Adjust serialized sort data for raw attributes.

1 files changed, 43 insertions, 16 deletions

diff --git a/searchlib/src/vespa/searchlib/attribute/raw_attribute.cpp b/searchlib/src/vespa/searchlib/attribute/raw_attribute.cpp
index 65841f59827..f8c6768ba5b 100644
--- a/searchlib/src/vespa/searchlib/attribute/raw_attribute.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/raw_attribute.cpp
@@ -1,6 +1,7 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
 #include "raw_attribute.h"
+#include <cassert>
 
 namespace search::attribute {
 
@@ -11,32 +12,58 @@ RawAttribute::RawAttribute(const vespalib::string& name, const Config& config)
 
 RawAttribute::~RawAttribute() = default;
 
-long
-RawAttribute::onSerializeForAscendingSort(DocId doc, void* serTo, long available, const common::BlobConverter*) const
+namespace {
+
+template <bool desc>
+unsigned char remap(unsigned char val)
 {
-    auto raw = get_raw(doc);
-    if (available >= (long)raw.size()) {
-        memcpy(serTo, raw.data(), raw.size());
+    return (desc ? (0xff - val) : val);
+}
+
+template <bool desc>
+long serialize_for_sort(vespalib::ConstArrayRef<char> raw, void* serTo, long available)
+{
+    auto src = reinterpret_cast<const unsigned char *>(raw.data());
+    auto src_end = src + raw.size();
+    size_t extra = 1;
+    for (auto p = src; p != src_end; ++p) {
+        if (*p >= 0xfe) {
+            ++extra;
+        }
+    }
+    if (available >= (long)(raw.size() + extra)) {
+        auto dst = static_cast<unsigned char *>(serTo);
+        auto dst_orig = dst;
+        for (auto p = src; p != src_end; ++p) {
+            if (*p >= 0xfe) {
+                *dst++ = remap<desc>(0xff);
+                *dst++ = remap<desc>(*p);
+            } else {
+                *dst++ = remap<desc>(*p + 1);
+            }
+        }
+        *dst++ = remap<desc>(0);
+        assert(raw.size() + extra + dst_orig == dst);
     } else {
         return -1;
     }
-    return raw.size();
+    return raw.size() + extra;
+}
+
+}
+
+long
+RawAttribute::onSerializeForAscendingSort(DocId doc, void* serTo, long available, const common::BlobConverter*) const
+{
+    auto raw = get_raw(doc);
+    return serialize_for_sort<false>(raw, serTo, available);
 }
 
 long
 RawAttribute::onSerializeForDescendingSort(DocId doc, void* serTo, long available, const common::BlobConverter*) const
 {
     auto raw = get_raw(doc);
-    if (available >= (long)raw.size()) {
-        auto *dst = static_cast<unsigned char *>(serTo);
-        const auto * src(reinterpret_cast<const uint8_t *>(raw.data()));
-        for (size_t i(0); i < raw.size(); ++i) {
-            dst[i] = 0xff - src[i];
-        }
-    } else {
-        return -1;
-    }
-    return raw.size();
+    return serialize_for_sort<true>(raw, serTo, available);
 }
 
 }