Implement QIODevice::peek() using read() + ungetBlock().

The previous implementation was doing ungetChar() in a loop.

Task-number: QTBUG-9654
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
Reviewed-by: mread

1 files changed, 9 insertions, 0 deletions

diff --git a/src/corelib/io/qiodevice_p.h b/src/corelib/io/qiodevice_p.h
index 94dadca76d..225a0b90a2 100644
--- a/src/corelib/io/qiodevice_p.h
+++ b/src/corelib/io/qiodevice_p.h
@@ -151,6 +151,15 @@ public:
         len++;
         *first = c;
     }
+    void ungetBlock(const char* block, int size) {
+        if ((first - buf) < size) {
+            // underflow, the existing valid data needs to move to the end of the (potentially bigger) buffer
+            makeSpace(len + size, freeSpaceAtStart);
+            memcpy(first - size, block, size);
+        }
+        first -= size;
+        len += size;
+    }
 
 private:
     enum FreeSpacePos {freeSpaceAtStart, freeSpaceAtEnd};