--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libcxx/src/strstream.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,335 @@
+//===------------------------ strstream.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "strstream"
+#include "algorithm"
+#include "climits"
+#include "cstring"
+#include "cstdlib"
+#include "__debug"
+#include "__undef_macros"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+strstreambuf::strstreambuf(streamsize __alsize)
+    : __strmode_(__dynamic),
+      __alsize_(__alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+}
+
+strstreambuf::strstreambuf(void* (*__palloc)(size_t), void (*__pfree)(void*))
+    : __strmode_(__dynamic),
+      __alsize_(__default_alsize),
+      __palloc_(__palloc),
+      __pfree_(__pfree)
+{
+}
+
+void
+strstreambuf::__init(char* __gnext, streamsize __n, char* __pbeg)
+{
+    if (__n == 0)
+        __n = static_cast<streamsize>(strlen(__gnext));
+    else if (__n < 0)
+        __n = INT_MAX;
+    if (__pbeg == nullptr)
+        setg(__gnext, __gnext, __gnext + __n);
+    else
+    {
+        setg(__gnext, __gnext, __pbeg);
+        setp(__pbeg, __pbeg + __n);
+    }
+}
+
+strstreambuf::strstreambuf(char* __gnext, streamsize __n, char* __pbeg)
+    : __strmode_(),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(__gnext, __n, __pbeg);
+}
+
+strstreambuf::strstreambuf(const char* __gnext, streamsize __n)
+    : __strmode_(__constant),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(__gnext), __n, nullptr);
+}
+
+strstreambuf::strstreambuf(signed char* __gnext, streamsize __n, signed char* __pbeg)
+    : __strmode_(),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, reinterpret_cast<char*>(__pbeg));
+}
+
+strstreambuf::strstreambuf(const signed char* __gnext, streamsize __n)
+    : __strmode_(__constant),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, nullptr);
+}
+
+strstreambuf::strstreambuf(unsigned char* __gnext, streamsize __n, unsigned char* __pbeg)
+    : __strmode_(),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, reinterpret_cast<char*>(__pbeg));
+}
+
+strstreambuf::strstreambuf(const unsigned char* __gnext, streamsize __n)
+    : __strmode_(__constant),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, nullptr);
+}
+
+strstreambuf::~strstreambuf()
+{
+    if (eback() && (__strmode_ & __allocated) != 0 && (__strmode_ & __frozen) == 0)
+    {
+        if (__pfree_)
+            __pfree_(eback());
+        else
+            delete [] eback();
+    }
+}
+
+void
+strstreambuf::swap(strstreambuf& __rhs)
+{
+    streambuf::swap(__rhs);
+    _VSTD::swap(__strmode_, __rhs.__strmode_);
+    _VSTD::swap(__alsize_, __rhs.__alsize_);
+    _VSTD::swap(__palloc_, __rhs.__palloc_);
+    _VSTD::swap(__pfree_, __rhs.__pfree_);
+}
+
+void
+strstreambuf::freeze(bool __freezefl)
+{
+    if (__strmode_ & __dynamic)
+    {
+        if (__freezefl)
+            __strmode_ |= __frozen;
+        else
+            __strmode_ &= ~__frozen;
+    }
+}
+
+char*
+strstreambuf::str()
+{
+    if (__strmode_ & __dynamic)
+        __strmode_ |= __frozen;
+    return eback();
+}
+
+int
+strstreambuf::pcount() const
+{
+    return static_cast<int>(pptr() - pbase());
+}
+
+strstreambuf::int_type
+strstreambuf::overflow(int_type __c)
+{
+    if (__c == EOF)
+        return int_type(0);
+    if (pptr() == epptr())
+    {
+        if ((__strmode_ & __dynamic) == 0 || (__strmode_ & __frozen) != 0)
+            return int_type(EOF);
+        size_t old_size = static_cast<size_t> ((epptr() ? epptr() : egptr()) - eback());
+        size_t new_size = max<size_t>(static_cast<size_t>(__alsize_), 2*old_size);
+        if (new_size == 0)
+            new_size = __default_alsize;
+        char* buf = nullptr;
+        if (__palloc_)
+            buf = static_cast<char*>(__palloc_(new_size));
+        else
+            buf = new char[new_size];
+        if (buf == nullptr)
+            return int_type(EOF);
+        if (old_size != 0) {
+            _LIBCPP_ASSERT(eback(), "overflow copying from NULL");
+            memcpy(buf, eback(), static_cast<size_t>(old_size));
+        }
