lib/core/bytes: Adding a redef of has method
[nit.git] / lib / core / bytes.nit
index ad1f6ef..3013321 100644 (file)
@@ -19,28 +19,216 @@ import kernel
 import collection::array
 intrude import text::flat
 
-redef class Byte
+# Any kind of entity which can be searched for in a Sequence of Byte
+interface BytePattern
+       # Return the first occurence of `self` in `b`, or -1 if not found
+       fun first_index_in(b: SequenceRead[Int]): Int do return first_index_in_from(b, 0)
+
+       # Return the first occurence of `self` in `b` starting at `from`, or -1 if not found
+       fun first_index_in_from(b: SequenceRead[Int], from: Int): Int is abstract
+
+       # Return the last occurence of `self` in `b`, or -1 if not found
+       fun last_index_in(b: SequenceRead[Int]): Int do return last_index_in_from(b, b.length - 1)
+
+       # Return the last occurence of `self` in `b`, or -1 if not found
+       fun last_index_in_from(b: SequenceRead[Int], from: Int): Int is abstract
+
+       # Returns the indexes of all the occurences of `self` in `b`
+       fun search_all_in(b: SequenceRead[Int]): SequenceRead[Int] is abstract
+
+       # Length of the pattern
+       fun pattern_length: Int is abstract
+
+       # Appends `self` to `b`
+       fun append_to(b: Sequence[Int]) is abstract
+
+       # Is `self` a prefix for `b` ?
+       fun is_prefix(b: SequenceRead[Int]): Bool is abstract
+
+       # Is `self` a suffix for `b` ?
+       fun is_suffix(b: SequenceRead[Int]): Bool is abstract
+end
+
+redef class Int
+       super BytePattern
+
+       # Write self as a string into `ns` at position `pos`
+       private fun add_digest_at(ns: CString, pos: Int) do
+               var tmp = (0xF0 & self) >> 4
+               ns[pos] = if tmp >= 0x0A then tmp + 0x37 else tmp + 0x30
+               tmp = 0x0F & self
+               ns[pos + 1] = if tmp >= 0x0A then tmp + 0x37 else tmp + 0x30
+       end
+
        # Is `self` a valid hexadecimal digit (in ASCII)
        #
        # ~~~nit
        # intrude import core::bytes
-       # assert not '/'.ascii.to_b.is_valid_hexdigit
-       # assert '0'.ascii.to_b.is_valid_hexdigit
-       # assert '9'.ascii.to_b.is_valid_hexdigit
-       # assert not ':'.ascii.to_b.is_valid_hexdigit
-       # assert not '@'.ascii.to_b.is_valid_hexdigit
-       # assert 'A'.ascii.to_b.is_valid_hexdigit
-       # assert 'F'.ascii.to_b.is_valid_hexdigit
-       # assert not 'G'.ascii.to_b.is_valid_hexdigit
-       # assert not '`'.ascii.to_b.is_valid_hexdigit
-       # assert 'a'.ascii.to_b.is_valid_hexdigit
-       # assert 'f'.ascii.to_b.is_valid_hexdigit
-       # assert not 'g'.ascii.to_b.is_valid_hexdigit
+       # assert not u'/'.is_valid_hexdigit
+       # assert u'0'.is_valid_hexdigit
+       # assert u'9'.is_valid_hexdigit
+       # assert not u':'.is_valid_hexdigit
+       # assert not u'@'.is_valid_hexdigit
+       # assert u'A'.is_valid_hexdigit
+       # assert u'F'.is_valid_hexdigit
+       # assert not u'G'.is_valid_hexdigit
+       # assert not u'`'.is_valid_hexdigit
+       # assert u'a'.is_valid_hexdigit
+       # assert u'f'.is_valid_hexdigit
+       # assert not u'g'.is_valid_hexdigit
        # ~~~
        private fun is_valid_hexdigit: Bool do
-               return (self >= 0x30u8 and self <= 0x39u8) or
-                      (self >= 0x41u8 and self <= 0x46u8) or
-                      (self >= 0x61u8 and self <= 0x66u8)
+               return (self >= 0x30 and self <= 0x39) or
+                      (self >= 0x41 and self <= 0x46) or
+                      (self >= 0x61 and self <= 0x66)
+       end
+
+       # `self` as a hexdigit to its byte value
+       #
+       # ~~~nit
+       # intrude import core::bytes
+       # assert 0x39.hexdigit_to_byteval == 0x09
+       # assert 0x43.hexdigit_to_byteval == 0x0C
+       # ~~~
+       #
+       # REQUIRE: `self.is_valid_hexdigit`
+       private fun hexdigit_to_byteval: Int do
+               if self >= 0x30 and self <= 0x39 then
+                       return self - 0x30
+               else if self >= 0x41 and self <= 0x46 then
+                       return self - 0x37
+               else if self >= 0x61 and self <= 0x66 then
+                       return self - 0x57
+               end
