ZBar bar code reader . http://zbar.sourceforge.net/ ZBar is licensed under the GNU LGPL 2.1 to enable development of both open source and commercial projects.
Dependents: GR-PEACH_Camera_in_barcode levkov_ov7670
LICENSE
The ZBar Bar Code Reader is Copyright (C) 2007-2009 Jeff Brown <spadix@users.sourceforge.net> The QR Code reader is Copyright (C) 1999-2009 Timothy B. Terriberry <tterribe@xiph.org>
You can redistribute this library and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
ISAAC is based on the public domain implementation by Robert J. Jenkins Jr., and is itself public domain.
Portions of the bit stream reader are copyright (C) The Xiph.Org Foundation 1994-2008, and are licensed under a BSD-style license.
The Reed-Solomon decoder is derived from an implementation (C) 1991-1995 Henry Minsky (hqm@ua.com, hqm@ai.mit.edu), and is licensed under the LGPL with permission.
zbar/qrcode/util.c
- Committer:
- RyoheiHagimoto
- Date:
- 2016-04-19
- Revision:
- 0:56c5742b9e2b
File content as of revision 0:56c5742b9e2b:
/*Copyright (C) 2008-2009 Timothy B. Terriberry (tterribe@xiph.org) You can redistribute this library and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.*/ #include <stdlib.h> #include "util.h" /*Computes floor(sqrt(_val)) exactly.*/ unsigned qr_isqrt(unsigned _val){ unsigned g; unsigned b; int bshift; /*Uses the second method from http://www.azillionmonkeys.com/qed/sqroot.html The main idea is to search for the largest binary digit b such that (g+b)*(g+b) <= _val, and add it to the solution g.*/ g=0; b=0x8000; for(bshift=16;bshift-->0;){ unsigned t; t=(g<<1)+b<<bshift; if(t<=_val){ g+=b; _val-=t; } b>>=1; } return g; } /*Computes sqrt(_x*_x+_y*_y) using CORDIC. This implementation is valid for all 32-bit inputs and returns a result accurate to about 27 bits of precision. It has been tested for all postiive 16-bit inputs, where it returns correctly rounded results in 99.998% of cases and the maximum error is 0.500137134862598032 (for _x=48140, _y=63018). Very nearly all results less than (1<<16) are correctly rounded. All Pythagorean triples with a hypotenuse of less than ((1<<27)-1) evaluate correctly, and the total bias over all Pythagorean triples is -0.04579, with a relative RMS error of 7.2864E-10 and a relative peak error of 7.4387E-9.*/ unsigned qr_ihypot(int _x,int _y){ unsigned x; unsigned y; int mask; int shift; int u; int v; int i; x=_x=abs(_x); y=_y=abs(_y); mask=-(x>y)&(_x^_y); x^=mask; y^=mask; _y^=mask; shift=31-qr_ilog(y); shift=QR_MAXI(shift,0); x=(unsigned)((x<<shift)*0x9B74EDAAULL>>32); _y=(int)((_y<<shift)*0x9B74EDA9LL>>32); u=x; mask=-(_y<0); x+=_y+mask^mask; _y-=u+mask^mask; u=x+1>>1; v=_y+1>>1; mask=-(_y<0); x+=v+mask^mask; _y-=u+mask^mask; for(i=1;i<16;i++){ int r; u=x+1>>2; r=(1<<2*i)>>1; v=_y+r>>2*i; mask=-(_y<0); x+=v+mask^mask; _y=_y-(u+mask^mask)<<1; } return x+((1U<<shift)>>1)>>shift; } #if defined(__GNUC__) && defined(HAVE_FEATURES_H) # include <features.h> # if __GNUC_PREREQ(3,4) # include <limits.h> # if INT_MAX>=2147483647 # define QR_CLZ0 sizeof(unsigned)*CHAR_BIT # define QR_CLZ(_x) (__builtin_clz(_x)) # elif LONG_MAX>=2147483647L # define QR_CLZ0 sizeof(unsigned long)*CHAR_BIT # define QR_CLZ(_x) (__builtin_clzl(_x)) # endif # endif #endif int qr_ilog(unsigned _v){ #if defined(QR_CLZ) /*Note that __builtin_clz is not defined when _x==0, according to the gcc documentation (and that of the x86 BSR instruction that implements it), so we have to special-case it.*/ return QR_CLZ0-QR_CLZ(_v)&-!!_v; #else int ret; int m; m=!!(_v&0xFFFF0000)<<4; _v>>=m; ret=m; m=!!(_v&0xFF00)<<3; _v>>=m; ret|=m; m=!!(_v&0xF0)<<2; _v>>=m; ret|=m; m=!!(_v&0xC)<<1; _v>>=m; ret|=m; ret|=!!(_v&0x2); return ret + !!_v; #endif } #if defined(QR_TEST_SQRT) #include <math.h> #include <stdio.h> /*Exhaustively test the integer square root function.*/ int main(void){ unsigned u; u=0; do{ unsigned r; unsigned s; r=qr_isqrt(u); s=(int)sqrt(u); if(r!=s)printf("%u: %u!=%u\n",u,r,s); u++; } while(u); return 0; } #endif