#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <getopt.h>
#include <err.h>

#define CHUNK_DEFAULT (0x1000)

#define MIN(a, b) (a < b? a : b)
#define MAX(a, b) (a > b? a : b)

int
usage(const char* progname)
{
	fprintf(stderr, "usage: %s [-c chunk] <-s size | -u size>\n", progname);
	return 1;
}

int
main(int argc, char** argv)
{
	int optch;
	int cflag = 0;
	const char* carg = NULL;
	enum { INV = -1, INT, UINT } tflag = INV;
	const char* sizearg = NULL;

	while ((optch = getopt(argc, argv, "c:s:u:h")) != -1) {
		switch (optch) {
		case 'c':
			cflag = 1;
			carg = optarg;
			break;
		case 's':
			tflag = INT;
			sizearg = optarg;
			break;
		case 'u':
			tflag = UINT;
			sizearg = optarg;
			break;
		case 'h':
		default:
			return usage(*argv);
		}
	}

	if (tflag == INV)
		return usage(*argv);

	size_t membsize = strtoull(sizearg, NULL, 10);
	size_t chunk = cflag? strtoull(carg, NULL, 10) : CHUNK_DEFAULT;
	
	uint8_t* intbuffer = aligned_alloc(0x40, chunk * membsize);
	float* floatbuffer = aligned_alloc(0x40, chunk * sizeof(float));
	size_t rd;

	if (intbuffer == NULL || floatbuffer == NULL)
		err(1, "malloc()");

	while ((rd = fread(intbuffer, membsize, chunk, stdin))) {
		for (size_t i = 0; i < rd; ++i) {
			void* p = &intbuffer[i * membsize];
			switch (tflag) {
			case INT:
				switch (membsize) {
				case 1: floatbuffer[i] = (float)*(int8_t*)p; break;
				case 2: floatbuffer[i] = (float)*(int16_t*)p; break;
				case 4: floatbuffer[i] = (float)*(int32_t*)p; break;
				case 8: floatbuffer[i] = (float)*(int64_t*)p; break;
				default: errx(1, "invalid size");
				}
				break;
			case UINT:
				switch (membsize) {
				case 1: floatbuffer[i] = (float)*(int8_t*)p; break;
				case 2: floatbuffer[i] = (float)*(int16_t*)p; break;
				case 4: floatbuffer[i] = (float)*(int32_t*)p; break;
				case 8: floatbuffer[i] = (float)*(int64_t*)p; break;
				default: errx(1, "invalid size");
				}
				break;
			default:
				errx(1, "invalid type");
			}
		}
		
		fwrite(floatbuffer, sizeof(float), rd, stdout);
	}

	return 0;
}