/* * Copyright (c) 2003 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 * */#include <stdio.h>#include <inttypes.h>#include <assert.h>#define F 100#define SIZE 2048uint64_t exp16_table[20]={     65537,     65538,     65540,     65544,     65552,     65568,     65600,     65664,     65793,     66050,     66568,     67616,     69763,     74262,     84150,    108051,    178145,    484249,   3578144, 195360063,};#if 1// 16.16 fixpoint exp()static unsigned int exp16(unsigned int a){    int i;    int out= 1<<16;    for(i=19;i>=0;i--){        if(a&(1<<i))            out= (out*exp16_table[i] + (1<<15))>>16;    }    return out;}// 16.16 fixpoint log()static uint64_t log16(uint64_t a){    int i;    int out=0;        assert(a >= (1<<16));    a<<=16;        for(i=19;i>=0;i--){        if(a<(exp16_table[i]<<16)) continue;        out |= 1<<i;        a = ((a<<16) + exp16_table[i]/2)/exp16_table[i];    }    return out;}#endifstatic uint64_t int_sqrt(uint64_t a){    uint64_t ret=0;    int s;    uint64_t ret_sq=0;    for(s=31; s>=0; s--){        uint64_t b= ret_sq + (1ULL<<(s*2)) + (ret<<s)*2;        if(b<=a){            ret_sq=b;            ret+= 1ULL<<s;        }    }    return ret;}int main(int argc,char* argv[]){    int i, j;    uint64_t sse=0;    uint64_t dev;    FILE *f[2];    uint8_t buf[2][SIZE];    uint64_t psnr;        if(argc!=3){        printf("tiny_psnr <file1> <file2>\n");        return -1;    }        f[0]= fopen(argv[1], "r");    f[1]= fopen(argv[2], "r");    for(i=0;;){        if( fread(buf[0], SIZE, 1, f[0]) != 1) break;        if( fread(buf[1], SIZE, 1, f[1]) != 1) break;                for(j=0; j<SIZE; i++,j++){            const int a= buf[0][j];            const int b= buf[1][j];            sse += (a-b) * (a-b);        }    }        dev= int_sqrt((sse*F*F)/i);    if(sse)        psnr= (log16(256*256*255*255LL*i/sse)*284619LL*F + (1<<31)) / (1LL<<32);    else        psnr= 100*F-1; //floating point free infinity :)        printf("stddev:%3d.%02d PSNR:%2d.%02d bytes:%d\n",         (int)(dev/F), (int)(dev%F),         (int)(psnr/F), (int)(psnr%F),        i);    return 0;}