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authorMichael Niedermayer <michaelni@gmx.at>2004-05-04 02:51:18 +0000
committerMichael Niedermayer <michaelni@gmx.at>2004-05-04 02:51:18 +0000
commit29adde838c244b59ea03f81cb8625deac5bf3cd6 (patch)
treec6271057fbe45f2341b746ea9c9f45773cab4dc0
parentce5b6f63c52ba399d80436937c64dea8c241b753 (diff)
downloadffmpeg-29adde838c244b59ea03f81cb8625deac5bf3cd6.tar.gz
arbitrary precision integer support
+ - * / % << >> log2 compare are supported and dont fear, no bloated lib, just 130 lines of c code Originally committed as revision 3105 to svn://svn.ffmpeg.org/ffmpeg/trunk
-rw-r--r--libavcodec/Makefile2
-rw-r--r--libavcodec/integer.c195
-rw-r--r--libavcodec/integer.h47
3 files changed, 243 insertions, 1 deletions
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 3b8f14b338..64b3b132ed 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -20,7 +20,7 @@ OBJS= common.o utils.o mem.o allcodecs.o \
roqvideo.o dpcm.o interplayvideo.o xan.o rpza.o cinepak.o msrle.o \
msvideo1.o vqavideo.o idcinvideo.o adx.o rational.o faandct.o 8bps.o \
smc.o parser.o flicvideo.o truemotion1.o vmdav.o lcl.o qtrle.o g726.o \
- flac.o vp3dsp.o
+ flac.o vp3dsp.o integer.o
ifeq ($(AMR_NB),yes)
ifeq ($(AMR_NB_FIXED),yes)
diff --git a/libavcodec/integer.c b/libavcodec/integer.c
new file mode 100644
index 0000000000..025560f9e8
--- /dev/null
+++ b/libavcodec/integer.c
@@ -0,0 +1,195 @@
+/*
+ * arbitrary precision integers
+ * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/**
+ * @file integer.c
+ * arbitrary precision integers.
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+#include "common.h"
+#include "integer.h"
+
+AVInteger av_add_i(AVInteger a, AVInteger b){
+ int i, carry=0;
+
+ for(i=0; i<AV_INTEGER_SIZE; i++){
+ carry= (carry>>16) + a.v[i] + b.v[i];
+ a.v[i]= carry;
+ }
+ return a;
+}
+
+AVInteger av_sub_i(AVInteger a, AVInteger b){
+ int i, carry=0;
+
+ for(i=0; i<AV_INTEGER_SIZE; i++){
+ carry= (carry>>16) + a.v[i] - b.v[i];
+ a.v[i]= carry;
+ }
+ return a;
+}
+
+int av_log2_i(AVInteger a){
+ int i;
+
+ for(i=AV_INTEGER_SIZE-1; i>=0; i--){
+ if(a.v[i])
+ return av_log2_16bit(a.v[i]) + 16*i;
+ }
+ return -1;
+}
+
+AVInteger av_mul_i(AVInteger a, AVInteger b){
+ AVInteger out;
+ int i, j;
+ int na= (av_log2_i(a)+16) >> 4;
+ int nb= (av_log2_i(b)+16) >> 4;
+
+ memset(&out, 0, sizeof(out));
+
+ for(i=0; i<na; i++){
+ unsigned int carry=0;
+
+ if(a.v[i])
+ for(j=i; j<AV_INTEGER_SIZE && j-i<=nb; j++){
+ carry= (carry>>16) + out.v[j] + a.v[i]*b.v[j-i];
+ out.v[j]= carry;
+ }
+ }
+
+ return out;
+}
+
+int av_cmp_i(AVInteger a, AVInteger b){
+ int i;
+ int v= (int16_t)a.v[AV_INTEGER_SIZE-1] - (int16_t)b.v[AV_INTEGER_SIZE-1];
+ if(v) return (v>>16)|1;
+
+ for(i=AV_INTEGER_SIZE-2; i>=0; i--){
+ int v= a.v[i] - b.v[i];
+ if(v) return (v>>16)|1;
+ }
+ return 0;
+}
+
+AVInteger av_shr_i(AVInteger a, int s){
+ AVInteger out;
+ int i;
+
+ for(i=0; i<AV_INTEGER_SIZE; i++){