+               # Happens only if the requirement is not met.
+               # i.e. this abort is here to please the compiler
+               abort
+       end
+
+       redef fun first_index_in_from(b, from) do
+               for i in [from .. b.length[ do if b[i] == self then return i
+               return -1
+       end
+
+       redef fun last_index_in_from(b, from) do
+               for i in [0 .. from].step(-1) do if b[i] == self then return i
+               return -1
+       end
+
+       redef fun search_all_in(b) do
+               var ret = new Array[Int]
+               var pos = 0
+               loop
+                       pos = first_index_in_from(b, pos)
+                       if pos == -1 then return ret
+                       ret.add pos
+                       pos += 1
+               end
+       end
+
+       redef fun pattern_length do return 1
+
+       redef fun append_to(b) do b.push self
+
+       #     assert u'b'.is_suffix("baqsdb".to_bytes)
+       #     assert not u'b'.is_suffix("baqsd".to_bytes)
+       redef fun is_suffix(b) do return b.length != 0 and b.last == self
+
+       #     assert u'b'.is_prefix("baqsdb".to_bytes)
+       #     assert not u'b'.is_prefix("aqsdb".to_bytes)
+       redef fun is_prefix(b) do return b.length != 0 and b.first == self
+
+       # A signed 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"
+       # ~~~
+       #
+       # Negative values are converted to their two's complement.
+       # Be careful as the result can be ambiguous.
+       #
+       # ~~~
+       # assert     (-1).to_bytes.hexdigest ==     "FF"
+       # assert    (-32).to_bytes.hexdigest ==     "E0"
+       # assert   (-512).to_bytes.hexdigest ==   "FE00"
+       # assert (-65794).to_bytes.hexdigest == "FEFEFE"
+       # ~~~
+       #
+       # Optionally, set `n_bytes` to the desired number of bytes in the output.
+       # This setting can disambiguate the result between positive and negative
+       # integers. Be careful with this parameter as the result may overflow.
+       #
+       # ~~~
+       # assert        1.to_bytes(2).hexdigest ==     "0001"
+       # assert    65535.to_bytes(2).hexdigest ==     "FFFF"
+       # assert     (-1).to_bytes(2).hexdigest ==     "FFFF"
+       # assert   (-512).to_bytes(4).hexdigest == "FFFFFE00"
+       # assert 0x123456.to_bytes(2).hexdigest ==     "3456"
+       # ~~~
+       #
+       # For 0, a Bytes object with single nul byte is returned (instead of an empty Bytes object).
+       #
+       # ~~~
+       # assert 0.to_bytes.hexdigest == "00"
+       # ~~~
+       #
+       # For positive integers, `Bytes::to_i` can reverse the operation.
+       #
+       # ~~~
+       # assert 1234.to_bytes.to_i == 1234
+       # ~~~
+       #
+       # Require self >= 0
+       fun to_bytes(n_bytes: nullable Int): Bytes do
+
+               # If 0, force using at least one byte
+               if self == 0 and n_bytes == null then n_bytes = 1
+
+               # Compute the len (log256)
+               var len = 1
+               var max = 256
+               var s = self.abs
+               while s >= max do
+                       len += 1
+                       max *= 256
+               end
+
+               # Two's complement
+               s = self
+               if self < 0 then
+                       var ff = 0
+                       for j in [0..len[ do
+                               ff *= 0x100
+                               ff += 0xFF
+                       end
+
+                       s = ((-self) ^ ff) + 1
+               end
+
+               # Cut long values
+               if n_bytes != null and len > n_bytes then len = n_bytes
+
+               # Allocate the buffer
+               var cap = n_bytes or else len
+               var res = new Bytes.with_capacity(cap)
+
+               var filler = if self < 0 then 0xFF else 0
+               for i in [0..cap[ do res[i] = filler
+
+               # Fill it starting with the end
+               var i = cap
+               var sum = s
+               while i > cap - len do
+                       i -= 1
+                       res[i] = sum % 256
+                       sum /= 256
+               end
+
+               return res
        end
 end
 
