Added MMap Handle object.

2 files changed, 118 insertions, 3 deletions

diff --git a/src/Buffer.cc b/src/Buffer.cc
index 42dbd52..b4dfbec 100644
--- a/src/Buffer.cc
+++ b/src/Buffer.cc
@@ -60,14 +60,29 @@ ssize_t Balau::Buffer::write(const void * buf, size_t count) throw (GeneralExcep
 }
 
 void Balau::Buffer::reset() {
-    if (!m_fromConst)
-        m_buffer = (uint8_t *) realloc(m_buffer, 0);
-    m_bufSize = 0;
+    if (!m_fromConst) {
+        m_buffer = (uint8_t *)realloc(m_buffer, 0);
+        m_bufSize = 0;
+    }
     m_numBlocks = 0;
     wseek(0);
     rseek(0);
 }
 
+void Balau::Buffer::clear() {
+    reset();
+    m_fromConst = false;
+    m_buffer = NULL;
+    m_bufSize = 0;
+}
+
+void Balau::Buffer::borrow(const uint8_t * buffer, size_t s) {
+    clear();
+    m_fromConst = true;
+    m_buffer = const_cast<uint8_t *>(buffer);
+    m_bufSize = s;
+}
+
 bool Balau::Buffer::isClosed() { return false; }
 bool Balau::Buffer::isEOF() { return rtell() == m_bufSize; }
 const char * Balau::Buffer::getName() { return "Buffer"; }
diff --git a/src/MMap.cc b/src/MMap.cc
new file mode 100644
index 0000000..18187b4
--- /dev/null
+++ b/src/MMap.cc
@@ -0,0 +1,100 @@
+#include <MMap.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+namespace Balau {
+
+#ifdef _WIN32
+
+class MMapPlatform {
+  public:
+    std::tuple<bool, const uint8_t *, size_t> open(String fname) {
+        bool result = false;
+        size_t s = 0;
+        TCHAR * fnameTchar;
+#ifdef UNICODE
+        fname.do_iconv("UTF-8", "UNICODELITTLE");
+        fnameTchar = (TCHAR *) alloca(fname.strlen() + 2);
+        memset(fnameTchar, 0, fname.strlen() + 2);
+        memcpy(fnameTchar, fname.to_charp(), fname.strlen());
+#else
+        fnameTchar = fname.to_charp();
+#endif
+
+        m_handle = CreateFile(fnameTchar, GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);
+
+        if (m_handle == INVALID_HANDLE_VALUE)
+            return std::tie(result, m_ptr, s);
+
+        ScopedLambda hc([&]() { if (!result) CloseHandle(m_handle); });
+
+        LARGE_INTEGER fsize;
+        if (!GetFileSizeEx(m_handle, (PLARGE_INTEGER) &fsize))
+            return std::tie(result, m_ptr, s);
+
+        s = fsize.QuadPart;
+
+        m_mapObject = CreateFileMapping(m_handle, 0, PAGE_READONLY, fsize.HighPart, fsize.LowPart, NULL);
+
+        if (m_mapObject == NULL)             // right, because getting NULL (which is 0) is better 
+            return std::tie(result, m_ptr, s); // than getting the usual INVALID_HANDLE_VALUE (which is -1),
+                                             // in order to make a sane and uniform API...
+        {
+            ScopedLambda mc([&]() { if (!result) CloseHandle(m_mapObject); });
+
+            // and of course, CreateFileMapping takes the 64 bits size in high / low format,
+            // whereas MapViewOfFile takes the 64 bits size in a single 64 bits size_t. Sure. Makes sense.
+            m_ptr = (const uint8_t *)MapViewOfFile(m_mapObject, FILE_MAP_READ, 0, 0, s);
+
+            result = !!m_ptr;
+        }
+
+        return std::tie(result, m_ptr, s);
+    }
+    void close() {
+        if (m_ptr)
+            UnmapViewOfFile(m_ptr);
+        if (m_mapObject)
+            CloseHandle(m_mapObject);
+        if (m_handle != INVALID_HANDLE_VALUE)
+            CloseHandle(m_handle);
+        m_ptr = NULL;
+        m_mapObject = (HANDLE) NULL;
+        m_handle = INVALID_HANDLE_VALUE;
+    }
+    HANDLE m_handle = INVALID_HANDLE_VALUE;
+    HANDLE m_mapObject = (HANDLE) NULL; // see comment above
+    const uint8_t * m_ptr = NULL;
+};
+
+#endif
+
+};
+
+Balau::MMap::MMap(const char * fname) {
+    m_fname = fname;
+    m_name.set("mmap of %s", m_fname);
+    m_platform = new MMapPlatform();
+}
+
+void Balau::MMap::open() {
+    bool result;
+    const uint8_t * ptr;
+    size_t s;
+    std::tie(result, ptr, s) = m_platform->open(m_fname);
+    if (!result)
+        throw GeneralException("Unable to map file");
+
+    borrow(ptr, s);
+}
+
+void Balau::MMap::close() {
+    m_platform->close();
+    Buffer::close();
+}
+
+Balau::MMap::~MMap() {
+    delete m_platform;
+}