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Virtual selectors

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Where ordinary selectors specify a value stored in some object,
virtual selectors specify a function to call to compute a value
associated with some object.

Use them to replace the special case xdump ver by new table
EF_VERSION.

Move configkeys[] to lib/common because nsc_init() needs it to
initialize empfile[EF_VERSION].cadef.
This commit is contained in:
Markus Armbruster 2008-03-04 21:02:00 +01:00
parent 38047a62f7
commit da8a1daeef
12 changed files with 541 additions and 482 deletions
Download patch file Download diff file Expand all files Collapse all files

34
include/nsc.h
View file

@ -95,14 +95,21 @@ typedef char packed_nsc_cat;
* promoted type.
* If category is NSC_OFF, the value is in a context object, and
* val_as.sym specifies how to get it, as follows.
* If type is NSC_STRINGY, the value is an array of sym.len characters
* starting at sym.offs in the context object. sym.idx must be zero.
* Else if sym.len is zero, the value is in the context object at offset
* sym.off. sym.idx must be zero.
* Else sym.len is non-zero, and the value has index sym.idx in an
* array of sym.len elements at offset sym.off in in the context
* object. I.e. the value is at sym.off + sym.idx * SZ, where SZ is
* the size of the value.
* If sym.get is null, and type is NSC_STRINGY, the value is an array
* of sym.len characters starting at sym.offs in the context object.
* sym.idx must be zero.
* Else if sym.get is null, and sym.len is zero, the value is in the
* context object at offset sym.off. sym.idx must be zero.
* Else if sym.get is null, sym.len is non-zero, and the value has
* index sym.idx in an array of sym.len elements at offset sym.off in
* in the context object. I.e. the value is at sym.off + sym.idx *
* SZ, where SZ is the size of the value.
* If sym.get is not null, you obtain the value by calling get() like
* VAL->get(VAL, CNUM, CTXO), where CNUM is the country to use for
* coordinate translation and access control, and CTXO is the context
* object. get() either returns a null pointer and sets VAL->val_as
* to the value, as appropriate for the type. Or it returns another
* context object and sets VAL->val_as.sym for it.
*/
struct valstr {
packed_nsc_type val_type; /* type of value */
@ -112,6 +119,7 @@ struct valstr {
ptrdiff_t off;
int len;
int idx;
void *(*get)(struct valstr *, natid, void *);
} sym;
double dbl; /* cat NSC_VAL, type NSC_DOUBLE */
struct { /* cat NSC_VAL, type NSC_STRING, cat NSC_ID */
@ -197,11 +205,16 @@ typedef unsigned char nsc_flags;
*
* A selector describes an attribute of some context object.
* A selector with ca_type NSC_NOTYPE is invalid.
* A valid selector describes a datum of type ca_type at offset
* ca_offs in the context object.
* If ca_get is null, the selector describes a datum of type ca_type
* at offset ca_offs in the context object.
* A datum of type NSC_STRINGY is an array of ca_len characters.
* A datum of any other type is either a scalar of that type (if
* ca_len is zero), or an array of ca_len elements of that type.
* If ca_get is not null, the selector is virtual. Values can be
* obtained by calling ca_get(VAL, CNUM, CTXO), where VAL has been
* initialized from the selector and an index, CNUM is the country to
* use for coordinate translation and access control, and CTXO is the
* context object. See struct valstr for details.
* If flag NSC_DEITY is set, only to deities can use this selector.
* If flag NSC_EXTRA is set, xdump ignores this selector.
* If flag NSC_CONST is set, the datum can't be changed from its
@ -216,6 +229,7 @@ struct castr {
ptrdiff_t ca_off;
packed_nsc_type ca_type;
unsigned short ca_len;
void *(*ca_get)(struct valstr *, natid, void *);
int ca_table;
nsc_flags ca_flags;
};