Add bytea equivalents of ltrim() and rtrim().

We had bytea btrim() already, but for some reason not the other two.

Joel Jacobson

Discussion: https://postgr.es/m/d10cd5cd-a901-42f1-b832-763ac6f7ff3a@www.fastmail.com

1 files changed, 113 insertions, 39 deletions

diff --git a/src/backend/utils/adt/oracle_compat.c b/src/backend/utils/adt/oracle_compat.c
index 99077a90b92..f737aa6fbde 100644
--- a/src/backend/utils/adt/oracle_compat.c
+++ b/src/backend/utils/adt/oracle_compat.c
@@ -24,6 +24,8 @@
 static text *dotrim(const char *string, int stringlen,
 					const char *set, int setlen,
 					bool doltrim, bool dortrim);
+static bytea *dobyteatrim(bytea *string, bytea *set,
+						  bool doltrim, bool dortrim);
 
 
 /********************************************************************
@@ -521,27 +523,12 @@ dotrim(const char *string, int stringlen,
 	return cstring_to_text_with_len(string, stringlen);
 }
 
-/********************************************************************
- *
- * byteatrim
- *
- * Syntax:
- *
- *	 bytea byteatrim(bytea string, bytea set)
- *
- * Purpose:
- *
- *	 Returns string with characters removed from the front and back
- *	 up to the first character not in set.
- *
- * Cloned from btrim and modified as required.
- ********************************************************************/
-
-Datum
-byteatrim(PG_FUNCTION_ARGS)
+/*
+ * Common implementation for bytea versions of btrim, ltrim, rtrim
+ */
+bytea *
+dobyteatrim(bytea *string, bytea *set, bool doltrim, bool dortrim)
 {
-	bytea	   *string = PG_GETARG_BYTEA_PP(0);
-	bytea	   *set = PG_GETARG_BYTEA_PP(1);
 	bytea	   *ret;
 	char	   *ptr,
 			   *end,
@@ -556,7 +543,7 @@ byteatrim(PG_FUNCTION_ARGS)
 	setlen = VARSIZE_ANY_EXHDR(set);
 
 	if (stringlen <= 0 || setlen <= 0)
-		PG_RETURN_BYTEA_P(string);
+		return string;
 
 	m = stringlen;
 	ptr = VARDATA_ANY(string);
@@ -564,39 +551,126 @@ byteatrim(PG_FUNCTION_ARGS)
 	ptr2start = VARDATA_ANY(set);
 	end2 = ptr2start + setlen - 1;
 
-	while (m > 0)
+	if (doltrim)
 	{
-		ptr2 = ptr2start;
-		while (ptr2 <= end2)
+		while (m > 0)
 		{
-			if (*ptr == *ptr2)
+			ptr2 = ptr2start;
+			while (ptr2 <= end2)
+			{
+				if (*ptr == *ptr2)
+					break;
+				++ptr2;
+			}
+			if (ptr2 > end2)
 				break;
-			++ptr2;
+			ptr++;
+			m--;
 		}
-		if (ptr2 > end2)
-			break;
-		ptr++;
-		m--;
 	}
 
-	while (m > 0)
+	if (dortrim)
 	{
-		ptr2 = ptr2start;
-		while (ptr2 <= end2)
+		while (m > 0)
 		{
-			if (*end == *ptr2)
+			ptr2 = ptr2start;
+			while (ptr2 <= end2)
+			{
+				if (*end == *ptr2)
+					break;
+				++ptr2;
+			}
+			if (ptr2 > end2)
 				break;
-			++ptr2;
+			end--;
+			m--;
 		}
-		if (ptr2 > end2)
-			break;
-		end--;
-		m--;
 	}
 
 	ret = (bytea *) palloc(VARHDRSZ + m);
 	SET_VARSIZE(ret, VARHDRSZ + m);
 	memcpy(VARDATA(ret), ptr, m);
+	return ret;
+}
+
+/********************************************************************
+ *
+ * byteatrim
+ *
+ * Syntax:
+ *
+ *	 bytea byteatrim(bytea string, bytea set)
+ *
+ * Purpose:
+ *
+ *	 Returns string with characters removed from the front and back
+ *	 up to the first character not in set.
+ *
+ * Cloned from btrim and modified as required.
+ ********************************************************************/
+
+Datum
+byteatrim(PG_FUNCTION_ARGS)
+{
+	bytea	   *string = PG_GETARG_BYTEA_PP(0);
+	bytea	   *set = PG_GETARG_BYTEA_PP(1);
+	bytea	   *ret;
+
+	ret = dobyteatrim(string, set, true, true);
+
+	PG_RETURN_BYTEA_P(ret);
+}
+
+/********************************************************************
+ *
+ * bytealtrim
+ *
+ * Syntax:
+ *
+ *	 bytea bytealtrim(bytea string, bytea set)
+ *
+ * Purpose:
+ *
+ *	 Returns string with initial characters removed up to the first
+ *	 character not in set.
+ *
+ ********************************************************************/
+
+Datum
+bytealtrim(PG_FUNCTION_ARGS)
+{
+	bytea	   *string = PG_GETARG_BYTEA_PP(0);
+	bytea	   *set = PG_GETARG_BYTEA_PP(1);
+	bytea	   *ret;
+
+	ret = dobyteatrim(string, set, true, false);
+
+	PG_RETURN_BYTEA_P(ret);
+}
+
+/********************************************************************
+ *
+ * byteartrim
+ *
+ * Syntax:
+ *
+ *	 bytea byteartrim(bytea string, bytea set)
+ *
+ * Purpose:
+ *
+ *	 Returns string with final characters removed after the last
+ *	 character not in set.
+ *
+ ********************************************************************/
+
+Datum
+byteartrim(PG_FUNCTION_ARGS)
+{
+	bytea	   *string = PG_GETARG_BYTEA_PP(0);
+	bytea	   *set = PG_GETARG_BYTEA_PP(1);
+	bytea	   *ret;
+
+	ret = dobyteatrim(string, set, false, true);
 
 	PG_RETURN_BYTEA_P(ret);
 }