externals: Track upstream opus

Tracks upstream opus, allowing the library to be easily updated. While
we're at it, we incorporate the CMakeLists.txt so that we have easy
control over the requirements of the build.

externals/opus/CMakeLists.txt

@@ -0,0 +1,250 @@
+cmake_minimum_required(VERSION 3.8)
+
+project(opus)
+
+option(OPUS_STACK_PROTECTOR "Use stack protection" OFF)
+option(OPUS_USE_ALLOCA "Use alloca for stack arrays (on non-C99 compilers)" OFF)
+option(OPUS_CUSTOM_MODES "Enable non-Opus modes, e.g. 44.1 kHz & 2^n frames" OFF)
+option(OPUS_FIXED_POINT "Compile as fixed-point (for machines without a fast enough FPU)" OFF)
+option(OPUS_ENABLE_FLOAT_API "Compile with the floating point API (for machines with float library" ON)
+
+include(opus/opus_functions.cmake)
+
+if(OPUS_STACK_PROTECTOR)
+    if(NOT MSVC) # GC on by default on MSVC
+        check_and_set_flag(STACK_PROTECTION_STRONG -fstack-protector-strong)
+    endif()
+else()
+    if(MSVC)
+        check_and_set_flag(BUFFER_SECURITY_CHECK /GS-)
+    endif()
+endif()
+
+add_library(opus STATIC
+    # CELT sources
+    opus/celt/bands.c
+    opus/celt/celt.c
+    opus/celt/celt_decoder.c
+    opus/celt/celt_encoder.c
+    opus/celt/celt_lpc.c
+    opus/celt/cwrs.c
+    opus/celt/entcode.c
+    opus/celt/entdec.c
+    opus/celt/entenc.c
+    opus/celt/kiss_fft.c
+    opus/celt/laplace.c
+    opus/celt/mathops.c
+    opus/celt/mdct.c
+    opus/celt/modes.c
+    opus/celt/pitch.c
+    opus/celt/quant_bands.c
+    opus/celt/rate.c
+    opus/celt/vq.c
+
+    # SILK sources
+    opus/silk/A2NLSF.c
+    opus/silk/CNG.c
+    opus/silk/HP_variable_cutoff.c
+    opus/silk/LPC_analysis_filter.c
+    opus/silk/LPC_fit.c
+    opus/silk/LPC_inv_pred_gain.c
+    opus/silk/LP_variable_cutoff.c
+    opus/silk/NLSF2A.c
+    opus/silk/NLSF_VQ.c
+    opus/silk/NLSF_VQ_weights_laroia.c
+    opus/silk/NLSF_decode.c
+    opus/silk/NLSF_del_dec_quant.c
+    opus/silk/NLSF_encode.c
+    opus/silk/NLSF_stabilize.c
+    opus/silk/NLSF_unpack.c
+    opus/silk/NSQ.c
+    opus/silk/NSQ_del_dec.c
+    opus/silk/PLC.c
+    opus/silk/VAD.c
+    opus/silk/VQ_WMat_EC.c
+    opus/silk/ana_filt_bank_1.c
+    opus/silk/biquad_alt.c
+    opus/silk/bwexpander.c
+    opus/silk/bwexpander_32.c
+    opus/silk/check_control_input.c
+    opus/silk/code_signs.c
+    opus/silk/control_SNR.c
+    opus/silk/control_audio_bandwidth.c
+    opus/silk/control_codec.c
+    opus/silk/dec_API.c
+    opus/silk/decode_core.c
+    opus/silk/decode_frame.c
+    opus/silk/decode_indices.c
+    opus/silk/decode_parameters.c
+    opus/silk/decode_pitch.c
+    opus/silk/decode_pulses.c
+    opus/silk/decoder_set_fs.c
+    opus/silk/enc_API.c
+    opus/silk/encode_indices.c
+    opus/silk/encode_pulses.c
+    opus/silk/gain_quant.c
+    opus/silk/init_decoder.c
+    opus/silk/init_encoder.c
+    opus/silk/inner_prod_aligned.c
+    opus/silk/interpolate.c
+    opus/silk/lin2log.c
+    opus/silk/log2lin.c
+    opus/silk/pitch_est_tables.c
+    opus/silk/process_NLSFs.c
+    opus/silk/quant_LTP_gains.c
+    opus/silk/resampler.c
+    opus/silk/resampler_down2.c
+    opus/silk/resampler_down2_3.c
+    opus/silk/resampler_private_AR2.c
+    opus/silk/resampler_private_IIR_FIR.c
+    opus/silk/resampler_private_down_FIR.c
+    opus/silk/resampler_private_up2_HQ.c
+    opus/silk/resampler_rom.c
+    opus/silk/shell_coder.c
+    opus/silk/sigm_Q15.c
+    opus/silk/sort.c
+    opus/silk/stereo_LR_to_MS.c
+    opus/silk/stereo_MS_to_LR.c
+    opus/silk/stereo_decode_pred.c
+    opus/silk/stereo_encode_pred.c
+    opus/silk/stereo_find_predictor.c
+    opus/silk/stereo_quant_pred.c
+    opus/silk/sum_sqr_shift.c
+    opus/silk/table_LSF_cos.c
+    opus/silk/tables_LTP.c
+    opus/silk/tables_NLSF_CB_NB_MB.c
+    opus/silk/tables_NLSF_CB_WB.c
+    opus/silk/tables_gain.c
+    opus/silk/tables_other.c
+    opus/silk/tables_pitch_lag.c
+    opus/silk/tables_pulses_per_block.c
+
+    # Opus sources
+    opus/src/analysis.c
+    opus/src/mapping_matrix.c
+    opus/src/mlp.c
+    opus/src/mlp_data.c
+    opus/src/opus.c
