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

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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
This commit is contained in:
Tom Lane
2021-01-18 15:11:32 -05:00
parent a3ed4d1efe
commit a6cf3df4eb
9 changed files with 203 additions and 57 deletions
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170
src/backend/utils/adt/oracle_compat.c
View File

@@ -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);
/********************************************************************
@@ -521,6 +523,76 @@ dotrim(const char *string, int stringlen,
return cstring_to_text_with_len(string, stringlen);
}
/*
* Common implementation for bytea versions of btrim, ltrim, rtrim
*/
bytea *
dobyteatrim(bytea *string, bytea *set, bool doltrim, bool dortrim)
{
bytea *ret;
char *ptr,
*end,
*ptr2,
*ptr2start,
*end2;
int m,
stringlen,
setlen;
stringlen = VARSIZE_ANY_EXHDR(string);
setlen = VARSIZE_ANY_EXHDR(set);
if (stringlen <= 0 || setlen <= 0)
return string;
m = stringlen;
ptr = VARDATA_ANY(string);
end = ptr + stringlen - 1;
ptr2start = VARDATA_ANY(set);
end2 = ptr2start + setlen - 1;
if (doltrim)
{
while (m > 0)
{
ptr2 = ptr2start;
while (ptr2 <= end2)
{
if (*ptr == *ptr2)
break;
++ptr2;
}
if (ptr2 > end2)
break;
ptr++;
m--;
}
}
if (dortrim)
{
while (m > 0)
{
ptr2 = ptr2start;
while (ptr2 <= end2)
{
if (*end == *ptr2)
break;
++ptr2;
}
if (ptr2 > end2)
break;
end--;
m--;
}
}
ret = (bytea *) palloc(VARHDRSZ + m);
SET_VARSIZE(ret, VARHDRSZ + m);
memcpy(VARDATA(ret), ptr, m);
return ret;
}
/********************************************************************
*
* byteatrim
@@ -543,60 +615,62 @@ byteatrim(PG_FUNCTION_ARGS)
bytea *string = PG_GETARG_BYTEA_PP(0);
bytea *set = PG_GETARG_BYTEA_PP(1);
bytea *ret;
char *ptr,
*end,
*ptr2,
*ptr2start,
*end2;
int m,
stringlen,
setlen;
stringlen = VARSIZE_ANY_EXHDR(string);
setlen = VARSIZE_ANY_EXHDR(set);
ret = dobyteatrim(string, set, true, true);
if (stringlen <= 0 || setlen <= 0)
PG_RETURN_BYTEA_P(string);
PG_RETURN_BYTEA_P(ret);
}
m = stringlen;
ptr = VARDATA_ANY(string);
end = ptr + stringlen - 1;
ptr2start = VARDATA_ANY(set);
end2 = ptr2start + setlen - 1;
/********************************************************************
*
* bytealtrim
*
* Syntax:
*
* bytea bytealtrim(bytea string, bytea set)
*
* Purpose:
*
* Returns string with initial characters removed up to the first
* character not in set.
*
********************************************************************/
while (m > 0)
{
ptr2 = ptr2start;
while (ptr2 <= end2)
{
if (*ptr == *ptr2)
break;
++ptr2;
}
if (ptr2 > end2)
break;
ptr++;
m--;
}
Datum
bytealtrim(PG_FUNCTION_ARGS)
{
bytea *string = PG_GETARG_BYTEA_PP(0);
bytea *set = PG_GETARG_BYTEA_PP(1);
bytea *ret;
while (m > 0)
{
ptr2 = ptr2start;
while (ptr2 <= end2)
{
if (*end == *ptr2)
break;
++ptr2;
}
if (ptr2 > end2)
break;
end--;
m--;
}
ret = dobyteatrim(string, set, true, false);
ret = (bytea *) palloc(VARHDRSZ + m);
SET_VARSIZE(ret, VARHDRSZ + m);
memcpy(VARDATA(ret), ptr, m);
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);
}