@@ -48,10 +236,11 @@ end
 #
 # Uses Copy-On-Write when persisted
 class Bytes
-       super AbstractArray[Byte]
+       super AbstractArray[Int]
+       super BytePattern
 
-       # A NativeString being a char*, it can be used as underlying representation here.
-       private var items: NativeString
+       # A CString being a char*, it can be used as underlying representation here.
+       var items: CString
 
        # Number of bytes in the array
        redef var length
@@ -67,29 +256,252 @@ class Bytes
        #     var b = new Bytes.empty
        #     assert b.to_s == ""
        init empty do
-               var ns = new NativeString(0)
+               var ns = new CString(0)
                init(ns, 0, 0)
        end
 
        # Init a `Bytes` with capacity `cap`
        init with_capacity(cap: Int) do
-               var ns = new NativeString(cap)
+               var ns = new CString(cap)
                init(ns, 0, cap)
        end
 
-       redef fun is_empty do return length != 0
+       redef fun pattern_length do return length
+
+       redef fun is_empty do return length == 0
 
        #     var b = new Bytes.empty
-       #     b.add 101u8
-       #     assert b[0] == 101u8
+       #     b.add 101
+       #     assert b[0] == 101
        redef fun [](i) do
                assert i >= 0
                assert i < length
                return items[i]
        end
 
+       # Returns a copy of `self`
+       fun clone: Bytes do
+               var b = new Bytes.with_capacity(length)
+               b.append(self)
+               return b
+       end
+
+       # Trims off the whitespaces at the beginning and the end of `self`
+       #
+       #     var b = "102041426E6F1020" .hexdigest_to_bytes
+       #     assert b.trim.hexdigest == "41426E6F"
+       #
+       # NOTE: A whitespace is defined here as a byte whose value is <= 0x20
+       fun trim: Bytes do
+               var st = 0
+               while st < length do
+                       if self[st] > 0x20 then break
+                       st += 1
+               end
+               if st >= length then return new Bytes.empty
+               var ed = length - 1
+               while ed > 0 do
+                       if self[ed] > 0x20 then break
+                       ed -= 1
+               end
+               return slice(st, ed - st + 1)
+       end
+
+       # Copy a subset of `self` starting at `from` and of `count` bytes
+       #
+       #     var b = "abcd".to_bytes
+       #     assert b.slice(1, 2).hexdigest == "6263"
+       #     assert b.slice(-1, 2).hexdigest == "61"
+       #     assert b.slice(1, 0).hexdigest == ""
+       #     assert b.slice(2, 5).hexdigest == "6364"
+       fun slice(from, count: Int): Bytes do
+               if count <= 0 then return new Bytes.empty
+
+               if from < 0 then
+                       count += from
+                       if count < 0 then count = 0
+                       from = 0
+               end
+
+               if (count + from) > length then count = length - from
+               if count <= 0 then return new Bytes.empty
+
+               var ret = new Bytes.with_capacity(count)
+
+               ret.append_ns(items.fast_cstring(from), count)
+               return ret
+       end
+
+       # Copy of `self` starting at `from`
+       #
+       #     var b = "abcd".to_bytes
+       #     assert b.slice_from(1).hexdigest  == "626364"
+       #     assert b.slice_from(-1).hexdigest == "61626364"
+       #     assert b.slice_from(2).hexdigest  == "6364"
+       fun slice_from(from: Int): Bytes do
+               if from >= length then return new Bytes.empty
+               if from < 0 then from = 0
+               return slice(from, length)
+       end
+
+       # Reverse the byte array in place
+       #
+       #     var b = "abcd".to_bytes
+       #     b.reverse
+       #     assert b.to_s == "dcba"
+       fun reverse
+       do
+               var l = length
+               for i in [0..l/2[ do
+                       var tmp = self[i]
+                       self[i] = self[l-i-1]
+                       self[l-i-1] = tmp
+               end
+       end
+
+       # Returns self as an hexadecimal digest.
+       #
+       # Also known as plain hexdump or postscript hexdump.
+       #
+       # ~~~
+       # var b = "abcd".to_bytes
+       # assert b.hexdigest == "61626364"
+       # assert b.hexdigest.hexdigest_to_bytes == b
+       # ~~~
+       fun hexdigest: String do
+               var elen = length * 2
+               var ns = new CString(elen)
+               var i = 0
+               var oi = 0
+               while i < length do
+                       self[i].add_digest_at(ns, oi)
+                       i += 1
+                       oi += 2
+               end
+               return new FlatString.full(ns, elen, 0, elen)
+       end
+
+       # Return self as a C hexadecimal digest where bytes are prefixed by `\x`
+       #
+       # The output is compatible with literal stream of bytes for most languages
+       # including C and Nit.
+       #
+       # ~~~
+       # var b = "abcd".to_bytes
+       # assert b.chexdigest == "\\x61\\x62\\x63\\x64"
+       # assert b.chexdigest.unescape_to_bytes == b
+       # ~~~
+       fun chexdigest: String do
+               var elen = length * 4
+               var ns = new CString(elen)
+               var i = 0
+               var oi = 0
+               while i < length do
+                       ns[oi] = u'\\'
+                       ns[oi+1] = u'x'
+                       self[i].add_digest_at(ns, oi+2)
+                       i += 1
+                       oi += 4
+               end
+               return new FlatString.full(ns, elen, 0, elen)
+       end
+
+
+       # Returns self as a stream of bits (0 and 1)
+       #
+       # ~~~
+       # var b = "abcd".to_bytes
+       # assert b.binarydigest == "01100001011000100110001101100100"
+       # assert b.binarydigest.binarydigest_to_bytes == b
+       # ~~~
+       fun binarydigest: String do
+               var elen = length * 8
+               var ns = new CString(elen)
+               var i = 0
+               var oi = 0
+               while i < length do
+                       var c = self[i]
+                       var b = 128
+                       while b > 0 do
+                               if c & b == 0 then
+                                       ns[oi] = u'0'
+                               else
+                                       ns[oi] = u'1'
+                               end
+                               oi += 1
+                               b = b >> 1
+                       end
+                       i += 1
+               end
+               return new FlatString.full(ns, elen, 0, elen)
+       end
+
+       # Interprets `self` as a big-endian integer (unsigned by default)
+       #
+       # ~~~
+       # var b = "0102".hexdigest_to_bytes
+       # assert b.to_i == 258
+       #
+       # assert   "01".hexdigest_to_bytes.to_i == 1
+       # assert   "FF".hexdigest_to_bytes.to_i == 255
+       # assert "0000".hexdigest_to_bytes.to_i == 0
+       # ~~~
+       #
+       # If `self.is_empty`, 0 is returned.
+       #
+       # ~~~
+       # assert "".hexdigest_to_bytes.to_i == 0
+       # ~~~
+       #
+       # If `signed == true`, the bytes are read as a signed integer.
+       # As usual, the sign bit is the left most bit, no matter the
+       # `length` of `self`.
+       #
+       # ~~~
+       # assert     "01".hexdigest_to_bytes.to_i(true) ==      1
+       # assert     "FF".hexdigest_to_bytes.to_i(true) ==     -1
+       # assert   "00FF".hexdigest_to_bytes.to_i(true) ==    255
+       # assert     "E0".hexdigest_to_bytes.to_i(true) ==    -32
+       # assert   "FE00".hexdigest_to_bytes.to_i(true) ==   -512
+       # assert "FEFEFE".hexdigest_to_bytes.to_i(true) == -65794
+       # ~~~
+       #
+       # `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"
+       #
+       # assert (-32).to_bytes.to_i(true) == -32
+       # ~~~
+       #
+       # Warning: `Int` might overflow for bytes with more than 60 bits.
+       fun to_i(signed: nullable Bool): Int do
+               var res = 0
+               var i = 0
+               while i < length do
+                       res *= 256
+                       res += self[i].to_i
+                       i += 1
+               end
+
+               # Two's complement is `signed`
+               if signed == true and not_empty and first > 0x80 then
+                       var ff = 0
+                       for j in [0..length[ do
+                               ff *= 0x100
+                               ff += 0xFF
+                       end
+
+                       res = -((res ^ ff) + 1)
+               end
+
+               return res
+       end
+
        #     var b = new Bytes.with_capacity(1)
-       #     b[0] = 101u8
+       #     b[0] = 101
        #     assert b.to_s == "e"
        redef fun []=(i, v) do
                if persisted then regen
@@ -100,7 +512,7 @@ class Bytes
        end
 
