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-rw-r--r--libio/libioP.h185
1 files changed, 145 insertions, 40 deletions
diff --git a/libio/libioP.h b/libio/libioP.h
index d3c871f..008f9b7 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); \