1 files changed, 103 insertions, 0 deletions
diff --git a/indra/llmath/llquantize.h b/indra/llmath/llquantize.h
new file mode 100644
index 0000000000..8aa03628f2
--- /dev/null
+++ b/indra/llmath/llquantize.h
@@ -0,0 +1,103 @@
+/** 
+ * @file llquantize.h
+ * @brief useful routines for quantizing floats to various length ints
+ * and back out again
+ *
+ * Copyright (c) 2001-$CurrentYear$, Linden Research, Inc.
+ * $License$
+ */
+
+#ifndef LL_LLQUANTIZE_H
+#define LL_LLQUANTIZE_H
+
+const U16 U16MAX = 65535;
+const F32 OOU16MAX = 1.f/(F32)(U16MAX);
+
+const U8 U8MAX = 255;
+const F32 OOU8MAX = 1.f/(F32)(U8MAX);
+
+const U8 FIRSTVALIDCHAR = 54;
+const U8 MAXSTRINGVAL = U8MAX - FIRSTVALIDCHAR; //we don't allow newline or null 
+
+
+inline U16 F32_to_U16(F32 val, F32 lower, F32 upper)
+{
+	val = llclamp(val, lower, upper);
+	// make sure that the value is positive and normalized to <0, 1>
+	val -= lower;
+	val /= (upper - lower);
+
+	// return the U16
+	return (U16)(llfloor(val*U16MAX));
+}
+
+inline F32 U16_to_F32(U16 ival, F32 lower, F32 upper)
+{
+	F32 val = ival*OOU16MAX;
+	F32 delta = (upper - lower);
+	val *= delta;
+	val += lower;
+
+	F32 max_error = delta*OOU16MAX;
+
+	// make sure that zero's come through as zero
+	if (fabsf(val) < max_error)
+		val = 0.f;
+
+	return val;
+}
+
+inline U8 F32_to_U8(F32 val, F32 lower, F32 upper)
+{
+	val = llclamp(val, lower, upper);
+	// make sure that the value is positive and normalized to <0, 1>
+	val -= lower;
+	val /= (upper - lower);
+
+	// return the U8
+	return (U8)(llfloor(val*U8MAX));
+}
+
+inline F32 U8_to_F32(U8 ival, F32 lower, F32 upper)
+{
+	F32 val = ival*OOU8MAX;
+	F32 delta = (upper - lower);
+	val *= delta;
+	val += lower;
+
+	F32 max_error = delta*OOU8MAX;
+
+	// make sure that zero's come through as zero
+	if (fabsf(val) < max_error)
+		val = 0.f;
+
+	return val;
+}
+
+inline U8 F32_TO_STRING(F32 val, F32 lower, F32 upper)
+{
+	val = llclamp(val, lower, upper); //[lower, upper]
+	// make sure that the value is positive and normalized to <0, 1>
+	val -= lower;					//[0, upper-lower]
+	val /= (upper - lower);			//[0,1]
+	val = val * MAXSTRINGVAL;		//[0, MAXSTRINGVAL]
+	val = floor(val + 0.5f);		//[0, MAXSTRINGVAL]
+
+	U8 stringVal = (U8)(val) + FIRSTVALIDCHAR;			//[FIRSTVALIDCHAR, MAXSTRINGVAL + FIRSTVALIDCHAR]
+	return stringVal;
+}
+
+inline F32 STRING_TO_F32(U8 ival, F32 lower, F32 upper)
+{
+	// remove empty space left for NULL, newline, etc.
+	ival -= FIRSTVALIDCHAR;								//[0, MAXSTRINGVAL]
+
+	F32 val = (F32)ival * (1.f / (F32)MAXSTRINGVAL);	//[0, 1]
+	F32 delta = (upper - lower);
+	val *= delta;										//[0, upper - lower]
+	val += lower;										//[lower, upper]
+
+	return val;
+}
+
+#endif