        #     var b = new Bytes.empty
-       #     b.add 101u8
+       #     b.add 101
        #     assert b.to_s == "e"
        redef fun add(c) do
                if persisted then regen
@@ -111,8 +523,29 @@ class Bytes
                length += 1
        end
 
+       # Adds the UTF-8 representation of `c` to `self`
+       #
+       #     var b = new Bytes.empty
+       #     b.add_char('A')
+       #     b.add_char('キ')
+       #     assert b.hexdigest == "41E382AD"
+       fun add_char(c: Char) do
+               if persisted then regen
+               var cln = c.u8char_len
+               var ln = length
+               enlarge(ln + cln)
+               items.set_char_at(length, c)
+               length += cln
+       end
+
+       redef fun has(c)
+       do
+               if not c isa Int then return false
+               return super(c&255)
+       end
+
        #     var b = new Bytes.empty
-       #     b.append([104u8, 101u8, 108u8, 108u8, 111u8])
+       #     b.append([104, 101, 108, 108, 111])
        #     assert b.to_s == "hello"
        redef fun append(arr) do
                if arr isa Bytes then
@@ -123,7 +556,7 @@ class Bytes
        end
 
        #     var b = new Bytes.empty
-       #     b.append([0x41u8, 0x41u8, 0x18u8])
+       #     b.append([0x41, 0x41, 0x18])
        #     b.pop
        #     assert b.to_s == "AA"
        redef fun pop do
@@ -136,13 +569,13 @@ class Bytes
 
        # Regenerates the buffer, necessary when it was persisted
        private fun regen do
-               var nns = new NativeString(capacity)
+               var nns = new CString(capacity)
                items.copy_to(nns, length, 0, 0)
                persisted = false
        end
 
        # Appends the `ln` first bytes of `ns` to self
-       fun append_ns(ns: NativeString, ln: Int) do
+       fun append_ns(ns: CString, ln: Int) do
                if persisted then regen
                var nlen = length + ln
                if nlen > capacity then enlarge(nlen)
@@ -151,7 +584,7 @@ class Bytes
        end
 
        # Appends `ln` bytes from `ns` starting at index `from` to self
-       fun append_ns_from(ns: NativeString, ln, from: Int) do
+       fun append_ns_from(ns: CString, ln, from: Int) do
                if persisted then regen
                var nlen = length + ln
                if nlen > capacity then enlarge(nlen)
@@ -159,11 +592,17 @@ class Bytes
                length += ln
        end
 
