diff --git a/util/cairo-script/cairo-script-file.c b/util/cairo-script/cairo-script-file.c
index c45cc5086..0da4bb649 100644
--- a/util/cairo-script/cairo-script-file.c
+++ b/util/cairo-script/cairo-script-file.c
@@ -162,7 +162,6 @@ csi_file_new_from_string (csi_t *ctx,
     file->base.ref = 1;
 
     if (src->deflate) {
-	uLongf len = src->deflate;
 	csi_object_t tmp_obj;
 	csi_string_t *tmp_str;
 	csi_status_t status;
@@ -179,20 +178,26 @@ csi_file_new_from_string (csi_t *ctx,
 	    break;
 
 	case ZLIB:
+        {
 #if HAVE_ZLIB
+            uLongf len = src->deflate;
 	    if (uncompress ((Bytef *) tmp_str->string, &len,
 			    (Bytef *) src->string, src->len) != Z_OK)
 #endif
 		status = _csi_error (CAIRO_STATUS_NO_MEMORY);
 	    break;
+        }
 	case LZO:
+        {
 #if HAVE_LZO
+            lzo_uint len = src->deflate;
 	    if (lzo2a_decompress ((lzo_bytep) src->string, src->len,
 				  (lzo_bytep) tmp_str->string, &len,
 				  NULL))
 #endif
 		status = _csi_error (CAIRO_STATUS_NO_MEMORY);
 	    break;
+        }
 	}
 	if (_csi_unlikely (status)) {
 	    csi_string_free (ctx, tmp_str);
diff --git a/util/cairo-script/cairo-script-operators.c b/util/cairo-script/cairo-script-operators.c
index a5eca6ffc..b3b03457f 100644
--- a/util/cairo-script/cairo-script-operators.c
+++ b/util/cairo-script/cairo-script-operators.c
@@ -1758,46 +1758,47 @@ _mmap_bytes (const struct mmap_vec *vec, int count)
 static void *
 inflate_string (csi_t *ctx, csi_string_t *src)
 {
-    uLongf len;
     uint8_t *bytes;
 
-    len = src->deflate;
-    bytes = _csi_alloc (ctx, len + 1);
+    bytes = _csi_alloc (ctx, src->deflate + 1);
     if (bytes == NULL)
 	return NULL;
 
     switch (src->method) {
-    default:
-    case NONE:
-	free (bytes);
-	return NULL;
-
     case ZLIB:
+    {
 #if HAVE_ZLIB
-	if (uncompress ((Bytef *) bytes, &len,
-			(Bytef *) src->string, src->len) != Z_OK)
-#endif
+        uLongf length = src->deflate;
+	if (uncompress ((Bytef *) bytes, &length,
+			(Bytef *) src->string, src->len) == Z_OK)
 	{
-	    _csi_free (ctx, bytes);
-	    return NULL;
+            bytes[length] = '\0';
+            return bytes;
 	}
-	break;
-
-    case LZO:
-#if HAVE_LZO
-	if (lzo2a_decompress ((Bytef *) src->string, src->len,
-			      (Bytef *) bytes, &len,
-			      NULL))
 #endif
-	{
-	    _csi_free (ctx, bytes);
-	    return NULL;
-	}
 	break;
     }
+    case LZO:
+    {
+#if HAVE_LZO
+        lzo_uint length = src->deflate;
+	if (lzo2a_decompress ((Bytef *) src->string, src->len,
+			      (Bytef *) bytes, &length,
+			      NULL) == LZO_E_OK)
+	{
+            bytes[length] = '\0';
+            return bytes;
+	}
+#endif
+	break;
+    }
+    case NONE:
+    default:
+        break;
+    }
 
-    bytes[len] = '\0';
-    return bytes;
+    _csi_free (ctx, bytes);
+    return NULL;
 }
 
 static csi_status_t
@@ -2982,7 +2983,6 @@ _image_read_raw (csi_t *ctx,
 	len == src->datum.string->deflate)
     {
 	csi_string_t *s = src->datum.string;
-	unsigned long out = s->deflate;
 
 	switch (s->method) {
 	default:
@@ -2992,21 +2992,27 @@ err_decompress:
 	    return _csi_error (CSI_STATUS_READ_ERROR);
 
 	case ZLIB:
+        {
 #if HAVE_ZLIB
+            uLongf out = s->deflate;
 	    if (uncompress ((Bytef *) data, &out,
 			    (Bytef *) s->string, s->len) != Z_OK)
 #endif
 		goto err_decompress;
 	    break;
+        }
 
 	case LZO:
+        {
 #if HAVE_LZO
+            lzo_uint out = s->deflate;
 	    if (lzo2a_decompress ((Bytef *) s->string, s->len,
 				  (Bytef *) data, &out,
 				  NULL))
 #endif
 		goto err_decompress;
 	    break;
+        }
 	}
     }
     else
diff --git a/util/cairo-script/cairo-script-scanner.c b/util/cairo-script/cairo-script-scanner.c
index 167cd7a1e..09677a1e1 100644
--- a/util/cairo-script/cairo-script-scanner.c
+++ b/util/cairo-script/cairo-script-scanner.c
@@ -1595,7 +1595,10 @@ _translate_string (csi_t *ctx,
 
 #if HAVE_LZO
     if (method == NONE && buf_len > 16) {
-	unsigned long mem_len = 2*string->len > LZO2A_999_MEM_COMPRESS ? 2*string->len : LZO2A_999_MEM_COMPRESS;
+        lzo_uint mem_len = 2 * (lzo_uint)string->len;
+        if (mem_len < LZO2A_999_MEM_COMPRESS)
+            mem_len = LZO2A_999_MEM_COMPRESS;
+
 	void *mem = malloc (mem_len);
 	void *work = malloc(LZO2A_999_MEM_COMPRESS);
 
@@ -1628,7 +1631,7 @@ _translate_string (csi_t *ctx,
 		method = NONE;
 		deflate = 0;
 	    } else {
-		unsigned long mem_len = 2*string->deflate;
+		lzo_uint mem_len = 2*string->deflate;
 		void *mem = malloc (mem_len);
 		void *work = malloc(LZO2A_999_MEM_COMPRESS);