ref: 6887fb518179a53f37c223986fde6539a2845b55
parent: c245a226ce5d456bc5568fc180e3f89bcaf03688
author: Jean-Marc Valin <[email protected]>
date: Thu Dec 6 20:40:02 EST 2007
Code for encoding Laplace-distributed variables (doesn't work).
--- a/libentcode/Makefile.am
+++ b/libentcode/Makefile.am
@@ -2,7 +2,7 @@
METASOURCES = AUTO
lib_LTLIBRARIES = libentcode.la
libentcode_la_SOURCES = bitrdec.c bitree.c bitrenc.c ecintrin.h entcode.c \
- entdec.c entenc.c mfrngdec.c mfrngenc.c probdec.c probenc.c probmod.c
+ entdec.c entenc.c laplace.c mfrngdec.c mfrngenc.c probdec.c probenc.c probmod.c
bin_PROGRAMS = ectest
ectest_SOURCES = ectest.c
ectest_LDADD = $(top_builddir)/libentcode/libentcode.la
--- /dev/null
+++ b/libentcode/laplace.c
@@ -1,0 +1,102 @@
+/* (C) 2007 Jean-Marc Valin, CSIRO
+*/
+/*
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ - Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ - Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ - Neither the name of the Xiph.org Foundation nor the names of its
+ contributors may be used to endorse or promote products derived from
+ this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
+ CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include "entenc.h"
+#include "entdec.h"
+#include <stdio.h>
+
+int ec_laplace_get_total(int decay)
+{+ return (1<<30)/((1<<14) - decay) - (1<<15) + 1;
+}
+
+void ec_laplace_encode(ec_enc *enc, int value, int decay)
+{+ int i, fl, fs, ft;
+ int s = 0;
+ if (value < 0)
+ {+ s = 1;
+ value = -value;
+ }
+ ft = ec_laplace_get_total(decay);
+ fl = -(1<<15);
+ fs = 1<<15;
+ for (i=0;i<value;i++)
+ {+ fl += fs*2;
+ fs = (fs*decay)>>14;
+ }
+ if (fl < 0)
+ fl = 0;
+ if (s)
+ fl += fs;
+ printf ("enc: %d %d %d\n", fl, fs, ft);+ ec_encode(enc, fl, fs, ft);
+}
+
+void ec_laplace_decode(ec_dec *dec, int decay)
+{+ int fl, fh, fs, ft, fm;
+ ft = ec_laplace_get_total(decay);
+
+ fm = ec_decode(dec, ft);
+ printf ("dec: %d/%d\n", fm, ft);+ //loop on values here to find fl, fh
+ //ec_dec_update(dec, fl, fh, ft);
+}
+
+#if 0
+int main()
+{+ ec_enc enc;
+ ec_dec dec;
+ ec_byte_buffer buf;
+
+ ec_byte_writeinit(&buf);
+ ec_enc_init(&enc,&buf);
+
+ ec_laplace_encode(&enc, 0, 10000);
+ ec_laplace_encode(&enc, 1, 12000);
+ ec_laplace_encode(&enc, -2, 9000);
+
+ ec_enc_done(&enc);
+
+ ec_byte_readinit(&buf,ec_byte_get_buffer(&buf),ec_byte_bytes(&buf));
+ ec_dec_init(&dec,&buf);
+
+ ec_laplace_decode(&dec, 10000);
+
+ ec_byte_writeclear(&buf);
+ return 0;
+}
+#endif
+