+    opus/src/opus_decoder.c
+    opus/src/opus_encoder.c
+    opus/src/opus_multistream.c
+    opus/src/opus_multistream_decoder.c
+    opus/src/opus_multistream_encoder.c
+    opus/src/opus_projection_decoder.c
+    opus/src/opus_projection_encoder.c
+    opus/src/repacketizer.c
+)
+
+if (DEBUG)
+    target_sources(opus PRIVATE opus/silk/debug.c)
+endif()
+
+if (OPUS_FIXED_POINT)
+    target_sources(opus PRIVATE
+        opus/silk/fixed/LTP_analysis_filter_FIX.c
+        opus/silk/fixed/LTP_scale_ctrl_FIX.c
+        opus/silk/fixed/apply_sine_window_FIX.c
+        opus/silk/fixed/autocorr_FIX.c
+        opus/silk/fixed/burg_modified_FIX.c
+        opus/silk/fixed/corrMatrix_FIX.c
+        opus/silk/fixed/encode_frame_FIX.c
+        opus/silk/fixed/find_LPC_FIX.c
+        opus/silk/fixed/find_LTP_FIX.c
+        opus/silk/fixed/find_pitch_lags_FIX.c
+        opus/silk/fixed/find_pred_coefs_FIX.c
+        opus/silk/fixed/k2a_FIX.c
+        opus/silk/fixed/k2a_Q16_FIX.c
+        opus/silk/fixed/noise_shape_analysis_FIX.c
+        opus/silk/fixed/pitch_analysis_core_FIX.c
+        opus/silk/fixed/prefilter_FIX.c
+        opus/silk/fixed/process_gains_FIX.c
+        opus/silk/fixed/regularize_correlations_FIX.c
+        opus/silk/fixed/residual_energy16_FIX.c
+        opus/silk/fixed/residual_energy_FIX.c
+        opus/silk/fixed/schur64_FIX.c
+        opus/silk/fixed/schur_FIX.c
+        opus/silk/fixed/solve_LS_FIX.c
+        opus/silk/fixed/vector_ops_FIX.c
+        opus/silk/fixed/warped_autocorrelation_FIX.c
+    )
+else()
+    target_sources(opus PRIVATE
+        opus/silk/float/LPC_analysis_filter_FLP.c
+        opus/silk/float/LPC_inv_pred_gain_FLP.c
+        opus/silk/float/LTP_analysis_filter_FLP.c
+        opus/silk/float/LTP_scale_ctrl_FLP.c
+        opus/silk/float/apply_sine_window_FLP.c
+        opus/silk/float/autocorrelation_FLP.c
+        opus/silk/float/burg_modified_FLP.c
+        opus/silk/float/bwexpander_FLP.c
+        opus/silk/float/corrMatrix_FLP.c
+        opus/silk/float/encode_frame_FLP.c
+        opus/silk/float/energy_FLP.c
+        opus/silk/float/find_LPC_FLP.c
+        opus/silk/float/find_LTP_FLP.c
+        opus/silk/float/find_pitch_lags_FLP.c
+        opus/silk/float/find_pred_coefs_FLP.c
+        opus/silk/float/inner_product_FLP.c
+        opus/silk/float/k2a_FLP.c
+        opus/silk/float/noise_shape_analysis_FLP.c
+        opus/silk/float/pitch_analysis_core_FLP.c
+        opus/silk/float/process_gains_FLP.c
+        opus/silk/float/regularize_correlations_FLP.c
+        opus/silk/float/residual_energy_FLP.c
+        opus/silk/float/scale_copy_vector_FLP.c
+        opus/silk/float/scale_vector_FLP.c
+        opus/silk/float/schur_FLP.c
+        opus/silk/float/sort_FLP.c
+        opus/silk/float/warped_autocorrelation_FLP.c
+        opus/silk/float/wrappers_FLP.c
+    )
+endif()
+
+target_compile_definitions(opus PRIVATE OPUS_BUILD ENABLE_HARDENING)
+
+if(NOT MSVC)
+    target_compile_definitions(opus PRIVATE _FORTIFY_SOURCE=2)
+endif()
+
+# It is strongly recommended to uncomment one of these VAR_ARRAYS: Use C99
+# variable-length arrays for stack allocation USE_ALLOCA: Use alloca() for stack
+# allocation If none is defined, then the fallback is a non-threadsafe global
+# array
+if(OPUS_USE_ALLOCA OR MSVC)
+    target_compile_definitions(opus PRIVATE USE_ALLOCA)
+else()
+    target_compile_definitions(opus PRIVATE VAR_ARRAYS)
+endif()
+
+if(OPUS_CUSTOM_MODES)
+    target_compile_definitions(opus PRIVATE CUSTOM_MODES)
+endif()
+
+if(NOT OPUS_ENABLE_FLOAT_API)
+    target_compile_definitions(opus PRIVATE DISABLE_FLOAT_API)
+endif()
+
+target_compile_definitions(opus
+PUBLIC
+    -DOPUS_VERSION="\\"1.3.1\\""
+
+PRIVATE
+    # Use C99 intrinsics to speed up float-to-int conversion
+    HAVE_LRINTF
+)
+
+if (FIXED_POINT)
+    target_compile_definitions(opus PRIVATE -DFIXED_POINT=1 -DDISABLE_FLOAT_API)
+endif()
+
+target_include_directories(opus
+PUBLIC
+    opus/include
+
+PRIVATE
+    opus/celt
+    opus/silk
+    opus/silk/fixed
+    opus/silk/float
+    opus/src
+)