#pragma once
// Copyright (C) 2002-2007 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine" and the "irrXML" project.
// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h
// ------------------------------------------------------------------------------------
// Original description: (Schrompf)
// Adapted to the ASSIMP library because the builtin atof indeed takes AGES to parse a
// float inside a large string. Before parsing, it does a strlen on the given point.
// Changes:
// 22nd October 08 (Aramis_acg): Added temporary cast to double, added strtoul10_64
// to ensure long numbers are handled correctly
// ------------------------------------------------------------------------------------
#ifndef FAST_A_TO_F_H_INCLUDED
#define FAST_A_TO_F_H_INCLUDED
#include <cmath>
#include <limits>
#include <stdint.h>
#include <stdexcept>
#include <assimp/defs.h>
#include "StringComparison.h"
#include <assimp/DefaultLogger.hpp>
#ifdef _MSC_VER
# include <stdint.h>
#else
# include <assimp/Compiler/pstdint.h>
#endif
namespace Assimp {
const double fast_atof_table[16] = { // we write [16] here instead of [] to work around a swig bug
0.0,
0.1,
0.01,
0.001,
0.0001,
0.00001,
0.000001,
0.0000001,
0.00000001,
0.000000001,
0.0000000001,
0.00000000001,
0.000000000001,
0.0000000000001,
0.00000000000001,
0.000000000000001
};
// ------------------------------------------------------------------------------------
// Convert a string in decimal format to a number
// ------------------------------------------------------------------------------------
inline
unsigned int strtoul10( const char* in, const char** out=0) {
unsigned int value = 0;
for ( ;; ) {
if ( *in < '0' || *in > '9' ) {
break;
}
value = ( value * 10 ) + ( *in - '0' );
++in;
}
if ( out ) {
*out = in;
}
return value;
}
// ------------------------------------------------------------------------------------
// Convert a string in octal format to a number
// ------------------------------------------------------------------------------------
inline
unsigned int strtoul8( const char* in, const char** out=0) {
unsigned int value( 0 );
for ( ;; ) {
if ( *in < '0' || *in > '7' ) {
break;
}
value = ( value << 3 ) + ( *in - '0' );
++in;
}
if ( out ) {
*out = in;
}
return value;
}
// ------------------------------------------------------------------------------------
// Convert a string in hex format to a number
// ------------------------------------------------------------------------------------
inline
unsigned int strtoul16( const char* in, const char** out=0) {
unsigned int value( 0 );
for ( ;; ) {
if ( *in >= '0' && *in <= '9' ) {
value = ( value << 4u ) + ( *in - '0' );
} else if (*in >= 'A' && *in <= 'F') {
value = ( value << 4u ) + ( *in - 'A' ) + 10;
} else if (*in >= 'a' && *in <= 'f') {
value = ( value << 4u ) + ( *in - 'a' ) + 10;
} else {
break;
}
++in;
}
if ( out ) {
*out = in;
}
return value;
}
// ------------------------------------------------------------------------------------
// Convert just one hex digit
// Return value is UINT_MAX if the input character is not a hex digit.
// ------------------------------------------------------------------------------------
inline
unsigned int HexDigitToDecimal(char in) {
unsigned int out( UINT_MAX );
if ( in >= '0' && in <= '9' ) {
out = in - '0';
} else if ( in >= 'a' && in <= 'f' ) {
out = 10u + in - 'a';
} else if ( in >= 'A' && in <= 'F' ) {
out = 10u + in - 'A';
}
// return value is UINT_MAX if the input is not a hex digit
return out;
}
// ------------------------------------------------------------------------------------
// Convert a hex-encoded octet (2 characters, i.e. df or 1a).
// ------------------------------------------------------------------------------------
inline
uint8_t HexOctetToDecimal(const char* in) {
return ((uint8_t)HexDigitToDecimal(in[0])<<4)+(uint8_t)HexDigitToDecimal(in[1]);
}
// ------------------------------------------------------------------------------------
// signed variant of strtoul10
// ------------------------------------------------------------------------------------
inline
int strtol10( const char* in, const char** out=0) {
bool inv = (*in=='-');
if ( inv || *in == '+' ) {
++in;
}
int value = strtoul10(in,out);
if (inv) {
value = -value;
}
return value;
}
// ------------------------------------------------------------------------------------
// Parse a C++-like integer literal - hex and oct prefixes.
// 0xNNNN - hex
// 0NNN - oct
// NNN - dec
// ------------------------------------------------------------------------------------
inline
unsigned int strtoul_cppstyle( const char* in, const char** out=0) {
if ('0' == in[0]) {
return 'x' == in[1] ? strtoul16(in+2,out) : strtoul8(in+1,out);
}
return strtoul10(in, out);
}
// ------------------------------------------------------------------------------------
// Special version of the function, providing higher accuracy and safety
// It is mainly used by fast_atof to prevent ugly and unwanted integer overflows.
