IMdkit-property-offset-cache.patch

diff --git a/util/IMdkit/Makefile.am b/util/IMdkit/Makefile.am
index e3946d7..8a3714c 100644
--- a/util/IMdkit/Makefile.am
+++ b/util/IMdkit/Makefile.am
@@ -29,6 +29,7 @@ libIMdkit_la_SOURCES = \
 	i18nIc.c \
 	i18nIMProto.c \
 	i18nMethod.c \
+	i18nOffsetCache.c \
 	i18nPtHdr.c \
 	i18nUtil.c \
 	i18nX.c \
diff --git a/util/IMdkit/Xi18n.h b/util/IMdkit/Xi18n.h
index 484cc62..e9d3426 100644
--- a/util/IMdkit/Xi18n.h
+++ b/util/IMdkit/Xi18n.h
@@ -45,6 +45,7 @@ IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #define XIM_EXT_MOVE				(0x33)
 #define COMMON_EXTENSIONS_NUM   		3
 
+#include <stddef.h>
 #include <stdlib.h>
 #include "IMdkit.h"
 
@@ -138,6 +139,19 @@ typedef struct
     char	*name;
 } XIMExt;
 
+typedef struct
+{
+    Atom key;
+    unsigned long offset;
+} Xi18nAtomOffsetPair;
+
+typedef struct
+{
+    size_t capacity;
+    size_t size;
+    Xi18nAtomOffsetPair *data;
+} Xi18nOffsetCache;
+
 typedef struct _Xi18nClient
 {
     int		connect_id;
@@ -149,8 +163,7 @@ typedef struct _Xi18nClient
      */
     int		sync;
     XIMPending  *pending;
-    /* property offset to read next data */
-    long        property_offset;
+    Xi18nOffsetCache offset_cache;
     void *trans_rec;		/* contains transport specific data  */
     struct _Xi18nClient *next;
 } Xi18nClient;
diff --git a/util/IMdkit/i18nOffsetCache.c b/util/IMdkit/i18nOffsetCache.c
new file mode 100644
index 0000000..da289c1
--- /dev/null
+++ b/util/IMdkit/i18nOffsetCache.c
@@ -0,0 +1,67 @@
+#include <X11/Xlib.h>
+#include <stddef.h>
+#include "IMdkit.h"
+#include "Xi18n.h"
+
+/*
+* The XIM specification does not limit the number of window properties
+* that can be used to transfer data, but Xlib uses the atom strings
+* _client0 through _client20.
+*
+* So use that as a sensible initial size for the offset cache.
+*/
+#define INITIAL_OFFSET_CACHE_CAPACITY 21
+#define OFFSET_CACHE_GROWTH_FACTOR 2
+
+void _Xi18nInitOffsetCache(Xi18nOffsetCache *offset_cache)
+{
+    offset_cache->size = 0;
+    offset_cache->capacity = INITIAL_OFFSET_CACHE_CAPACITY;
+    offset_cache->data = (Xi18nAtomOffsetPair *)malloc(
+        INITIAL_OFFSET_CACHE_CAPACITY * sizeof(Xi18nAtomOffsetPair));
+}
+
+unsigned long _Xi18nLookupPropertyOffset(Xi18nOffsetCache *offset_cache,
+                                         Atom key)
+{
+    Xi18nAtomOffsetPair *data = offset_cache->data;
+    size_t i;
+
+    for (i = 0; i < offset_cache->size; ++i)
+    {
+        if (data[i].key == key)
+        {
+            return data[i].offset;
+        }
+    }
+
+    return 0;
+}
+
+void _Xi18nSetPropertyOffset(Xi18nOffsetCache *offset_cache, Atom key,
+                             unsigned long offset)
+{
+    Xi18nAtomOffsetPair *data = offset_cache->data;
+    size_t i;
+
+    for (i = 0; i < offset_cache->size; ++i)
+    {
+        if (data[i].key == key)
+        {
+            data[i].offset = offset;
+            return;
+        }
+    }
+
+    if (++offset_cache->size > offset_cache->capacity)
+    {
+        offset_cache->capacity *= OFFSET_CACHE_GROWTH_FACTOR;
+        data = (Xi18nAtomOffsetPair *)realloc(data,
+                offset_cache->capacity * sizeof(Xi18nAtomOffsetPair));
+        offset_cache->data = data;
+    }
+
+    data[i].key = key;
+    data[i].offset = offset;
+}
+
diff --git a/util/IMdkit/i18nUtil.c b/util/IMdkit/i18nUtil.c
index c07de48..e04e290 100644
--- a/util/IMdkit/i18nUtil.c
+++ b/util/IMdkit/i18nUtil.c
@@ -36,6 +36,7 @@ IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "XimFunc.h"
 
