X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2F_PDCLIB%2Fscan.c;h=c392a5393727dabd7ebf36a15ae4ccc1c78d3ee5;hp=f41079bd78ee98908e98642e14011ff3ac21718a;hb=5522316811fdce2216c4d1320af68dd54909aed5;hpb=0c316ee3b4dc0712797877f5dc0f4a789646154d diff --git a/functions/_PDCLIB/scan.c b/functions/_PDCLIB/scan.c index f41079b..c392a53 100644 --- a/functions/_PDCLIB/scan.c +++ b/functions/_PDCLIB/scan.c @@ -31,27 +31,46 @@ #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 ) @@ -60,7 +79,7 @@ static void UNGET( int c, struct _PDCLIB_status_t * status ) } else { - *(--(status->s)) = c; + --(status->s); } --(status->i); --(status->this); @@ -79,7 +98,11 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) switch ( rc ) { case EOF: - /* matching failure */ + /* input error */ + if ( status->n == 0 ) + { + status->n = -1; + } return NULL; case '%': return ++spec; @@ -204,16 +227,19 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) 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; @@ -221,7 +247,11 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) } 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; } } @@ -235,11 +265,13 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) { if ( value_parsed ) { + /* matching sequence terminated by whitespace */ *c = '\0'; return spec; } else { + /* leading whitespace not counted against width */ --(status->this); } } @@ -258,6 +290,11 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) } else { + /* input error, no character read */ + if ( status->n == 0 ) + { + status->n = -1; + } return NULL; } } @@ -285,8 +322,23 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) 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 '-': @@ -296,6 +348,7 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) sign = 1; break; default: + /* not a sign; put back character */ sign = 1; UNGET( rc, status ); break; @@ -303,9 +356,11 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) } 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; @@ -314,11 +369,14 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) } 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 ) ) { @@ -326,20 +384,29 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) } 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 @@ -348,6 +415,7 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) if ( digitptr == NULL ) { /* end of input item */ + UNGET( rc, status ); break; } value *= status->base; @@ -355,12 +423,18 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) 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 ) ) @@ -383,8 +457,9 @@ const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status ) /* 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. */