+        ptrdiff_t ninp = gptr()  - eback();
+        ptrdiff_t einp = egptr() - eback();
+        ptrdiff_t nout = pptr()  - pbase();
+        if (__strmode_ & __allocated)
+        {
+            if (__pfree_)
+                __pfree_(eback());
+            else
+                delete [] eback();
+        }
+        setg(buf, buf + ninp, buf + einp);
+        setp(buf + einp, buf + new_size);
+        __pbump(nout);
+        __strmode_ |= __allocated;
+    }
+    *pptr() = static_cast<char>(__c);
+    pbump(1);
+    return int_type(static_cast<unsigned char>(__c));
+}
+
+strstreambuf::int_type
+strstreambuf::pbackfail(int_type __c)
+{
+    if (eback() == gptr())
+        return EOF;
+    if (__c == EOF)
+    {
+        gbump(-1);
+        return int_type(0);
+    }
+    if (__strmode_ & __constant)
+    {
+        if (gptr()[-1] == static_cast<char>(__c))
+        {
+            gbump(-1);
+            return __c;
+        }
+        return EOF;
+    }
+    gbump(-1);
+    *gptr() = static_cast<char>(__c);
+    return __c;
+}
+
+strstreambuf::int_type
+strstreambuf::underflow()
+{
+    if (gptr() == egptr())
+    {
+        if (egptr() >= pptr())
+            return EOF;
+        setg(eback(), gptr(), pptr());
+    }
+    return int_type(static_cast<unsigned char>(*gptr()));
+}
+
+strstreambuf::pos_type
+strstreambuf::seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __which)
+{
+    off_type __p(-1);
+    bool pos_in = (__which & ios::in) != 0;
+    bool pos_out = (__which & ios::out) != 0;
+    bool legal = false;
+    switch (__way)
+    {
+    case ios::beg:
+    case ios::end:
+        if (pos_in || pos_out)
+            legal = true;
+        break;
+    case ios::cur:
+        if (pos_in != pos_out)
+            legal = true;
+        break;
+    }
+    if (pos_in && gptr() == nullptr)
+        legal = false;
+    if (pos_out && pptr() == nullptr)
+        legal = false;
+    if (legal)
+    {
+        off_type newoff;
+        char* seekhigh = epptr() ? epptr() : egptr();
+        switch (__way)
+        {
+        case ios::beg:
+            newoff = 0;
+            break;
+        case ios::cur:
+            newoff = (pos_in ? gptr() : pptr()) - eback();
+            break;
+        case ios::end:
+            newoff = seekhigh - eback();
+            break;
+        default:
+            _LIBCPP_UNREACHABLE();
+        }
+        newoff += __off;
+        if (0 <= newoff && newoff <= seekhigh - eback())
+        {
+            char* newpos = eback() + newoff;
+            if (pos_in)
+                setg(eback(), newpos, _VSTD::max(newpos, egptr()));
+            if (pos_out)
+            {
+                // min(pbase, newpos), newpos, epptr()
+                __off = epptr() - newpos;
+                setp(min(pbase(), newpos), epptr());
+                __pbump((epptr() - pbase()) - __off);
+            }
+            __p = newoff;
+        }
+    }
+    return pos_type(__p);
+}
+
+strstreambuf::pos_type
+strstreambuf::seekpos(pos_type __sp, ios_base::openmode __which)
+{
+    off_type __p(-1);
+    bool pos_in = (__which & ios::in) != 0;
+    bool pos_out = (__which & ios::out) != 0;
+    if (pos_in || pos_out)
+    {
+        if (!((pos_in && gptr() == nullptr) || (pos_out && pptr() == nullptr)))
+        {
+            off_type newoff = __sp;
+            char* seekhigh = epptr() ? epptr() : egptr();
+            if (0 <= newoff && newoff <= seekhigh - eback())
+            {
+                char* newpos = eback() + newoff;
+                if (pos_in)
+                    setg(eback(), newpos, _VSTD::max(newpos, egptr()));
+                if (pos_out)
+                {
+                    // min(pbase, newpos), newpos, epptr()
+                    off_type temp = epptr() - newpos;
+                    setp(min(pbase(), newpos), epptr());
+                    __pbump((epptr() - pbase()) - temp);
+                }
+                __p = newoff;
+            }
+        }
+    }
+    return pos_type(__p);
+}
+
+istrstream::~istrstream()
+{
+}
+
+ostrstream::~ostrstream()
+{
+}
+
+strstream::~strstream()
+{
+}
+
+_LIBCPP_END_NAMESPACE_STD