[libgsf] Utils: Ensure GSF_LE_SET_GU?INT{16, 32, 64} do not depend on C implementation

[Morten Welinder <mortenw src gnome org>]

commit bfec34e0ea1ecc76aa44d593ab2b0e2677f1e63f
Author: Morten Welinder <terra gnome org>
Date:   Mon Dec 1 17:25:57 2014 -0500

    Utils: Ensure GSF_LE_SET_GU?INT{16,32,64} do not depend on C implementation
    
    Shifting negative values to the right is implementation defined.

 ChangeLog             |    4 ++++
 NEWS                  |    1 +
 gsf/gsf-outfile-zip.c |    2 +-
 gsf/gsf-utils.h       |   32 ++++++++++++++++----------------
 4 files changed, 22 insertions(+), 17 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 34a06ad..8429c20 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,10 @@
 
 2014-11-30  Morten Welinder  <terra gnome org>
 
+       * gsf/gsf-utils.h (GSF_LE_SET_GU?INT{16,32,64}): Add casts to make
+       things more function-like and avoid implementation defined
+       behaviour.
+
        * gsf/gsf-outfile-zip.c (zip_dirent_write): The the archive is in
        auto mode and the member is not using a zip64 extra field, use an
        IGNORE extra field to work around known zipinfo bug.
diff --git a/NEWS b/NEWS
index c145ef0..389a601 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,7 @@ Morten:
        * Write zip archives with more than 64k+ members.
        * Store unix modtime in zip.  (Until that overflows.)
        * Fix seekability checks in GsfOutputIOChannel.
+       * Avoid implementation defined behaviour of shifts.
 
 --------------------------------------------------------------------------
 libgsf 1.14.30
diff --git a/gsf/gsf-outfile-zip.c b/gsf/gsf-outfile-zip.c
index ecfe7d8..4e921a0 100644
--- a/gsf/gsf-outfile-zip.c
+++ b/gsf/gsf-outfile-zip.c
@@ -170,7 +170,7 @@ zip_dirent_write (GsfOutfileZip *zip, const GsfZipDirent *dirent)
                char tmp[8];
 
                /*
-                * We could unconditinally store the offset here, but
+                * We could unconditionally store the offset here, but
                 * zipinfo has a known bug in which it fails to account
                 * for differences in extra fields between the global
                 * and the local headers.  So we try to make them the
diff --git a/gsf/gsf-utils.h b/gsf/gsf-utils.h
index 01b53e1..359c445 100644
--- a/gsf/gsf-utils.h
+++ b/gsf/gsf-utils.h
@@ -155,9 +155,9 @@ double  gsf_le_get_double  (void const *p);
  *
  * Store @dat in little endian order in memory pointed to by @p.
  */
-#define GSF_LE_SET_GUINT16(p, dat)                     \
-       ((*((guint8 *)(p) + 0) = ((dat)        & 0xff)),\
-        (*((guint8 *)(p) + 1) = ((dat) >>  8) & 0xff))
+#define GSF_LE_SET_GUINT16(p, dat)                                     \
+       ((*((guint8 *)(p) + 0) = (guint8)((guint16)(dat))       & 0xff), \
+        (*((guint8 *)(p) + 1) = (guint8)((guint16)(dat) >>  8) & 0xff))
 
 /**
  * GSF_LE_SET_GUINT32:
@@ -166,11 +166,11 @@ double  gsf_le_get_double  (void const *p);
  *
  * Store @dat in little endian order in memory pointed to by @p.
  */
-#define GSF_LE_SET_GUINT32(p, dat)                             \
-       ((*((guint8 *)(p) + 0) = (guchar) ((dat))       & 0xff),        \
-        (*((guint8 *)(p) + 1) = (guchar) ((dat) >>  8) & 0xff),        \
-        (*((guint8 *)(p) + 2) = (guchar) ((dat) >> 16) & 0xff),        \
-        (*((guint8 *)(p) + 3) = (guchar) ((dat) >> 24) & 0xff))
+#define GSF_LE_SET_GUINT32(p, dat)                                     \
+       ((*((guint8 *)(p) + 0) = (guint8)((guint32)(dat))       & 0xff), \
+        (*((guint8 *)(p) + 1) = (guint8)((guint32)(dat) >>  8) & 0xff), \
+        (*((guint8 *)(p) + 2) = (guint8)((guint32)(dat) >> 16) & 0xff), \
+        (*((guint8 *)(p) + 3) = (guint8)((guint32)(dat) >> 24) & 0xff))
 
 /**
  * GSF_LE_SET_GUINT64:
@@ -180,14 +180,14 @@ double  gsf_le_get_double  (void const *p);
  * Store @dat in little endian order in memory pointed to by @p.
  */
 #define GSF_LE_SET_GUINT64(p, dat)                     \
-       ((*((guint8 *)(p) + 0) = (guchar) ((dat))       & 0xff),        \
-        (*((guint8 *)(p) + 1) = (guchar) ((dat) >>  8) & 0xff),        \
-        (*((guint8 *)(p) + 2) = (guchar) ((dat) >> 16) & 0xff),        \
-        (*((guint8 *)(p) + 3) = (guchar) ((dat) >> 24) & 0xff),        \
-        (*((guint8 *)(p) + 4) = (guchar) ((dat) >> 32) & 0xff),        \
-        (*((guint8 *)(p) + 5) = (guchar) ((dat) >> 40) & 0xff),        \
-        (*((guint8 *)(p) + 6) = (guchar) ((dat) >> 48) & 0xff),        \
-        (*((guint8 *)(p) + 7) = (guchar) ((dat) >> 56) & 0xff))
+       ((*((guint8 *)(p) + 0) = (guint8)((guint64)(dat))       & 0xff), \
+        (*((guint8 *)(p) + 1) = (guint8)((guint64)(dat) >>  8) & 0xff), \
+        (*((guint8 *)(p) + 2) = (guint8)((guint64)(dat) >> 16) & 0xff), \
+        (*((guint8 *)(p) + 3) = (guint8)((guint64)(dat) >> 24) & 0xff), \
+        (*((guint8 *)(p) + 4) = (guint8)((guint64)(dat) >> 32) & 0xff), \
+        (*((guint8 *)(p) + 5) = (guint8)((guint64)(dat) >> 40) & 0xff), \
+        (*((guint8 *)(p) + 6) = (guint8)((guint64)(dat) >> 48) & 0xff), \
+        (*((guint8 *)(p) + 7) = (guint8)((guint64)(dat) >> 56) & 0xff))
 
 /**
  * GSF_LE_SET_GINT8: