#include "util.h"

void*
checkp(void *p)
{
	if (!p) die("pointer assertion failed, OOM?\n");
	return p;
}

void*
die(const char *fmtstr, ...)
{
	va_list ap;

	va_start(ap, fmtstr);
	vfprintf(stderr, fmtstr, ap);
	va_end(ap);

	exit(EXIT_FAILURE);
}

char*
aprintf(const char *fmtstr, ...)
{
	va_list ap, cpy;
	size_t nb;
	char *str;

	va_copy(cpy, ap);

	va_start(cpy, fmtstr);
	nb = vsnprintf(NULL, 0, fmtstr, cpy);
	va_end(cpy);

	if (nb <= 0) die("Invalid fmtstr!\n");
	str = checkp(malloc(nb+1));

	va_start(ap, fmtstr);
	nb = vsnprintf(str, nb+1, fmtstr, ap);
	va_end(ap);

	return str;
}

const char*
mhash(const char *filename, int len)
{
	static const char *hexalph = "0123456789ABCDEF";
	static char buf[2 * MHASHLEN + 1];
	int i, k;

	if (len == -1) len = strlen(filename);

	for (i = 0; i < MIN(MHASHLEN, len); i++) {
		unsigned char v = 0;
		for (k = i; k < len; k += MHASHLEN)
			v ^= filename[k];
		buf[i*2+0] = hexalph[(v >> 4) & 0x0f];
		buf[i*2+1] = hexalph[(v >> 0) & 0x0f];
	}

	if (i == 0) {
		memset(buf, '0', MHASHLEN);
	} else if (i < MHASHLEN) {
		for (k = 0; k < MHASHLEN; k++)
			buf[k] = buf[k % i];
	}

	buf[MHASHLEN] = '\0';

	return buf;
}

void
freadstr(FILE *f, char **dst)
{
	size_t start, len;
	char c;

	start = ftell(f);
	for (len = 0; (c = fgetc(f)) != EOF && c; len++);
	fseek(f, start, SEEK_SET);

	*dst = checkp(calloc(1, len + 1));
	fread(*dst, len, 1, f);
	fgetc(f);
}

void
fputstr(FILE *f, char *s)
{
	fprintf(f, "%s", s);
	fputc(0, f);
}

const char*
ask(const char *fmtstr, ...)
{
	static char linebuf[256];
	va_list ap;
	int fail;

	va_start(ap, fmtstr);
	vprintf(fmtstr, ap);
	va_end(ap);

	fail = !fgets(linebuf, sizeof(linebuf), stdin);

	if (!fail) linebuf[strlen(linebuf) - 1] = '\0';

	return fail ? "" : linebuf;
}

void
dump(const char *filename)
{
	char buf[256];
	FILE *f;
	int nb;

	if (!(f = fopen(filename, "r"))) return;

	while ((nb = fread(buf, 1, sizeof(buf), f)))
		printf("%.*s\n", nb, buf);

	fclose(f);
}

int
strpfcmp(const char *prefix, const char *str)
{
	return strncmp(prefix, str, strlen(prefix));
}