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

anarazel · anarazel · commit 70c2d1be2b1e · 2017-10-11T16:01:52.000-07:00
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
diff --git a/src/backend/lib/stringinfo.c b/src/backend/lib/stringinfo.c
@@ -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
  *
diff --git a/src/backend/libpq/pqformat.c b/src/backend/libpq/pqformat.c
@@ -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);
 }
 
 /* --------------------------------
diff --git a/src/include/lib/stringinfo.h b/src/include/lib/stringinfo.h
@@ -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.

Original file line number	Diff line number	Diff line change
`@@ -138,13 +138,13 @@ pq_sendcountedtext(StringInfo buf, const char *str, int slen,`
`138`	`138`	`{`
`139`	`139`	`slen = strlen(p);`
`140`	`140`	`pq_sendint(buf, slen + extra, 4);`
`141`		`- appendBinaryStringInfo(buf, p, slen);`
	`141`	`+ appendBinaryStringInfoNT(buf, p, slen);`
`142`	`142`	`pfree(p);`
`143`	`143`	`}`
`144`	`144`	`else`
`145`	`145`	`{`
`146`	`146`	`pq_sendint(buf, slen + extra, 4);`
`147`		`- appendBinaryStringInfo(buf, str, slen);`
	`147`	`+ appendBinaryStringInfoNT(buf, str, slen);`
`148`	`148`	`}`
`149`	`149`	`}`
`150`	`150`
`@@ -191,11 +191,11 @@ pq_sendstring(StringInfo buf, const char *str)`
`191`	`191`	`if (p != str) /* actual conversion has been done? */`
`192`	`192`	`{`
`193`	`193`	`slen = strlen(p);`
`194`		`- appendBinaryStringInfo(buf, p, slen + 1);`
	`194`	`+ appendBinaryStringInfoNT(buf, p, slen + 1);`
`195`	`195`	`pfree(p);`
`196`	`196`	`}`
`197`	`197`	`else`
`198`		`- appendBinaryStringInfo(buf, str, slen + 1);`
	`198`	`+ appendBinaryStringInfoNT(buf, str, slen + 1);`
`199`	`199`	`}`
`200`	`200`
`201`	`201`	`/* --------------------------------`
`@@ -242,15 +242,15 @@ pq_sendint(StringInfo buf, int i, int b)`
`242`	`242`	`{`
`243`	`243`	`case 1:`
`244`	`244`	`n8 = (unsigned char) i;`
`245`		`- appendBinaryStringInfo(buf, (char *) &n8, 1);`
	`245`	`+ appendBinaryStringInfoNT(buf, (char *) &n8, 1);`
`246`	`246`	`break;`
`247`	`247`	`case 2:`
`248`	`248`	`n16 = pg_hton16((uint16) i);`
`249`		`- appendBinaryStringInfo(buf, (char *) &n16, 2);`
	`249`	`+ appendBinaryStringInfoNT(buf, (char *) &n16, 2);`
`250`	`250`	`break;`
`251`	`251`	`case 4:`
`252`	`252`	`n32 = pg_hton32((uint32) i);`
`253`		`- appendBinaryStringInfo(buf, (char *) &n32, 4);`
	`253`	`+ appendBinaryStringInfoNT(buf, (char *) &n32, 4);`
`254`	`254`	`break;`
`255`	`255`	`default:`
`256`	`256`	`elog(ERROR, "unsupported integer size %d", b);`
`@@ -271,7 +271,7 @@ pq_sendint64(StringInfo buf, int64 i)`
`271`	`271`	`{`
`272`	`272`	`uint64 n64 = pg_hton64(i);`
`273`	`273`
`274`		`- appendBinaryStringInfo(buf, (char *) &n64, sizeof(n64));`
	`274`	`+ appendBinaryStringInfoNT(buf, (char *) &n64, sizeof(n64));`
`275`	`275`	`}`
`276`	`276`
`277`	`277`	`/* --------------------------------`
`@@ -297,7 +297,7 @@ pq_sendfloat4(StringInfo buf, float4 f)`
`297`	`297`	`swap.f = f;`
`298`	`298`	`swap.i = pg_hton32(swap.i);`
`299`	`299`
`300`		`- appendBinaryStringInfo(buf, (char *) &swap.i, 4);`
	`300`	`+ appendBinaryStringInfoNT(buf, (char *) &swap.i, 4);`
`301`	`301`	`}`
`302`	`302`
`303`	`303`	`/* --------------------------------`