lib/geometry: change triangulate API for easier usage

[nit.git] / lib / core / bytes.nit

diff --git a/lib/core/bytes.nit b/lib/core/bytes.nit
index 232f8c7..7b25d61 100644 (file)
--- a/lib/core/bytes.nit
+++ b/lib/core/bytes.nit
@@ -328,6 +328,45 @@ class Bytes
                return new FlatString.full(ns, elen, 0, elen)
        end
 
+       # Interprets `self` as a big-endian positive integer.
+       #
+       # ~~~
+       # var b = "0102".hexdigest_to_bytes
+       # assert b.to_i == 258
+       # ~~~
+       #
+       # Nul bytes on the left are trimmed.
+       # 0 is returned for an empty Bytes object.
+       #
+       # ~~~
+       # assert "01".hexdigest_to_bytes.to_i == 1
+       # assert "0001".hexdigest_to_bytes.to_i == 1
+       #
+       # assert "0000".hexdigest_to_bytes.to_i == 0
+       # assert "00".hexdigest_to_bytes.to_i == 0
+       # assert "".hexdigest_to_bytes.to_i == 0
+       # ~~~
+       #
+       # `Int::to_bytes` is a loosely reverse method.
+       #
+       # ~~~
+       # assert b.to_i.to_bytes == b
+       # assert (b.to_i + 1).to_bytes.hexdigest == "0103"
+       # assert "0001".hexdigest_to_bytes.to_i.to_bytes.hexdigest == "01"
+       # ~~~
+       #
+       # Warning: `Int` might overflow for bytes with more than 60 bits.
+       fun to_i: Int do
+               var res = 0
+               var i = 0
+               while i < length do
+                       res *= 256
+                       res += self[i].to_i
+                       i += 1
+               end
+               return res
+       end
+
        #     var b = new Bytes.with_capacity(1)
        #     b[0] = 101u8
        #     assert b.to_s == "e"
@@ -613,6 +652,58 @@ private class BytesIterator
        redef fun item do return tgt[index]
 end
 
+redef class Int
+       # A big-endian representation of self.
+       #
+       # ~~~
+       # assert     1.to_bytes.hexdigest ==     "01"
+       # assert   255.to_bytes.hexdigest ==     "FF"
+       # assert   256.to_bytes.hexdigest ==   "0100"
+       # assert 65535.to_bytes.hexdigest ==   "FFFF"
+       # assert 65536.to_bytes.hexdigest == "010000"
+       # ~~~
+       #
+       # For 0, a Bytes object with single nul byte is returned (instead of an empty Bytes object).
+       #
+       # ~~~
+       # assert 0.to_bytes.hexdigest == "00"
+       # ~~~
+       #
+       # `Bytes::to_i` can be used to do the reverse operation.
+       #
+       # ~~~
+       # assert 1234.to_bytes.to_i == 1234
+       # ~~~
+       #
+       # Require self >= 0
+       fun to_bytes: Bytes do
+               if self == 0 then return "\0".to_bytes
+               assert self > 0
+
+               # Compute the len (log256)
+               var len = 1
+               var max = 256
+               while self >= max do
+                       len += 1
+                       max *= 256
+               end
+
+               # Allocate the buffer
+               var res = new Bytes.with_capacity(len)
+               for i in [0..len[ do res[i] = 0u8
+
+               # Fill it starting with the end
+               var i = len
+               var sum = self
+               while i > 0 do
+                       i -= 1
+                       res[i] = (sum % 256).to_b
+                       sum /= 256
+               end
+               return res
+       end
+end
+
 redef class Text
        # Returns a mutable copy of `self`'s bytes
        #