use signal safe ust_safe_snprintf()

[ust.git] / snprintf / various.h

diff --git a/snprintf/various.h b/snprintf/various.h
new file mode 100644 (file)
index 0000000..dab78ed
--- /dev/null
+++ b/snprintf/various.h
@@ -0,0 +1,91 @@
+#ifndef UST_SNPRINTF_VARIOUS_H
+#define UST_SNPRINTF_VARIOUS_H
+
+#include <stdarg.h>
+
+struct __sbuf {
+        unsigned char *_base;
+        int     _size;
+};
+
+/*
+ * 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.
+ */
+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() */
+        short   _flags;         /* flags, below; this FILE is free if 0 */
+        short   _file;          /* fileno, if Unix descriptor, else -1 */
+        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 */
+} LFILE;
+
+#define __SLBF  0x0001          /* line buffered */
+#define __SNBF  0x0002          /* unbuffered */
+#define __SRD   0x0004          /* OK to read */
+#define __SWR   0x0008          /* OK to write */
+        /* RD and WR are never simultaneously asserted */
+#define __SRW   0x0010          /* open for reading & writing */
+#define __SEOF  0x0020          /* found EOF */
+#define __SERR  0x0040          /* found error */
+#define __SMBF  0x0080          /* _buf is from malloc */
+#define __SAPP  0x0100          /* fdopen()ed in append mode */
+#define __SSTR  0x0200          /* this is an sprintf/snprintf string */
+#define __SOPT  0x0400          /* do fseek() optimisation */
+#define __SNPT  0x0800          /* do not do fseek() optimisation */
+#define __SOFF  0x1000          /* set iff _offset is in fact correct */
+#define __SMOD  0x2000          /* true => fgetln modified _p text */
+#define __SALC  0x4000          /* allocate string space dynamically */
+
+#define __sferror(p)    (((p)->_flags & __SERR) != 0)
+
+extern int ust_safe_fflush(LFILE *fp);
+extern int ust_safe_vfprintf(LFILE *fp, const char *fmt0, va_list ap);
+
+#endif /* UST_SNPRINTF_VARIOUS_H */