1 files changed, 87 insertions, 1 deletions
diff --git a/src/VBox/Runtime/r3/fileio.cpp b/src/VBox/Runtime/r3/fileio.cpp
index 5b4e8873..fd1a2898 100644
--- a/src/VBox/Runtime/r3/fileio.cpp
+++ b/src/VBox/Runtime/r3/fileio.cpp
@@ -4,7 +4,7 @@
  */
 
 /*
- * Copyright (C) 2006-2007 Oracle Corporation
+ * Copyright (C) 2006-2011 Oracle Corporation
  *
  * This file is part of VirtualBox Open Source Edition (OSE), as
  * available from http://www.virtualbox.org. This file is free software;
@@ -208,6 +208,49 @@ RTR3DECL(int)  RTFileReadAt(RTFILE File, RTFOFF off, void *pvBuf, size_t cbToRea
 
 
 /**
+ * Read bytes from a file at a given offset into a S/G buffer.
+ * This function may modify the file position.
+ *
+ * @returns iprt status code.
+ * @param   hFile       Handle to the file.
+ * @param   off         Where to read.
+ * @param   pSgBuf      Pointer to the S/G buffer to read into.
+ * @param   cbToRead    How much to read.
+ * @param   pcbRead     How much we actually read.
+ *                      If NULL an error will be returned for a partial read.
+ */
+RTR3DECL(int)  RTFileSgReadAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToRead, size_t *pcbRead)
+{
+    int rc = VINF_SUCCESS;
+    size_t cbRead = 0;
+
+    while (cbToRead)
+    {
+        size_t cbThisRead = 0;
+        size_t cbBuf = cbToRead;
+        void *pvBuf = RTSgBufGetNextSegment(pSgBuf, &cbBuf);
+
+        rc = RTFileReadAt(hFile, off, pvBuf, cbBuf, pcbRead ? &cbThisRead : NULL);
+        if (RT_SUCCESS(rc))
+            cbRead += cbThisRead;
+
+        if (   RT_FAILURE(rc)
+            || (   cbThisRead < cbBuf
+                && pcbRead))
+            break;
+
+        cbToRead -= cbBuf;
+        off += cbBuf;
+    }
+
+    if (pcbRead)
+        *pcbRead = cbRead;
+
+    return rc;
+}
+
+
+/**
  * Write bytes to a file at a given offset.
  * This function may modify the file position.
  *
@@ -229,6 +272,49 @@ RTR3DECL(int)  RTFileWriteAt(RTFILE File, RTFOFF off, const void *pvBuf, size_t
 
 
 /**
+ * Write bytes from a S/G buffer to a file at a given offset.
+ * This function may modify the file position.
+ *
+ * @returns iprt status code.
+ * @param   hFile       Handle to the file.
+ * @param   off         Where to write.
+ * @param   pSgBuf      What to write.
+ * @param   cbToWrite   How much to write.
+ * @param   pcbWritten  How much we actually wrote.
+ *                      If NULL an error will be returned for a partial write.
+ */
+RTR3DECL(int)  RTFileSgWriteAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    int rc = VINF_SUCCESS;
+    size_t cbWritten = 0;
+
+    while (cbToWrite)
+    {
+        size_t cbThisWritten = 0;
+        size_t cbBuf = cbToWrite;
+        void *pvBuf = RTSgBufGetNextSegment(pSgBuf, &cbBuf);
+
+        rc = RTFileWriteAt(hFile, off, pvBuf, cbBuf, pcbWritten ? &cbThisWritten : NULL);
+        if (RT_SUCCESS(rc))
+            cbWritten += cbThisWritten;
+
+        if (   RT_FAILURE(rc)
+            || (   cbThisWritten < cbBuf
+                && pcbWritten))
+            break;
+
+        cbToWrite -= cbBuf;
+        off += cbBuf;
+    }
+
+    if (pcbWritten)
+        *pcbWritten = cbWritten;
+
+    return rc;
+}
+
+
+/**
  * Gets the current file position.
  *
  * @returns File offset.