// ------------------------------------------------------------------------------------
inline
uint64_t strtoul10_64( const char* in, const char** out=0, unsigned int* max_inout=0) {
unsigned int cur = 0;
uint64_t value = 0;
if ( *in < '0' || *in > '9' ) {
throw std::invalid_argument( std::string( "The string \"" ) + in + "\" cannot be converted into a value." );
}
for ( ;; ) {
if ( *in < '0' || *in > '9' ) {
break;
}
const uint64_t new_value = ( value * (uint64_t) 10 ) + ( (uint64_t) ( *in - '0' ) );
// numeric overflow, we rely on you
if ( new_value < value ) {
ASSIMP_LOG_WARN_F( "Converting the string \"", in, "\" into a value resulted in overflow." );
return 0;
}
value = new_value;
++in;
++cur;
if (max_inout && *max_inout == cur) {
if (out) { /* skip to end */
while ( *in >= '0' && *in <= '9' ) {
++in;
}
*out = in;
}
return value;
}
}
if ( out ) {
*out = in;
}
if ( max_inout ) {
*max_inout = cur;
}
return value;
}
// ------------------------------------------------------------------------------------
// signed variant of strtoul10_64
// ------------------------------------------------------------------------------------
inline
int64_t strtol10_64(const char* in, const char** out = 0, unsigned int* max_inout = 0) {
bool inv = (*in == '-');
if ( inv || *in == '+' ) {
++in;
}
int64_t value = strtoul10_64(in, out, max_inout);
if (inv) {
value = -value;
}
return value;
}
// Number of relevant decimals for floating-point parsing.
#define AI_FAST_ATOF_RELAVANT_DECIMALS 15
// ------------------------------------------------------------------------------------
//! Provides a fast function for converting a string into a float,
//! about 6 times faster than atof in win32.
// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
// ------------------------------------------------------------------------------------
template<typename Real>
inline
const char* fast_atoreal_move(const char* c, Real& out, bool check_comma = true) {
Real f = 0;
bool inv = (*c == '-');
if (inv || *c == '+') {
++c;
}
if ((c[0] == 'N' || c[0] == 'n') && ASSIMP_strincmp(c, "nan", 3) == 0) {
out = std::numeric_limits<Real>::quiet_NaN();
c += 3;
return c;
}
if ((c[0] == 'I' || c[0] == 'i') && ASSIMP_strincmp(c, "inf", 3) == 0) {
out = std::numeric_limits<Real>::infinity();
if (inv) {
out = -out;
}
c += 3;
if ((c[0] == 'I' || c[0] == 'i') && ASSIMP_strincmp(c, "inity", 5) == 0) {
c += 5;
}
return c;
}
if (!(c[0] >= '0' && c[0] <= '9') &&
!((c[0] == '.' || (check_comma && c[0] == ',')) && c[1] >= '0' && c[1] <= '9')) {
throw std::invalid_argument("Cannot parse string "
"as real number: does not start with digit "
"or decimal point followed by digit.");
}
if (*c != '.' && (! check_comma || c[0] != ',')) {
f = static_cast<Real>( strtoul10_64 ( c, &c) );
}
if ((*c == '.' || (check_comma && c[0] == ',')) && c[1] >= '0' && c[1] <= '9') {
++c;
// NOTE: The original implementation is highly inaccurate here. The precision of a single
// IEEE 754 float is not high enough, everything behind the 6th digit tends to be more
// inaccurate than it would need to be. Casting to double seems to solve the problem.
// strtol_64 is used to prevent integer overflow.
// Another fix: this tends to become 0 for long numbers if we don't limit the maximum
// number of digits to be read. AI_FAST_ATOF_RELAVANT_DECIMALS can be a value between
// 1 and 15.
unsigned int diff = AI_FAST_ATOF_RELAVANT_DECIMALS;
double pl = static_cast<double>( strtoul10_64 ( c, &c, &diff ));
pl *= fast_atof_table[diff];
f += static_cast<Real>( pl );
}
// For backwards compatibility: eat trailing dots, but not trailing commas.
else if (*c == '.') {
++c;
}
// A major 'E' must be allowed. Necessary for proper reading of some DXF files.
// Thanks to Zhao Lei to point out that this if() must be outside the if (*c == '.' ..)
if (*c == 'e' || *c == 'E') {
++c;
const bool einv = (*c=='-');
if (einv || *c=='+') {
++c;
}
// The reason float constants are used here is that we've seen cases where compilers
// would perform such casts on compile-time constants at runtime, which would be
// bad considering how frequently fast_atoreal_move<float> is called in Assimp.
Real exp = static_cast<Real>( strtoul10_64(c, &c) );
if (einv) {
exp = -exp;
}
f *= std::pow(static_cast<Real>(10.0), exp);
}
if (inv) {
f = -f;
}
out = f;
return c;
}
// ------------------------------------------------------------------------------------
// The same but more human.
inline
ai_real fast_atof(const char* c) {
ai_real ret(0.0);
fast_atoreal_move<ai_real>(c, ret);
return ret;
}
inline
ai_real fast_atof( const char* c, const char** cout) {
ai_real ret(0.0);
*cout = fast_atoreal_move<ai_real>(c, ret);
return ret;
}
inline
ai_real fast_atof( const char** inout) {
ai_real ret(0.0);
*inout = fast_atoreal_move<ai_real>(*inout, ret);
return ret;
}
} //! namespace Assimp
#endif // FAST_A_TO_F_H_INCLUDED