+       # Appends the bytes of `str` to `self`
+       fun append_text(str: Text) do str.append_to_bytes self
+
+       redef fun append_to(b) do b.append self
+
        redef fun enlarge(sz) do
                if capacity >= sz then return
                persisted = false
+               if capacity < 16 then capacity = 16
                while capacity < sz do capacity = capacity * 2 + 2
-               var ns = new NativeString(capacity)
+               var ns = new CString(capacity)
                items.copy_to(ns, length, 0, 0)
                items = ns
        end
@@ -171,92 +610,177 @@ class Bytes
        redef fun to_s do
                persisted = true
                var b = self
-               if not is_utf8 then
-                       b = clean_utf8
-                       persisted = false
-               end
-               return new FlatString.with_infos(b.items, b.length, 0, b.length -1)
+               var r = b.items.to_s_unsafe(length, copy=false)
+               if r != items then persisted = false
+               return r
        end
 
        redef fun iterator do return new BytesIterator.with_buffer(self)
 
-       # Is the byte collection valid UTF-8 ?
-       fun is_utf8: Bool do
-               var charst = once [0x80u8, 0u8, 0xE0u8, 0xC0u8, 0xF0u8, 0xE0u8, 0xF8u8, 0xF0u8]
-               var lobounds = once [0, 0x80, 0x800, 0x10000]
-               var hibounds = once [0x7F, 0x7FF, 0xFFFF, 0x10FFFF]
-               var pos = 0
-               var len = length
-               var mits = items
-               while pos < len do
-                       var nxst = mits.length_of_char_at(pos)
-                       var charst_index = (nxst - 1) * 2
-                       if mits[pos] & charst[charst_index] == charst[charst_index + 1] then
-                               var c = mits.char_at(pos)
-                               var cp = c.ascii
-                               if cp <= hibounds[nxst - 1] and cp >= lobounds[nxst - 1] then
-                                       if cp >= 0xD800 and cp <= 0xDFFF or
-                                          cp == 0xFFFE or cp == 0xFFFF then return false
-                               else
-                                       return false
-                               end
-                       else
-                               return false
-                       end
-                       pos += nxst
+       redef fun first_index_in_from(b, from) do
+               if is_empty then return -1
+               var fst = self[0]
+               var bpos = fst.first_index_in_from(self, from)
+               for i in [0 .. length[ do
+                       if self[i] != b[bpos] then return first_index_in_from(b, bpos + 1)
+                       bpos += 1
                end
-               return true
+               return bpos
+       end
+
+       redef fun last_index_in_from(b, from) do
+               if is_empty then return -1
+               var lst = self[length - 1]
+               var bpos = lst.last_index_in_from(b, from)
+               for i in [0 .. length[.step(-1) do
+                       if self[i] != b[bpos] then return last_index_in_from(b, bpos - 1)
+                       bpos -= 1
+               end
+               return bpos
        end
 
