Take an assert off the hot path.

[plocate] / database-builder.cpp

diff --git a/database-builder.cpp b/database-builder.cpp
index 439e25a59e88980ef6a2f8f7bb9d38c43f7134ec..75b96f8c02a6c4108f2b0497e2aa5881167db80a 100644 (file)
--- a/database-builder.cpp
+++ b/database-builder.cpp
@@ -5,6 +5,9 @@
 
 #include <algorithm>
 #include <assert.h>
+#ifdef HAS_ENDIAN_H
+#include <endian.h>
+#endif
 #include <fcntl.h>
 #include <string.h>
 #include <string_view>
@@ -26,20 +29,14 @@ constexpr unsigned num_overflow_slots = 16;
 
 string zstd_compress(const string &src, ZSTD_CDict *cdict, string *tempbuf);
 
-static inline uint32_t read_unigram(const string_view s, size_t idx)
-{
-       if (idx < s.size()) {
-               return (unsigned char)s[idx];
-       } else {
-               return 0;
-       }
-}
-
+// NOTE: Will read one byte past the end of the trigram, but it's OK,
+// since we always call it from contexts where there's a terminating zero byte.
 static inline uint32_t read_trigram(const string_view s, size_t start)
 {
-       return read_unigram(s, start) |
-               (read_unigram(s, start + 1) << 8) |
-               (read_unigram(s, start + 2) << 16);
+       uint32_t trgm;
+       memcpy(&trgm, s.data() + start, sizeof(trgm));
+       trgm = le32toh(trgm);
+       return trgm & 0xffffff;
 }
 
 class PostingListBuilder {
@@ -48,7 +45,7 @@ public:
        inline void add_first_docid(uint32_t docid);
        void finish();
 
-       string encoded;
+       vector<unsigned char> encoded;
        size_t num_docids = 0;
 
 private:
@@ -67,8 +64,6 @@ void PostingListBuilder::add_docid(uint32_t docid)
                return;
        }
 
-       assert(num_docids != 0);
-
        pending_deltas.push_back(docid - last_docid - 1);
        last_docid = docid;
        if (pending_deltas.size() == 128) {
@@ -96,7 +91,7 @@ void PostingListBuilder::finish()
        // No interleaving for partial blocks.
        unsigned char buf[P4NENC_BOUND(128)];
        unsigned char *end = encode_pfor_single_block<128>(pending_deltas.data(), pending_deltas.size(), /*interleaved=*/false, buf);
-       encoded.append(reinterpret_cast<char *>(buf), reinterpret_cast<char *>(end));
+       encoded.insert(encoded.end(), buf, end);
 }
 
 void PostingListBuilder::append_block()
@@ -104,14 +99,14 @@ void PostingListBuilder::append_block()
        unsigned char buf[P4NENC_BOUND(128)];
        assert(pending_deltas.size() == 128);
        unsigned char *end = encode_pfor_single_block<128>(pending_deltas.data(), 128, /*interleaved=*/true, buf);
-       encoded.append(reinterpret_cast<char *>(buf), reinterpret_cast<char *>(end));
+       encoded.insert(encoded.end(), buf, end);
 }
 
 void PostingListBuilder::write_header(uint32_t docid)
 {
        unsigned char buf[P4NENC_BOUND(1)];
        unsigned char *end = write_baseval(docid, buf);
-       encoded.append(reinterpret_cast<char *>(buf), end - buf);
+       encoded.insert(encoded.end(), buf, end);
 }
 
 void DictionaryBuilder::add_file(string filename, dir_time)
@@ -617,7 +612,7 @@ void DatabaseBuilder::finish_corpus()
                        continue;
                }
 
-               const string &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
+               const vector<unsigned char> &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
                offset += encoded.size();
        }
 
@@ -631,7 +626,7 @@ void DatabaseBuilder::finish_corpus()
                if (hashtable[i].num_docids == 0) {
                        continue;
                }
-               const string &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
+               const vector<unsigned char> &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
                fwrite(encoded.data(), encoded.size(), 1, outfp);
        }