356 lines
9.6 KiB
C++
356 lines
9.6 KiB
C++
// Copyright (C) 2002-2007 Nikolaus Gebhardt
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// This file is part of the "Irrlicht Engine" and the "irrXML" project.
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// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h
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// ------------------------------------------------------------------------------------
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// Original description: (Schrompf)
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// Adapted to the ASSIMP library because the builtin atof indeed takes AGES to parse a
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// float inside a large string. Before parsing, it does a strlen on the given point.
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// Changes:
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// 22nd October 08 (Aramis_acg): Added temporary cast to double, added strtoul10_64
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// to ensure long numbers are handled correctly
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// ------------------------------------------------------------------------------------
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#ifndef __FAST_A_TO_F_H_INCLUDED__
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#define __FAST_A_TO_F_H_INCLUDED__
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#include <math.h>
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#include <limits.h>
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namespace Assimp
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{
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const double fast_atof_table[16] = { // we write [16] here instead of [] to work around a swig bug
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0.0,
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0.1,
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0.01,
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0.001,
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0.0001,
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0.00001,
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0.000001,
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0.0000001,
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0.00000001,
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0.000000001,
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0.0000000001,
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0.00000000001,
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0.000000000001,
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0.0000000000001,
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0.00000000000001,
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0.000000000000001
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};
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// ------------------------------------------------------------------------------------
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// Convert a string in decimal format to a number
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// ------------------------------------------------------------------------------------
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inline unsigned int strtoul10( const char* in, const char** out=0)
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{
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unsigned int value = 0;
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bool running = true;
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while ( running )
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{
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if ( *in < '0' || *in > '9' )
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break;
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value = ( value * 10 ) + ( *in - '0' );
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++in;
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}
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if (out)*out = in;
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return value;
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}
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// ------------------------------------------------------------------------------------
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// Convert a string in octal format to a number
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// ------------------------------------------------------------------------------------
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inline unsigned int strtoul8( const char* in, const char** out=0)
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{
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unsigned int value = 0;
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bool running = true;
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while ( running )
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{
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if ( *in < '0' || *in > '7' )
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break;
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value = ( value << 3 ) + ( *in - '0' );
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++in;
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}
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if (out)*out = in;
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return value;
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}
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// ------------------------------------------------------------------------------------
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// Convert a string in hex format to a number
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// ------------------------------------------------------------------------------------
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inline unsigned int strtoul16( const char* in, const char** out=0)
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{
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unsigned int value = 0;
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bool running = true;
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while ( running )
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{
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if ( *in >= '0' && *in <= '9' )
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{
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value = ( value << 4u ) + ( *in - '0' );
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}
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else if (*in >= 'A' && *in <= 'F')
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{
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value = ( value << 4u ) + ( *in - 'A' ) + 10;
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}
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else if (*in >= 'a' && *in <= 'f')
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{
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value = ( value << 4u ) + ( *in - 'a' ) + 10;
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}
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else break;
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++in;
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}
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if (out)*out = in;
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return value;
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}
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// ------------------------------------------------------------------------------------
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// Convert just one hex digit
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// Return value is UINT_MAX if the input character is not a hex digit.
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// ------------------------------------------------------------------------------------
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inline unsigned int HexDigitToDecimal(char in)
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{
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unsigned int out = UINT_MAX;
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if (in >= '0' && in <= '9')
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out = in - '0';
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else if (in >= 'a' && in <= 'f')
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out = 10u + in - 'a';
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else if (in >= 'A' && in <= 'F')
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out = 10u + in - 'A';
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// return value is UINT_MAX if the input is not a hex digit
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return out;
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}
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// ------------------------------------------------------------------------------------
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// Convert a hex-encoded octet (2 characters, i.e. df or 1a).
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// ------------------------------------------------------------------------------------
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inline uint8_t HexOctetToDecimal(const char* in)
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{
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return ((uint8_t)HexDigitToDecimal(in[0])<<4)+(uint8_t)HexDigitToDecimal(in[1]);
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}
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// ------------------------------------------------------------------------------------
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// signed variant of strtoul10
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// ------------------------------------------------------------------------------------
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inline int strtol10( const char* in, const char** out=0)
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{
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bool inv = (*in=='-');
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if (inv || *in=='+')
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++in;
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int value = strtoul10(in,out);
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if (inv) {
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value = -value;
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}
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return value;
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}
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// ------------------------------------------------------------------------------------
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// Parse a C++-like integer literal - hex and oct prefixes.
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// 0xNNNN - hex
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// 0NNN - oct
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// NNN - dec
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// ------------------------------------------------------------------------------------
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inline unsigned int strtoul_cppstyle( const char* in, const char** out=0)
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{
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if ('0' == in[0])
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{
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return 'x' == in[1] ? strtoul16(in+2,out) : strtoul8(in+1,out);
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}
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return strtoul10(in, out);
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}
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// ------------------------------------------------------------------------------------
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// Special version of the function, providing higher accuracy and safety
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// It is mainly used by fast_atof to prevent ugly and unwanted integer overflows.
