Hi,
I have attached a rebased patch if someone wants to review in the next CF.
No changes as compared to v4.
Regards,
Hunaid Sohail
>
From 951f3e9620f0d50fcdaff095652a07d6304b490c Mon Sep 17 00:00:00 2001
From: Hunaid Sohail <hunaid2000@gmail.com>
Date: Wed, 30 Oct 2024 12:00:47 +0500
Subject: [PATCH v5] Add roman support for to_number function
---
doc/src/sgml/func.sgml | 13 ++-
src/backend/utils/adt/formatting.c | 154 +++++++++++++++++++++++++-
src/test/regress/expected/numeric.out | 41 +++++++
src/test/regress/sql/numeric.sql | 21 ++++
4 files changed, 224 insertions(+), 5 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 05f630c6a6..5f91f0401b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -8628,7 +8628,7 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
</row>
<row>
<entry><literal>RN</literal></entry>
- <entry>Roman numeral (input between 1 and 3999)</entry>
+ <entry>Roman numeral (valid for numbers 1 to 3999)</entry>
</row>
<row>
<entry><literal>TH</literal> or <literal>th</literal></entry>
@@ -8756,6 +8756,17 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
(e.g., <literal>9.99EEEE</literal> is a valid pattern).
</para>
</listitem>
+
+ <listitem>
+ <para>
+ In <function>to_number</function>, <literal>RN</literal> pattern converts
+ roman numerals to standard numbers. It is case-insensitive (e.g., <literal>'XIV'</literal>,
+ <literal>'xiv'</literal>, and <literal>'Xiv'</literal> are all seen as <literal>14</literal>).
+ <literal>RN</literal> cannot be used in combination with any other formatting patterns
+ or modifiers, with the exception of <literal>FM</literal>, which is applicable only in
+ <function>to_char()</function> and is ignored in <function>to_number()</function>.
+ </para>
+ </listitem>
</itemizedlist>
</para>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 85a7dd4561..5e5e763388 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -49,7 +49,6 @@
* - better number building (formatting) / parsing, now it isn't
* ideal code
* - use Assert()
- * - add support for roman number to standard number conversion
* - add support for number spelling
* - add support for string to string formatting (we must be better
* than Oracle :-),
@@ -270,6 +269,31 @@ static const char *const rm100[] = {"C", "CC", "CCC", "CD", "D", "DC", "DCC", "D
static const char *const numTH[] = {"ST", "ND", "RD", "TH", NULL};
static const char *const numth[] = {"st", "nd", "rd", "th", NULL};
+/* ----------
+ * MACRO: Check if the current and next characters
+ * form a valid subtraction combination for roman numerals
+ * ----------
+ */
+#define IS_VALID_SUB_COMB(curr, next) \
+ (((curr) == 'I' && ((next) == 'V' || (next) == 'X')) || \
+ ((curr) == 'X' && ((next) == 'L' || (next) == 'C')) || \
+ ((curr) == 'C' && ((next) == 'D' || (next) == 'M')))
+
+/* ----------
+ * MACRO: Roman number value
+ * ----------
+ */
+#define ROMAN_VAL(r) \
+ ((r) == 'I' ? 1 : \
+ (r) == 'V' ? 5 : \
+ (r) == 'X' ? 10 : \
+ (r) == 'L' ? 50 : \
+ (r) == 'C' ? 100 : \
+ (r) == 'D' ? 500 : \
+ (r) == 'M' ? 1000 : 0)
+
+#define MAX_ROMAN_LEN 15
+
/* ----------
* Flags & Options:
* ----------
@@ -1074,6 +1098,7 @@ static bool do_to_timestamp(text *date_txt, text *fmt, Oid collid, bool std,
static char *fill_str(char *str, int c, int max);
static FormatNode *NUM_cache(int len, NUMDesc *Num, text *pars_str, bool *shouldFree);
static char *int_to_roman(int number);
+static int roman_to_int(char* s, int len);
static void NUM_prepare_locale(NUMProc *Np);
static char *get_last_relevant_decnum(char *num);
static void NUM_numpart_from_char(NUMProc *Np, int id, int input_len);
@@ -1284,6 +1309,15 @@ NUMDesc_prepare(NUMDesc *num, FormatNode *n)
case NUM_rn:
case NUM_RN:
+ if (IS_ROMAN(num))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cannot use \"RN\" twice")));
+ if (IS_BLANK(num) || IS_LSIGN(num) || IS_BRACKET(num) ||
+ IS_MINUS(num) || IS_PLUS(num) || IS_MULTI(num))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("\"RN\" is incompatible with other formats")));
num->flag |= NUM_F_ROMAN;
break;
@@ -5247,7 +5281,107 @@ int_to_roman(int number)
return result;
}
+/* Convert a standard roman numeral to an integer.
+ * Result is an integer between 1 and 3999.
+ *
+ * If input is invalid, return -1.
+ */
+static int
+roman_to_int(char* s, int len)
+{
+ int repeatCount = 1;
+ int vCount = 0, lCount = 0, dCount = 0;
+ bool subtractionEncountered = false;
+ char lastSubtractedChar = 0;
+ int total = 0;
+
+ /* Ensure the input is not too long or empty.
+ * 'MMMDCCCLXXXVIII' (3888) is the longest valid roman numeral (15 chars).
+ */
+ if (len == 0 || len > MAX_ROMAN_LEN)
+ return -1;
+
+ for (int i = 0; i < len; ++i)
+ {
+ char currChar = pg_ascii_toupper(s[i]);
+ int currValue = ROMAN_VAL(currChar);
+
+ if (currValue == 0)
+ return -1;
+
+ /* Ensure no character greater than or equal to the subtracted
+ * character appears after the subtraction.
