/* neoadpcmextract.c (C) 2017, 2019, 2020 a dinosaur (zlib) */

#include "neoadpcmextract.h"
#include <stdlib.h>


int vgmReadSample(FILE* fin, Buffer* buf)
{
	// Get sample data length.
	uint32_t sampLen = 0;
	fread(&sampLen, sizeof(uint32_t), 1, fin);
	if (sampLen < sizeof(uint64_t))
		return 1;
	sampLen -= sizeof(uint64_t);

	// Resize buffer if needed.
	buf->size = sampLen;
	if (!buf->data || buf->reserved < sampLen)
	{
		free(buf->data);
		buf->reserved = sampLen;
		buf->data = malloc(sampLen);
		if (!buf->data)
			return 1;
	}

	// Ignore 8 bytes.
	uint64_t dummy;
	fread(&dummy, sizeof(uint64_t), 1, fin);

	// Read adpcm data.
	fread(buf->data, sizeof(uint8_t), sampLen, fin);

	return 0;
}

int vgmScanSample(FILE* file)
{
	// Scan for pcm headers.
	while (1)
	{
		if (feof(file) || ferror(file))
			return 0;

		// Patterns to match (in hex):
		// 67 66 82 - ADPCM-A
		// 67 66 83 - ADPCM-B
		if (fgetc(file) != 0x67 || fgetc(file) != 0x66)
			continue;

		uint8_t byte = fgetc(file);
		if (byte == 0x82)
			return 'A';
		else if (byte == 0x83)
			return 'B';
	}
}