Play argv wavs using ALSA

wav_play.c

#include <alloca.h> /*needed (yet not included) by asoundlib in c99*/
#include <alsa/asoundlib.h>/* build with -lasound */
#include <stdint.h>
#define $(x) if ((x) < 0) { fprintf(stderr, "Error:%s", # x); return -1; }
#define MIN(A, B) ((A) < (B) ? (A) : (B))
typedef struct {
	char RIFF[4];
	uint32_t ChunkSize;
	char WAVE[4];
	char fmt[4];
	uint32_t Subchunk1Size;
	int16_t AudioFormat;
	int16_t NumOfChannels;
	uint32_t SamplesPerSec;
	uint32_t bytesPerSec;
	int16_t blockAlign;
	int16_t bitsPerSample;
	char Subchunk2ID[4];
	uint32_t Subchunk2Size;
	char data[1];
} wavHeader;

typedef struct {
	void* data;
	wavHeader*wav_hdr;
	size_t wav_size;
	char* wav_data;
}sound_file_t;

sound_file_t wavs[256];
size_t wavs_loaded = 0;
void load_wavs(char** paths, size_t total)
{
	for (int i = 0; i < total; i++) {
		sound_file_t*wav = &wavs[wavs_loaded];
		FILE *file = fopen(paths[i], "rb");
		if (file == NULL)
			continue;
		fseek(file, 0, SEEK_END);
		wav->wav_size = ftell(file);
		fseek(file, 0, SEEK_SET);
		wav->data = malloc(wav->wav_size);
		if (wav->data != NULL) {
			fread(wav->data, 1, wav->wav_size, file);
			wav->wav_hdr = wav->data;
			wav->wav_data = ((char*)wav->data) + sizeof(wavHeader) + wav->wav_hdr->Subchunk2Size;
			wav->wav_size = wav->wav_size + sizeof(wavHeader) + wav->wav_hdr->Subchunk2Size;
			wavs_loaded++;
		}
		fclose(file);
	}
}
void unload_wavs()
{
	for (int i = 0; i < wavs_loaded; i++)
		free(wavs[i].data);
}

int main(int argc, char**argv)
{
	int i;
	load_wavs(argv + 1, argc - 1);
	snd_pcm_t *handle;
	$(snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0));
	snd_pcm_hw_params_t *params;
	snd_pcm_hw_params_alloca(&params);
	snd_pcm_hw_params_any(handle, params);
	snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
	snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
	snd_pcm_hw_params_set_channels(handle, params, wavs[0].wav_hdr->NumOfChannels);
	snd_pcm_hw_params_set_rate_near(handle, params, &wavs[0].wav_hdr->SamplesPerSec, &i);
	$(snd_pcm_hw_params(handle, params));
//	snd_pcm_prepare(handle);

	for (int wav = 0; wav < wavs_loaded; wav) {
		char*wav_data = wavs[wav].wav_data;
		snd_pcm_uframes_t frames_size = wavs[wav].wav_hdr->NumOfChannels * sizeof(uint16_t);
		int frames_remain = wavs[wav].wav_size / frames_size;
		unsigned frames_step = 1024;
		while (frames_remain > 0) {
			snd_pcm_writei(handle, wav_data, MIN(frames_remain, frames_step));
			frames_remain -= frames_step;
			wav_data += frames_step * frames_size;
		}
	}
	snd_pcm_drain(handle);
	snd_pcm_close(handle);
	unload_wavs();
	return 0;
}