rkavanap commented on a change in pull request #11052:
URL: https://github.com/apache/arrow/pull/11052#discussion_r740730066
##########
File path: cpp/src/gandiva/precompiled/string_ops.cc
##########
@@ -2195,4 +2195,74 @@ const char* byte_substr_binary_int32_int32(gdv_int64
context, const char* text,
memcpy(ret, text + startPos, *out_len);
return ret;
}
+
+// Array that maps each letter from the alphabet to its corresponding number
for the soundex algorithm.
+// ABCDEFGHIJKLMNOPQRSTUVWXYZ -> 01230120022455012623010202
+static char mappings[] =
{'0','1','2','3','0','1','2','0','0','2','2','4','5','5','0','1','2','6','2','3','0','1','0','2','0','2'};
+
+// Returns the soundex code for a given string
+//
+// The soundex function evaluates expression and returns the most significant
letter in
+// the input string followed by a phonetic code. Characters that are not
alphabetic are
+// ignored. If expression evaluates to the null value, null is returned.
+//
+// The soundex algorith works with the following steps:
+// 1. Retain the first letter of the string and drop all other occurrences
of a, e, i, o, u, y, h, w.
+// 2. Replace consonants with digits as follows (after the first letter):
+// b, f, p, v → 1
+// c, g, j, k, q, s, x, z → 2
+// d, t → 3
+// l → 4
+// m, n → 5
+// r → 6
+// 3. If two or more letters with the same number are adjacent in the
original name
+// (before step 1), only retain the first letter; also two letters with the
same number
+// separated by 'h' or 'w' are coded as a single number, whereas such
letters separated
+// by a vowel are coded twice. This rule also applies to the first letter.
+// 4. If the string have too few letters in the word that you can't assign
three numbers,
+// append with zeros until there are three numbers. If you have four or
more numbers,
+// retain only the first three.
+FORCE_INLINE
+const char* soundex_utf8(gdv_int64 ctx, const char* in, gdv_int32 in_len,
+ int32_t* out_len) {
+ if (in_len <= 0) {
+ *out_len = 0;
+ return "";
+ }
+
+ // The soundex code is composed by one letter and three numbers
+ char* ret = reinterpret_cast<char*>(gdv_fn_context_arena_malloc(ctx, 4));
+ if (ret == nullptr) {
+ gdv_fn_context_set_error_msg(ctx, "Could not allocate memory for output
string");
+ *out_len = 0;
+ return "";
+ }
+
+ int si = 1;
+ unsigned char c;
+ ret[0] = toupper(in[0]);
Review comment:
what if the first character is not a letter?. Shouldn't we skip it to
run the algorithm? e.g "1SMITH" or "123SMYTHE"
##########
File path: cpp/src/gandiva/precompiled/string_ops.cc
##########
@@ -2195,4 +2195,74 @@ const char* byte_substr_binary_int32_int32(gdv_int64
context, const char* text,
memcpy(ret, text + startPos, *out_len);
return ret;
}
+
+// Array that maps each letter from the alphabet to its corresponding number
for the soundex algorithm.
+// ABCDEFGHIJKLMNOPQRSTUVWXYZ -> 01230120022455012623010202
+static char mappings[] =
{'0','1','2','3','0','1','2','0','0','2','2','4','5','5','0','1','2','6','2','3','0','1','0','2','0','2'};
+
+// Returns the soundex code for a given string
+//
+// The soundex function evaluates expression and returns the most significant
letter in
+// the input string followed by a phonetic code. Characters that are not
alphabetic are
+// ignored. If expression evaluates to the null value, null is returned.
+//
+// The soundex algorith works with the following steps:
+// 1. Retain the first letter of the string and drop all other occurrences
of a, e, i, o, u, y, h, w.
+// 2. Replace consonants with digits as follows (after the first letter):
+// b, f, p, v → 1
+// c, g, j, k, q, s, x, z → 2
+// d, t → 3
+// l → 4
+// m, n → 5
+// r → 6
+// 3. If two or more letters with the same number are adjacent in the
original name
+// (before step 1), only retain the first letter; also two letters with the
same number
+// separated by 'h' or 'w' are coded as a single number, whereas such
letters separated
+// by a vowel are coded twice. This rule also applies to the first letter.
+// 4. If the string have too few letters in the word that you can't assign
three numbers,
+// append with zeros until there are three numbers. If you have four or
more numbers,
+// retain only the first three.
+FORCE_INLINE
+const char* soundex_utf8(gdv_int64 ctx, const char* in, gdv_int32 in_len,
+ int32_t* out_len) {
+ if (in_len <= 0) {
+ *out_len = 0;
+ return "";
+ }
+
+ // The soundex code is composed by one letter and three numbers
+ char* ret = reinterpret_cast<char*>(gdv_fn_context_arena_malloc(ctx, 4));
+ if (ret == nullptr) {
+ gdv_fn_context_set_error_msg(ctx, "Could not allocate memory for output
string");
+ *out_len = 0;
+ return "";
+ }
+
+ int si = 1;
+ unsigned char c;
+ ret[0] = toupper(in[0]);
+ for(int i = 1, l = in_len; i < l; i++) {
+ c = toupper(in[i]) - 65;
Review comment:
just wondering if it is faster to check isAlpha (basically remove if in
2247 and do lines 2245 to 2256 only if it is a letter)
##########
File path: cpp/src/gandiva/precompiled/string_ops_test.cc
##########
@@ -1755,4 +1755,23 @@ TEST(TestStringOps, TestConvertToBigEndian) {
#endif
}
+TEST(TestStringOps, TestSoundex) {
+ gandiva::ExecutionContext ctx;
+ auto ctx_ptr = reinterpret_cast<int64_t>(&ctx);
+ int32_t out_len = 0;
+ const char* out;
+
+ out = soundex_utf8(ctx_ptr, "Miller", 6, &out_len);
+ EXPECT_EQ(std::string(out, out_len), "M460");
+
+ out = soundex_utf8(ctx_ptr, "abc", 3, &out_len);
+ EXPECT_EQ(std::string(out, out_len), "A120");
+
+ out = soundex_utf8(ctx_ptr, "test", 4, &out_len);
+ EXPECT_EQ(std::string(out, out_len), "T230");
Review comment:
A test case having non letter at the beginning and vowels in the
beginning..?
"3Miller", "Elvis", "waterloo" ,"eowolf"
also a test case that compares the output of 2 similar sounding values. e.g
Smith and Smythe are similar sounding and probably should return same value?.
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