Add missing constructors to the String

source/tanya/container/string.d

@@ -12,13 +12,35 @@
  */
 module tanya.container.string;
 
-import core.checkedint;
 import core.exception;
 import std.algorithm.comparison;
 import std.algorithm.mutation;
+import std.range;
 import std.traits;
 import tanya.memory;
 
+private ref const(wchar) front(const wchar[] str)
+pure nothrow @safe @nogc
+in
+{
+    assert(str.length > 0);
+}
+body
+{
+    return str[0];
+}
+
+private void popFront(ref const(wchar)[] str, const size_t s = 1)
+pure nothrow @safe @nogc
+in
+{
+    assert(str.length >= s);
+}
+body
+{
+    str = str[s .. $];
+}
+
 /**
  * Thrown on encoding errors.
  */
@@ -41,12 +63,12 @@ class UTFException : Exception
 }
 
 /**
- * Byte range.
+ * Iterates $(D_PSYMBOL String) by UTF-8 code unit.
  *
  * Params:
  *  E = Element type ($(D_KEYWORD char) or $(D_INLINECODE const(char))).
  */
-struct ByteRange(E)
+struct ByCodeUnit(E)
     if (is(Unqual!E == char))
 {
     private E* begin, end;
@@ -77,7 +99,7 @@ struct ByteRange(E)
 
     @disable this();
 
-    @property ByteRange save()
+    @property ByCodeUnit save()
     {
         return this;
     }
@@ -144,17 +166,17 @@ struct ByteRange(E)
         return *(this.begin + i);
     }
 
-    ByteRange opIndex()
+    ByCodeUnit opIndex()
     {
         return typeof(return)(*this.container, this.begin, this.end);
     }
 
-    ByteRange!(const E) opIndex() const
+    ByCodeUnit!(const E) opIndex() const
     {
         return typeof(return)(*this.container, this.begin, this.end);
     }
 
-    ByteRange opSlice(const size_t i, const size_t j) @trusted
+    ByCodeUnit opSlice(const size_t i, const size_t j) @trusted
     in
     {
         assert(i <= j);
@@ -165,7 +187,7 @@ struct ByteRange(E)
         return typeof(return)(*this.container, this.begin + i, this.begin + j);
     }
 
-    ByteRange!(const E) opSlice(const size_t i, const size_t j) const @trusted
+    ByCodeUnit!(const E) opSlice(const size_t i, const size_t j) const @trusted
     in
     {
         assert(i <= j);
@@ -180,7 +202,6 @@ struct ByteRange(E)
     {
         return this.begin[0 .. length];
     }
-
 }
 
 /**
@@ -192,13 +213,16 @@ struct String
     private char* data;
     private size_t capacity_;
 
-    invariant
+    pure nothrow @safe @nogc invariant
     {
         assert(this.length_ <= this.capacity_);
     }
 
     /**
+     * Constructs the string from a stringish range.
+     *
      * Params:
+     *  R         = String type.
      *  str       = Initial string.
      *  allocator = Allocator.
      *
@@ -206,127 +230,79 @@ struct String
      *
      * Precondition: $(D_INLINECODE allocator is null).
      */
-    this(const char[] str, shared Allocator allocator = defaultAllocator)
+    this(R)(const R str, shared Allocator allocator = defaultAllocator)
-    @trusted @nogc
+        if (!isInfinite!R
+         && isInputRange!R
+         && isSomeChar!(ElementEncodingType!R))
     {
         this(allocator);
-        reserve(str.length);
+        insertBack(str);
-        this.length_ = str.length;
-        str.copy(this.data[0 .. this.length_]);
-    }
-
-    /// Ditto.
-    this(const wchar[] str, shared Allocator allocator = defaultAllocator)
-    @trusted @nogc
-    {
-        this(allocator);
-        reserve(str.length * 2);
-
-        size_t s;
-        auto sourceLength = str.length;
-        for (auto c = str.ptr; sourceLength != 0; ++c, --sourceLength)
-        {
-            if (length - s < 5) // More space required.
-            {
-                bool overflow;
-                auto size = addu(length, str.length, overflow);
-                assert(!overflow);
-                reserve(size);
-            }
-            if (*c < 0x80)
-            {
-                this.data[s++] = *c & 0x7f;
-                this.length_ += 1;
-            }
-            else if (*c < 0x800)
-            {
-                this.data[s++] = 0xc0 | (*c >> 6) & 0xff;
-                this.data[s++] = 0x80 | (*c & 0x3f);
-                this.length_ += 2;
-            }
-            else if (*c < 0xd800 || *c - 0xe000 < 0x2000)
-            {
-                this.data[s++] = 0xe0 | (*c >> 12) & 0xff;
-                this.data[s++] = 0x80 | ((*c >> 6) & 0x3f);
-                this.data[s++] = 0x80 | (*c & 0x3f);
-                this.length_ += 3;
-            }
-            else if ((*c - 0xd800) < 2048 && sourceLength > 0 && *(c + 1) - 0xdc00 < 0x400)
-            { // Surrogate pair
-                dchar d = (*c - 0xd800) | ((*c++ - 0xdc00) >> 10);
-
-                this.data[s++] = 0xf0 | (d >> 18);
-                this.data[s++] = 0x80 | ((d >> 12) & 0x3f);
-                this.data[s++] = 0x80 | ((d >> 6) & 0x3f);
-                this.data[s++] = 0x80 | (d & 0x3f);
-                --sourceLength;
-                this.length_ += 4;
-            }
-            else
-            {
-                throw defaultAllocator.make!UTFException("Wrong UTF-16 sequeunce");
-            }
-        }
     }
 
