1 files changed, 150 insertions, 0 deletions
diff --git a/gpr/source/lib/vc5_common/syntax.c b/gpr/source/lib/vc5_common/syntax.c
new file mode 100755
index 0000000..bf64afe
--- /dev/null
+++ b/gpr/source/lib/vc5_common/syntax.c
@@ -0,0 +1,150 @@
+/*! @file syntax.c
+ *
+ *  @brief Implementation of functions for parsing the bitstream syntax of encoded samples.
+ *
+ *  @version 1.0.0
+ *
+ *  (C) Copyright 2018 GoPro Inc (http://gopro.com/).
+ *
+ *  Licensed under either:
+ *  - Apache License, Version 2.0, http://www.apache.org/licenses/LICENSE-2.0
+ *  - MIT license, http://opensource.org/licenses/MIT
+ *  at your option.
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include "common.h"
+
+//TODO: Simplify the definition of the marker bits
+#define CODEC_LOWPASS_START_CODE		0x1A4A
+#define CODEC_LOWPASS_START_SIZE		16
+#define CODEC_LOWPASS_END_CODE			0x1B4B
+#define CODEC_LOWPASS_END_SIZE			16
+
+#define CODEC_HIGHPASS_START_CODE		0x0D0D
+#define CODEC_HIGHPASS_START_SIZE		16
+#define CODEC_HIGHPASS_END_CODE			0x0C0C
+#define CODEC_HIGHPASS_END_SIZE			16
+
+#define CODEC_BAND_START_CODE			0x0E0E
+#define CODEC_BAND_START_SIZE			16
+//#define CODEC_BAND_END_CODE 			0x038F0B3E	//Codeset dependent cs9
+//#define CODEC_BAND_END_SIZE 			26			//Codeset dependent cs9
+#define CODEC_BAND_END_CODE				0x0000E33F	//Codeset dependent cs15
+#define CODEC_BAND_END_SIZE				16			//Codeset dependent cs15
+
+#define CODEC_SAMPLE_STOP_CODE			0x1E1E
+#define CODEC_SAMPLE_STOP_SIZE			16
+
+#define CODEC_COEFFICIENT_START_CODE	0x0F0F
+#define CODEC_COEFFICIENT_START_SIZE	16
+
+//! Size of a tag or value (in bits)
+#define BITSTREAM_TAG_SIZE				16
+
+
+// Bits in the interlace structure flags
+
+#define CODEC_FLAGS_INTERLACED			0x01	//!< Interlaced flags
+#define CODEC_FLAGS_FIELD1_FIRST		0x02	//!< NTSC has this bit cleared
+#define CODEC_FLAGS_FIELD1_ONLY			0x04	//!< Indicates missing fields
+#define CODEC_FLAGS_FIELD2_ONLY			0x08
+#define CODEC_FLAGS_DOMINANCE			0x10
+
+#define CODEC_FLAGS_INTERLACED_MASK		0x1F	//!< Unused bits must be zero
+
+// Useful macros for testing the interlaced flags
+
+#define INTERLACED(flags)			(((flags) & CODEC_FLAGS_INTERLACED) != 0)
+#define PROGRESSIVE(flags)			(((flags) & CODEC_FLAGS_INTERLACED) == 0)
+#define FIELD_ORDER_NTSC(flags)		(((flags) & CODEC_FLAGS_FIELD1_FIRST) == 0)
+#define FIELD_ORDER_PAL(flags)		(((flags) & CODEC_FLAGS_FIELD1_FIRST) != 0)
+#define FIELD_ONE_ONLY(flags)		(((flags) & CODEC_FLAGS_FIELD1_ONLY) != 0)
+#define FIELD_TWO_ONLY(flags)		(((flags) & CODEC_FLAGS_FIELD2_ONLY) != 0)
+#define FIELD_ONE_PRESENT(flags)	(((flags) & CODEC_FLAGS_FIELD2_ONLY) == 0)
+#define FIELD_TWO_PRESENT(flags)	(((flags) & CODEC_FLAGS_FIELD1_ONLY) == 0)
+#define FIELD_BOTH_PRESENT(flags)	(((flags) & (CODEC_FLAGS_FIELD1_ONLY | CODEC_FLAGS_FIELD1_ONLY)) == 0)
+
+// Bits in the copy protection flags
+
+#define CODEC_FLAGS_PROTECTED			0x01	//!< Copy protection flags
+#define CODEC_FLAGS_PROTECTION_MASK		0x01	//!< Unused bits must be zero
+
+/*!
+	@brief Check that the bitstream is aligned to a segment boundary
+ 
+ This function definition duplicates the same function in common/src/syntax.c,
+ but that file includes definitions intended only for the encoder.
+ 
+ @todo Remove duplicate function definitions.
+ */
+bool IsAlignedSegment(BITSTREAM *stream)
+{
+    return (stream->count == 0 || stream->count == bit_word_count);
+}
+
+/*!
+	@brief Convert the tag to an optional tag
+
+	An optional tag has a negative value.
+*/
+TAGWORD OptionalTag(TAGWORD tag)
+{
+	return ((tag < 0) ? tag : neg(tag));
+}
+
+/*!
+	@brief Convert the tag to a required tag
+
+	An optional tag has a negative value.
+*/
+TAGWORD RequiredTag(TAGWORD tag)
+{
+	return ((tag >= 0) ? tag : neg(tag));
+}
+
+
+/*!
+	@brief Check that the bitstream is aligned to a tag word boundary
+
+	@todo Check the places in the code where this function is used to
+	determine whether the bitstream should actually be aligned to a
+	segment boundary.
+*/
+bool IsAlignedTag(BITSTREAM *stream)
+{
+	return ((stream->count % BITSTREAM_TAG_SIZE) == 0);
+}
+
+/*!
+	@brief Pack the vector of prescale values into a single word
+
+	The wavelet transform uses a vector of prescale values indexed by the
+	wavelet level with the input image at level zero to specify the amount
+	of prescaling that should be performed on the input the wavelet transform.
+
+	This routine packs the prescale values into a segment value that can be
+	written into the bitstream.
+*/
+TAGWORD PackTransformPrescale(TRANSFORM *transform)
+{
+	TAGWORD packed_prescale = 0;
+	int i;
+
+	// Encode the prescale values that are actually used
+	for (i = 0; i < MAX_WAVELET_COUNT; i++)
+	{
+		assert((transform->prescale[i] & ~0x03) == 0);
+		packed_prescale += transform->prescale[i] << (14 - i * 2);
+	}
+
+	// The remaining prescale values with filled with zeros
+
+	return packed_prescale;
+}
+