Implement IPv6 parser, fix #49

source/tanya/net/ip.d

@@ -17,9 +17,11 @@ module tanya.net.ip;
 import tanya.algorithm.mutation;
 import tanya.container.string;
 import tanya.conv;
+import tanya.encoding.ascii;
 import tanya.format;
 import tanya.meta.trait;
 import tanya.meta.transform;
+import tanya.net.iface;
 import tanya.net.inet;
 import tanya.range;
 import tanya.typecons;
@@ -158,7 +160,7 @@ struct Address4
      * Returns: $(D_KEYWORD true) if this is a multicast address,
      *          $(D_KEYWORD false) otherwise.
      *
-     * See_Also: $(D_PSYMBOL isMulticast).
+     * See_Also: $(D_PSYMBOL isUnicast).
      */
     bool isMulticast() const @nogc nothrow pure @safe
     {
@@ -274,7 +276,7 @@ struct Address4
  *          successful, or nothing otherwise.
  */
 Option!Address4 address4(R)(R range)
-if (isInputRange!R && isSomeChar!(ElementType!R))
+if (isForwardRange!R && is(Unqual!(ElementType!R) == char) && hasLength!R)
 {
     Address4 result;
     version (LittleEndian)
@@ -394,16 +396,237 @@ struct Address6
     // Raw bytes
     private ubyte[16] address;
 
+    /// Scope ID.
+    uint scopeID;
+
     /**
-     * Constructs an $(D_PSYMBOL Address6) from an unsigned integer in host
+     * Constructs an $(D_PSYMBOL Address6) from an array containing raw bytes
-     * byte order.
+     * in network byte order and scope ID.
      *
      * Params:
      *  address = The address as an unsigned integer in host byte order.
+     *  scopeID = Scope ID.
      */
-    this(ulong address)
+    this(ubyte[16] address, uint scopeID = 0) @nogc nothrow pure @safe
     {
-        copy(NetworkOrder!8(address), this.address[]);
+        copy(address[], this.address[]);
+        this.scopeID = scopeID;
+    }
+
+    ///
+    @nogc nothrow pure @safe unittest
+    {
+        const ubyte[16] expected = [ 0, 1, 0, 2, 0, 3, 0, 4,
+                                     0, 5, 0, 6, 0, 7, 0, 8 ];
+        auto actual = Address6(expected, 1);
+        assert(actual.toBytes() == expected);
+        assert(actual.scopeID == 1);
+    }
+
+    /**
+     * Returns object that represents ::.
+     *
+     * Returns: Object that represents any address.
+     */
+    static Address6 any() @nogc nothrow pure @safe
+    {
+        return Address6();
+    }
+
+    ///
+    @nogc nothrow pure @safe unittest
+    {
+        assert(Address6.any().isAny());
+    }
+
+    /**
+     * Returns object that represents ::1.
+     *
+     * Returns: Object that represents the Loopback address.
+     */
+    static Address6 loopback() @nogc nothrow pure @safe
+    {
+        typeof(return) address;
+        address.address[$ - 1] = 1;
+        return address;
+    }
+
+    ///
+    @nogc nothrow pure @safe unittest
+    {
+        assert(Address6.loopback().isLoopback());
+    }
+
+    /**
+     * :: can represent any address. This function checks whether this
+     * address is ::.
+     *
+     * Returns: $(D_KEYWORD true) if this is an unspecified address,
+     *          $(D_KEYWORD false) otherwise.
+     */
+    bool isAny() const @nogc nothrow pure @safe
+    {
+        return this.address == any.address;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        assert(address6("::").isAny());
+    }
+
+    /**
+     * Loopback address is ::1.
+     *
+     * Returns: $(D_KEYWORD true) if this is a loopback address,
+     *          $(D_KEYWORD false) otherwise.
+     */
+    bool isLoopback() const @nogc nothrow pure @safe
+    {
+        return this.address == loopback.address;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        assert(address6("::1").isLoopback());
+    }
+
+    /**
+     * Determines whether this address' destination is a group of endpoints.
+     *
+     * Returns: $(D_KEYWORD true) if this is a multicast address,
+     *          $(D_KEYWORD false) otherwise.
+     *
+     * See_Also: $(D_PSYMBOL isUnicast).
+     */
+    bool isMulticast() const @nogc nothrow pure @safe
+    {
+        return this.address[0] == 0xff;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        assert(address6("ff00::").isMulticast());
+    }
+
+    /**
+     * Determines whether this address' destination is a single endpoint.
+     *
+     * Returns: $(D_KEYWORD true) if this is a multicast address,
+     *          $(D_KEYWORD false) otherwise.
+     *
+     * See_Also: $(D_PSYMBOL isMulticast).
+     */
+    bool isUnicast() const @nogc nothrow pure @safe
+    {
+        return !isMulticast();
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        assert(address6("::1").isUnicast());
+    }
+
+    /**
+     * Determines whether this address is a link-local unicast address.
+     *
+     * Returns: $(D_KEYWORD true) if this is a link-local address,
+     *          $(D_KEYWORD false) otherwise.
+     */
+    bool isLinkLocal() const @nogc nothrow pure @safe
+    {
+        return this.address[0] == 0xfe && (this.address[1] & 0xc0) == 0x80;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        assert(address6("fe80::1").isLinkLocal());
+    }
+
+    /**
+     * Determines whether this address is an Unique Local Address (ULA).
+     *
+     * Returns: $(D_KEYWORD true) if this is an Unique Local Address,
+     *          $(D_KEYWORD false) otherwise.
+     */
+    bool isUniqueLocal() const @nogc nothrow pure @safe
+    {
+        return this.address[0] == 0xfc || this.address[0] == 0xfd;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        assert(address6("fd80:124e:34f3::1").isUniqueLocal());
+    }
+
+    /**
+     * Returns text representation of this address.
+     *
+     * Returns: text representation of this address.
+     */
+    String stringify() const @nogc nothrow pure @safe
+    {
+        String output;
+        foreach (i, b; this.address)
+        {
+            ubyte low = b & 0xf;
+            ubyte high = b >> 4;
+
+            if (high < 10)
+            {
+                output.insertBack(cast(char) (high + '0'));
+            }
+            else
+            {
+                output.insertBack(cast(char) (high - 10 + 'a'));
+            }
+            if (low < 10)
+            {
+                output.insertBack(cast(char) (low + '0'));
+            }
+            else
+            {
+                output.insertBack(cast(char) (low - 10 + 'a'));
+            }
+            if (i % 2 != 0 && i != (this.address.length - 1))
+            {
+                output.insertBack(':');
+            }
+        }
+
+        return output;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        import tanya.algorithm.comparison : equal;
+
+        assert(equal(address6("1:2:3:4:5:6:7:8").stringify()[],
+               "0001:0002:0003:0004:0005:0006:0007:0008"));
+    }
+
+    /**
+     * Produces a byte array containing this address in network byte order.
+     *
+     * Returns: This address as raw bytes in network byte order.
+     */
+    ubyte[16] toBytes() const @nogc nothrow pure @safe
+    {
+        return this.address;
+    }
+
+    ///
+    @nogc nothrow @safe unittest
+    {
+        auto actual = address6("1:2:3:4:5:6:7:8");
+        ubyte[16] expected = [0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0, 8];
+        assert(actual.toBytes() == expected);
     }
 }
 
