Port initial methods from old repository

cpp/src/gandiva/function_registry_hash.cc

@@ -1,3 +1,4 @@
+
 // Licensed to the Apache Software Foundation (ASF) under one
 // or more contributor license agreements.  See the NOTICE file
 // distributed with this work for additional information

cpp/src/gandiva/gdv_function_stubs.cc

@@ -122,6 +122,15 @@ int32_t gdv_fn_populate_varlen_vector(int64_t context_ptr, int8_t* data_ptr,
   return 0;
 }
 
+char* gdv_fn_sha256_from_numeric(int64_t context, double value){
+
+
+}
+
+char* hash_sha256_from_string(int64_t context, const char* value){
+
+}
+
 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,
                                int64_t* dec_high_from_str, uint64_t* dec_low_from_str) {

cpp/src/gandiva/gdv_function_stubs.h

@@ -48,6 +48,10 @@ bool in_expr_lookup_utf8(int64_t ptr, const char* data, int data_len, bool in_va
 int gdv_fn_time_with_zone(int* time_fields, const char* zone, int zone_len,
                           int64_t* ret_time);
 
+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);
+
 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,
                                int64_t* dec_high_from_str, uint64_t* dec_low_from_str);

cpp/src/gandiva/hash_utils.cc

@@ -0,0 +1,46 @@
+#include "hash_utils.h"
+#include "openssl/evp.h"
+
+namespace gandiva {
+  char* HashUtils::hash_using_SHA256(const void *message, const size_t message_length) {
+    EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
+
+    EVP_DigestInit_ex(md_ctx, EVP_sha256(), nullptr);
+
+    EVP_DigestUpdate(md_ctx, message, message_length);
+
+    int sha256_hash_size = EVP_MD_size(EVP_sha256());
+
+    auto* result = (unsigned char*) OPENSSL_malloc(sha256_hash_size);
+
+    unsigned int result_length;
+
+    EVP_DigestFinal_ex(md_ctx, result, &result_length);
+
+    char* hex_buffer = new char[4];
+    char* result_buffer = new char[65];
+
+    clean_char_array(hex_buffer);
+    clean_char_array(result_buffer);
+
+    for (unsigned int j = 0; j < result_length; j++) {
+      unsigned char hex_number = result[j];
+      sprintf(hex_buffer, "%02x", hex_number);
+
+      strcat(result_buffer, hex_buffer);
+    }
+
+    result_buffer[64] = '\0';
+
+    // free the resources to avoid memory leaks
+    EVP_MD_CTX_free(md_ctx);
+    free(hex_buffer);
+    free(result);
+
+    return result_buffer;
+  }
+
+  void HashUtils::clean_char_array(char *buffer) {
+    buffer[0] = '\0';
+  }
+}

cpp/src/gandiva/hash_utils.h

@@ -0,0 +1,16 @@
+#ifndef ARROW_SRC_HASH_UTILS_H_
+#define ARROW_SRC_HASH_UTILS_H_
+
+#include "gandiva/visibility.h"
+
+namespace gandiva {
+  class GANDIVA_EXPORT HashUtils {
+   public:
+    static inline char* hash_using_SHA256(const void* message, const size_t message_length);
+
+   private:
+    static inline void clean_char_array(char *buffer);
+  };
+};
+
+#endif //ARROW_SRC_HASH_UTILS_H_