#include <limits.h>
#include <errno.h>
#include <ctype.h>
#include "uwide128.h"
#include "shgetc.h"

/* Lookup table for digit values. -1==255>=36 -> invalid */
static const unsigned char table[] = { -1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
};

static uwide128 const uwide128_max  = { { -1, -1, } };
static uwide128 const uwide128_zero = { {  0,  0, } };

static const uwide128 __uwide128_limit[37] = {
	comp2(0,	0),
	comp2(-1,	-1),
	comp2(-1,	9223372036854775807),
	comp2(6148914691236517205,	6148914691236517205),
	comp2(-1,	4611686018427387903),
	comp2(3689348814741910323,	3689348814741910323),
	comp2(-6148914691236517206,	3074457345618258602),
	comp2(5270498306774157604,	2635249153387078802),
	comp2(-1,	2305843009213693951),
	comp2(-4099276460824344804,	2049638230412172401),
	comp2(-7378697629483820647,	1844674407370955161),
	comp2(8384883669867978007,	1676976733973595601),
	comp2(6148914691236517205,	1537228672809129301),
	comp2(4256940940086819603,	1418980313362273201),
	comp2(2635249153387078802,	1317624576693539401),
	comp2(1229782938247303441,	1229782938247303441),
	comp2(-1,	1152921504606846975),
	comp2(1085102592571150095,	1085102592571150095),
	comp2(-2049638230412172402,	1024819115206086200),
	comp2(-1941762534074689644,	970881267037344821),
	comp2(-3689348814741910324,	922337203685477580),
	comp2(-4392081922311798004,	878416384462359600),
	comp2(-5030930201920786805,	838488366986797800),
	comp2(4812194106185100421,	802032351030850070),
	comp2(-6148914691236517206,	768614336404564650),
	comp2(-6640827866535438582,	737869762948382064),
	comp2(-7094901566811366007,	709490156681136600),
	comp2(-1366425486941448268,	683212743470724133),
	comp2(-7905747460161236407,	658812288346769700),
	comp2(-3180473116156819245,	636094623231363848),
	comp2(-8608480567731124088,	614891469123651720),
	comp2(-8925843906633654008,	595056260442243600),
	comp2(-1,	576460752303423487),
	comp2(8943875914525843207,	558992244657865200),
	comp2(-8680820740569200761,	542551296285575047),
	comp2(8432797290838652167,	527049830677415760),
	comp2(8198552921648689607,	512409557603043100),
};

uwide128 __intscan(FILE *f, unsigned base, int pok, uwide128 lim)
{
	const unsigned char *val = table+1;
	int c, neg=0;
	unsigned x;
	uint64_t z;
	uwide128 y;
	if (base > 36 || base == 1) {
		errno = EINVAL;
		return uwide128_zero;
	}
	while (isspace((c=shgetc(f))));
	if (c=='+' || c=='-') {
		neg = -(c=='-');
		c = shgetc(f);
	}
	if ((base == 0 || base == 2 || base == 16) && c=='0') {
		c = shgetc(f);
		if ((c|32)=='x' && base != 2) {
			c = shgetc(f);
			if (val[c]>=16) {
				shunget(f);
				if (pok) shunget(f);
				else shlim(f, 0);
				return uwide128_zero;
			}
			base = 16;
		} else if ((c|32)=='b' && base != 16) {
			c = shgetc(f);
			if (val[c]>=2) {
				shunget(f);
				if (pok) shunget(f);
				else shlim(f, 0);
				return uwide128_zero;
			}
			base = 2;
		} else if (base == 0) {
			base = 8;
		}
	} else {
		if (base == 0) base = 10;
		if (val[c] >= base) {
			shunget(f);
			shlim(f, 0);
			errno = EINVAL;
			return uwide128_zero;
		}
	}
	if (base == 10) {
		for (x=0; c-'0'<10U && x<=UINT_MAX/10-1; c=shgetc(f))
			x = x*10 + (c-'0');
		for (z=x; c-'0'<10U && z<=UINT64_MAX/10-1; c=shgetc(f))
			z = z*10 + (c-'0');
		y=__uwide128_u64(x);
		if (c-'0'<10U) {
			uwide128 y10 = __uwide128_mul(y, 10);
			while (c-'0'<10U
				&& __uwide128_le(y, __uwide128_limit[10])
				&& __uwide128_le(y10, __uwide128_sub(uwide128_max, (c-'0')))) {
				y = __uwide128_add(y10, (c-'0'));
				y10 = __uwide128_mul(y, 10);
				c=shgetc(f);
			}
		}
		if (c-'0'>=10U) goto done;
	} else {
		for (x=0; val[c]<base && x<=UINT_MAX/36-1; c=shgetc(f))
			x = x*base + val[c];
		for (z=x; val[c]<base && z<=UINT64_MAX/36-1; c=shgetc(f))
			z = z*base + val[c];
		y=__uwide128_u64(z);
		if (val[c]<base) {
			uwide128 yBase = __uwide128_mul(y, base);
			while (val[c]<base
				&& __uwide128_le(y, __uwide128_limit[base])
				&& __uwide128_le(yBase, __uwide128_sub(uwide128_max, val[c]))) {
				y = __uwide128_add(yBase, val[c]);
				yBase = __uwide128_mul(y, base);
				c=shgetc(f);
			}
		}
	}
	if (val[c]<base) {
		for (; val[c]<base; c=shgetc(f));
		errno = ERANGE;
		y = lim;
		if (lim.v64[word64(0)]&1) neg = 0;
	}
done:
	shunget(f);
	if (__uwide128_le(lim, y)) {
		if (!(lim.v64[word64(0)]&1) && !neg) {
			errno = ERANGE;
			return __uwide128_sub(lim, 1);
		} else if (!__uwide128_le(y, lim)) {
			errno = ERANGE;
			return lim;
		}
	}
	return neg ? __uwide128_neg(y) : y;
}