     ///
-    unittest
+    @safe @nogc unittest
     {
         auto s = String("\u10437"w);
         assert("\u10437" == s.get());
     }
 
-    /// Ditto.
-    this(const dchar[] str, shared Allocator allocator = defaultAllocator)
-    @trusted @nogc
-    {
-        this(allocator);
-
-        reserve(str.length * 4);
-
-        auto s = data;
-        foreach (c; str)
-        {
-            if (c < 0x80)
-            {
-                *s++ = c & 0x7f;
-                this.length_ += 1;
-            }
-            else if (c < 0x800)
-            {
-                *s++ = 0xc0 | (c >> 6) & 0xff;
-                *s++ = 0x80 | (c & 0x3f);
-                this.length_ += 2;
-            }
-            else if (c < 0xd800 || c - 0xe000 < 0x2000)
-            {
-                *s++ = 0xe0 | (c >> 12) & 0xff;
-                *s++ = 0x80 | ((c >> 6) & 0x3f);
-                *s++ = 0x80 | (c & 0x3f);
-                this.length_ += 3;
-            }
-            else if (c - 0x10000 < 0x100000)
-            {
-                *s++ = 0xf0 | (c >> 18);
-                *s++ = 0x80 | ((c >> 12) & 0x3f);
-                *s++ = 0x80 | ((c >> 6) & 0x3f);
-                *s++ = 0x80 | (c & 0x3f);
-                this.length_ += 4;
-            }
-            else
-            {
-                throw defaultAllocator.make!UTFException("Wrong UTF-32 sequeunce");
-            }
-        }
-    }
-
     ///
-    unittest
+    @safe @nogc unittest
     {
         auto s = String("Отказаться от вина - в этом страшная вина."d);
         assert("Отказаться от вина - в этом страшная вина." == s.get());
     }
 
+    /**
+     * Initializes this string from another one.
+     *
+     * If $(D_PARAM init) is passed by value, it won't be copied, but moved.
+     * If the allocator of ($D_PARAM init) matches $(D_PARAM allocator),
+     * $(D_KEYWORD this) will just take the ownership over $(D_PARAM init)'s
+     * storage, otherwise, the storage will be allocated with
+     * $(D_PARAM allocator). $(D_PARAM init) will be destroyed at the end.
+     *
+     * If $(D_PARAM init) is passed by reference, it will be copied.
+     *
+     * Params:
+     *  init      = Source string.
+     *  allocator = Allocator.
+     *
+     * Precondition: $(D_INLINECODE allocator is null).
+     */
+    this(String init, shared Allocator allocator = defaultAllocator)
+    nothrow @trusted @nogc
+    {
+        this(allocator);
+        if (allocator !is init.allocator)
+        {
+            // Just steal all references and the allocator.
+            this.data = init.data;
+            this.length_ = init.length_;
+            this.capacity_ = init.capacity_;
+
+            // Reset the source string, so it can't destroy the moved storage.
+            init.length_ = init.capacity_ = 0;
+            init.data = null;
+        }
+        else
+        {
+            reserve(init.length);
+            init.data[0 .. init.length].copy(this.data[0 .. init.length]);
+            this.length_ = init.length;
+        }
+    }
+
+    /// Ditto.
+    this(ref const String init, shared Allocator allocator = defaultAllocator)
+    nothrow @trusted @nogc
+    {
+        this(allocator);
+        reserve(init.length);
+        init.data[0 .. init.length].copy(this.data[0 .. init.length]);
+        this.length_ = init.length;
+    }
+
     /// Ditto.
     this(shared Allocator allocator) pure nothrow @safe @nogc
     in
@@ -338,6 +314,59 @@ struct String
         this.allocator_ = allocator;
     }
 
