X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=libchimara%2Fdoc.c;h=092eda2ee0fd874666dcc767d02f3acc4c082ddd;hb=ee81c9edf038fbd02460c512e64504bdf994d91e;hp=c9c6e33c936f59fb483142f6fb2bd77a8639d819;hpb=7637a8d2987f253973b1f1e0eac52e49490254db;p=rodin%2Fchimara.git diff --git a/libchimara/doc.c b/libchimara/doc.c index c9c6e33..092eda2 100644 --- a/libchimara/doc.c +++ b/libchimara/doc.c @@ -840,6 +840,69 @@ * else. */ +/** + * SECTION:dispatch-interrogating + * @short_description: Finding out what functions the Glk library exports + * @include: libchimara/glk.h, libchimara/gi_dispa.h + * + * These are the ancilliary functions that let you enumerate. + */ + +/** + * SECTION:dispatch-dispatching + * @short_description: Dispatching the call to the Glk library + * @include: libchimara/glk.h, libchimara/gi_dispa.h + */ + +/** + * SECTION:dispatch-prototypes + * @short_description: Querying Glk function prototypes + * @include: libchimara/glk.h, libchimara/gi_dispa.h + * + * There are many possible ways to set up a #gluniversal_t array, and it's + * illegal to call gidispatch_call() with an array which doesn't match the + * function. Furthermore, some references are passed in, some passed out, and + * some both. How do you know how to handle the argument list? + * + * One possibility is to recognize each function selector, and set up the + * arguments appropriately. However, this entails writing special code for each + * Glk function; which is exactly what we don't want to do. + * + * Instead, you can call gidispatch_prototype(). + */ + +/** + * SECTION:dispatch-library-functions + * @short_description: Platform-dependent dispatch layer functions + * @include: libchimara/glk.h, libchimara/gi_dispa.h + * + * Ideally, the three layers — program, dispatch layer, Glk library + * — would be completely modular; each would refer only to the layers + * beneath it. Sadly, there are a few places where the library must notify the + * program that something has happened. Worse, these situations are only + * relevant to programs which use the dispatch layer, and then only some of + * those. + * + * Since C is uncomfortable with the concept of calling functions which may not + * exist, Glk handles this with call-back function pointers. The program can + * pass callbacks in to the library; if it does, the library will call them, and + * if not, the library doesn't try. + * + * These callbacks are optional, in the sense that the program may or may not + * set them. However, any library which wants to interoperate with the dispatch + * layer must allow the program to set them; it is the + * program's choice. The library does this by implementing + * set_registry functions — the functions to which the + * program passes its callbacks. + * + * + * Even though these callbacks and the functions to set them are declared in + * gi_dispa.h, they are not defined in + * gi_dispa.c. The dispatch layer merely coordinates + * them. The program defines the callback functions; the library calls them. + * + */ + /** * SECTION:blorb-program * @short_description: How to use the Blorb layer in your program @@ -2144,6 +2207,510 @@ * A value for %stylehint_Justification representing right-justified text. */ +/*---------- TYPES, FUNCTIONS AND CONSTANTS FROM GI_DISPA.H ------------------*/ + +/** + * gidispatch_count_classes: + * + * Returns the number of opaque object classes used by the library. You will + * need to know this if you want to keep track of opaque objects as they are + * created; see Opaque Object + * Registry. + * + * As of Glk API 0.7.0, there are four classes: windows, streams, filerefs, and + * sound channels (numbered 0, 1, 2, and 3 respectively.) + * + * Returns: Number of opaque object classes used by the library. + */ + +/** + * gidispatch_count_intconst: + * + * Returns the number of integer constants exported by the library. + * + * Returns: Number of integer constants exported by the library. + */ + +/** + * gidispatch_get_intconst: + * @index: Unique integer index of the integer constant. + * + * Returns a structure describing an integer constant which the library exports. + * These are, roughly, all the constants defined in the glk.h file. @index can range from 0 to + * N - 1N - + * 1, where N is the value returned by + * gidispatch_count_intconst(). + * + * Returns: A #gidispatch_intconst_t structure describing the integer constant. + */ + +/** + * gidispatch_intconst_t: + * @name: Symbolic name of the integer constant. + * @val: Value of the integer constant. + * + * This structure simply contains a string and a value. The string is a + * symbolic name of the value, and can be re-exported to anyone interested in + * using Glk constants. + */ + +/** + * gidispatch_count_functions: + * + * Returns the number of functions exported by the library. + * + * Returns: Number of functions exported by the library. + */ + +/** + * gidispatch_get_function: + * @index: Unique integer