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Allow to avoid NUL-byte management for stringinfos and use in format.c.

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In a lot of the places having appendBinaryStringInfo() maintain a
trailing NUL byte wasn't actually meaningful, e.g. when appending an
integer which can contain 0 in one of its bytes.

Removing this yields some small speedup, but more importantly will be
more consistent when providing faster variants of pq_sendint etc.

Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
This commit is contained in:
Andres Freund 2017-10-11 16:01:52 -07:00
parent 0b974dba2d
commit 70c2d1be2b
3 changed files with 37 additions and 10 deletions
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21
src/backend/lib/stringinfo.c
View File

@ -202,7 +202,7 @@ appendStringInfoSpaces(StringInfo str, int count)
* appendBinaryStringInfo
*
* Append arbitrary binary data to a StringInfo, allocating more space
* if necessary.
* if necessary. Ensures that a trailing null byte is present.
*/
void
appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
@ -224,6 +224,25 @@ appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
str->data[str->len] = '\0';
}
/*
* appendBinaryStringInfoNT
*
* Append arbitrary binary data to a StringInfo, allocating more space
* if necessary. Does not ensure a trailing null-byte exists.
*/
void
appendBinaryStringInfoNT(StringInfo str, const char *data, int datalen)
{
Assert(str != NULL);
/* Make more room if needed */
enlargeStringInfo(str, datalen);
/* OK, append the data */
memcpy(str->data + str->len, data, datalen);
str->len += datalen;
}
/*
* enlargeStringInfo
*

18
src/backend/libpq/pqformat.c
View File

@ -138,13 +138,13 @@ pq_sendcountedtext(StringInfo buf, const char *str, int slen,
{
slen = strlen(p);
pq_sendint(buf, slen + extra, 4);
appendBinaryStringInfo(buf, p, slen);
appendBinaryStringInfoNT(buf, p, slen);
pfree(p);
}
else
{
pq_sendint(buf, slen + extra, 4);
appendBinaryStringInfo(buf, str, slen);
appendBinaryStringInfoNT(buf, str, slen);
}
}
@ -191,11 +191,11 @@ pq_sendstring(StringInfo buf, const char *str)
if (p != str) /* actual conversion has been done? */
{
slen = strlen(p);
appendBinaryStringInfo(buf, p, slen + 1);
appendBinaryStringInfoNT(buf, p, slen + 1);
pfree(p);
}
else
appendBinaryStringInfo(buf, str, slen + 1);
appendBinaryStringInfoNT(buf, str, slen + 1);
}
/* --------------------------------
@ -242,15 +242,15 @@ pq_sendint(StringInfo buf, int i, int b)
{
case 1:
n8 = (unsigned char) i;
appendBinaryStringInfo(buf, (char *) &n8, 1);
appendBinaryStringInfoNT(buf, (char *) &n8, 1);
break;
case 2:
n16 = pg_hton16((uint16) i);
appendBinaryStringInfo(buf, (char *) &n16, 2);
appendBinaryStringInfoNT(buf, (char *) &n16, 2);
break;
case 4:
n32 = pg_hton32((uint32) i);
appendBinaryStringInfo(buf, (char *) &n32, 4);
appendBinaryStringInfoNT(buf, (char *) &n32, 4);
break;
default:
elog(ERROR, "unsupported integer size %d", b);
@ -271,7 +271,7 @@ pq_sendint64(StringInfo buf, int64 i)
{
uint64 n64 = pg_hton64(i);
appendBinaryStringInfo(buf, (char *) &n64, sizeof(n64));
appendBinaryStringInfoNT(buf, (char *) &n64, sizeof(n64));
}
/* --------------------------------
@ -297,7 +297,7 @@ pq_sendfloat4(StringInfo buf, float4 f)
swap.f = f;
swap.i = pg_hton32(swap.i);
appendBinaryStringInfo(buf, (char *) &swap.i, 4);
appendBinaryStringInfoNT(buf, (char *) &swap.i, 4);
}
/* --------------------------------

8
src/include/lib/stringinfo.h
View File

@ -143,6 +143,14 @@ extern void appendStringInfoSpaces(StringInfo str, int count);
extern void appendBinaryStringInfo(StringInfo str,
const char *data, int datalen);
/*------------------------
* appendBinaryStringInfoNT
* Append arbitrary binary data to a StringInfo, allocating more space
* if necessary. Does not ensure a trailing null-byte exists.
*/
extern void appendBinaryStringInfoNT(StringInfo str,
const char *data, int datalen);
/*------------------------
* enlargeStringInfo
* Make sure a StringInfo's buffer can hold at least 'needed' more bytes.