From 04969928a7578aec48dfe8b4b82fc1030e77c74b Mon Sep 17 00:00:00 2001
From: Max Bachmann <kontakt@maxbachmann.de>
Date: Sun, 2 Jan 2022 15:44:28 +0100
Subject: [PATCH] Fix incorrect normalization for legacy scorers

---
 src/cpp_string_metric.hpp | 58 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 4 deletions(-)

diff --git a/src/cpp_string_metric.hpp b/src/cpp_string_metric.hpp
index acee291..6084639 100644
--- a/src/cpp_string_metric.hpp
+++ b/src/cpp_string_metric.hpp
@@ -1,6 +1,56 @@
 #pragma once
 #include "cpp_common.hpp"
 
+
+template<typename CachedScorer>
+static inline bool legacy_scorer_func_wrapper_f64(const RF_ScorerFunc* self, const RF_String* str, double score_cutoff, double* result)
+{
+    CachedScorer& scorer = *(CachedScorer*)self->context;
+    try {
+        *result = visit(*str, [&](auto s){
+            return scorer.ratio(s, score_cutoff);
+        }) * 100;
+    } catch(...) {
+      PyGILState_STATE gilstate_save = PyGILState_Ensure();
+      CppExn2PyErr();
+      PyGILState_Release(gilstate_save);
+      return false;
+    }
+    return true;
+}
+
+template<template <typename> class CachedScorer, typename Sentence, typename ...Args>
+static inline RF_ScorerFunc legacy_get_ScorerContext_f64(Sentence str, Args... args)
+{
+    RF_ScorerFunc context;
+    context.context = (void*) new CachedScorer<Sentence>(str, args...);
+
+    context.call.f64 = legacy_scorer_func_wrapper_f64<CachedScorer<Sentence>>;
+    context.dtor = scorer_deinit<CachedScorer<Sentence>>;
+    return context;
+}
+
+template<template <typename> class CachedScorer, typename ...Args>
+static inline bool legacy_scorer_init_f64(RF_ScorerFunc* self, size_t str_count, const RF_String* strings, Args... args)
+{
+    try {
+        /* todo support different string counts, which is required e.g. for SIMD */
+        if (str_count != 1)
+        {
+            throw std::logic_error("Only str_count == 1 supported");
+        }
+        *self = visit(*strings, [&](auto s){
+            return legacy_get_ScorerContext_f64<CachedScorer>(s, args...);
+        });
+    } catch(...) {
+      PyGILState_STATE gilstate_save = PyGILState_Ensure();
+      CppExn2PyErr();
+      PyGILState_Release(gilstate_save);
+      return false;
+    }
+    return true;
+}
+
 static inline size_t levenshtein_func(const RF_String& s1, const RF_String& s2,
     size_t insertion, size_t deletion, size_t substitution, size_t max)
 {
@@ -26,7 +76,7 @@ static inline double normalized_levenshtein_func(const RF_String& s1, const RF_S
 }
 static inline bool NormalizedLevenshteinInit(RF_ScorerFunc* self, const RF_Kwargs* kwargs, size_t str_count, const RF_String* str)
 {
-    return scorer_init_f64<string_metric::CachedNormalizedLevenshtein>(
+    return legacy_scorer_init_f64<string_metric::CachedNormalizedLevenshtein>(
         self, str_count, str, *(rapidfuzz::LevenshteinWeightTable*)(kwargs->context)
     );
 }
@@ -50,7 +100,7 @@ static inline double normalized_hamming_func(const RF_String& s1, const RF_Strin
 }
 static inline bool NormalizedHammingInit(RF_ScorerFunc* self, const RF_Kwargs*, size_t str_count, const RF_String* str)
 {
-    return scorer_init_f64<string_metric::CachedNormalizedHamming>(self, str_count, str);
+    return legacy_scorer_init_f64<string_metric::CachedNormalizedHamming>(self, str_count, str);
 }
 
 static inline double jaro_similarity_func(const RF_String& s1, const RF_String& s2, double score_cutoff)
@@ -61,7 +111,7 @@ static inline double jaro_similarity_func(const RF_String& s1, const RF_String&
 }
 static inline bool JaroSimilarityInit(RF_ScorerFunc* self, const RF_Kwargs*, size_t str_count, const RF_String* str)
 {
-    return scorer_init_f64<string_metric::CachedJaroSimilarity>(self, str_count, str);
+    return legacy_scorer_init_f64<string_metric::CachedJaroSimilarity>(self, str_count, str);
 }
 
 static inline double jaro_winkler_similarity_func(const RF_String& s1, const RF_String& s2,
@@ -73,7 +123,7 @@ static inline double jaro_winkler_similarity_func(const RF_String& s1, const RF_
 }
 static inline bool JaroWinklerSimilarityInit(RF_ScorerFunc* self, const RF_Kwargs* kwargs, size_t str_count, const RF_String* str)
 {
-    return scorer_init_f64<string_metric::CachedJaroWinklerSimilarity>(self, str_count, str, *(double*)(kwargs->context));
+    return legacy_scorer_init_f64<string_metric::CachedJaroWinklerSimilarity>(self, str_count, str, *(double*)(kwargs->context));
 }
 
 static inline std::vector<rapidfuzz::LevenshteinEditOp> levenshtein_editops_func(