+    /**
+     * Fills the string with $(D_PARAM n) consecutive copies of character $(D_PARAM chr).
+     *
+     * Params:
+     *  C   = Type of the character to fill the string with.
+     *  n   = Number of characters to copy.
+     *  chr = Character to fill the string with.
+     */
+    this(C)(const size_t n, const C chr,
+            shared Allocator allocator = defaultAllocator) @trusted
+        if (isSomeChar!C)
+    {
+        this(allocator);
+        if (n == 0)
+        {
+            return;
+        }
+        insertBack(chr);
+
+        // insertBack should validate the character, so we can just copy it
+        // n - 1 times.
+        auto remaining = length * n;
+
+        reserve(remaining);
+
+        // Use a quick copy.
+        for (auto i = this.length_ * 2; i <= remaining; i *= 2)
+        {
+            this.data[0 .. this.length_].copy(this.data[this.length_ .. i]);
+            this.length_ = i;
+        }
+        remaining -= length;
+        copy(this.data[this.length_ - remaining .. this.length_],
+             this.data[this.length_ .. this.length_ + remaining]);
+        this.length_ += remaining;
+    }
+
+    private unittest
+    {
+        {
+            auto s = String(1, 'О');
+            assert(s.length == 2);
+        }
+        {
+            auto s = String(3, 'О');
+            assert(s.length == 6);
+        }
+        {
+            auto s = String(8, 'О');
+            assert(s.length == 16);
+        }
+    }
+
     /**
      * Destroys the string.
      */
@@ -346,6 +375,278 @@ struct String
         allocator.deallocate(this.data[0 .. this.capacity_]);
     }
 
