wav.c

/*
robot36 - encode and decode images using SSTV in Robot 36 mode
Written in 2011 by <Ahmet Inan> <xdsopl@googlemail.com>
To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.
You should have received a copy of the CC0 Public Domain Dedication along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
*/


#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include "wav.h"
#include "mmap_file.h"

struct wav_head {
	uint32_t ChunkID;
	uint32_t ChunkSize;
	uint32_t Format;
	uint32_t Subchunk1ID;
	uint32_t Subchunk1Size;
	uint16_t AudioFormat;
	uint16_t NumChannels;
	uint32_t SampleRate;
	uint32_t ByteRate;
	uint16_t BlockAlign;
	uint16_t BitsPerSample;
	uint32_t Subchunk2ID;
	uint32_t Subchunk2Size;
};

struct wav {
	struct pcm base;
	void *p;
	short *b;
	size_t size;
	int index;
	int frames;
	int r;
	int c;
};

void close_wav(struct pcm *pcm)
{
	struct wav *wav = (struct wav *)(pcm->data);
	munmap_file(wav->p, wav->size);
	free(wav);
}

void info_wav(struct pcm *pcm)
{
	struct wav *wav = (struct wav *)(pcm->data);
	fprintf(stderr, "%d channel(s), %d rate, %.2f seconds\n", wav->c, wav->r, (float)wav->frames / (float)wav->r);
}
int rate_wav(struct pcm *pcm)
{
	struct wav *wav = (struct wav *)(pcm->data);
	return wav->r;
}
int channels_wav(struct pcm *pcm)
{
	struct wav *wav = (struct wav *)(pcm->data);
	return wav->c;
}
int read_wav(struct pcm *pcm, short *buff, int frames)
{
	struct wav *wav = (struct wav *)(pcm->data);
	if ((wav->index + frames) > wav->frames)
		return 0;
	memcpy(buff, wav->b + wav->index * wav->c, sizeof(short) * frames * wav->c);
	wav->index += frames;
	return 1;
}
int write_wav(struct pcm *pcm, short *buff, int frames)
{
	struct wav *wav = (struct wav *)(pcm->data);
	if ((wav->index + frames) > wav->frames)
		return 0;
	memcpy(wav->b + wav->index * wav->c, buff, sizeof(short) * frames * wav->c);
	wav->index += frames;
	return 1;
}

int open_wav_read(struct pcm **p, char *name)
{
	struct wav *wav = (struct wav *)malloc(sizeof(struct wav));
	wav->base.close = close_wav;
	wav->base.info = info_wav;
	wav->base.rate = rate_wav;
	wav->base.channels = channels_wav;
	wav->base.rw = read_wav;
	wav->base.data = (void *)wav;
	if (!mmap_file_ro(&wav->p, name, &wav->size)) {
		fprintf(stderr, "couldnt open wav file %s!\n", name);
		free(wav);
		return 0;
	}
	struct wav_head *head = (struct wav_head *)wav->p;
	wav->b = (short *)(wav->p + sizeof(struct wav_head));

	if (head->ChunkID != 0x46464952 || head->Format != 0x45564157 ||
			head->Subchunk1ID != 0x20746d66 || head->Subchunk1Size != 16 ||
			head->AudioFormat != 1 || head->Subchunk2ID != 0x61746164) {
		fprintf(stderr, "unsupported WAV file!\n");
		munmap_file(wav->p, wav->size);
		free(wav);
		return 0;
	}
	if (head->BitsPerSample != 16) {
		fprintf(stderr, "only 16bit WAV supported!\n");
		munmap_file(wav->p, wav->size);
		free(wav);
		return 0;
	}
	wav->index = 0;
	wav->frames = head->Subchunk2Size / (sizeof(short) * head->NumChannels);
	wav->r = head->SampleRate;
	wav->c = head->NumChannels;
	*p = &(wav->base);
	return 1;
}

int open_wav_write(struct pcm **p, char *name, int rate, int channels, float seconds)
{
	struct wav *wav = (struct wav *)malloc(sizeof(struct wav));
	wav->base.close = close_wav;
	wav->base.info = info_wav;
	wav->base.rate = rate_wav;
	wav->base.channels = channels_wav;
	wav->base.rw = write_wav;
	wav->base.data = (void *)wav;
	int frames = seconds * rate;
	wav->size = frames * channels * sizeof(short) + sizeof(struct wav_head);
	if (!mmap_file_rw(&wav->p, name, wav->size)) {
		fprintf(stderr, "couldnt open wav file %s!\n", name);
		free(wav);
		return 0;
	}
	struct wav_head *head = (struct wav_head *)wav->p;
	wav->b = (short *)(wav->p + sizeof(struct wav_head));

	head->ChunkID = 0x46464952;
	head->ChunkSize = 36 + frames * sizeof(short) * channels;
	head->Format = 0x45564157;
	head->Subchunk1ID = 0x20746d66;
	head->Subchunk1Size = 16;
	head->AudioFormat = 1;
	head->NumChannels = channels;
	head->SampleRate = rate;
	head->ByteRate = 2 * rate;
	head->BlockAlign = 2;
	head->BitsPerSample = 16;
	head->Subchunk2ID = 0x61746164;
	head->Subchunk2Size = frames * sizeof(short) * channels;

	wav->r = rate;
	wav->c = channels;
	wav->frames = frames;
	wav->index = 0;

	*p = &(wav->base);
	return 1;
}