diff options
Diffstat (limited to 'libio/libioP.h')
| -rw-r--r-- | libio/libioP.h | 185 |
1 files changed, 145 insertions, 40 deletions
diff --git a/libio/libioP.h b/libio/libioP.h index d3c871fbeb..008f9b7edf 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -57,71 +57,180 @@ extern "C" { #define _IO_seek_cur 1 #define _IO_seek_end 2 -typedef int (*_IO_overflow_t) __P((_IO_FILE*, int)); -typedef int (*_IO_underflow_t) __P((_IO_FILE*)); -typedef _IO_size_t (*_IO_xsputn_t) __P((_IO_FILE*,const void*,_IO_size_t)); -typedef _IO_size_t (*_IO_xsgetn_t) __P((_IO_FILE*, void*, _IO_size_t)); -typedef _IO_ssize_t (*_IO_read_t) __P((_IO_FILE*, void*, _IO_ssize_t)); -typedef _IO_ssize_t (*_IO_write_t) __P((_IO_FILE*,const void*,_IO_ssize_t)); -typedef int (*_IO_stat_t) __P((_IO_FILE*, void*)); -typedef _IO_fpos_t (*_IO_seek_t) __P((_IO_FILE*, _IO_off_t, int)); -typedef int (*_IO_doallocate_t) __P((_IO_FILE*)); -typedef int (*_IO_pbackfail_t) __P((_IO_FILE*, int)); -typedef _IO_FILE* (*_IO_setbuf_t) __P((_IO_FILE*, char *, _IO_ssize_t)); -typedef int (*_IO_sync_t) __P((_IO_FILE*)); -typedef void (*_IO_finish_t) __P((_IO_FILE*)); /* finalize */ -typedef int (*_IO_close_t) __P((_IO_FILE*)); /* finalize */ -typedef _IO_fpos_t (*_IO_seekoff_t) __P((_IO_FILE*, _IO_off_t, int, int)); - -/* The _IO_seek_cur and _IO_seek_end options are not allowed. */ -typedef _IO_fpos_t (*_IO_seekpos_t) __P((_IO_FILE*, _IO_fpos_t, int)); +/* THE JUMPTABLE FUNCTIONS. + + * The _IO_FILE type is used to implement the FILE type in GNU libc, + * as well as the streambuf class in GNU iostreams for C++. + * These are all the same, just used differently. + * An _IO_FILE (or FILE) object is allows followed by a pointer to + * a jump table (of pointers to functions). The pointer is accessed + * with the _IO_JUMPS macro. The jump table has a eccentric format, + * so as to be compatible with the layout of a C++ virtual function table. + * (as implemented by g++). When a pointer to a steambuf object is + * coerced to an (_IO_FILE*), then _IO_JUMPS on the result just + * happens to point to the virtual function table of the streambuf. + * Thus the _IO_JUMPS function table used for C stdio/libio does + * double duty as the virtual functiuon table for C++ streambuf. + * + * The entries in the _IO_JUMPS function table (and hence also the + * virtual functions of a streambuf) are described below. + * The first parameter of each function entry is the _IO_FILE/streambuf + * object being acted on (i.e. the 'this' parameter). + */ -#if !_IO_UNIFIED_JUMPTABLES -#define _IO_JUMPS(THIS) (THIS)->_jumps -#else #define _IO_JUMPS(THIS) ((struct _IO_FILE_plus*)(THIS))->vtable -#endif - -#if !_IO_UNIFIED_JUMPTABLES +#ifdef _G_USING_THUNKS #define JUMP_FIELD(TYPE, NAME) TYPE NAME #define JUMP0(FUNC, THIS) _IO_JUMPS(THIS)->FUNC(THIS) #define JUMP1(FUNC, THIS, X1) _IO_JUMPS(THIS)->FUNC(THIS, X1) #define JUMP2(FUNC, THIS, X1, X2) _IO_JUMPS(THIS)->FUNC(THIS, X1, X2) -#define JUMP3(FUNC, THIS, X1, X2, X3) _IO_JUMPS(THIS)->FUNC(THIS, X1, X2, X3) +#define JUMP3(FUNC, THIS, X1,X2,X3) _IO_JUMPS(THIS)->FUNC(THIS, X1,X2, X3) #define JUMP_INIT(NAME, VALUE) VALUE +#define JUMP_INIT_DUMMY JUMP_INIT(dummy, 