From 74258a170a20fd5a8fb6afe420b7d877d674c100 Mon Sep 17 00:00:00 2001
From: Jeroen van Rijn <Kelimion@users.noreply.github.com>
Date: Wed, 28 Jul 2021 15:59:39 +0200
Subject: [PATCH] big: fix `itoa` base PoT other than 16.

---
 core/math/big/example.odin |  5 +--
 core/math/big/helpers.odin | 78 ++++++++++++++++++++++++--------------
 core/math/big/radix.odin   |  2 +-
 3 files changed, 52 insertions(+), 33 deletions(-)

diff --git a/core/math/big/example.odin b/core/math/big/example.odin
index 60e2a4447..f6b7236c6 100644
--- a/core/math/big/example.odin
+++ b/core/math/big/example.odin
@@ -76,7 +76,6 @@ demo :: proc() {
 	defer destroy(destination, source, quotient, remainder, numerator, denominator);
 
 	err = rand(destination, 120, r);
-	// print("destination", destination, 10);
 	for _ in 0 ..< 10_000 {
 		if err != .None {
 			fmt.printf("set error: %v\n", err);
@@ -85,7 +84,7 @@ demo :: proc() {
 			as, err = itoa(destination, 16);
 			e := time.tick_since(s);
 			Timings[.itoa].t += e; Timings[.itoa].c += 1;
-			assert(as == "B38677A01B8EF75CF434CA68677495", as);
+			//assert(as == "ADCC737B67B0FCD7F189074CBE088B718141A383F9CF09B4D3824A09A3AEBAC155B810C29D62385F8F85616794C25393A757CEDEEBE3B0FE24573894DF7842A76F543D64A78FFD24D325CE044E9A0F69DE00CFFCC41427170096BC6D3537C856CD930A3794F03DB558CD5DB6A65971E618C5D0DBAE1E7AF52DDB8F5F84CD5BFC0B2EEEDBFB70E6B38677A01B8EF75CF434CA68677495", as);
 			delete(as);
 		}
 	}
@@ -104,7 +103,7 @@ main :: proc() {
 		if v.c > 0 {
 			avg   := time.duration_milliseconds(time.Duration(f64(v.t) / f64(v.c)));
 			total := time.duration_milliseconds(time.Duration(v.t));
-			fmt.printf("%v: %.3f ms (avg), %.3f (total, %v calls)\n", i, avg, total, v.c);
+			fmt.printf("%v: %.3f ms (avg), %.3f ms (total, %v calls)\n", i, avg, total, v.c);
 		}
 	}
 
diff --git a/core/math/big/helpers.odin b/core/math/big/helpers.odin
index dc4fc697d..d5cf16b33 100644
--- a/core/math/big/helpers.odin
+++ b/core/math/big/helpers.odin
@@ -177,7 +177,7 @@ neg :: proc(dest, src: ^Int, allocator := context.allocator) -> (err: Error) {
 /*
 	Helpers to extract values from the `Int`.
 */
-int_extract_bit :: proc(a: ^Int, bit_offset: int) -> (bit: DIGIT, err: Error) {
+extract_bit :: proc(a: ^Int, bit_offset: int) -> (bit: DIGIT, err: Error) {
 	/*
 		Check that `a`is usable.
 	*/
@@ -195,6 +195,9 @@ int_extract_bit :: proc(a: ^Int, bit_offset: int) -> (bit: DIGIT, err: Error) {
 	return 1 if ((a.digit[limb] & i) != 0) else 0, .None;
 }
 
+/*
+	TODO: Optimize.
+*/
 int_bitfield_extract :: proc(a: ^Int, offset, count: int) -> (res: _WORD, err: Error) {
 	/*
 		Check that `a`is usable.
@@ -207,40 +210,57 @@ int_bitfield_extract :: proc(a: ^Int, offset, count: int) -> (res: _WORD, err: E
 		return 0, .Invalid_Argument;
 	}
 
-	limb_lo :=  offset          / _DIGIT_BITS;
-	bits_lo :=  offset          % _DIGIT_BITS;
-	limb_hi := (offset + count) / _DIGIT_BITS;
-	bits_hi := (offset + count) % _DIGIT_BITS;
+	when true {
+		v: DIGIT;
+		e: Error;
 
-	if limb_lo < 0 || limb_lo >= a.used || limb_hi < 0 || limb_hi >= a.used {
-		return 0, .Invalid_Argument;
-	}
-
-	for i := limb_hi; i >= limb_lo; i -= 1 {
-		res <<= _DIGIT_BITS;
-
-		/*
-			Determine which bits to extract from each DIGIT. The whole DIGIT's worth by default.
-		*/
-		bit_count  := _DIGIT_BITS;
-		bit_offset := 0;
-		if i == limb_lo {
-			bit_count  -= bits_lo;
-			bit_offset = _DIGIT_BITS - bit_count;
-		} else if i == limb_hi {
-			bit_count  = bits_hi;
-			bit_offset = 0;
+		for shift := 0; shift < count; shift += 1 {
+			o   := offset + shift;
+			v, e = extract_bit(a, o);
+			if e != .None {
+				break;
+			}
+			res = res + _WORD(v) << uint(shift);
 		}
 
-		d := a.digit[i];
+		return res, e;
+	} else {
+		limb_lo :=  offset          / _DIGIT_BITS;
+		bits_lo :=  offset          % _DIGIT_BITS;
+		limb_hi := (offset + count) / _DIGIT_BITS;
+		bits_hi := (offset + count) % _DIGIT_BITS;
 
-		v := (d >> uint(bit_offset)) & DIGIT(1 << uint(bit_count - 1));
-		m := DIGIT(1 << uint(bit_count-1));
-		r := v & m;
+		if limb_lo < 0 || limb_lo >= a.used || limb_hi < 0 || limb_hi >= a.used {
+			return 0, .Invalid_Argument;
+		}
+
+		for i := limb_hi; i >= limb_lo; i -= 1 {
+			res <<= _DIGIT_BITS;
+
+			/*
+				Determine which bits to extract from each DIGIT. The whole DIGIT's worth by default.
+			*/
+			bit_count  := _DIGIT_BITS;
+			bit_offset := 0;
+			if i == limb_lo {
+				bit_count  -= bits_lo;
+				bit_offset = _DIGIT_BITS - bit_count;
+			} else if i == limb_hi {
+				bit_count  = bits_hi;
+				bit_offset = 0;
+			}
+
+			d := a.digit[i];
+
+			v := (d >> uint(bit_offset)) & DIGIT(1 << uint(bit_count - 1));
+			m := DIGIT(1 << uint(bit_count-1));
+			r := v & m;
+
+			res |= _WORD(r);
+		}
+		return res, .None;
 
-		res |= _WORD(r);
 	}
-	return res, .None;
 }
 
 /*
diff --git a/core/math/big/radix.odin b/core/math/big/radix.odin
index 06066af18..572adec6a 100644
--- a/core/math/big/radix.odin
+++ b/core/math/big/radix.odin
@@ -200,7 +200,7 @@ int_itoa_raw :: proc(a: ^Int, radix: i8, buffer: []u8, size := int(-1), zero_ter
 		count, err = count_bits(a);
 		digit: _WORD;
 
-		for offset := 0; offset < count; offset += 4 {
+		for offset := 0; offset < count; offset += shift {
 			bits_to_get := int(min(count - offset, shift));
 			if digit, err = int_bitfield_extract(a, offset, bits_to_get); err != .None {
 				return len(buffer) - available, .Invalid_Argument;