index of the function. + * + * Returns a structure describing a Glk function. @index can range from 0 to + * N - 1N - + * 1, where N is the value returned by + * gidispatch_count_functions(). + * + * Returns: A #gidispatch_function_t structure describing the function. + */ + +/** + * gidispatch_function_t: + * @id: Dispatch selector of the function. + * @fnptr: Pointer to the function. + * @name: Name of the function, without the glk_ prefix. + * + * The @id field is a selector — a numeric constant used to refer to the + * function in question. @name is the function name, as it is given in the + * glk.h file, but without the + * glk_ prefix. And @fnptr is the address of the + * function itself. + * + * + * This is included because it might be useful, but it is not recommended. To + * call an arbitrary Glk function, you should use gidispatch_call(). + * + * + * See Table of Selectors for + * the selector definitions. See Dispatching for more about calling Glk + * functions by selector. + */ + +/** + * gidispatch_get_function_by_id: + * @id: A selector. + * + * Returns a structure describing the Glk function with selector @id. If there + * is no such function in the library, this returns %NULL. + * + * Returns: a #gidispatch_function_t structure, or %NULL. + */ + +/** + * gidispatch_call: + * @funcnum: Selector of the function to call. + * @numargs: Length of @arglist. + * @arglist: List of arguments to pass to the function. + * + * @funcnum is the function number to invoke; see Table of Selectors. @arglist is + * the list of arguments, and @numargs is the length of the list. + * + * The arguments are all stored as #gluniversal_t objects. + * Basic Types + * Numeric arguments are passed in the obvious way — one argument per + * #gluniversal_t, with the @uint or @sint field set to the numeric value. + * Characters and strings are also passed in this way — #chars in + * the @uch, @sch, or @ch fields (depending on whether the #char is signed) and + * strings in the @charstr field. Opaque objects (windows, streams, etc) are + * passed in the @opaqueref field (which is void*, in order to + * handle all opaque pointer types.) + * + * However, pointers (other than C strings), arrays, and structures complicate + * life. So do return values. + * + * References + * A reference to a numeric type or object reference — that is, + * #glui32*, #winid_t*, and so on — takes + * one or two #gluniversal_t objects. The first is a flag + * indicating whether the reference argument is %NULL or not. The @ptrflag field + * of this #gluniversal_t should be %FALSE if the reference is %NULL, and %TRUE + * otherwise. If %FALSE, that is the end of the argument; you should not use a + * #gluniversal_t to explicitly store the %NULL reference. If the flag is %TRUE, + * you must then put a #gluniversal_t storing the base type of the reference. + * + * For example, consider a hypothetical function, with selector + * 0xABCD: + * |[ + * void glk_glomp(#glui32 num, #winid_t win, #glui32 *numref, #strid_t *strref); + * ]| + * ...and the calls: + * |[ + * #glui32 value; + * #winid_t mainwin; + * #strid_t gamefile; + * glk_glomp(5, mainwin, &value, &gamefile); + * ]| + * + * To perform this through gidispatch_call(), you would do the following: + * |[ + * #gluniversal_t arglist[6]; + * arglist[0].uint = 5; + * arglist[1].opaqueref = mainwin; + * arglist[2].ptrflag = TRUE; + * arglist[3].uint = value; + * arglist[4].ptrflag = TRUE; + * arglist[5].opaqueref = gamefile; + * #gidispatch_call(0xABCD, 6, arglist); + * value = arglist[3].uint; + * gamefile = arglist[5].opaqueref; + * ]| + * + * Note that you copy the value of the reference arguments into and out of + * @arglist. Of course, it may be that glk_glomp() only uses these as pass-out + * references or pass-in references; if so, you could skip copying in or out. + * + * For further examples: + * |[ + * glk_glomp(7, mainwin, NULL, NULL); + * ...or... + * #gluniversal_t arglist[4]; + * arglist[0].uint = 7; + * arglist[1].opaqueref = mainwin; + * arglist[2].ptrflag = FALSE; + * arglist[3].ptrflag = FALSE; + * #gidispatch_call(0xABCD, 4, arglist); + * ]| + * + * |[ + * glk_glomp(13, NULL, NULL, &gamefile); + * ...or... + * #gluniversal_t arglist[5]; + * arglist[0].uint = 13; + * arglist[1].opaqueref = NULL; + * arglist[2].ptrflag = FALSE; + * arglist[3].ptrflag = TRUE; + * arglist[4].opaqueref = gamefile; + * #gidispatch_call(0xABCD, 5, arglist); + * gamefile = arglist[4].opaqueref; + * ]| + * + * |[ + * glk_glomp(17, NULL, &value, NULL); + * ...or... + * #gluniversal_t arglist[5]; + * arglist[0].uint = 17; + * arglist[1].opaqueref = NULL; + * arglist[2].ptrflag = TRUE; + * arglist[3].uint = value; + * arglist[4].ptrflag = FALSE; + * #gidispatch_call(0xABCD, 5, arglist); + * value = arglist[3].uint; + * ]| + * + * As you see, the length of @arglist depends on how many of the reference + * arguments are %NULL. + * + * Structures + * A structure pointer is represented