[qcms] Make half float code self-contained: add halffloat.h

third_party/qcms/src/transform_util.h

 /* vim: set ts=8 sw=8 noexpandtab: */
 //  qcms
 //  Copyright (C) 2009 Mozilla Foundation
 //  Copyright (C) 1998-2007 Marti Maria
 //
 // Permission is hereby granted, free of charge, to any person obtaining 
 // a copy of this software and associated documentation files (the "Software"), 
 // to deal in the Software without restriction, including without limitation 
 // the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 // and/or sell copies of the Software, and to permit persons to whom the Software 
@@ skipping 37 matching lines @@
 
 
 float *build_input_gamma_table(struct curveType *TRC);
 struct matrix build_colorant_matrix(qcms_profile *p);
 void build_output_lut(struct curveType *trc,
                       uint16_t **output_gamma_lut, size_t *output_gamma_lut_length);
 
 struct matrix matrix_invert(struct matrix mat);
 qcms_bool compute_precache(struct curveType *trc, uint8_t *output);
 
-static inline unsigned short float_to_half_float(float f)
-{
-        extern const unsigned short qcms_half_float_base_table[512];
-        extern const unsigned char qcms_half_float_shift_table[512];
-
-        // See Blink::Source/platform/graphics/gpu/WebGLImageConversion.cpp::convertFloatToHalfFloat()
-        // and http://crbug.com/491784
-
-        unsigned temp = *((unsigned *)(&f));
-        unsigned signexp = (temp >> 23) & 0x1ff;
-        return qcms_half_float_base_table[signexp] + ((temp & 0x007fffff) >> qcms_half_float_shift_table[signexp]);
-}
-
 #endif