+    private void write4Bytes(ref const dchar src)
+    pure nothrow @trusted @nogc
+    in
+    {
+        assert(capacity - length >= 4);
+        assert(src - 0x10000 < 0x100000);
+    }
+    body
+    {
+        auto dst = this.data + length;
+
+        *dst++ = 0xf0 | (src >> 18);
+        *dst++ = 0x80 | ((src >> 12) & 0x3f);
+        *dst++ = 0x80 | ((src >> 6) & 0x3f);
+        *dst = 0x80 | (src & 0x3f);
+
+        this.length_ += 4;
+    }
+
+    private size_t insertWideChar(C)(auto ref const C chr) @trusted
+        if (is(C == wchar) || is(C == dchar))
+    in
+    {
+        assert(capacity - length >= C.sizeof);
+    }
+    body
+    {
+        auto dst = this.data + length;
+        if (chr < 0x80)
+        {
+            *dst = chr & 0x7f;
+            this.length_ += 1;
+            return 1;
+        }
+        else if (chr < 0x800)
+        {
+            *dst++ = 0xc0 | (chr >> 6) & 0xff;
+            *dst = 0x80 | (chr & 0x3f);
+            this.length_ += 2;
+            return 2;
+        }
+        else if (chr < 0xd800 || chr - 0xe000 < 0x2000)
+        {
+            *dst++ = 0xe0 | (chr >> 12) & 0xff;
+            *dst++ = 0x80 | ((chr >> 6) & 0x3f);
+            *dst = 0x80 | (chr & 0x3f);
+            this.length_ += 3;
+            return 3;
+        }
+        return 0;
+    }
+
+    /**
+     * Inserts a single character at the end of the string.
+     *
+     * Params:
+     *  chr = The character should be inserted.
+     *
+     * Returns: The number of bytes inserted.
+     *
+     * Throws: $(D_PSYMBOL UTFException).
+     */
+    size_t insertBack(const char chr) @trusted @nogc
+    {
+        if ((chr & 0x80) != 0)
+        {
+            throw defaultAllocator.make!UTFException("Invalid UTF-8 character");
+        }
+        reserve(length + 1);
+
+        *(data + length) = chr;
+        ++this.length_;
+
+        return 1;
+    }
+
+    /// Ditto.
+    size_t insertBack(const wchar chr) @trusted @nogc
+    {
+        reserve(length + wchar.sizeof);
+
+        auto ret = insertWideChar(chr);
+        if (ret == 0)
+        {
+            throw defaultAllocator.make!UTFException("Invalid UTF-16 sequeunce");
+        }
+        return ret;
+    }
+
+    /// Ditto.
+    size_t insertBack(const dchar chr) @trusted @nogc
+    {
+        reserve(length + dchar.sizeof);
+
+        auto ret = insertWideChar(chr);
+        if (ret > 0)
+        {
+            return ret;
+        }
+        else if (chr - 0x10000 < 0x100000)
+        {
+            write4Bytes(chr);
+            return 4;
+        }
+        else
+        {
+            throw defaultAllocator.make!UTFException("Invalid UTF-32 sequeunce");
+        }
+    }
+
+    /**
+     * Inserts a stringish range at the end of the string.
+     *
+     * Params:
+     *  R   = Type of the inserted string.
+     *  str = String should be inserted.
+     *
+     * Returns: The number of bytes inserted.
+     *
+     * Throws: $(D_PSYMBOL UTFException).
+     */
+    size_t insertBack(R)(R str) @trusted
+        if (!isInfinite!R
+         && isInputRange!R
+         && is(Unqual!(ElementEncodingType!R) == char))
+    {
+        size_t size;
+        static if (hasLength!R || isNarrowString!R)
+        {
+            size = str.length + length;
+            reserve(size);
+        }
+
+        static if (isNarrowString!R)
+        {
+            str.copy(this.data[length .. size]);
+            this.length_ = size;
+            return str.length;
+        }
+        else
+        {
+            size_t insertedLength;
+            while (!str.empty)
+            {
+                ubyte expectedLength;
+                if ((str.front & 0x80) == 0x00)
+                {
+                    expectedLength = 1;
+                }
+                else if ((str.front & 0xe0) == 0xc0)
+                {
+                    expectedLength = 2;
+                }
+                else if ((str.front & 0xf0) == 0xe0)
+                {
+                    expectedLength = 3;
+                }
+                else if ((str.front & 0xf8) == 0xf0)
+                {
+                    expectedLength = 4;
+                }
+                else
+                {
+                    throw defaultAllocator.make!UTFException("Invalid UTF-8 sequeunce");
+                }
+                size = length + expectedLength;
+                reserve(size);
+
+                for (; expectedLength > 0; --expectedLength)
+                {
+                    if (str.empty)
+                    {
+                        throw defaultAllocator.make!UTFException("Invalid UTF-8 sequeunce");
+                    }
+                    *(data + length) = str.front;
+                    str.popFront();
+                }
+                insertedLength += expectedLength;
+                this.length_ = size;
+            }
+            return insertedLength;
+        }
+    }
+
+    /// Ditto.
+    size_t insertBack(R)(R str) @trusted
+        if (!isInfinite!R
+         && isInputRange!R
+         && is(Unqual!(ElementEncodingType!R) == wchar))
+    {
+        static if (hasLength!R || isNarrowString!R)
+        {
+            reserve(length + str.length * wchar.sizeof);
+        }
+
+        static if (isNarrowString!R)
+        {
+            const(wchar)[] range = str;
+        }
+        else
+        {
+            alias range = str;
+        }
+
+        auto oldLength = length;
+
+        while (!range.empty)
+        {
+            reserve(length + 4);
+
+            auto ret = insertWideChar(range.front);
+            if (ret > 0)
+            {
+                range.popFront();
+            }
+            else if (range.front - 0xd800 < 2048)
+            { // Surrogate pair.
+                static if (isNarrowString!R)
+                {
+                    if (range.length < 2 || range[1] - 0xdc00 >= 0x400)
+                    {
+                        throw defaultAllocator.make!UTFException("Invalid UTF-16 sequeunce");
+                    }
+                    dchar d = (range[0] - 0xd800) | ((range[1] - 0xdc00) >> 10);
+
+                    range.popFront(2);
+                }
+                else
+                {
+                    dchar d = range.front - 0xd800;
+                    range.popFront();
+
+                    if (range.empty || range.front - 0xdc00 >= 0x400)
+                    {
+                        throw defaultAllocator.make!UTFException("Invalid UTF-16 sequeunce");
+                    }
+                    d |= (range.front - 0xdc00) >> 10;
+
+                    range.popFront();
+                }
+                write4Bytes(d);
+            }
+            else
+            {
+                throw defaultAllocator.make!UTFException("Invalid UTF-16 sequeunce");
+            }
+        }
+        return this.length_ - oldLength;
+    }
+
+    /// Ditto.
+    size_t insertBack(R)(R str) @trusted
+        if (!isInfinite!R
+         && isInputRange!R
+         && is(Unqual!(ElementEncodingType!R) == dchar))
+    {
+        static if (hasLength!R || isSomeString!R)
+        {
+            reserve(length + str.length * 4);
+        }
+
+        size_t insertedLength;
+        foreach (const dchar c; str)
+        {
+            insertedLength += insertBack(c);
+        }
+        return insertedLength;
+    }
+
+    /// Ditto.
+    alias insert = insertBack;
+
     /**
      * Reserves $(D_PARAM size) bytes for the string.
      *
@@ -450,7 +751,7 @@ struct String
     }
 
