Changeset 46245 in vbox

Timestamp:

May 23, 2013 7:15:19 PM (12 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

85974

Message:

Runtime: RTFileSg{Read|Write}At API

Location:

trunk

Files:

• include/iprt/file.h (modified) (3 diffs)
• src/VBox/Runtime/r3/fileio.cpp (modified) (2 diffs)

trunk/include/iprt/file.h

@@ -31 +31 @@
 #include <iprt/stdarg.h>
 #include <iprt/fs.h>
+#include <iprt/sg.h>
 
 RT_C_DECLS_BEGIN
@@ -382 +383 @@
 
 /**
+ * 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.
+ */
+RTDECL(int)  RTFileSgReadAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToRead, size_t *pcbRead);
+
+/**
  * Write bytes to a file.
  *
@@ -406 +421 @@
  */
 RTDECL(int)  RTFileWriteAt(RTFILE File, RTFOFF off, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten);
+
+/**
+ * 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.
+ */
+RTDECL(int)  RTFileSgWriteAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToWrite, size_t *pcbWritten);
 
 /**

trunk/src/VBox/Runtime/r3/fileio.cpp

@@ -209 +209 @@
 
 /**
+ * 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;
+    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)
+            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.
@@ -225 +267 @@
     if (RT_SUCCESS(rc))
         rc = RTFileWrite(File, pvBuf, cbToWrite, pcbWritten);
+    return rc;
+}
+
+
+/**
+ * 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;
+    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)
+            break;
+
+        cbToWrite -= cbBuf;
+        off += cbBuf;
+    }
+
+    if (pcbWritten)
+        *pcbWritten = cbWritten;
+
     return rc;
 }