by a single @ptrflag, possibly followed by + * a sequence of #gluniversal_t objects (one for each field of the structure.) + * Again, if the structure pointer is non-%NULL, the @ptrflag should be %TRUE + * and be followed by values; if not, the @ptrflag should be %NULL and stands + * alone. + * + * For example, the function glk_select() can be invoked as follows: + * |[ + * #event_t ev; + * #gluniversal_t arglist[5]; + * arglist[0].ptrflag = TRUE; + * #gidispatch_call(0x00C0, 5, arglist); + * ev.type = arglist[1].uint; + * ev.win = arglist[2].opaqueref; + * ev.val1 = arglist[3].uint; + * ev.val2 = arglist[4].uint; + * ]| + * + * Since the structure passed to glk_select() is a pass-out reference (the entry + * values are ignored), you don't need to fill in arglist[1..4] + * before calling gidispatch_call(). + * + * + * Theoretically, you would invoke #glk_select(%NULL) by setting' + * arglist[0].ptrflag to %FALSE, and using a one-element @arglist + * instead of five-element. But it's illegal to pass %NULL to glk_select(). So + * you cannot actually do this. + * + * Arrays + * In the Glk API, an array argument is always followed by a numeric argument + * giving the array's length. These two C arguments are a single logical + * argument, which is represented by one or three + * #gluniversal_t objects. The first is a @ptrflag, indicating whether the + * argument is %NULL or not. The second is a pointer, stored in the @array + * field. The third is the array length, stored in the @uint field. And again, + * if the @ptrflag is %NULL, the following two are omitted. + * + * For example, the function glk_put_buffer() can be invoked as follows: + * |[ + * #char buf[64]; + * #glui32 len = 64; + * #glk_put_buffer(buf, len); + * ...or... + * #gluniversal_t arglist[3]; + * arglist[0].ptrflag = TRUE; + * arglist[1].array = buf; + * arglist[2].uint = len; + * #gidispatch_call(0x0084, 3, arglist); + * ]| + * + * Since you are passing a C char array to gidispatch_call(), the contents will + * be read directly from that. There is no need to copy data into @arglist, as + * you would for a basic type. + * + * If you are implementing a VM whose native representation of char arrays is + * more complex, you will have to do more work. You should allocate a C char + * array, copy your characters into it, make the call, and then free the array. + * + * + * glk_put_buffer() does not modify the array passed to it, so there is no + * need to copy the characters out. + * + * Return Values + * The return value of a function is not treated specially. It is simply + * considered to be a pass-out reference argument which may not be %NULL. It + * comes after all the other arguments of the function. + * + * For example, the function glk_window_get_rock() can be invoked as follows: + * |[ + * #glui32 rock; + * #winid_t win; + * rock = #glk_window_get_rock(win); + * ...or... + * #gluniversal_t arglist[3]; + * arglist[0].opaqueref = win; + * arglist[1].ptrflag = TRUE; + * #gidispatch_call(0x0021, 3, arglist); + * rock = arglist[2].uint; + * ]| + * + */ + +/** + * gluniversal_t: + * @uint: Stores a #glui32. + * @sint: Stores a #glsi32. + * @opaqueref: Stores a #winid_t, #strid_t, #frefid_t, or #schanid_t. + * @uch: Stores an #unsigned #char. + * @sch: Stores a #signed #char. + * @ch: Stores a #char with the default signedness. + * @charstr: Stores a %NULL-terminated string. + * @array: Stores a pointer to an array, and should be followed by another + * #gluniversal_t with the array length stored in the @uint member. + * @ptrflag: If %FALSE, represents an opaque reference or array that is %NULL, + * in which case it represents the entire argument. If %TRUE, should be followed + * by another #gluniversal_t with the pointer in its @opaqueref or @array field. + * + * This is a union, encompassing all the types that can be passed to Glk + * functions. + */ + +/** + * gidispatch_prototype: + * @funcnum: A selector for the function to be queried. + * + * This returns a string which encodes the proper argument list for the given + * function. If there is no such function in the library, this returns %NULL. + * + * The prototype string for the glk_glomp() function described above would be: + * "4IuQa&Iu&Qb:". The "4" is the number of + * arguments (including the return value, if there is one, which in this case + * there isn't.) "Iu" denotes an unsigned integer; + * "Qa" is an opaque object of class 0 (window). + * "&Iu" is a reference to an unsigned + * integer, and "&Qb" is a reference to a stream. The colon at + * the end terminates the argument list; the return value would follow it, if + * there was one. + * + * Note that the initial number ("4" in this case) is the number of + * logical arguments, not the number of #gluniversal_t objects which will be + * passed to gidispatch_call(). The glk_glomp() call uses anywhere from four to + * six #gluniversal_t objects, as demonstrated above. + * + * The basic type