From 5f0b12845c8dd3cf14e5533eac10e369897f4b2a Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Thu, 10 May 2012 15:10:58 +0200
Subject: [PATCH] CData: added a cast to double precision.

The cast may only be done explicitly.
---
 src/cdata.c       | 16 ++++++++++++++++
 src/postrr.h.in   |  2 ++
 src/postrr.sql.in |  9 +++++++++
 3 files changed, 27 insertions(+)

diff --git a/src/cdata.c b/src/cdata.c
index 32e8e4d..03fefbc 100644
--- a/src/cdata.c
+++ b/src/cdata.c
@@ -79,6 +79,7 @@ PG_FUNCTION_INFO_V1(cdata_typmodout);
 
 PG_FUNCTION_INFO_V1(cdata_to_cdata);
 PG_FUNCTION_INFO_V1(int32_to_cdata);
+PG_FUNCTION_INFO_V1(cdata_to_float8);
 
 PG_FUNCTION_INFO_V1(cdata_update);
 
@@ -331,6 +332,21 @@ int32_to_cdata(PG_FUNCTION_ARGS)
 	PG_RETURN_CDATA_P(data);
 } /* int32_to_cdata */
 
+Datum
+cdata_to_float8(PG_FUNCTION_ARGS)
+{
+	cdata_t *data;
+
+	if (PG_NARGS() != 1)
+		ereport(ERROR, (
+					errmsg("cdata_to_float8() expects one argument"),
+					errhint("Usage: cdata_to_float8(cdata)")
+				));
+
+	data = PG_GETARG_CDATA_P(0);
+	PG_RETURN_FLOAT8(data->value);
+} /* cdata_to_float8 */
+
 Datum
 cdata_update(PG_FUNCTION_ARGS)
 {
diff --git a/src/postrr.h.in b/src/postrr.h.in
index c309ef0..798fd3f 100644
--- a/src/postrr.h.in
+++ b/src/postrr.h.in
@@ -134,6 +134,8 @@ Datum
 cdata_to_cdata(PG_FUNCTION_ARGS);
 Datum
 int32_to_cdata(PG_FUNCTION_ARGS);
+Datum
+cdata_to_float8(PG_FUNCTION_ARGS);
 
 /* aux. functions */
 Datum
diff --git a/src/postrr.sql.in b/src/postrr.sql.in
index 9339e32..68c47df 100644
--- a/src/postrr.sql.in
+++ b/src/postrr.sql.in
@@ -280,6 +280,15 @@ CREATE CAST (integer AS cdata)
 	WITH FUNCTION CData(integer, integer, boolean)
 	AS ASSIGNMENT;
 
+CREATE OR REPLACE FUNCTION Float8(cdata)
+	RETURNS double precision
+	AS 'postrr-@POSTRR_MAJOR_VERSION@.@POSTRR_MINOR_VERSION@', 'cdata_to_float8'
+	LANGUAGE 'C' IMMUTABLE STRICT;
+
+CREATE CAST (cdata AS double precision)
+	WITH FUNCTION Float8(cdata);
+	-- EXPLICIT
+
 CREATE OR REPLACE FUNCTION CData_update(cdata, cdata)
 	RETURNS cdata
 	AS 'postrr-@POSTRR_MAJOR_VERSION@.@POSTRR_MINOR_VERSION@', 'cdata_update'
-- 
2.30.2