121 lines
2.6 KiB
C++
121 lines
2.6 KiB
C++
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/*
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A test program to which explores the ability to round trip a nanometer
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internal unit in the form of a 32 bit int, out to ASCII floating point
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millimeters and back in without variation. It tests all 4 billion values
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that an int can hold, and converts to ASCII and back and verifies integrity
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of the round tripped value.
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Author: Dick Hollenbeck
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*/
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#include <limits.h>
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#include <stdio.h>
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#include <cmath>
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#include <string>
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#include <string.h>
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#include <stdlib.h>
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#include <stdint.h>
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static inline int KiROUND( double v )
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{
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return int( v < 0 ? v - 0.5 : v + 0.5 );
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}
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typedef int BIU;
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#define BIU_PER_MM 1e6
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//double scale = BIU_PER_MM;
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//double scale = UM_PER_BIU;
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double scale = 1.0/BIU_PER_MM;
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std::string biuFmt( BIU aValue )
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{
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double engUnits = aValue * scale;
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char temp[48];
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int len;
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if( engUnits != 0.0 && fabsl( engUnits ) <= 0.0001 )
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{
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len = snprintf( temp, sizeof( temp ), "%.10f", engUnits );
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while( --len > 0 && temp[len] == '0' )
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temp[len] = '\0';
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++len;
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}
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else
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{
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len = snprintf( temp, sizeof( temp ), "%.10g", engUnits );
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}
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return std::string( temp, len );;
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}
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int parseBIU( const char* s )
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{
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double d = strtod( s, NULL );
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return KiROUND( double( d * BIU_PER_MM ) );
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// return int( d * BIU_PER_MM );
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}
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int main( int argc, char** argv )
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{
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unsigned mismatches = 0;
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if( argc > 1 )
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{
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// take a value on the command line and round trip it back to ASCII.
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int i = parseBIU( argv[1] );
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printf( "%s: i:%d\n", __func__, i );
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std::string s = biuFmt( i );
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printf( "%s: s:%s\n", __func__, s.c_str() );
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exit(0);
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}
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// printf( "sizeof(long double): %zd\n", sizeof( long double ) );
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// Empirically prove that we can round trip all 4 billion 32 bit integers representative
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// of nanometers out to textual floating point millimeters, and back without error using
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// the above two functions.
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// for( int i = INT_MIN; int64_t( i ) <= int64_t( INT_MAX ); ++i )
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for( int64_t j = INT_MIN; j <= int64_t( INT_MAX ); ++j )
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{
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int i = int( j );
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std::string s = biuFmt( int( i ) );
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int r = parseBIU( s.c_str() );
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if( r != i )
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{
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printf( "i:%d biuFmt:%s r:%d\n", i, s.c_str(), r );
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++mismatches;
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}
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if( !( i & 0xFFFFFF ) )
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{
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printf( " %08x", i );
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fflush( stdout );
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}
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}
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printf( "mismatches:%u\n", mismatches );
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return 0;
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}
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