 Xi18nClient *_Xi18nFindClient (Xi18n, CARD16);
+void _Xi18nInitOffsetCache(Xi18nOffsetCache *);
 
 int
 _Xi18nNeedSwap (Xi18n i18n_core, CARD16 connect_id)
@@ -70,7 +71,7 @@ Xi18nClient *_Xi18nNewClient(Xi18n i18n_core)
     client->sync = False;
     client->byte_order = '?'; 	/* initial value */
     memset (&client->pending, 0, sizeof (XIMPending *));
-    client->property_offset = 0;
+    _Xi18nInitOffsetCache(&client->offset_cache);
     client->next = i18n_core->address.clients;
     i18n_core->address.clients = client;
 
diff --git a/util/IMdkit/i18nX.c b/util/IMdkit/i18nX.c
index 0a54058..98e1bcc 100644
--- a/util/IMdkit/i18nX.c
+++ b/util/IMdkit/i18nX.c
@@ -29,6 +29,7 @@ IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 ******************************************************************/
 
+#include <stddef.h>
 #include <limits.h>
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>
@@ -41,6 +42,8 @@ IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern Xi18nClient *_Xi18nFindClient(Xi18n, CARD16);
 extern Xi18nClient *_Xi18nNewClient(Xi18n);
 extern void _Xi18nDeleteClient(Xi18n, CARD16);
+extern unsigned long _Xi18nLookupPropertyOffset(Xi18nOffsetCache *, Atom);
+extern void _Xi18nSetPropertyOffset(Xi18nOffsetCache *, Atom, unsigned long);
 static Bool WaitXConnectMessage(Display*, Window,
                                 XEvent*, XPointer);
 static Bool WaitXIMProtocol(Display*, Window, XEvent*, XPointer);
@@ -129,7 +132,6 @@ static unsigned char *ReadXIMMessage (XIMS ims,
     else if (ev->format == 32) {
         /* ClientMessage and WindowProperty */
         unsigned long length = (unsigned long) ev->data.l[0];
-        unsigned long get_length;
         Atom atom = (Atom) ev->data.l[1];
         int return_code;
         Atom actual_type_ret;
@@ -137,21 +139,28 @@ static unsigned char *ReadXIMMessage (XIMS ims,
         unsigned long bytes_after_ret;
         unsigned char *prop;
         unsigned long nitems;
-
-        /* Round up length to next 4 byte value. */
-        get_length = length + 3;
-        if (get_length > LONG_MAX)
-            get_length = LONG_MAX;
-        get_length /= 4;
-        if (get_length == 0) {
-            fprintf(stderr, "%s: invalid length 0\n", __func__);
+        Xi18nOffsetCache *offset_cache = &client->offset_cache;
+        unsigned long offset;
+        unsigned long end;
+        unsigned long long_begin;
+        unsigned long long_end;
+
+        if (length == 0) {
+            fprintf (stderr, "%s: invalid length 0\n", __func__);
             return NULL;
         }
+
+        offset = _Xi18nLookupPropertyOffset (offset_cache, atom);
+        end = offset + length;
+
+        /* The property data is retrieved in 32-bit chunks */
+        long_begin = offset / 4;
+        long_end = (end + 3) / 4;
         return_code = XGetWindowProperty (i18n_core->address.dpy,
                                           x_client->accept_win,
                                           atom,
-                                          client->property_offset / 4,
-                                          get_length,
+                                          long_begin,
+                                          long_end - long_begin,
                                           True,
                                           AnyPropertyType,
                                           &actual_type_ret,
@@ -162,32 +171,22 @@ static unsigned char *ReadXIMMessage (XIMS ims,
         if (return_code != Success || actual_format_ret == 0 || nitems == 0) {
             if (return_code == Success)
                 XFree (prop);
-            client->property_offset = 0;
+            fprintf (stderr,
+                    "(XIM-IMdkit) ERROR: XGetWindowProperty failed.\n"
+                    "Protocol data is likely to be inconsistent.\n");
+            _Xi18nSetPropertyOffset (offset_cache, atom, 0);
             return (unsigned char *) NULL;
         }
         /* Update the offset to read next time as needed */
         if (bytes_after_ret > 0)
-            client->property_offset += length;
+            _Xi18nSetPropertyOffset (offset_cache, atom, offset + length);
         else
-            client->property_offset = 0;
-        switch (actual_format_ret) {
-        case 8:
-        case 16:
-        case 32:
-            length = nitems * actual_format_ret / 8;
-            break;
-        default:
-            fprintf(stderr, "%s: unknown property return format: %d\n",
-                        __func__, actual_format_ret);
-            XFree(prop);
-            client->property_offset = 0;
-            return NULL;
-        }
+            _Xi18nSetPropertyOffset (offset_cache, atom, 0);
         /* if hit, it might be an error */
         if ((p = (unsigned char *) malloc (length)) == NULL)
             return (unsigned char *) NULL;
 
-        memmove (p, prop, length);
+        memcpy (p, prop + (offset % 4), length);
         XFree (prop);
     }
     return (unsigned char *) p;