     /**
-     * Returns: Byte length.
+     * Returns: The number of code units that are required to encode the string.
      */
     @property size_t length() const pure nothrow @safe @nogc
     {
@@ -498,17 +799,36 @@ struct String
      * Returns: Random access range that iterates over the string by bytes, in
      *          forward order.
      */
-    ByteRange!char opIndex() pure nothrow @trusted @nogc
+    ByCodeUnit!char opIndex() pure nothrow @trusted @nogc
     {
         return typeof(return)(this, this.data, this.data + length);
     }
 
     /// Ditto.
-    ByteRange!(const char) opIndex() const pure nothrow @trusted @nogc
+    ByCodeUnit!(const char) opIndex() const pure nothrow @trusted @nogc
     {
         return typeof(return)(this, this.data, this.data + length);
     }
 
+    ///
+    unittest
+    {
+        auto s = String("Plutarchus");
+        auto r = s[];
+        assert(r.front == 'P');
+        assert(r.back == 's');
+
+        r.popFront();
+        assert(r.front == 'l');
+        assert(r.back == 's');
+
+        r.popBack();
+        assert(r.front == 'l');
+        assert(r.back == 'u');
+
+        assert(r.length == 8);
+    }
+
     /**
      * Returns: $(D_KEYWORD true) if the vector is empty.
      */
@@ -518,47 +838,67 @@ struct String
     }
 
     /**
-     * Returns: The first byte.
+     * Params:
+     *  i = Slice start.
+     *  j = Slice end.
      *
-     * Precondition: $(D_INLINECODE !empty).
+     * Returns: A range that iterates over the string by bytes from
+     *          index $(D_PARAM i) up to (excluding) index $(D_PARAM j).
+     *
+     * Precondition: $(D_INLINECODE i <= j && j <= length).
      */
-    @property ref inout(char) front() inout pure nothrow @safe @nogc
+    ByCodeUnit!char opSlice(const size_t i, const size_t j)
+    pure nothrow @trusted @nogc
     in
     {
-        assert(!empty);
+        assert(i <= j);
+        assert(j <= length);
     }
     body
     {
-        return *this.data;
+        return typeof(return)(this, this.data + i, this.data + j);
     }
 
-    ///
+    /// Ditto.
-    @safe unittest
+    ByCodeUnit!(const char) opSlice(const size_t i, const size_t j)
-    {
+    const pure nothrow @trusted @nogc
-        auto s = String("Vladimir Soloviev");
-        assert(s.front == 'V');
-    }
-
-    /**
-     * Returns: The last byte.
-     *
-     * Precondition: $(D_INLINECODE !empty).
-     */
-    @property ref inout(char) back() inout pure nothrow @trusted @nogc
     in
     {
-        assert(!empty);
+        assert(i <= j);
+        assert(j <= length);
     }
     body
     {
-        return *(this.data + length - 1);
+        return typeof(return)(this, this.data + i, this.data + j);
     }
 
     ///
     unittest
     {
-        auto s = String("Caesar");
+        auto s = String("Vladimir Soloviev");
-        assert(s.back == 'r');
+        auto r = s[9 .. $];
+
+        assert(r.front == 'S');
+        assert(r.back == 'v');
+
+        r.popFront();
+        r.popBack();
+        assert(r.front == 'o');
+        assert(r.back == 'e');
+
+        r.popFront();
+        r.popBack();
+        assert(r.front == 'l');
+        assert(r.back == 'i');
+
+        r.popFront();
+        r.popBack();
+        assert(r.front == 'o');
+        assert(r.back == 'v');
+
+        r.popFront();
+        r.popBack();
+        assert(r.empty);
     }
 
     mixin DefaultAllocator;