/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

Copyright (c) 2006-2019, assimp team


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  following disclaimer.

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----------------------------------------------------------------------
*/

/** @file Definition of platform independent string workers:

   ASSIMP_itoa10
   ASSIMP_stricmp
   ASSIMP_strincmp

   These functions are not consistently available on all platforms,
   or the provided implementations behave too differently.
*/
#ifndef INCLUDED_AI_STRING_WORKERS_H
#define INCLUDED_AI_STRING_WORKERS_H

#include <assimp/ai_assert.h>
#include <assimp/defs.h>
#include "StringComparison.h"

#include <string.h>
#include <stdint.h>
#include <string>

namespace Assimp    {

// -------------------------------------------------------------------------------
/** @brief itoa with a fixed base 10
 * 'itoa' is not consistently available on all platforms so it is quite useful
 * to have a small replacement function here. No need to use a full sprintf()
 * if we just want to print a number ...
 * @param out Output buffer
 * @param max Maximum number of characters to be written, including '\0'.
 *   This parameter may not be 0.
 * @param number Number to be written
 * @return Length of the output string, excluding the '\0'
 */
AI_FORCE_INLINE
unsigned int ASSIMP_itoa10( char* out, unsigned int max, int32_t number) {
    ai_assert(NULL != out);

    // write the unary minus to indicate we have a negative number
    unsigned int written = 1u;
    if (number < 0 && written < max)    {
        *out++ = '-';
        ++written;
        number = -number;
    }

    // We begin with the largest number that is not zero.
    int32_t cur = 1000000000; // 2147483648
    bool mustPrint = false;
    while (written < max)   {

        const unsigned int digit = number / cur;
        if (mustPrint || digit > 0 || 1 == cur) {
            // print all future zeroe's from now
            mustPrint = true;

            *out++ = '0'+static_cast<char>(digit);

            ++written;
            number -= digit*cur;
            if (1 == cur) {
                break;
            }
        }
        cur /= 10;
    }

    // append a terminal zero
    *out++ = '\0';
    return written-1;
}

// -------------------------------------------------------------------------------
/** @brief itoa with a fixed base 10 (Secure template overload)
 *  The compiler should choose this function if he or she is able to determine the
 *  size of the array automatically.
 */
template <size_t length>
AI_FORCE_INLINE
unsigned int ASSIMP_itoa10( char(& out)[length], int32_t number) {
    return ASSIMP_itoa10(out,length,number);
}

// -------------------------------------------------------------------------------
/** @brief Helper function to do platform independent string comparison.
 *
 *  This is required since stricmp() is not consistently available on
 *  all platforms. Some platforms use the '_' prefix, others don't even
 *  have such a function.
 *
 *  @param s1 First input string
 *  @param s2 Second input string
 *  @return 0 if the given strings are identical
 */
AI_FORCE_INLINE
int ASSIMP_stricmp(const char *s1, const char *s2) {
    ai_assert( NULL != s1 );
    ai_assert( NULL != s2 );

#if (defined _MSC_VER)

    return ::_stricmp(s1,s2);
#elif defined( __GNUC__ )

    return ::strcasecmp(s1,s2);
#else

    char c1, c2;
    do  {
        c1 = tolower(*s1++);
        c2 = tolower(*s2++);
    }
    while ( c1 && (c1 == c2) );
    return c1 - c2;
#endif
}

// -------------------------------------------------------------------------------
/** @brief Case independent comparison of two std::strings
 *
 *  @param a First  string
 *  @param b Second string
 *  @return 0 if a == b
 */
AI_FORCE_INLINE
int ASSIMP_stricmp(const std::string& a, const std::string& b) {
    int i = (int)b.length()-(int)a.length();
    return (i ? i : ASSIMP_stricmp(a.c_str(),b.c_str()));
}

// -------------------------------------------------------------------------------
/** @brief Helper function to do platform independent string comparison.
 *
 *  This is required since strincmp() is not consistently available on
 *  all platforms. Some platforms use the '_' prefix, others don't even
 *  have such a function.
 *
 *  @param s1 First input string
 *  @param s2 Second input string
 *  @param n Macimum number of characters to compare
 *  @return 0 if the given strings are identical
 */
AI_FORCE_INLINE
int ASSIMP_strincmp(const char *s1, const char *s2, unsigned int n) {
    ai_assert( NULL != s1 );
    ai_assert( NULL != s2 );
    if ( !n ) {
        return 0;
    }

#if (defined _MSC_VER)

    return ::_strnicmp(s1,s2,n);

#elif defined( __GNUC__ )

    return ::strncasecmp(s1,s2, n);

#else
    char c1, c2;
    unsigned int p = 0;
    do
    {
        if (p++ >= n)return 0;
        c1 = tolower(*s1++);
        c2 = tolower(*s2++);
    }
    while ( c1 && (c1 == c2) );

    return c1 - c2;
#endif
}


// -------------------------------------------------------------------------------
/** @brief Evaluates an integer power
 *
 * todo: move somewhere where it fits better in than here
 */
AI_FORCE_INLINE
unsigned int integer_pow( unsigned int base, unsigned int power ) {
    unsigned int res = 1;
    for ( unsigned int i = 0; i < power; ++i ) {
        res *= base;
    }

    return res;
}

} // end of namespace

#endif // !  AI_STRINGCOMPARISON_H_INC
