/*
    (C) 1995-96 AROS - The Amiga Replacement OS
    $Id: strtolong.c,v 1.8 1997/02/18 15:50:50 digulla Exp $

    Desc: Convert a string into a long
    Lang: english
*/

/*****************************************************************************

    NAME */
#include <proto/dos.h>

	AROS_LH2I(LONG, StrToLong,

/*  SYNOPSIS */
	AROS_LHA(STRPTR, string, D1),
	AROS_LHA(LONG *, value,  D2),

/*  LOCATION */
	struct DosLibrary *, DOSBase, 136, Dos)

/*  FUNCTION
	Convert a string to a long number.

    INPUTS
	string - The value to convert
	value - The result is returned here

    RESULT
	How many characters in the string were considered when it was
	converted or -1 if no valid number could be found.

    NOTES
	The routine doesn't check if the number if too large.

    EXAMPLE
	// Valid number are: 5, -1, +3, +0007, etc.

    BUGS

    SEE ALSO

    INTERNALS

    HISTORY

*****************************************************************************/
{
    AROS_LIBFUNC_INIT
    AROS_LIBBASE_EXT_DECL(struct DosLibrary *,DOSBase)

    LONG sign=0, v=0;
    STRPTR s=string;

    /* Skip leading whitespace characters */
    if(*s==' '||*s=='\t')
	s++;

    /* Swallow sign */
    if(*s=='+'||*s=='-')
	sign=*s++;

    /* If there is no number return an error. */
    if(*s<'0'||*s>'9')
    {
	*value=0;
	return -1;
    }

    /* Calculate result */
    do
	v=v*10+*s++-'0';
    while(*s>='0'&&*s<='9');

    /* Negative? */
    if(sign=='-')
	v=-v;

    /* All done. */
    *value=v;
    return s-string;
    AROS_LIBFUNC_EXIT
} /* StrToLong */