/*
 * w6a — amd64 assembler driver. Read .s, parse, encode, emit ELF .o.
 */
#include "a.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int
slurp(const char *path, char **buf, u64 *len)
{
	FILE *f = fopen(path, "rb");
	if (f == NULL) return -1;
	fseek(f, 0, SEEK_END);
	long n = ftell(f);
	fseek(f, 0, SEEK_SET);
	if (n < 0) { fclose(f); return -1; }
	char *b = malloc((size_t)n + 1);
	if (fread(b, 1, (size_t)n, f) != (size_t)n) { free(b); fclose(f); return -1; }
	b[n] = 0;
	fclose(f);
	*buf = b;
	*len = (u64)n;
	return 0;
}

int
main(int argc, char **argv)
{
	const char *src = NULL;
	const char *out = NULL;
	for (int i = 1; i < argc; i++) {
		if (strcmp(argv[i], "-o") == 0 && i + 1 < argc) out = argv[++i];
		else if (argv[i][0] == '-') {
			fprintf(stderr, "w6a: unknown flag %s\n", argv[i]); return 2;
		} else if (src == NULL) src = argv[i];
		else { fprintf(stderr, "w6a: only one input\n"); return 2; }
	}
	if (src == NULL || out == NULL) {
		fputs("usage: w6a -o file.o file.s\n", stderr);
		return 2;
	}
	char *buf;
	u64 len;
	if (slurp(src, &buf, &len) < 0) {
		fprintf(stderr, "w6a: cannot read %s\n", src);
		return 1;
	}
	Asm a;
	a_init(&a, src, buf, len);
	if (a_parse(&a) != 0) return 1;
	if (a_encode(&a) != 0) return 1;
	FILE *f = fopen(out, "wb");
	if (f == NULL) { fprintf(stderr, "w6a: cannot open %s\n", out); return 1; }
	int rc = a_emit_elf(&a, f);
	fclose(f);
	free(buf);
	return rc;
}