@@ -417,6 +640,25 @@ private void write2Bytes(R)(ref R range, ubyte[] address)
 /**
  * Parses a string containing an IPv6 address.
  *
+ * This function isn't pure since an IPv6 address can contain interface name
+ * or interface ID (separated from the address by `%`). If an interface name
+ * is specified (i.e. first character after `%` is not a digit), the parser
+ * tries to convert it to the ID of that interface. If the interface with the
+ * given name can't be found, the parser doesn't fail, but just ignores the
+ * invalid interface name.
+ *
+ * If an ID is given (i.e. first character after `%` is a digit),
+ * $(D_PSYMBOL address6) just stores it in $(D_PSYMBOL Address6.scopeID) without
+ * checking whether an interface with this ID really exists. If the ID is
+ * invalid (if it is too long or contains non decimal characters), parsing
+ * and nothing is returned.
+ *
+ * If neither an ID nor a name is given, $(D_PSYMBOL Address6.scopeID) is set
+ * to `0`.
+ *
+ * The parser doesn't support notation with an embedded IPv4 address (e.g.
+ * ::1.2.3.4).
+ *
  * Params:
  *  R     = Input range type.
  *  range = Stringish range containing the address.
@@ -425,15 +667,19 @@ private void write2Bytes(R)(ref R range, ubyte[] address)
  *          successful, or nothing otherwise.
  */
 Option!Address6 address6(R)(R range)
-if (isInputRange!R && isSomeChar!(ElementType!R))
+if (isForwardRange!R && is(Unqual!(ElementType!R) == char) && hasLength!R)
 {
     if (range.empty)
     {
         return typeof(return)();
     }
     Address6 result;
+    ubyte[12] tail;
     size_t i;
+    size_t j;
 
+    // An address begins with a number, not ':'. But there is a special case
+    // if the address begins with '::'.
     if (range.front == ':')
     {
         range.popFront();
@@ -445,6 +691,8 @@ if (isInputRange!R && isSomeChar!(ElementType!R))
         goto ParseTail;
     }
 
+    // Parse the address before '::'.
+    // This loop parses the whole address if it doesn't contain '::'.
     for (; i < 13; i += 2)
     {
         write2Bytes(range, result.address[i .. $]);
@@ -465,15 +713,50 @@ if (isInputRange!R && isSomeChar!(ElementType!R))
     }
     write2Bytes(range, result.address[14 .. $]);
 