-       # Cleans the bytes of `self` to be UTF-8 compliant
-       private fun clean_utf8: Bytes do
-               var charst = once [0x80u8, 0u8, 0xE0u8, 0xC0u8, 0xF0u8, 0xE0u8, 0xF8u8, 0xF0u8]
-               var badchar = once [0xEFu8, 0xBFu8, 0xBDu8]
-               var lobounds = once [0, 0x80, 0x800, 0x10000]
-               var hibounds = once [0x7F, 0x7FF, 0xFFFF, 0x10FFFF]
+       redef fun search_all_in(b) do
+               var ret = new Array[Int]
+               var pos = first_index_in_from(b, 0)
+               if pos == -1 then return ret
+               pos = pos + 1
+               ret.add pos
+               loop
+                       pos = first_index_in_from(b, pos)
+                       if pos == -1 then return ret
+                       ret.add pos
+                       pos += length
+               end
+       end
+
+       # Splits the content on self when encountering `b`
+       #
+       #     var a = "String is string".to_bytes.split_with(u's')
+       #     assert a.length == 3
+       #     assert a[0].hexdigest == "537472696E672069"
+       #     assert a[1].hexdigest == "20"
+       #     assert a[2].hexdigest == "7472696E67"
+       fun split_with(b: BytePattern): Array[Bytes] do
+               var fst = b.search_all_in(self)
+               if fst.is_empty then return [clone]
+               var retarr = new Array[Bytes]
+               var prev = 0
+               for i in fst do
+                       retarr.add(slice(prev, i - prev))
+                       prev = i + b.pattern_length
+               end
+               retarr.add slice_from(prev)
+               return retarr
+       end
+
+       # Splits `self` in two parts at the first occurence of `b`
+       #
+       #     var a = "String is string".to_bytes.split_once_on(u's')
+       #     assert a[0].hexdigest == "537472696E672069"
+       #     assert a[1].hexdigest == "20737472696E67"
+       fun split_once_on(b: BytePattern): Array[Bytes] do
+               var spl = b.first_index_in(self)
+               if spl == -1 then return [clone]
+               var ret = new Array[Bytes].with_capacity(2)
+               ret.add(slice(0, spl))
+               ret.add(slice_from(spl + b.pattern_length))
+               return ret
+       end
+
+       # Replaces all the occurences of `this` in `self` by `by`
+       #
+       #     var b = "String is string".to_bytes.replace(0x20, 0x41)
+       #     assert b.hexdigest == "537472696E6741697341737472696E67"
+       fun replace(pattern: BytePattern, bytes: BytePattern): Bytes do
+               if is_empty then return new Bytes.empty
+               var pos = pattern.search_all_in(self)
+               if pos.is_empty then return clone
+               var ret = new Bytes.with_capacity(length)
+               var prev = 0
+               for i in pos do
+                       ret.append_ns(items.fast_cstring(prev), i - prev)
+                       bytes.append_to ret
+                       prev = i + pattern.pattern_length
+               end
+               ret.append(slice_from(pos.last + pattern.pattern_length))
+               return ret
+       end
+
+       # Decode `self` from percent (or URL) encoding to a clear string
+       #
+       # Invalid '%' are not decoded.
+       #
+       #     assert "aBc09-._~".to_bytes.from_percent_encoding == "aBc09-._~".to_bytes
+       #     assert "%25%28%29%3c%20%3e".to_bytes.from_percent_encoding == "%()< >".to_bytes
+       #     assert ".com%2fpost%3fe%3dasdf%26f%3d123".to_bytes.from_percent_encoding == ".com/post?e=asdf&f=123".to_bytes
+       #     assert "%25%28%29%3C%20%3E".to_bytes.from_percent_encoding == "%()< >".to_bytes
+       #     assert "incomplete %".to_bytes.from_percent_encoding == "incomplete %".to_bytes
+       #     assert "invalid % usage".to_bytes.from_percent_encoding == "invalid % usage".to_bytes
+       #     assert "%c3%a9%e3%81%82%e3%81%84%e3%81%86".to_bytes.from_percent_encoding == "éあいう".to_bytes
+       #     assert "%1 %A %C3%A9A9".to_bytes.from_percent_encoding == "%1 %A éA9".to_bytes
+       fun from_percent_encoding: Bytes do
+               var tmp = new Bytes.with_capacity(length)
                var pos = 0
-               var len = length
-               var ret = new Bytes.with_capacity(len)
-               var mits = items
-               while pos < len do
-                       var nxst = mits.length_of_char_at(pos)
-                       var charst_index = (nxst - 1) * 2
-                       if mits[pos] & charst[charst_index] == charst[charst_index + 1] then
-                               var c = mits.char_at(pos)
-                               var cp = c.ascii
-                               if cp <= hibounds[nxst - 1] and cp >= lobounds[nxst - 1] then
-                                       if cp >= 0xD800 and cp <= 0xDFFF or
-                                          cp == 0xFFFE or cp == 0xFFFF then
-                                               ret.append badchar
-                                               pos += 1
-                                       else
-                                               var pend = pos + nxst
-                                               for i in [pos .. pend[ do ret.add mits[i]
-                                               pos += nxst
-                                       end
-                               else
-                                       ret.append badchar
-                                       pos += 1
-                               end
-                       else
-                               ret.append badchar
+               while pos < length do
+                       var b = self[pos]
+                       if b != u'%' then
+                               tmp.add b
                                pos += 1
+                               continue
                        end
+                       if length - pos < 2 then
+                               tmp.add u'%'
+                               pos += 1
+                               continue
+                       end
+                       var bn = self[pos + 1]
+                       var bnn = self[pos + 2]
+                       if not bn.is_valid_hexdigit or not bnn.is_valid_hexdigit then
+                               tmp.add u'%'
+                               pos += 1
+                               continue
+                       end
+                       tmp.add((bn.hexdigit_to_byteval << 4) + bnn.hexdigit_to_byteval)
+                       pos += 3
                end
-               return ret
+               return tmp
+       end
+
+       # Is `b` a prefix of `self` ?
+       fun has_prefix(b: BytePattern): Bool do return b.is_prefix(self)
+
+       # Is `b` a suffix of `self` ?
+       fun has_suffix(b: BytePattern): Bool do return b.is_suffix(self)
+
+       redef fun is_suffix(b) do
+               if length > b.length then return false
+               var j = b.length - 1
+               var i = length - 1
+               while i > 0 do
+                       if self[i] != b[j] then return false
+                       i -= 1
+                       j -= 1
+               end
+               return true
+       end
+
+       redef fun is_prefix(b) do
+               if length > b.length then return false
+               for i in [0 .. length[ do if self[i] != b[i] then return false
+               return true
        end
 end
 
 private class BytesIterator
-       super IndexedIterator[Byte]
+       super IndexedIterator[Int]
 