0), JUMP_INIT(dummy2, 0) #else +/* These macros will change when we re-implement vtables to use "thunks"! */ #define JUMP_FIELD(TYPE, NAME) struct { short delta1, delta2; TYPE pfn; } NAME #define JUMP0(FUNC, THIS) _IO_JUMPS(THIS)->FUNC.pfn(THIS) #define JUMP1(FUNC, THIS, X1) _IO_JUMPS(THIS)->FUNC.pfn(THIS, X1) #define JUMP2(FUNC, THIS, X1, X2) _IO_JUMPS(THIS)->FUNC.pfn(THIS, X1, X2) #define JUMP3(FUNC, THIS, X1,X2,X3) _IO_JUMPS(THIS)->FUNC.pfn(THIS, X1,X2, X3) #define JUMP_INIT(NAME, VALUE) {0, 0, VALUE} -#endif #define JUMP_INIT_DUMMY JUMP_INIT(dummy, 0) +#endif +/* The 'finish' function does any final cleaning up of an _IO_FILE object. + It does not delete (free) it, but does everything else to finalize it/ + It matches the streambuf::~streambuf virtual destructor. */ +typedef void (*_IO_finish_t) __P((_IO_FILE*)); /* finalize */ #define _IO_FINISH(FP) JUMP0(__finish, FP) + +/* The 'overflow' hook flushes the buffer. + The second argument is a character, or EOF. + It matches the streambuf::overflow virtual function. */ +typedef int (*_IO_overflow_t) __P((_IO_FILE*, int)); #define _IO_OVERFLOW(FP, CH) JUMP1(__overflow, FP, CH) + +/* The 'underflow' hook tries to fills the get buffer. + It returns the next character (as an unsigned char) or EOF. The next + character remains in the get buffer, and the get postion is not changed. + It matches the streambuf::underflow virtual function. */ +typedef int (*_IO_underflow_t) __P((_IO_FILE*)); #define _IO_UNDERFLOW(FP) JUMP0(__underflow, FP) + +/* The 'uflow' hook returns the next character in the input stream + (cast to unsigned char), and increments the read position; + EOF is returned on failure. + It matches the streambuf::uflow virtual function, which is not in the + cfront implementation, but was added to C++ by the ANSI/ISO committee. */ #define _IO_UFLOW(FP) JUMP0(__uflow, FP) + +/* The 'pbackfail' hook handles backing up. + It matches the streambuf::pbackfail virtual function. */ +typedef int (*_IO_pbackfail_t) __P((_IO_FILE*, int)); #define _IO_PBACKFAIL(FP, CH) JUMP1(__pbackfail, FP, CH) + +/* The 'xsputn' hook writes upto N characters from buffer DATA. + Returns the number of character actually written. + It matches the streambuf::xsputn virtual function. */ +typedef _IO_size_t (*_IO_xsputn_t) + __P((_IO_FILE *FP, const void *DATA, _IO_size_t N)); #define _IO_XSPUTN(FP, DATA, N) JUMP2(__xsputn, FP, DATA, N) + +/* The 'xsgetn' hook reads upto N characters into buffer DATA. + Returns the number of character actually read. + It matches the streambuf::xsgetn virtual function. */ +typedef _IO_size_t (*_IO_xsgetn_t) __P((_IO_FILE*FP, void*DATA, _IO_size_t N)); #define _IO_XSGETN(FP, DATA, N) JUMP2(__xsgetn, FP, DATA, N) + +/* The 'seekoff' hook moves the stream position to a new position + relative to the start of the file (if DIR==0), the current position + (MODE==1), or the end of the file (MODE==2). + It matches the streambuf::seekoff virtual function. + It is also used for the ANSI fseek function. */ +typedef _IO_fpos_t (*_IO_seekoff_t) + __P((_IO_FILE* FP, _IO_off_t OFF, int DIR, int MODE)); #define _IO_SEEKOFF(FP, OFF, DIR, MODE) JUMP3(__seekoff, FP, OFF, DIR, MODE) + +/* The 