Implements and expose hash functions

cpp/src/gandiva/gdv_function_stubs.cc

@@ -21,6 +21,7 @@
 #include <vector>
 
 #include "arrow/util/value_parsing.h"
+#include "gandiva/hash_utils.h"
 #include "gandiva/engine.h"
 #include "gandiva/exported_funcs.h"
 #include "gandiva/in_holder.h"
@@ -123,12 +124,13 @@ int32_t gdv_fn_populate_varlen_vector(int64_t context_ptr, int8_t* data_ptr,
 }
 
 char* gdv_fn_sha256_from_numeric(int64_t context, double value){
+  uint64_t value_as_long = gandiva::HashUtils::double_to_long(value);
 
-
+  return gandiva::HashUtils::hash_using_SHA256(context, &value_as_long, sizeof(value_as_long));
 }
 
-char* hash_sha256_from_string(int64_t context, const char* value){
-
+char* gdv_fn_hash_sha256_from_string(int64_t context, const char* value, uint64_t value_length){
+  return gandiva::HashUtils::hash_using_SHA256(context, value, value_length);
 }
 
 int32_t gdv_fn_dec_from_string(int64_t context, const char* in, int32_t in_length,
@@ -214,6 +216,16 @@ void ExportedStubFunctions::AddMappings(Engine* engine) const {
                                   types->i32_type() /*return_type*/, args,
                                   reinterpret_cast<void*>(gdv_fn_dec_from_string));
 
+  // gdv_fn_sha256_from_numeric
+  args = {
+      types->i64_type(),      // context
+      types->double_type()    // value
+  };
+
+  engine->AddGlobalMappingForFunc("gdv_fn_sha256_from_numeric",
+                                  types->i8_ptr_type() /*return_type*/, args,
+                                  reinterpret_cast<void *>(gdv_fn_sha256_from_numeric));
+
   // gdv_fn_dec_to_string
   args = {
       types->i64_type(),      // context

cpp/src/gandiva/gdv_function_stubs.h

@@ -50,7 +50,7 @@ int gdv_fn_time_with_zone(int* time_fields, const char* zone, int zone_len,
 
 char* gdv_fn_sha256_from_numeric(int64_t context, double value);
 
-char* hash_sha256_from_string(int64_t context, const char* value, int32_t value_length);
+char* gdv_fn_hash_sha256_from_string(int64_t context, const char* value, uint64_t value_length);
 
 int32_t gdv_fn_dec_from_string(int64_t context, const char* in, int32_t in_length,
                                int32_t* precision_from_str, int32_t* scale_from_str,

cpp/src/gandiva/hash_utils.cc

@@ -1,9 +1,9 @@
 #include <cstring>
-#include "hash_utils.h"
+#include "gandiva/hash_utils.h"
 #include "openssl/evp.h"
 
 namespace gandiva {
-  char * HashUtils::hash_using_SHA256(int64_t context, const void *message, size_t message_length) {
+  char* HashUtils::hash_using_SHA256(int64_t context, const void *message, size_t message_length) {
     EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
 
     EVP_DigestInit_ex(md_ctx, EVP_sha256(), nullptr);
@@ -41,6 +41,12 @@ namespace gandiva {
     return result_buffer;
   }
 
+  uint64_t HashUtils::double_to_long(double value) {
+    uint64_t result;
+    memcpy(&result, &value, sizeof(result));
+    return result;
+  }
+
   void HashUtils::clean_char_array(char *buffer) {
     buffer[0] = '\0';
   }

cpp/src/gandiva/hash_utils.h

@@ -2,6 +2,7 @@
 #define ARROW_SRC_HASH_UTILS_H_
 
 #include <cstdlib>
+#include <cstdint>
 #include "gandiva/visibility.h"
 
 namespace gandiva {
@@ -9,6 +10,7 @@ namespace gandiva {
    public:
     static inline char *hash_using_SHA256(int64_t context, const void *message, size_t message_length);
 
+    static uint64_t double_to_long(double value);
    private:
     static inline void clean_char_array(char *buffer);
   };