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Make struct FILE opaque.

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Bug: http://b/24807045
Change-Id: I3cb4e436325a65bef3b203e3970e4d967101fcce
This commit is contained in:
Elliott Hughes
2015-10-12 12:44:23 -07:00
parent e78392637d
commit f0141dfab1
4 changed files with 111 additions and 180 deletions
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97
libc/include/stdio.h
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@@ -38,14 +38,6 @@
#ifndef _STDIO_H_
#define _STDIO_H_
/*
* This file must contain a reference to __gnuc_va_list so that GCC's
* fixincludes knows that that's what's being used for va_list, and so
* to leave our <stdio.h> alone. (fixincludes gets in the way of pointing
* one toolchain at various different sets of platform headers.)
* If you alter this comment, be sure to keep "__gnuc_va_list" in it!
*/
#include <sys/cdefs.h>
#include <sys/types.h>
@@ -59,94 +51,9 @@ __BEGIN_DECLS
typedef off_t fpos_t; /* stdio file position type */
/*
* NB: to fit things in six character monocase externals, the stdio
* code uses the prefix `__s' for stdio objects, typically followed
* by a three-character attempt at a mnemonic.
*/
struct __sFILE;
typedef struct __sFILE FILE;
/* stdio buffers */
#if defined(__LP64__)
struct __sbuf {
unsigned char* _base;
size_t _size;
};
#else
struct __sbuf {
unsigned char *_base;
int _size;
};
#endif
/*
* stdio state variables.
*
* The following always hold:
*
* if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
* _lbfsize is -_bf._size, else _lbfsize is 0
* if _flags&__SRD, _w is 0
* if _flags&__SWR, _r is 0
*
* This ensures that the getc and putc macros (or inline functions) never
* try to write or read from a file that is in `read' or `write' mode.
* (Moreover, they can, and do, automatically switch from read mode to
* write mode, and back, on "r+" and "w+" files.)
*
* _lbfsize is used only to make the inline line-buffered output stream
* code as compact as possible.
*
* _ub, _up, and _ur are used when ungetc() pushes back more characters
* than fit in the current _bf, or when ungetc() pushes back a character
* that does not match the previous one in _bf. When this happens,
* _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
* _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
*
* NOTE: if you change this structure, you also need to update the
* std() initializer in findfp.c.
*/
typedef struct __sFILE {
unsigned char *_p; /* current position in (some) buffer */
int _r; /* read space left for getc() */
int _w; /* write space left for putc() */
#if defined(__LP64__)
int _flags; /* flags, below; this FILE is free if 0 */
int _file; /* fileno, if Unix descriptor, else -1 */
#else
short _flags; /* flags, below; this FILE is free if 0 */
short _file; /* fileno, if Unix descriptor, else -1 */
#endif
struct __sbuf _bf; /* the buffer (at least 1 byte, if !NULL) */
int _lbfsize; /* 0 or -_bf._size, for inline putc */
/* operations */
void *_cookie; /* cookie passed to io functions */
int (*_close)(void *);
int (*_read)(void *, char *, int);
fpos_t (*_seek)(void *, fpos_t, int);
int (*_write)(void *, const char *, int);
/* extension data, to avoid further ABI breakage */
struct __sbuf _ext;
/* data for long sequences of ungetc() */
unsigned char *_up; /* saved _p when _p is doing ungetc data */
int _ur; /* saved _r when _r is counting ungetc data */
/* tricks to meet minimum requirements even when malloc() fails */
unsigned char _ubuf[3]; /* guarantee an ungetc() buffer */
unsigned char _nbuf[1]; /* guarantee a getc() buffer */
/* separate buffer for fgetln() when line crosses buffer boundary */
struct __sbuf _lb; /* buffer for fgetln() */
/* Unix stdio files get aligned to block boundaries on fseek() */
int _blksize; /* stat.st_blksize (may be != _bf._size) */
fpos_t _offset; /* current lseek offset */
} FILE;
/* Legacy BSD implementation of stdin/stdout/stderr. */
extern FILE __sF[];
/* More obvious implementation. */
extern FILE* stdin;
extern FILE* stdout;
extern FILE* stderr;