#define E_unsigned 1<<16
+/* Helper macro for assigning a readily converted integer value to the correct
+ parameter type, used in a switch on status->flags (see E_* flags above).
+ case_cond: combination of the E_* flags above, used for the switch-case
+ type: integer type, used to get the correct type from the parameter
+ stack as well as for cast target.
+*/
#define ASSIGN( case_cond, type ) \
case case_cond: \
*( va_arg( status->arg, type * ) ) = (type)( value * sign ); \
break
+/* Helper function to get a character from the string or stream, whatever is
+ used for input. When reading from a string, returns EOF on end-of-string
+ so that handling of the return value can be uniform for both streams and
+ strings.
+*/
static int GET( struct _PDCLIB_status_t * status )
{
- ++(status->i);
- ++(status->this);
+ int rc;
if ( status->stream != NULL )
{
- return getc( status->stream );
+ rc = getc( status->stream );
}
else
{
- return ( *status->s == '\0' ) ? EOF : *((status->s)++);
+ rc = ( *status->s == '\0' ) ? EOF : (unsigned char)*((status->s)++);
+ }
+ if ( rc != EOF )
+ {
+ ++(status->i);
+ ++(status->this);
}
+ return rc;
}
+/* Helper function to put a read character back into the string or stream,
+ whatever is used for input.
+*/
static void UNGET( int c, struct _PDCLIB_status_t * status )
{
if ( status->stream != NULL )
}
else
{
- *(--(status->s)) = c;
+ --(status->s);
}
--(status->i);
--(status->this);
switch ( rc )
{
case EOF:
- /* matching failure */
+ /* input error */
+ if ( status->n == 0 )
+ {
+ status->n = -1;
+ }
return NULL;
case '%':
return ++spec;
case 'c':
{
char * c = va_arg( status->arg, char * );
+ /* for %c, default width is one */
if ( status->width == SIZE_MAX )
{
status->width = 1;
}
+ /* reading until width reached or input exhausted */
while ( ( status->this < status->width ) &&
( ( rc = GET( status ) ) != EOF ) )
{
*(c++) = rc;
value_parsed = true;
}
+ /* width or input exhausted */
if ( value_parsed )
{
++status->n;
}
else
{
- /* FIXME: Need two kinds of "no match" here: zero width, and input error */
+ /* input error, no character read */
+ if ( status->n == 0 )
+ {
+ status->n = -1;
+ }
return NULL;
}
}
{
if ( value_parsed )
{
+ /* matching sequence terminated by whitespace */
*c = '\0';
return spec;
}
else
{
+ /* leading whitespace not counted against width */
--(status->this);
}
}
}
else
{
+ /* input error, no character read */
+ if ( status->n == 0 )
+ {
+ status->n = -1;
+ }
return NULL;
}
}
while ( ( status->this < status->width ) &&
( ( rc = GET( status ) ) != EOF ) )
{
- if ( ! sign )
+ if ( isspace( rc ) )
+ {
+ if ( sign )
+ {
+ /* matching sequence terminated by whitespace */
+ UNGET( rc, status );
+ break;
+ }
+ else
+ {
+ /* leading whitespace not counted against width */
+ status->this--;
+ }
+ }
+ else if ( ! sign )
{
+ /* no sign parsed yet */
switch ( rc )
{
case '-':
sign = 1;
break;
default:
+ /* not a sign; put back character */
sign = 1;
UNGET( rc, status );
break;
}
else if ( ! prefix_parsed )
{
+ /* no prefix (0x... for hex, 0... for octal) parsed yet */
prefix_parsed = true;
if ( rc != '0' )
{
+ /* not a prefix; if base not yet set, set to decimal */
if ( status->base == 0 )
{
status->base = 10;
}
else
{
+ /* starts with zero, so it might be a prefix. */
+ /* check what follows next (might be 0x...) */
if ( ( status->this < status->width ) &&
( ( rc = GET( status ) ) != EOF ) )
{
if ( tolower( rc ) == 'x' )
{
+ /* 0x... would be prefix for hex base... */
if ( ( status->base == 0 ) ||
( status->base == 16 ) )
{
}
else
{
+ /* ...unless already set to other value */
UNGET( rc, status );
value_parsed = true;
}
}
else
{
+ /* 0... but not 0x.... would be octal prefix */
UNGET( rc, status );
if ( status->base == 0 )
{
status->base = 8;
}
+ /* in any case we have read a zero */
value_parsed = true;
}
}
+ else
+ {
+ /* failed to read beyond the initial zero */
+ value_parsed = true;
+ break;
+ }
}
}
else
if ( digitptr == NULL )
{
/* end of input item */
+ UNGET( rc, status );
break;
}
value *= status->base;
value_parsed = true;
}
}
- /* width exceeded, EOF, read error, non-matching character */
+ /* width or input exhausted, or non-matching character */
if ( ! value_parsed )
{
- /* matching error */
+ /* out of input before anything could be parsed - input error */
+ /* FIXME: if first character does not match, value_parsed is not set - but it is NOT an input error */
+ if ( status->n == 0 )
+ {
+ status->n = -1;
+ }
return NULL;
}
+ /* convert value to target type and assign to parameter */
switch ( status->flags & ( E_char | E_short | E_long | E_llong |
E_intmax | E_size | E_ptrdiff |
E_unsigned ) )
/* ASSIGN( E_ptrdiff | E_unsigned, unsigned ptrdiff_t ); */
default:
puts( "UNSUPPORTED SCANF FLAG COMBINATION" );
- return NULL;
+ return NULL; /* behaviour unspecified */
}
+ ++(status->n);
return ++spec;
}
/* TODO: Floats. */
projects / pdclib / blobdiff