Document and enforce that the usable range of setseed() arguments is

tglsfdc · tglsfdc · commit 23c356ccecaf · 2008-03-10T12:39:23.000Z
-1 to 1, not 0 to 1.  The actual behavior for values within this range
does not change.  Kris Jurka
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.423 2008/03/06 18:49:32 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.424 2008/03/10 12:39:22 tgl Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -828,7 +828,7 @@
       <row>
        <entry><literal><function>setseed</function>(<type>dp</type>)</literal></entry>
        <entry><type>void</type></entry>
-       <entry>set seed for subsequent <literal>random()</literal> calls (value between 0 and 1.0)</entry>
+       <entry>set seed for subsequent <literal>random()</literal> calls (value between -1.0 and 1.0)</entry>
        <entry><literal>setseed(0.54823)</literal></entry>
        <entry></entry>
       </row>
diff --git a/doc/src/sgml/ref/set.sgml b/doc/src/sgml/ref/set.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/set.sgml,v 1.91 2007/09/11 00:06:41 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/set.sgml,v 1.92 2008/03/10 12:39:22 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -166,7 +166,7 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
       <para>
        Sets the internal seed for the random number generator (the
        function <function>random</function>).  Allowed values are
-       floating-point numbers between 0 and 1, which are then
+       floating-point numbers between -1 and 1, which are then
        multiplied by 2<superscript>31</>-1.
       </para>
 
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.153 2008/01/01 19:45:52 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.154 2008/03/10 12:39:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1684,8 +1684,12 @@ Datum
 setseed(PG_FUNCTION_ARGS)
 {
 	float8		seed = PG_GETARG_FLOAT8(0);
-	int			iseed = (int) (seed * MAX_RANDOM_VALUE);
+	int			iseed;
 
+	if (seed < -1 || seed > 1)
+		elog(ERROR, "setseed parameter %f out of range [-1,1]", seed);
+
+	iseed = (int) (seed * MAX_RANDOM_VALUE);
 	srandom((unsigned int) iseed);
 
 	PG_RETURN_VOID();
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.435 2008/03/10 03:22:29 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.436 2008/03/10 12:39:23 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -1849,7 +1849,7 @@ static struct config_real ConfigureNamesReal[] =
 			GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
 		},
 		&phony_random_seed,
-		0.5, 0.0, 1.0, assign_random_seed, show_random_seed
+		0.0, -1.0, 1.0, assign_random_seed, show_random_seed
 	},
 
 	{

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.153 2008/01/01 19:45:52 momjian Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.154 2008/03/10 12:39:22 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -1684,8 +1684,12 @@ Datum`
`1684`	`1684`	`setseed(PG_FUNCTION_ARGS)`
`1685`	`1685`	`{`
`1686`	`1686`	`float8 seed = PG_GETARG_FLOAT8(0);`
`1687`		`- int iseed = (int) (seed * MAX_RANDOM_VALUE);`
	`1687`	`+ int iseed;`
`1688`	`1688`
	`1689`	`+ if (seed < -1 \|\| seed > 1)`
	`1690`	`+ elog(ERROR, "setseed parameter %f out of range [-1,1]", seed);`
	`1691`	`+`
	`1692`	`+ iseed = (int) (seed * MAX_RANDOM_VALUE);`
`1689`	`1693`	`srandom((unsigned int) iseed);`
`1690`	`1694`
`1691`	`1695`	`PG_RETURN_VOID();`
Original file line number	Diff line number	Diff line change
`@@ -10,7 +10,7 @@`
`10`	`10`	`* Written by Peter Eisentraut <peter_e@gmx.net>.`
`11`	`11`	`*`
`12`	`12`	`* IDENTIFICATION`
`13`		`- * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.435 2008/03/10 03:22:29 tgl Exp $`
	`13`	`+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.436 2008/03/10 12:39:23 tgl Exp $`
`14`	`14`	`*`
`15`	`15`	`*--------------------------------------------------------------------`
`16`	`16`	`*/`
`@@ -1849,7 +1849,7 @@ static struct config_real ConfigureNamesReal[] =`
`1849`	`1849`	`GUC_NO_SHOW_ALL \| GUC_NO_RESET_ALL \| GUC_NOT_IN_SAMPLE \| GUC_DISALLOW_IN_FILE`
`1850`	`1850`	`},`
`1851`	`1851`	`&phony_random_seed,`
`1852`		`- 0.5, 0.0, 1.0, assign_random_seed, show_random_seed`
	`1852`	`+ 0.0, -1.0, 1.0, assign_random_seed, show_random_seed`
`1853`	`1853`	`},`
`1854`	`1854`
`1855`	`1855`	`{`