From 96f81be8f602195ab40e2e1b33129e050dfe5c6a Mon Sep 17 00:00:00 2001
From: Nick Bowler <nbowler@draconx.ca>
Date: Sat, 19 May 2012 23:05:34 -0400
Subject: [PATCH] uobject: Add support for float properties.

Since it's not too hard to add these, do so.  Add the DrawScale property
to Engine.Texture to demonstrate it.
---
 m4/.gitignore          | 14 ++++++++++++++
 m4/gnulib-cache.m4     |  4 +++-
 src/engine/texture.gob |  8 ++++++++
 src/uobject/uobject.c  | 43 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/m4/.gitignore b/m4/.gitignore
index f6d1341..d191dec 100644
--- a/m4/.gitignore
+++ b/m4/.gitignore
@@ -1,19 +1,33 @@
 00gnulib.m4
 argz.m4
+copysignf.m4
+exponentd.m4
+exponentf.m4
+exponentl.m4
 extensions.m4
+float_h.m4
+fpieee.m4
 getopt.m4
 gnulib-common.m4
 gnulib-comp.m4
 gnulib-tool.m4
 include_next.m4
+isnand.m4
+isnanf.m4
+isnanl.m4
+ldexp.m4
+ldexpf.m4
 libtool.m4
 ltdl.m4
 ltoptions.m4
 ltsugar.m4
 ltversion.m4
 lt~obsolete.m4
+math_h.m4
+mathfunc.m4
 nocrash.m4
 off_t.m4
+signbit.m4
 ssize_t.m4
 stddef_h.m4
 strcase.m4
diff --git a/m4/gnulib-cache.m4 b/m4/gnulib-cache.m4
index 3b9685c..da9334c 100644
--- a/m4/gnulib-cache.m4
+++ b/m4/gnulib-cache.m4
@@ -27,12 +27,14 @@
 
 
 # Specification in the form of a command-line invocation:
-#   gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=. --makefile-name=gnulib.mk.in --conditional-dependencies --libtool --macro-prefix=gl --no-vc-files getopt-gnu strcase
+#   gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=. --makefile-name=gnulib.mk.in --conditional-dependencies --libtool --macro-prefix=gl --no-vc-files copysignf getopt-gnu ldexpf strcase
 
 # Specification in the form of a few gnulib-tool.m4 macro invocations:
 gl_LOCAL_DIR([])
 gl_MODULES([
+  copysignf
   getopt-gnu
+  ldexpf
   strcase
 ])
 gl_AVOID([])
diff --git a/src/engine/texture.gob b/src/engine/texture.gob
index ea5e266..49af538 100644
--- a/src/engine/texture.gob
+++ b/src/engine/texture.gob
@@ -117,6 +117,8 @@ class Engine:Texture from U:Object (dynamic)
 	private unsigned VClamp;
 	private unsigned VBits;
 
+	private float DrawScale;
+
 	private Engine:Palette *Palette;
 	private Engine:Texture *DetailTexture;
 
@@ -270,6 +272,12 @@ class Engine:Texture from U:Object (dynamic)
 		, link
 		);
 
+	property FLOAT DrawScale
+		( nick = "Draw Scale"
+		, blurb = "Relative size to parent surface"
+		, link
+		);
+
 	property OBJECT Palette
 		( nick = "Palette"
 		, blurb = "Reference to the texture's palette."
diff --git a/src/uobject/uobject.c b/src/uobject/uobject.c
index a082690..627abe6 100644
--- a/src/uobject/uobject.c
+++ b/src/uobject/uobject.c
@@ -19,6 +19,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <math.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <inttypes.h>
@@ -299,6 +300,41 @@ static int decode_object_property(UObject *uo, GValue *val, unsigned long len)
 	return 0;
 }
 
+/*
+ * Deserialize an IEEE 754 binary32 value in "little endian" (for whatever
+ * that term is worth in this context).  That is, when interpreted as a little
+ * endian 32-bit unsigned integer: bit 31 is the sign, bits 30-23 are the
+ * (biased) exponent, and bits 22-0 are the encoded part of the significand.
+ *
+ * The implementation is designed to be agnostic of the platform's actual
+ * float type, but the conversion may be lossy if "float" is not itself a
+ * binary32 format.  NaN payloads are not preserved.
+ */
+static float unpack_binary32_le(const unsigned char *buf)
+{
+	unsigned long raw;
+	long significand;
+	int exponent;
+	float result;
+
+	raw = unpack_32_le(buf);
+	exponent = (raw & 0x7f800000) >> 23;
+	significand = (raw & 0x007fffff) >> 0;
+
+	switch (exponent) {
+	case 255:
+		result = significand ? NAN : INFINITY;
+		break;
+	default:
+		significand |= 0x00800000;
+		/* fall through */
+	case 0:
+		result = ldexpf(significand, exponent-126-24);
+	}
+
+	return copysignf(result, raw & 0x80000000 ? -1 : 1);
+}
+
 static unsigned long deserialize_property(UObject *uo, struct prop_head *head)
 {
 	struct u_object_priv *priv = U_OBJECT_GET_PRIV(uo);
@@ -340,6 +376,13 @@ static unsigned long deserialize_property(UObject *uo, struct prop_head *head)
 			return 0;
 		g_object_set_property(G_OBJECT(uo), head->prop_name, &val);
 		break;
+	case PROPERTY_FLOAT:
+		if (head->size != 4 || priv->nbuf-len < head->size)
+			return 0;
+		g_value_init(&val, G_TYPE_FLOAT);
+		g_value_set_float(&val, unpack_binary32_le(priv->buf+len));
+		g_object_set_property(G_OBJECT(uo), head->prop_name, &val);
+		break;
 	default:
 		u_warn(uo, "%s: unsupported property type %u",
 		           head->prop_name, (unsigned)head->type);
-- 
2.43.0