-       var tgt: NativeString
+       var tgt: CString
 
        redef var index
 
        var max: Int
 
-       init with_buffer(b: Bytes) do init(b.items, 0, b.length - 1)
+       init with_buffer(b: Bytes) do init(b.items, 0, b.length)
 
        redef fun is_ok do return index < max
 
@@ -270,10 +794,10 @@ redef class Text
        #
        # ~~~nit
        # assert "String".to_bytes isa Bytes
-       # assert "String".to_bytes == [83u8, 116u8, 114u8, 105u8, 110u8, 103u8]
+       # assert "String".to_bytes == [83, 116, 114, 105, 110, 103]
        # ~~~
        fun to_bytes: Bytes do
-               var b = new Bytes.with_capacity(bytelen)
+               var b = new Bytes.with_capacity(byte_length)
                append_to_bytes b
                return b
        end
@@ -291,22 +815,243 @@ redef class Text
        fun append_to_bytes(b: Bytes) do
                for s in substrings do
                        var from = if s isa FlatString then s.first_byte else 0
-                       b.append_ns_from(s.items, s.bytelen, from)
+                       b.append_ns_from(s.items, s.byte_length, from)
                end
        end
+
+       # Returns a new `Bytes` instance with the digest as content
+       #
+       #     assert "0B1F4D".hexdigest_to_bytes == [0x0B, 0x1F, 0x4D]
+       #     assert "0B1F4D".hexdigest_to_bytes.hexdigest == "0B1F4D"
+       #
+       # Characters that are not hexadecimal digits are ignored.
+       #
+       #     assert "z0B1 F4\nD".hexdigest_to_bytes.hexdigest == "0B1F4D"
+       #     assert "\\x0b1 \\xf4d".hexdigest_to_bytes.hexdigest == "0B1F4D"
+       #
+       # When the number of hexadecimal digit is not even, then a leading 0 is
+       # implicitly considered to fill the left byte (the most significant one).
+       #
+       #     assert "1".hexdigest_to_bytes.hexdigest == "01"
+       #     assert "FFF".hexdigest_to_bytes.hexdigest == "0FFF"
+       #
+       # `Bytes::hexdigest` is a loosely reverse method since its
+       # results contain only pairs of uppercase hexadecimal digits.
+       #
+       #     assert "ABCD".hexdigest_to_bytes.hexdigest == "ABCD"
+       #     assert "a b c".hexdigest_to_bytes.hexdigest == "0ABC"
+       fun hexdigest_to_bytes: Bytes do
+               var b = bytes
+               var max = byte_length
+
+               var dlength = 0 # Number of hex digits
+               var pos = 0
+               while pos < max do
+                       var c = b[pos]
+                       if c.is_valid_hexdigit then dlength += 1
+                       pos += 1
+               end
+
+               # Allocate the result buffer
+               var ret = new Bytes.with_capacity((dlength+1) / 2)
+
+               var i = (dlength+1) % 2 # current hex digit (1=high, 0=low)
+               var byte = 0 # current accumulated byte value
+
+               pos = 0
+               while pos < max do
+                       var c = b[pos]
+                       if c.is_valid_hexdigit then
+                               byte = byte << 4 | c.hexdigit_to_byteval
+                               i -= 1
+                               if i < 0 then
+                                       # Last digit known: store and restart
+                                       ret.add byte
+                                       i = 1
+                                       byte = 0
+                               end
+                       end
+                       pos += 1
+               end
+               return ret
+       end
+
+       # Gets the hexdigest of the bytes of `self`
+       #
+       #     assert "&lt;STRING&#47;&rt;".hexdigest == "266C743B535452494E47262334373B2672743B"
+       fun hexdigest: String do
+               var ln = byte_length
+               var outns = new CString(ln * 2)
+               var oi = 0
+               for i in [0 .. ln[ do
+                       bytes[i].add_digest_at(outns, oi)
+                       oi += 2
+               end
+               return new FlatString.with_infos(outns, ln * 2, 0)
+       end
+
+       # Return a `Bytes` instance where Nit escape sequences are transformed.
+       #
+       #     assert "B\\n\\x41\\u0103D3".unescape_to_bytes.hexdigest == "420A41F0908F93"
+       #
+       # `Bytes::chexdigest` is a loosely reverse methods since its result is only made
+       # of `"\x??"` escape sequences.
+       #
+       #     assert "\\x41\\x42\\x43".unescape_to_bytes.chexdigest == "\\x41\\x42\\x43"
+       #     assert "B\\n\\x41\\u0103D3".unescape_to_bytes.chexdigest == "\\x42\\x0A\\x41\\xF0\\x90\\x8F\\x93"
+       fun unescape_to_bytes: Bytes do
+               var res = new Bytes.with_capacity(self.byte_length)
+               var was_slash = false
+               var i = 0
+               while i < length do
+                       var c = self[i]
+                       if not was_slash then
+                               if c == '\\' then
+                                       was_slash = true
+                               else
+                                       res.add_char(c)
+                               end
+                               i += 1
+                               continue
+                       end
+                       was_slash = false
+                       if c == 'n' then
+                               res.add_char('\n')
+                       else if c == 'r' then
+                               res.add_char('\r')
+                       else if c == 't' then
+                               res.add_char('\t')
+                       else if c == '0' then
+                               res.add_char('\0')
+                       else if c == 'x' or c == 'X' then
+                               var hx = substring(i + 1, 2)
+                               if hx.is_hex then
+                                       res.add hx.to_hex
+                               else
+                                       res.add_char(c)
+                               end
+                               i += 2
+                       else if c == 'u' or c == 'U' then
+                               var hx = substring(i + 1, 6)
+                               if hx.is_hex then
+                                       res.add_char(hx.to_hex.code_point)
+                               else
+                                       res.add_char(c)
+                               end
+                               i += 6
+                       else
+                               res.add_char(c)
+                       end
+                       i += 1
+               end
+               return res
+       end
+
+       # Return a `Bytes` by reading 0 and 1.
+       #
+       #     assert "1010101100001101".binarydigest_to_bytes.hexdigest == "AB0D"
+       #
+       # Note that characters that are neither 0 or 1 are just ignored.
+       #
+       #     assert "a1B01 010\n1100あ001101".binarydigest_to_bytes.hexdigest == "AB0D"
+       #     assert "hello".binarydigest_to_bytes.is_empty
+       #
+       # When the number of bits is not divisible by 8, then leading 0 are
+       # implicitly considered to fill the left byte (the most significant one).
+       #
+       #     assert "1".binarydigest_to_bytes.hexdigest == "01"
+       #     assert "1111111".binarydigest_to_bytes.hexdigest == "7F"
+       #     assert "1000110100".binarydigest_to_bytes.hexdigest == "0234"
+       #
+       # `Bytes::binarydigest` is a loosely reverse method since its
+       # results contain only 1 and 0 by blocks of 8.
+       #
+       #     assert "1010101100001101".binarydigest_to_bytes.binarydigest == "1010101100001101"
+       #     assert "1".binarydigest_to_bytes.binarydigest == "00000001"
+       fun binarydigest_to_bytes: Bytes
+       do
+               var b = bytes
+               var max = byte_length
+
+               # Count bits
+               var bitlen = 0
+               var pos = 0
+               while pos < max do
+                       var c = b[pos]
+                       pos += 1
+                       if c == u'0' or c == u'1' then bitlen += 1
+               end
+
+               # Allocate (and take care of the padding)
+               var ret = new Bytes.with_capacity((bitlen+7) / 8)
+
+               var i = (bitlen+7) % 8 # current bit (7th=128, 0th=1)
+               var byte = 0 # current accumulated byte value
+
+               pos = 0
+               while pos < max do
+                       var c = b[pos]
+                       pos += 1
+                       if c == u'0' then
+                               byte = byte << 1
+                       else if c == u'1' then
+                               byte = byte << 1 | 1
+                       else
+                               continue
+                       end
+
+                       i -= 1
+                       if i < 0 then
+                               # Last bit known: store and restart
+                               ret.add byte
+                               i = 7
+                               byte = 0
+                       end
+               end
+               return ret
+       end
 end
 
