Click here to Skip to main content
15,891,423 members
Articles / Desktop Programming / MFC

Tiny C Runtime Library

Rate me:
Please Sign up or sign in to vote.
4.86/5 (60 votes)
25 Mar 20079 min read 333.4K   5.7K   123  
Reduce code bloat for those simple utility programs by using a streamlined C runtime - now with Unicode support!
// atol.cpp

// based on:
// LIBCTINY - Matt Pietrek 2001
// MSDN Magazine, January 2001

// 08/12/06 (mv)

#include <stdlib.h>
#include <ctype.h>
#include "libct.h"

BEGIN_EXTERN_C
	
long atol(const char *str)
{
    while (isspace(*str))			// skip whitespace
        ++str;

    int cur = *str++;
    int neg = cur;					// Save the negative sign, if it exists

    if (cur == '-' || cur == '+')
        cur = *str++;

    // While we have digits, add 'em up.

	long total = 0;
    while (isdigit(cur))
    {
        total = 10*total + (cur-'0');			// Add this digit to the total.
        cur = *str++;							// Do the next character.
    }

    // If we have a negative sign, convert the value.
    if (neg == '-')
        return -total;
    else
        return total;
}

int atoi(const char *str)
{
    return (int)atol(str);
}



long wtol(const wchar_t *str)
{
    while (iswspace(*str))			// skip whitespace
        ++str;

    wint_t cur = *str++;
    wint_t neg = cur;					// Save the negative sign, if it exists

    if (cur == L'-' || cur == L'+')
        cur = *str++;

    // While we have digits, add 'em up.

	long total = 0;
    while (iswdigit(cur))
    {
        total = 10*total + (cur-L'0');			// Add this digit to the total.
        cur = *str++;							// Do the next character.
    }

    // If we have a negative sign, convert the value.
    if (neg == L'-')
        return -total;
    else
        return total;
}

int wtoi(const wchar_t *str)
{
    return (int)wtol(str);
}

END_EXTERN_C

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
United States United States
Mike_V is currently a student at UCLA.

After a few years on the Dark Side, he reformed and now chants "Death to VB." His computer-related interests include C++, C#, and ASP.NET (in C#, of course). He writes operating systems in C++ and assembler as a hobby.

Comments and Discussions