+ */
+ if (subtractionEncountered && (currValue >= ROMAN_VAL(lastSubtractedChar)))
+ return -1;
+
+ /* Check for invalid repetitions of characters V, L, or D. */
+ if (currChar == 'V') vCount++;
+ if (currChar == 'L') lCount++;
+ if (currChar == 'D') dCount++;
+ if (vCount > 1 || lCount > 1 || dCount > 1)
+ return -1;
+
+ if (i < len - 1)
+ {
+ char nextChar = pg_ascii_toupper(s[i + 1]);
+ int nextValue = ROMAN_VAL(nextChar);
+
+ if (nextValue == 0)
+ return -1;
+
+ /* If the current value is less than the next value,
+ * handle subtraction. Verify valid subtractive
+ * combinations and update the total accordingly.
+ */
+ if (currValue < nextValue)
+ {
+ /* Check for invalid repetitions of characters V, L, or D. */
+ if (nextChar == 'V') vCount++;
+ if (nextChar == 'L') lCount++;
+ if (nextChar == 'D') dCount++;
+ if (vCount > 1 || lCount > 1 || dCount > 1)
+ return -1;
+
+ /* For cases where the same character is repeated
+ * with subtraction (e.g. 'MCCM' or 'DCCCD').
+ */
+ if (repeatCount > 1)
+ return -1;
+ if (!IS_VALID_SUB_COMB(currChar, nextChar))
+ return -1;
+
+ /* Skip the next character as it is part of
+ * the subtractive combination.
+ */
+ i++;
+ repeatCount = 1;
+ subtractionEncountered = true;
+ lastSubtractedChar = currChar;
+ total += (nextValue - currValue);
+ }
+ else
+ {
+ /* For same characters, check for repetition. */
+ if (currChar == nextChar)
+ {
+ repeatCount++;
+ if (repeatCount > 3)
+ return -1;
+ }
+ else
+ repeatCount = 1;
+ total += currValue;
+ }
+ }
+ /* Add the value of the last character. */
+ else
+ total += currValue;
+ }
+
+ return total;
+}
/* ----------
* Locale
@@ -5829,9 +5963,21 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
if (IS_ROMAN(Np->Num))
{
if (!Np->is_to_char)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("\"RN\" not supported for input")));
+ {
+ int roman_result;
+
+ roman_result = roman_to_int(inout, input_len);
+ if (roman_result == -1)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+ errmsg("invalid roman numeral")));
+ else
+ {
+ Np->Num->pre = sprintf(number, "%d", roman_result);
+ Np->Num->post = 0;
+ return number;
+ }
+ }
Np->Num->lsign = Np->Num->pre_lsign_num = Np->Num->post =
Np->Num->pre = Np->out_pre_spaces = Np->sign = 0;
diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out
index 0898107ec3..f141f094e6 100644
--- a/src/test/regress/expected/numeric.out
+++ b/src/test/regress/expected/numeric.out
@@ -2384,6 +2384,47 @@ SELECT to_number('123456', '99999V99');
1234.560000000000000000
(1 row)
+-- Test for correct conversion between numbers and Roman numerals
+WITH rows AS
+ (SELECT i, to_char(i, 'FMRN') AS roman FROM generate_series(1, 3999) AS i)
+SELECT
+ bool_and(to_number(roman, 'RN') = i) as valid
+FROM rows;
+ valid
+-------
+ t
+(1 row)
+
+SELECT to_number('CvIiI', 'rn');
+ to_number
+-----------
+ 108
+(1 row)
+
+SELECT to_number('viv', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('DCCCD', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('XIXL', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('MCCM', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('MMMM', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('CM', 'MIRN');
+ERROR: "RN" is incompatible with other formats
+SELECT to_number('CM', 'RNRN');
+ERROR: cannot use "RN" twice
+SELECT to_number(' XIV ', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('MMXX ', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('M CC', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number('', 'RN');
+ERROR: invalid roman numeral
+SELECT to_number(' ', 'RN');
+ERROR: invalid roman numeral
RESET lc_numeric;
--
-- Input syntax
diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql
index 9da12c6b9e..1543c52233 100644
--- a/src/test/regress/sql/numeric.sql
+++ b/src/test/regress/sql/numeric.sql
@@ -1085,6 +1085,27 @@ SELECT to_number('1234.56','L99,999.99');
SELECT to_number('1,234.56','L99,999.99');
SELECT to_number('42nd', '99th');
SELECT to_number('123456', '99999V99');
+
+-- Test for correct conversion between numbers and Roman numerals
+WITH rows AS
+ (SELECT i, to_char(i, 'FMRN') AS roman FROM generate_series(1, 3999) AS i)
+SELECT
+ bool_and(to_number(roman, 'RN') = i) as valid
+FROM rows;
+
+SELECT to_number('CvIiI', 'rn');
+SELECT to_number('viv', 'RN');
+SELECT to_number('DCCCD', 'RN');
+SELECT to_number('XIXL', 'RN');
+SELECT to_number('MCCM', 'RN');
+SELECT to_number('MMMM', 'RN');
+SELECT to_number('CM', 'MIRN');
+SELECT to_number('CM', 'RNRN');
+SELECT to_number(' XIV ', 'RN');
+SELECT to_number('MMXX ', 'RN');
+SELECT to_number('M CC', 'RN');
+SELECT to_number('', 'RN');
+SELECT to_number(' ', 'RN');
RESET lc_numeric;
--
--
2.34.1
