Replace the bigram list position with the map and filter

Passing the position will not allow us a reasonable lookup
time. Replace this with a map and bloom filter for very fast
lookup.

Bug: 6313806
Change-Id: I3a61c0001cbc987c1c3c7b8df635d4590a370144

1 files changed, 5 insertions, 0 deletions

diff --git a/native/jni/src/bigram_dictionary.cpp b/native/jni/src/bigram_dictionary.cpp
index d120261ae..220b340d1 100644
--- a/native/jni/src/bigram_dictionary.cpp
+++ b/native/jni/src/bigram_dictionary.cpp
@@ -158,6 +158,11 @@ static inline void setInFilter(uint8_t *filter, const int position) {
     filter[bucket >> 3] |= (1 << (bucket & 0x7));
 }
 
+static inline bool isInFilter(uint8_t *filter, const int position) {
+    const unsigned int bucket = position % BIGRAM_FILTER_MODULO;
+    return filter[bucket >> 3] & (1 << (bucket & 0x7));
+}
+
 void BigramDictionary::fillBigramAddressToFrequencyMapAndFilter(const int32_t *prevWord,
         const int prevWordLength, std::map<int, int> *map, uint8_t *filter) {
     memset(filter, 0, BIGRAM_FILTER_BYTE_SIZE);