 redef class FlatText
        redef fun append_to_bytes(b) do
                var from = if self isa FlatString then first_byte else 0
-               b.append_ns_from(items, bytelen, from)
+               if isset _items then b.append_ns_from(items, byte_length, from)
        end
 end
 
-redef class NativeString
-       # Creates a new `Bytes` object from `self` with `strlen` as length
-       fun to_bytes: Bytes do
-               var len = cstring_length
+redef class CString
+       # Creates a new `Bytes` object from `self` with `len` as length
+       #
+       # If `len` is null, strlen will determine the length of the Bytes
+       fun to_bytes(len: nullable Int): Bytes do
+               if len == null then len = cstring_length
                return new Bytes(self, len, len)
        end
+
+       # Creates a new `Bytes` object from a copy of `self` with `len` as length
+       #
+       # If `len` is null, strlen will determine the length of the Bytes
+       fun to_bytes_with_copy(len: nullable Int): Bytes do
+               if len == null then len = cstring_length
+               var nns = new CString(len)
+               copy_to(nns, len, 0, 0)
+               return new Bytes(nns, len, len)
+       end
+end
+
+# Joins an array of bytes `arr` separated by `sep`
+#
+#     assert join_bytes(["String".to_bytes, "is".to_bytes, "string".to_bytes], u' ').hexdigest == "537472696E6720697320737472696E67"
+fun join_bytes(arr: Array[Bytes], sep: nullable BytePattern): Bytes do
+       if arr.is_empty then return new Bytes.empty
+       sep = sep or else new Bytes.empty
+       var endln = sep.pattern_length * (arr.length - 1)
+       for i in arr do endln += i.length
+       var ret = new Bytes.with_capacity(endln)
+       ret.append(arr.first)
+       for i in  [1 .. arr.length[ do
+               sep.append_to(ret)
+               ret.append arr[i]
+       end
+       return ret
 end