'seekpos' hook also moves the stream position, + but to an absolute position given by a fpos_t (seekpos). + It matches the streambuf::seekpos virtual function. + It is also used for the ANSI fgetpos and fsetpos functions. */ +/* The _IO_seek_cur and _IO_seek_end options are not allowed. */ +typedef _IO_fpos_t (*_IO_seekpos_t) __P((_IO_FILE*, _IO_fpos_t, int)); #define _IO_SEEKPOS(FP, POS, FLAGS) JUMP2(__seekpos, FP, POS, FLAGS) + +/* The 'setbuf' hook gives a buffer to the file. + It matches the streambuf::setbuf virtual function. */ +typedef _IO_FILE* (*_IO_setbuf_t) __P((_IO_FILE*, char *, _IO_ssize_t)); #define _IO_SETBUF(FP, BUFFER, LENGTH) JUMP2(__setbuf, FP, BUFFER, LENGTH) + +/* The 'sync' hook attempts to synchronize the internal data structures + of the file with the external state. + It matches the streambuf::sync virtual function. */ +typedef int (*_IO_sync_t) __P((_IO_FILE*)); #define _IO_SYNC(FP) JUMP0(__sync, FP) + +/* The 'doallocate' hook is used to tell the file to allocate a buffer. + It matches the streambuf::doallocate virtual function, which is not + in the ANSI/ISO C++ standard, but is part traditional implementations. */ +typedef int (*_IO_doallocate_t) __P((_IO_FILE*)); #define _IO_DOALLOCATE(FP) JUMP0(__doallocate, FP) + +/* The following four hooks (sysread, syswrite, sysclose, sysseek, and + sysstat) are low-level hooks specific to this implementation. + There is no correspondance in the ANSI/ISO C++ standard library. + The hooks basically correspond to the Unix system functions + (read, write, close, lseek, and stat) except that a _IO_FILE* + parameter is used instead of a integer file descriptor; the default + implementation used for normal files just calls those functions. + The advantage of overriding these functions instead of the higher-level + ones (underflow, overflow etc) is that you can leave all the buffering + higher-level functions. */ + +/* The 'sysread' hook is used to read data from the external file into + an existing buffer. It generalizes the Unix read(2) function. + It matches the streambuf::sys_read virtual function, which is + specific to this implementaion. */ +typedef _IO_ssize_t (*_IO_read_t) __P((_IO_FILE*, void*, _IO_ssize_t)); #define _IO_SYSREAD(FP, DATA, LEN) JUMP2(__read, FP, DATA, LEN) + +/* The 'syswrite' hook is used to write data from an existing buffer + to an external file. It generalizes the Unix write(2) function. + It matches the streambuf::sys_write virtual function, which is + specific to this implementaion. */ +typedef _IO_ssize_t (*_IO_write_t) __P((_IO_FILE*,const void*,_IO_ssize_t)); #define _IO_SYSWRITE(FP, DATA, LEN) JUMP2(__write, FP, DATA, LEN) + +/* The 'sysseek' hook is used to re-position an external file. + It generalizes the Unix lseek(2) function. + It matches the streambuf::sys_seek virtual function, which is + specific to this implementaion. */ +typedef _IO_fpos_t (*_IO_seek_t) __P((_IO_FILE*, _IO_off_t, int)); #define _IO_SYSSEEK(FP, OFFSET, MODE) JUMP2(__seek, FP, OFFSET, MODE) + +/* The 'sysclose' hook is used to finalize (close, finish up) an + external file. It generalizes the Unix close(2) function. + It matches the streambuf::sys_close virtual