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// ------------------------------------------------------------------------------------
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inline uint64_t strtoul10_64( const char* in, const char** out=0, unsigned int* max_inout=0)
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{
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unsigned int cur = 0;
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uint64_t value = 0;
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if ( *in < '0' || *in > '9' )
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throw std::invalid_argument(std::string("The string \"") + in + "\" cannot be converted into a value.");
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bool running = true;
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while ( running )
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{
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if ( *in < '0' || *in > '9' )
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break;
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const uint64_t new_value = ( value * 10 ) + ( *in - '0' );
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if (new_value < value) /* numeric overflow, we rely on you */
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throw std::overflow_error(std::string("Converting the string \"") + in + "\" into a value resulted in overflow.");
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value = new_value;
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++in;
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++cur;
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if (max_inout && *max_inout == cur) {
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if (out) { /* skip to end */
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while (*in >= '0' && *in <= '9')
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++in;
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*out = in;
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}
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return value;
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}
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}
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if (out)
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*out = in;
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if (max_inout)
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*max_inout = cur;
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return value;
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}
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// Number of relevant decimals for floating-point parsing.
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#define AI_FAST_ATOF_RELAVANT_DECIMALS 15
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// ------------------------------------------------------------------------------------
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//! Provides a fast function for converting a string into a float,
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//! about 6 times faster than atof in win32.
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// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
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// ------------------------------------------------------------------------------------
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template <typename Real>
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inline const char* fast_atoreal_move( const char* c, Real& out, bool check_comma = true)
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{
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Real f = 0;
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bool inv = (*c == '-');
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if (inv || *c == '+') {
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++c;
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}
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if (!isdigit(*c) && !(*c == '.' && isdigit(c[1])))
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{
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throw std::invalid_argument("Cannot parse string "
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"as real number: does not start with digit "
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"or decimal point followed by digit.");
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}
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if (*c != '.')
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{
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f = static_cast<Real>( strtoul10_64 ( c, &c) );
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}
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if ((*c == '.' || (check_comma && c[0] == ',')) && c[1] >= '0' && c[1] <= '9')
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{
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++c;
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// NOTE: The original implementation is highly inaccurate here. The precision of a single
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// IEEE 754 float is not high enough, everything behind the 6th digit tends to be more
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// inaccurate than it would need to be. Casting to double seems to solve the problem.
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// strtol_64 is used to prevent integer overflow.
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// Another fix: this tends to become 0 for long numbers if we don't limit the maximum
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// number of digits to be read. AI_FAST_ATOF_RELAVANT_DECIMALS can be a value between
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// 1 and 15.
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unsigned int diff = AI_FAST_ATOF_RELAVANT_DECIMALS;
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double pl = static_cast<double>( strtoul10_64 ( c, &c, &diff ));
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pl *= fast_atof_table[diff];
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f += static_cast<Real>( pl );
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}
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// For backwards compatibility: eat trailing dots, but not trailing commas.
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else if (*c == '.') {
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++c;
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}
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// A major 'E' must be allowed. Necessary for proper reading of some DXF files.
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// Thanks to Zhao Lei to point out that this if() must be outside the if (*c == '.' ..)
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if (*c == 'e' || *c == 'E') {
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++c;
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const bool einv = (*c=='-');
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if (einv || *c=='+') {
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++c;
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}
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// The reason float constants are used here is that we've seen cases where compilers
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// would perform such casts on compile-time constants at runtime, which would be
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// bad considering how frequently fast_atoreal_move<float> is called in Assimp.
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Real exp = static_cast<Real>( strtoul10_64(c, &c) );
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if (einv) {
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exp = -exp;
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}
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f *= pow(static_cast<Real>(10.0), exp);
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}
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if (inv) {
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f = -f;
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}
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out = f;
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return c;
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}
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// ------------------------------------------------------------------------------------
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// The same but more human.
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inline float fast_atof(const char* c)
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{
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float ret;
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fast_atoreal_move<float>(c, ret);
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return ret;
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}
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inline float fast_atof( const char* c, const char** cout)
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{
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float ret;
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*cout = fast_atoreal_move<float>(c, ret);
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return ret;
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}
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inline float fast_atof( const char** inout)
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{
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float ret;
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*inout = fast_atoreal_move<float>(*inout, ret);
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return ret;
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}
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inline double fast_atod(const char* c)
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{
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double ret;
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fast_atoreal_move<double>(c, ret);
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return ret;
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}
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inline double fast_atod( const char* c, const char** cout)
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{
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double ret;
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*cout = fast_atoreal_move<double>(c, ret);
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return ret;
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}
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inline double fast_atod( const char** inout)
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{
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double ret;
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*inout = fast_atoreal_move<double>(*inout, ret);
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return ret;
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}
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} // end of namespace Assimp
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#endif
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