+ int index= i + (s>>4);
+ unsigned int v=0;
+ if(index+1<AV_INTEGER_SIZE && index+1>=0) v = a.v[index+1]<<16;
+ if(index <AV_INTEGER_SIZE && index >=0) v+= a.v[index ];
+ out.v[i]= v >> (s&15);
+ }
+ return out;
+}
+
+AVInteger av_mod_i(AVInteger *quot, AVInteger a, AVInteger b){
+ int i= av_log2_i(a) - av_log2_i(b);
+ AVInteger quot_temp;
+ if(!quot) quot = &quot_temp;
+
+ assert((int16_t)a[AV_INTEGER_SIZE-1] >= 0 && (int16_t)b[AV_INTEGER_SIZE-1] >= 0);
+ assert(av_log2(b)>=0);
+
+ if(i > 0)
+ b= av_shr_i(b, -i);
+
+ memset(quot, 0, sizeof(AVInteger));
+
+ while(i-- >= 0){
+ *quot= av_shr_i(*quot, -1);
+ if(av_cmp_i(a, b) >= 0){
+ a= av_sub_i(a, b);
+ quot->v[0] += 1;
+ }
+ b= av_shr_i(b, 1);
+ }
+ return a;
+}
+
+AVInteger av_div_i(AVInteger a, AVInteger b){
+ AVInteger quot;
+ av_mod_i(&quot, a, b);
+ return quot;
+}
+
+AVInteger av_int2i(int64_t a){
+ AVInteger out;
+ int i;
+
+ for(i=0; i<AV_INTEGER_SIZE; i++){
+ out.v[i]= a;
+ a>>=16;
+ }
+ return out;
+}
+
+int64_t av_i2int(AVInteger a){
+ int i;
+ int64_t out=(int8_t)a.v[AV_INTEGER_SIZE-1];
+
+ for(i= AV_INTEGER_SIZE-2; i>=0; i--){
+ out = (out<<16) + a.v[i];
+ }
+ return out;
+}
+
+#if 0
+#undef NDEBUG
+#include <assert.h>
+
+const uint8_t ff_log2_tab[256]={
+ 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+ 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+};
+
+main(){
+ int64_t a,b;
+
+ for(a=7; a<256*256*256; a+=13215){
+ for(b=3; b<256*256*256; b+=27118){
+ AVInteger ai= av_int2i(a);
+ AVInteger bi= av_int2i(b);
+
+ assert(av_i2int(ai) == a);
+ assert(av_i2int(bi) == b);
+ assert(av_i2int(av_add_i(ai,bi)) == a+b);
+ assert(av_i2int(av_sub_i(ai,bi)) == a-b);
+ assert(av_i2int(av_mul_i(ai,bi)) == a*b);
+ assert(av_i2int(av_shr_i(ai, 9)) == a>>9);
+ assert(av_i2int(av_shr_i(ai,-9)) == a<<9);
+ assert(av_i2int(av_shr_i(ai, 17)) == a>>17);
+ assert(av_i2int(av_shr_i(ai,-17)) == a<<17);
+ assert(av_log2_i(ai) == av_log2(a));
+ assert(av_i2int(av_div_i(ai,bi)) == a/b);
+ }
+ }
+}
+#endif
diff --git a/libavcodec/integer.h b/libavcodec/integer.h
new file mode 100644
index 0000000000..ef1b2a089e
--- /dev/null
+++ b/libavcodec/integer.h
@@ -0,0 +1,47 @@
+/*
+ * arbitrary precision integers
+ * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/**
+ * @file integer.h
+ * arbitrary precision integers
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+#ifndef INTEGER_H
+#define INTEGER_H
+
+#define AV_INTEGER_SIZE 8
+
+typedef struct AVInteger{
+ uint16_t v[AV_INTEGER_SIZE];
+} AVInteger;
+
+AVInteger av_add_i(AVInteger a, AVInteger b);
+AVInteger av_sub_i(AVInteger a, AVInteger b);
+int av_log2_i(AVInteger a);
+AVInteger av_mul_i(AVInteger a, AVInteger b);
+int av_cmp_i(AVInteger a, AVInteger b);
+AVInteger av_shr_i(AVInteger a, int s);
+AVInteger av_mod_i(AVInteger *quot, AVInteger a, AVInteger b);
+AVInteger av_div_i(AVInteger a, AVInteger b);
+AVInteger av_int2i(int64_t a);
+int64_t av_i2int(AVInteger a);
+
+#endif // INTEGER_H