codes: + * + * + * Iu, Is + * Unsigned and signed 32-bit integer. + * + * + * Cn, Cu, Cs + * Character, #unsigned #char, and #signed #char. + * Of course Cn will be the same as either + * Cu or Cs, depending on the platform. For this + * reason, Glk avoids using it, but it is included here for completeness. + * + * + * + * + * S + * A C-style string (null-terminated array of #char). In Glk, + * strings are always treated as read-only and used immediately; the library + * does not retain a reference to a string between Glk calls. A Glk call that + * wants to use writable char arrays will use an array type + * ("#C"), not string ("S"). + * + * + * U + * A zero-terminated array of 32-bit integers. This is + * primarily intended as a Unicode equivalent of "S". Like + * "S" strings, "U" strings are read-only and used + * immediately. A Glk call that wants to use writable Unicode arrays will use + * an array type ("#Iu") instead of "U". + * + * + * + * F + * A floating-point value. Glk does not currently use + * floating-point values, but we might as well define a code for them. + * + * + * + * Qa, Qb, Qc... + * A reference to an opaque object. The second letter + * determines which class is involved. (The number of classes can be gleaned + * from gidispatch_count_classes(); see Interrogating the + * Interface). + * + * If Glk expands to have more than 26 classes, we'll think of something. + * + * + * + * Any type code can be prefixed with one or more of the following characters + * (order does not matter): + * + * + * & + * A reference to the type; or, if you like, a variable passed + * by reference. The reference is passed both in and out, so you must copy the + * value in before calling gidispatch_call() and copy it out afterward. + * + * + * + * < + * A reference which is pass-out only. The initial value is + * ignored, so you only need copy out the value after the call. + * + * + * + * > + * A reference which is pass-in only. + * + * This is not generally used for simple types, but is useful for structures + * and arrays. + * + * + * + * + + * Combined with "&", "<", or + * ">", indicates that a valid reference is mandatory; %NULL + * cannot be passed. + * + * Note that even though the @ptrflag #gluniversal_t for a "+" + * reference is always %TRUE, it cannot be omitted. + * + * + * + * : + * The colon separates the arguments from the return value, or + * terminates the string if there is no return value. Since return values are + * always non-%NULL pass-out references, you may treat ":" as + * equivalent to "<+". The colon is never combined with any + * other prefix character. + * + * + * [...] + * Combined with "&", "<", or + * ">", indicates a structure reference. Between the brackets + * is a complete argument list encoding string, including the number of + * arguments. + * + * For example, the prototype string for glk_select() is + * "1<+[4IuQaIuIu]:" — one argument, which is a + * pass-out non-%NULL reference to a structure, which contains four + * arguments. + * + * Currently, structures in Glk contain only basic types. + * + * + * + * # + * Combined with "&", "<", or + * ">", indicates an array reference. As described above, this + * encompasses up to three #gluniversal_t objects — @ptrflag, pointer, + * and integer length. + * + * Depending on the design of your program, you may wish to pass a pointer + * directly to your program's memory, or allocate an array and copy the + * contents in and out. See Arrays. + * + * + * + * ! + * Combined with "#", indicates that the + * array is retained by the library. The library will keep a reference to the + * array; the contents are undefined until further notice. You should not use + * or copy the contents of the array out after the call, even for + * "&#!" or "<#!" arrays. Instead, do + * it when the library releases the array. + * + * For example, glk_stream_open_memory() retains the array that you pass it, + * and releases it when the stream is closed. The library can notify you + * automatically when arrays are retained and released; see Retained Array + * Registry. + * + * + * + * + * Returns: A string which encodes the prototype of the specified Glk function. + */ + +/** + * gidisp_Class_Window: + * + * Represents a #winid_t opaque object. + */ + +/** + * gidisp_Class_Stream: + * + * Represents a #strid_t opaque object. + */ + +/** + * gidisp_Class_Fileref: + * + * Represents a #frefid_t opaque object. + */ + +/** + * gidisp_Class_Schannel: + * + * Represents a #schanid_t opaque object. + */ + +/** + * gidispatch_rock_t: + * @num: Space for storing an integer. + * @ptr: Space for storing a pointer. + * + * You can store any value you want in this object; return it from your object + * registry and retained array registry callbacks, and the library will stash it + * away. You can retrieve it with gidispatch_get_objrock(). + */ + /*---------- TYPES, FUNCTIONS AND CONSTANTS FROM GI_BLORB.H ------------------*/ /**