Add isnumeric function and base conversion corner case fix

Author: edubart

Makefile

@@ -21,7 +21,7 @@ clean:
 	rm -f *.out
 
 install:
-	luarocks make --local $(ROCKSPEC)
+	luarocks make --local
 
 upload:
 	luarocks upload --api-key=$(LUAROCKS_APIKEY) $(ROCKSPEC)

bint.lua

@@ -109,6 +109,7 @@ local bint = {}
 bint.__index = bint
 
 -- Constants used internally and modified by bint.scale
+local BIGINT_BITS
 local BIGINT_SIZE
 local BIGINT_WORDBITS
 local BIGINT_WORDMAX
@@ -137,6 +138,7 @@ function bint.scale(bits, wordbits)
   assert(bits % wordbits == 0, 'bitsize is not multiple of word bitsize')
   assert(2*wordbits <= luainteger_bitsize(), 'word bitsize must be half of the lua integer bitsize')
   assert(bits >= 64, 'bitsize must be >= 64')
+  BIGINT_BITS = bits
   BIGINT_SIZE = bits // wordbits
   BIGINT_WORDBITS = wordbits
   BIGINT_WORDMAX = (1 << BIGINT_WORDBITS) - 1
@@ -388,7 +390,8 @@ end
 -- @param[opt] base Base to be represented, defaults to 10.
 -- Must be at least 2 and at most 36.
 -- @param[opt] unsigned Whether to output as unsigned integer.
--- Defaults to true for base 10 and false for others.
+-- Defaults to false for base 10 and true for others.
+-- When unsigned is false the symbol '-' is prepended in negative values.
 -- @return A string representing the input.
 -- @raise An assert is thrown in case the base is invalid.
 function bint.tobase(x, base, unsigned)
@@ -402,22 +405,22 @@ function bint.tobase(x, base, unsigned)
     -- number base is too large
     return nil
   end
+  if unsigned == nil then
+    unsigned = base ~= 10
+  end
   if base == 10 or base == 16 then
     local inluarange = x >= BIGINT_MATHMININTEGER and x <= BIGINT_MATHMAXINTEGER
     if inluarange then
       -- integer is small, use tostring or string.format (faster)
       local n = x:tointeger()
       if base == 10 then
         return tostring(n)
-      else
+      elseif unsigned then
         return string.format('%x', n)
       end
     end
   end
   local ss = {}
-  if unsigned == nil then
-    unsigned = base ~= 10
-  end
   local neg = not unsigned and x:isneg()
   if neg then
     x = x:abs()
@@ -577,10 +580,16 @@ end
 
 --- Check if the input is a lua integer or a bint.
 -- @param x Any lua value.
-function bint.isinteger(x)
+function bint.isintegral(x)
   return isbint(x) or math.type(x) == 'integer'
 end
 
+--- Check if the input is a bint or a lua number.
+-- @param x Any lua value.
+function bint.isnumeric(x)
+  return isbint(x) or type(x) == 'number'
+end
+
 --- Check the number type of the input (bint, integer or float).
 -- @param x Any lua value.
 -- Returns "bint" for bints, "integer" fot lua integers,
@@ -819,10 +828,24 @@ function bint.ceil(x)
   end
 end
 
---- Truncate a lua number to a bint.
+-- Wrap around bits of an integer (discarding left bits) considering bints.
+-- @param x A bint or a lua integer.
+-- @param y Number of right bits to preserve.
+function bint.bwrap(x, y)
+  x = bint_assert_convert(x)
+  if y <= 0 then
+    return bint.zero()
+  elseif y < BIGINT_BITS then
+    return x & (bint.one() << y):_dec()
+  else
+    return bint.new(x)
+  end
+end
+
+--- Truncate a number to a bint.
 -- Floats numbers are truncated, that is, the fractional port is discarded.
--- @param x A value to initialize from convertible to a lua number.
--- @return A new bint or nil in case the input cannot be represented by an integer.
+-- @param x A number to truncate.
+-- @return A new bint or nil in case the input does not fit in a bint or is not a number.
 function bint.trunc(x)
   if not isbint(x) then
     x = tonumber(x)

