[pypy-commit] pypy faster-rstruct: fix runpack('d') on win32 and 32bit ARM. I tried to keep the fix and the implementation as least invasive as possible, because it will go away as soon as we have gc_load; but in the meantime, this fixes it with reasonable performance

[antocuni]

Author: Antonio Cuni <anto.cuni at gmail.com>
Branch: faster-rstruct
Changeset: r80871:59a4b706d487
Date: 2015-11-23 21:37 +0100
http://bitbucket.org/pypy/pypy/changeset/59a4b706d487/

Log:	fix runpack('d') on win32 and 32bit ARM. I tried to keep the fix and
	the implementation as least invasive as possible, because it will go
	away as soon as we have gc_load; but in the meantime, this fixes it
	with reasonable performance

diff --git a/rpython/rlib/rstruct/standardfmttable.py b/rpython/rlib/rstruct/standardfmttable.py
--- a/rpython/rlib/rstruct/standardfmttable.py
+++ b/rpython/rlib/rstruct/standardfmttable.py
@@ -185,6 +185,13 @@
             data = fmtiter.read(size)
             fmtiter.appendobj(ieee.unpack_float(data, fmtiter.bigendian))
             return
+        if not str_storage_supported(TYPE):
+            # this happens e.g. on win32 and ARM32: we cannot read the string
+            # content as an array of doubles because it's not properly
+            # aligned. But we can read a longlong and convert to float
+            assert TYPE == rffi.DOUBLE
+            assert rffi.sizeof(TYPE) == 8
+            return unpack_longlong2float(fmtiter)
         try:
             # fast path
             val = unpack_fastpath(TYPE)(fmtiter)
@@ -195,6 +202,16 @@
         fmtiter.appendobj(float(val))
     return unpack_ieee
 
+ at specialize.argtype(0)
+def unpack_longlong2float(fmtiter):
+    from rpython.rlib.rstruct.runpack import runpack
+    from rpython.rlib.longlong2float import longlong2float
+    s = fmtiter.read(8)
+    llval = runpack('q', s) # this is a bit recursive, I know
+    doubleval = longlong2float(llval)
+    fmtiter.appendobj(doubleval)
+
+
 unpack_double = make_ieee_unpacker(rffi.DOUBLE)
 unpack_float = make_ieee_unpacker(rffi.FLOAT)