[PATCH v1] Added string conversion utility functions

[Bill Spitzak]

There is no need to pass endptr, because your functions will always fail 
if it is not set to point to the terminating null.

I also suspect that the base is never used. In addition a possible 
future fix would be to accept 0x for hex but a leading zero is decimal, 
not octal, which means this function would generate the base.

I am also worried about passing the out ptr. Depending on the sizes of 
int, long, and long long this will easily result in code that compiles 
on one platform but not on another. Returning the value would avoid this 
and reduce the number of functions. Instead pass a pointer to a variable 
to store the error into, or use errno?

Would prefer you not test the addresses of out parameters for null. It 
should crash at this point, as this is a programming error, not a 
runtime error. Returning false will make it hard to figure out what is 
wrong.

It is useful to pass -1 for strtoul and this should continue to work. It 
is the only easily-recognized value for "largest number possible". May 
be ok to not allow other negative numbers however.

On 11/21/2014 07:38 AM, Imran Zaman wrote:

> +static bool
> +convert_strtol(const char *str, char **endptr, int base, long *val)
> +{
> +       char *end = NULL;
> +       long v;
> +       int prev_errno = errno;
> +

> +       if (!str || !val)
> +               return false;
Please do not do the above tests!

> +       if (!endptr)
> +               endptr = &end;
> +
> +       errno = 0;
> +       v = strtol(str, endptr, base);
> +       if (errno != 0 || *endptr == str || **endptr != '\0')
> +               return false;
> +
> +       errno = prev_errno;
> +       *val = v;
> +       return true;
> +}
> +
> +static bool
> +convert_strtoul (const char *str, char **endptr, int base, unsigned long *val)
> +{
> +       char *end = NULL;
> +       unsigned long v;
> +       int i = 0;
> +       int prev_errno = errno;
> +
> +       if (!str || !val)
> +	       return false;

> +       /* check for negative numbers */
> +       while (str[i]) {
> +	       if (!isspace(str[i])) {
> +		       if (str[i] == '-')
> +			       return false;
> +		       else
> +			       break;
> +	       }
> +	       i++;
> +       }
You could do the above test afterwards and check for and allow the -1 value.

> +
> +       if (!endptr)
> +	       endptr = &end;
> +
> +       errno = 0;
> +       v = strtoul(str, endptr, base);
> +       if (errno != 0 || *endptr == str || **endptr != '\0')
> +	       return false;
> +
> +       errno = prev_errno;
> +       *val = v;
> +       return true;
> +}
> +
> +WL_EXPORT bool
> +weston_strtoi(const char *str, char **endptr, int base, int *val)
> +{
> +	long v;
> +
> +	if (!convert_strtol(str, endptr, base, &v) || v > INT_MAX
> +			|| v < INT_MIN)
> +		return false;
> +
> +	*val = (int)v;
> +	return true;
> +}
> +
> +WL_EXPORT bool
> +weston_strtol(const char *str, char **endptr, int base, long *val)
> +{
> +	return convert_strtol(str, endptr, base, val);
> +}
> +
> +WL_EXPORT bool
> +weston_strtoui(const char *str, char **endptr, int base, unsigned int *val)
> +{
> +	unsigned long v;
> +
> +	if (!convert_strtoul(str, endptr, base, &v) || v > UINT_MAX)
> +		return false;
> +
> +	*val = (unsigned int)v;
> +	return true;
> +}
> +
> +WL_EXPORT bool
> +weston_strtoul(const char *str, char **endptr, int base, unsigned long *val)
> +{
> +	return convert_strtoul(str, endptr, base, val);
> +}