Changeset 28113 in vbox

Timestamp:

Apr 8, 2010 8:11:33 PM (15 years ago)

Author:

vboxsync

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

59831

Message:

Runtime/Sg: Add a method to advance the internal buffer pointer

Location:

trunk

Files:

• include/iprt/sg.h (modified) (1 diff)
• src/VBox/Runtime/common/misc/sg.cpp (modified) (1 diff)

trunk/include/iprt/sg.h

@@ -169 +169 @@
 
 /**
+ * Advances the internal buffer pointer.
+ *
+ * @returns Number of bytes the pointer was moved forward.
+ * @param   pSgBuf      The S/G buffer.
+ * @param   cbAdvance   Number of bytes to move forward.
+ */
+RTDECL(size_t) RTSgBufAdvance(PRTSGBUF pSgBuf, size_t cbAdvance);
+
+/**
  * Constructs a new segment array starting from the current position
  * and describing the given number of bytes.

trunk/src/VBox/Runtime/common/misc/sg.cpp

@@ -250 +250 @@
 
 
+RTDECL(size_t) RTSgBufAdvance(PRTSGBUF pSgBuf, size_t cbAdvance)
+{
+    AssertPtrReturn(pSgBuf, 0);
+
+    size_t cbLeft = cbAdvance;
+
+    while (cbLeft)
+    {
+        size_t cbThisAdvance = cbLeft;
+        void *pv = sgBufGet(pSgBuf, &cbThisAdvance);
+
+        NOREF(pv);
+
+        if (!cbThisAdvance)
+            break;
+
+        cbLeft -= cbThisAdvance;
+    }
+
+    return cbAdvance - cbLeft;
+}
+
+
 RTDECL(size_t) RTSgBufSegArrayCreate(PRTSGBUF pSgBuf, PRTSGSEG paSeg, unsigned *pcSeg, size_t cbData)
 {