-    return range.empty ? typeof(return)(result) : typeof(return)();
+    if (range.empty)
-
-ParseTail:
-    ubyte[12] tail;
-    size_t j;
-
-    for (; !range.empty; i += 2, j += 2, range.popFront())
     {
-        if (i > 11 || range.front == ':')
+        return typeof(return)(result);
+    }
+    else if (range.front == '%')
+    {
+        goto ParseIface;
+    }
+    else
+    {
+        return typeof(return)();
+    }
+
+ParseTail: // after ::
+    // Normally the address can't end with ':', but a special case is if the
+    // address ends with '::'. So the first iteration of the loop below is
+    // unrolled to check whether the address contains something after '::' at
+    // all.
+    if (range.empty)
+    {
+        return typeof(return)(result); // ends with ::
+    }
+    if (range.front == ':')
+    {
+        return typeof(return)();
+    }
+    write2Bytes(range, tail[j .. $]);
+    if (range.empty)
+    {
+        goto CopyTail;
+    }
+    else if (range.front == '%')
+    {
+        goto ParseIface;
+    }
+    else if (range.front != ':')
+    {
+        return typeof(return)();
+    }
+    range.popFront();
+
+    for (i = 2, j = 2; i <= 11; i += 2, j += 2, range.popFront())
+    {
+        if (range.empty || range.front == ':')
         {
             return typeof(return)();
         }
@@ -481,19 +764,47 @@ ParseTail:
 
         if (range.empty)
         {
-            break;
+            goto CopyTail;
         }
-        if (range.front != ':')
+        else if (range.front == '%')
+        {
+            goto ParseIface;
+        }
+        else if (range.front != ':')
         {
             return typeof(return)();
         }
     }
-    copy(tail[0 .. j + 2], result.address[$ - j - 2 .. $]);
 
+ParseIface: // Scope name or ID
+    range.popFront();
+    if (range.empty)
+    {
+        return typeof(return)();
+    }
+    else if (isDigit(range.front))
+    {
+        const scopeID = readIntegral!uint(range);
+        if (range.empty)
+        {
+            result.scopeID = scopeID;
+        }
+        else
+        {
+            return typeof(return)();
+        }
+    }
+    else
+    {
+        result.scopeID = nameToIndex(range);
+    }
+
+CopyTail:
+    copy(tail[0 .. j + 2], result.address[$ - j - 2 .. $]);
     return typeof(return)(result);
 }
 
-@nogc nothrow pure @safe unittest
+@nogc nothrow @safe unittest
 {
     {
         ubyte[16] expected = [0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0, 8];
@@ -518,10 +829,62 @@ ParseTail:
 }
 
 // Rejects malformed addresses
-@nogc nothrow pure @safe unittest
+@nogc nothrow @safe unittest
 {
     assert(address6("").isNothing);
     assert(address6(":").isNothing);
     assert(address6(":a").isNothing);
     assert(address6("a:").isNothing);
+    assert(address6("1:2:3:4::6:").isNothing);
+    assert(address6("1:2:3:4::6:7:8%").isNothing);
+}
+
+/**
+ * Constructs an $(D_PSYMBOL Address6) from raw bytes in network byte order and
+ * the scope ID.
+ *
+ * Params:
+ *  R       = Input range type.
+ *  range   = $(D_KEYWORD ubyte) range containing the address.
+ *  scopeID = Scope ID.
+ *
+ * Returns: $(D_PSYMBOL Option) containing the address if the $(D_PARAM range)
+ *          contains exactly 16 bytes, or nothing otherwise.
+ */
+Option!Address6 address6(R)(R range, uint scopeID = 0)
+if (isInputRange!R && is(Unqual!(ElementType!R) == ubyte))
+{
+    Address6 result;
+    int i;
+
+    for (; i < 16 && !range.empty; ++i, range.popFront())
+    {
+        result.address[i] = range.front;
+    }
+    result.scopeID = scopeID;
+
+    return range.empty && i == 16 ? typeof(return)(result) : typeof(return)();
+}
+
+///
+@nogc nothrow pure @safe unittest
+{
+    {
+        ubyte[16] actual = [ 1, 2, 3, 4, 5, 6, 7, 8,
+                             9, 10, 11, 12, 13, 14, 15, 16 ];
+        assert(!address6(actual[]).isNothing);
+    }
+    {
+        ubyte[15] actual = [ 1, 2, 3, 4, 5, 6, 7, 8,
+                             9, 10, 11, 12, 13, 14, 15 ];
+        assert(address6(actual[]).isNothing);
+    }
+    {
+        ubyte[17] actual = [ 1, 2, 3, 4, 5, 6, 7, 8, 9,
+                             10, 11, 12, 13, 14, 15, 16, 17 ];
+        assert(address6(actual[]).isNothing);
+    }
+    {
+        assert(address6(cast(ubyte[]) []).isNothing);
+    }
 }