docs/index.html

@@ -196,10 +196,14 @@ <h2><a href="#Functions">Functions</a></h2>
 	<td class="summary">Check if the input is a bint.</td>
 	</tr>
 	<tr>
-	<td class="name" nowrap><a href="#isinteger">isinteger (x)</a></td>
+	<td class="name" nowrap><a href="#isintegral">isintegral (x)</a></td>
 	<td class="summary">Check if the input is a lua integer or a bint.</td>
 	</tr>
 	<tr>
+	<td class="name" nowrap><a href="#isnumeric">isnumeric (x)</a></td>
+	<td class="summary">Check if the input is a bint or a lua number.</td>
+	</tr>
+	<tr>
 	<td class="name" nowrap><a href="#type">type (x)</a></td>
 	<td class="summary">Check the number type of the input (bint, integer or float).</td>
 	</tr>
@@ -281,7 +285,7 @@ <h2><a href="#Functions">Functions</a></h2>
 	</tr>
 	<tr>
 	<td class="name" nowrap><a href="#trunc">trunc (x)</a></td>
-	<td class="summary">Truncate a lua number to a bint.</td>
+	<td class="summary">Truncate a number to a bint.</td>
 	</tr>
 	<tr>
 	<td class="name" nowrap><a href="#max">max (x, y)</a></td>
@@ -667,7 +671,8 @@ <h3>Parameters:</h3>
         </li>
         <li><span class="parameter">unsigned</span>
          Whether to output as unsigned integer.
- Defaults to true for base 10 and false for others.
+ Defaults to false for base 10 and true for others.
+ When unsigned is false the symbol '-' is prepended in negative values.
          (<em>optional</em>)
         </li>
     </ul>
@@ -868,8 +873,8 @@ <h3>Parameters:</h3>
 
 </dd>
     <dt>
-    <a name = "isinteger"></a>
-    <strong>isinteger (x)</strong>
+    <a name = "isintegral"></a>
+    <strong>isintegral (x)</strong>
     </dt>
     <dd>
     Check if the input is a lua integer or a bint.
@@ -886,6 +891,26 @@ <h3>Parameters:</h3>
 
 
 
+</dd>
+    <dt>
+    <a name = "isnumeric"></a>
+    <strong>isnumeric (x)</strong>
+    </dt>
+    <dd>
+    Check if the input is a bint or a lua number.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">x</span>
+         Any lua value.
+        </li>
+    </ul>
+
+
+
+
+
 </dd>
     <dt>
     <a name = "type"></a>
@@ -1243,21 +1268,21 @@ <h3>Parameters:</h3>
     <strong>trunc (x)</strong>
     </dt>
     <dd>
-    Truncate a lua number to a bint.
+    Truncate a number to a bint.
  Floats numbers are truncated, that is, the fractional port is discarded.
 
 
     <h3>Parameters:</h3>
     <ul>
         <li><span class="parameter">x</span>
-         A value to initialize from convertible to a lua number.
+         A number to truncate.
         </li>
     </ul>
 
     <h3>Returns:</h3>
     <ol>
 
-        A new bint or nil in case the input cannot be represented by an integer.
+        A new bint or nil in case the input does not fit in a bint or is not a number.
     </ol>
 
 
@@ -2222,7 +2247,7 @@ <h3>See also:</h3>
 </div> <!-- id="main" -->
 <div id="about">
 <i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
-<i style="float:right;">Last updated 2020-07-09 09:15:25 </i>
+<i style="float:right;">Last updated 2020-07-09 17:52:38 </i>
 </div> <!-- id="about" -->
 </div> <!-- id="container" -->
 </body>

tests.lua

@@ -78,8 +78,11 @@ local function test(bits)
 
     assert(bint.isbint(1) == false)
     assert(bint.isbint(bint(1)) == true)
-    assert(bint.isinteger(1) == true)
-    assert(bint.isinteger(bint(1)) == true)
+    assert(bint.isintegral(1) == true)
+    assert(bint.isintegral(bint(1)) == true)
+    assert(bint.isnumeric(1) == true)
+    assert(bint.isnumeric(1.5) == true)
+    assert(bint.isnumeric(bint(1)) == true)
     assert(bint.type(1) == 'integer')
     assert(bint.type(1.5) == 'float')
     assert(bint.type(bint(1)) == 'bint')
@@ -189,6 +192,12 @@ local function test(bits)
     assert_eq(bint.tobase(8, 7), '11')
     assert_eq(bint.tobase(1, 37), nil)
     assert_eq(bint.tobase(1.5, 10), nil)
+    assert_eq(bint.tobase(0xff, 16, true), 'ff')
+    assert_eq(bint.tobase(-0xff, 16, false), '-ff')
+    if bits > 64 then
+      assert_eq(bint.tobase(-1, 16, true), 'ffffffffffffffff')
+      assert_eq(bint.tobase(-2, 16, true), 'fffffffffffffffe')
+    end
 
     test_ops(0)
     test_ops(1)
@@ -339,9 +348,13 @@ local function test(bits)
     local function test_shrone(x)
       assert_eq(bint(x):_shrone():tointeger(), x >> 1)
     end
+    local function test_bwrap(x, y)
+      assert_eq(bint.bwrap(x, y):tointeger(), x & ((1 << math.max(y, 0))-1))
+    end
     local function test_ops(x, y)
       test_shl(x, y) test_shl(x, -y)
       test_shr(x, y) test_shr(x, -y)
+      test_bwrap(x, y) test_bwrap(x, -y) test_bwrap(-x, y)
       test_shlone(x) test_shlone(y)
       test_shrone(x) test_shrone(y)
     end