function, which is + specific to this implementation. */ +typedef int (*_IO_close_t) __P((_IO_FILE*)); /* finalize */ #define _IO_SYSCLOSE(FP) JUMP0(__close, FP) + +/* The 'sysstat' hook is used to get information about an external file + into a struct stat buffer. It generalizes the Unix fstat(2) call. + It matches the streambuf::sys_stat virtual function, which is + specific to this implementaion. */ +typedef int (*_IO_stat_t) __P((_IO_FILE*, void*)); #define _IO_SYSSTAT(FP, BUF) JUMP1(__stat, FP, BUF) + #define _IO_CHAR_TYPE char /* unsigned char ? */ #define _IO_INT_TYPE int struct _IO_jump_t { JUMP_FIELD(_G_size_t, __dummy); +#ifdef _G_USING_THUNKS + JUMP_FIELD(_G_size_t, __dummy2); +#endif JUMP_FIELD(_IO_finish_t, __finish); JUMP_FIELD(_IO_overflow_t, __overflow); JUMP_FIELD(_IO_underflow_t, __underflow); @@ -147,16 +256,13 @@ struct _IO_jump_t { }; /* We always allocate an extra word following an _IO_FILE. + This contains a pointer to the function jump table used. This is for compatibility with C++ streambuf; the word can be used to smash to a pointer to a virtual function table. */ struct _IO_FILE_plus { _IO_FILE file; -#if _IO_UNIFIED_JUMPTABLES const struct _IO_jump_t *vtable; -#else - const void *vtable; -#endif }; /* Generic functions */ @@ -225,7 +331,7 @@ extern void _IO_flush_all_linebuffered __P((void)); #define _IO_have_backup(fp) ((fp)->_IO_save_base != NULL) #define _IO_in_backup(fp) ((fp)->_flags & _IO_IN_BACKUP) #define _IO_have_markers(fp) ((fp)->_markers != NULL) -#define _IO_blen(p) ((fp)->_IO_buf_end - (fp)->_IO_buf_base) +#define _IO_blen(fp) ((fp)->_IO_buf_end - (fp)->_IO_buf_base) /* Jumptable functions for files. */ @@ -290,12 +396,16 @@ extern void (*_IO_cleanup_registration_needed) __P ((void)); #define EOF (-1) #endif #ifndef NULL -#if !defined(__cplusplus) || defined(__GNUC__) +#ifdef __GNUG__ +#define NULL (__null) +#else +#if !defined(__cplusplus) #define NULL ((void*)0) #else #define NULL (0) #endif #endif +#endif #define FREE_BUF(_B) free(_B) #define ALLOC_BUF(_S) (char*)malloc(_S) @@ -337,22 +447,17 @@ extern int _IO_vscanf __P((const char *, _IO_va_list)); } #endif -#if _IO_UNIFIED_JUMPTABLES -#define _IO_FJUMP /* nothing */ -#else -#define _IO_FJUMP &_IO_file_jumps, -#endif #ifdef _IO_MTSAFE_IO /* check following! */ #define FILEBUF_LITERAL(CHAIN, FLAGS, FD) \ { _IO_MAGIC+_IO_LINKED+_IO_IS_FILEBUF+FLAGS, \ - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, CHAIN, _IO_FJUMP FD, \ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, CHAIN, FD, \ 0, 0, 0, 0, { 0 }, &_IO_stdfile_##FD##_lock } #else /* check following! */ #define FILEBUF_LITERAL(CHAIN, FLAGS, FD) \ { _IO_MAGIC+_IO_LINKED+_IO_IS_FILEBUF+FLAGS, \ - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, CHAIN, _IO_FJUMP FD } + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, CHAIN, FD } #endif /* VTABLE_LABEL defines NAME as of the CLASS class. @@ -402,7 +507,7 @@ extern struct _IO_fake_stdiobuf _IO_stdin_buf, _IO_stdout_buf, _IO_stderr_buf; #define MAYBE_SET_EINVAL /* nothing */ #endif -#ifdef DEBUG +#ifdef IO_DEBUG #define CHECK_FILE(FILE,RET) \ if ((FILE) == NULL) { MAYBE_SET_EINVAL; return RET; } \ else { COERCE_FILE(FILE); \ |