte_count);

	if (err < 0) {

		*frame_count = 0;

		return err;

	}

	cntr->handled_byte_count += target_byte_count;

	if (cntr->handled_byte_count == cntr->max_size)

		cntr->eof = true;

	*frame_count = target_byte_count / bytes_per_frame;

	return 0;

}

int container_context_post_process(struct container_context *cntr,

				   uint64_t *frame_count)

{

	int err = 0;

	assert(cntr);

	assert(frame_count);

	if (cntr->verbose && cntr->handled_byte_count > 0) {

		fprintf(stderr, "  Handled bytes: %lu\n",

			cntr->handled_byte_count);

	}

	// NOTE* we cannot seek when using standard input/output.

	if (!cntr->stdio && cntr->ops && cntr->ops->post_process) {

		// Usually, need to write out processed bytes in container

		// header even it this program is interrupted.

		cntr->interrupted = false;

		err = cntr->ops->post_process(cntr, cntr->handled_byte_count);

	}

	// Ensure to perform write-back from disk cache.

	if (cntr->type == CONTAINER_TYPE_BUILDER)

		fsync(cntr->fd);

	if (err < 0)

		return err;

	if (cntr->bytes_per_sample == 0 || cntr->samples_per_frame == 0) {

		*frame_count = 0;

	} else {

		*frame_count = cntr->handled_byte_count /

			       cntr->bytes_per_sample /

			       cntr->samples_per_frame;

	}

	return 0;

}

void container_context_destroy(struct container_context *cntr)

{

	assert(cntr);

	close(cntr->fd);

	if (cntr->private_data)

		free(cntr->private_data);

	cntr->fd = 0;

	cntr->private_data = NULL;

}