support/mph.h

   1 /*
   2  * Common/shared macros and routines.
   3  *
   4  * This file contains macros of the form
   5  *
   6  *   mph_return_if_TYPE_overflow(val);
   7  *
   8  * Which tests `val' for a TYPE underflow/overflow (that is, is `val' within
   9  * the range for TYPE?).  If `val' can't fit in TYPE, errno is set to
  10  * EOVERFLOW, and `return -1' is executed (which is why it's a macro).
  11  *
  12  * Assumptions:
  13  *
  14  * I'm working from GLibc, so that's the basis for my assumptions.  They may
  15  * not be completely portable, in which case I'll need to fix my assumptions.
  16  * :-(
  17  *
  18  * See the typedefs for type size assumptions.  These typedefs *must* be kept
  19  * in sync with the types used in Mono.Posix.dll.
  20  */
  21
  22 #ifndef INC_mph_H
  23 #define INC_mph_H
  24
  25 #include <config.h>
  26
  27 #include <limits.h>             /* LONG_MAX, ULONG_MAX */
  28 #include <errno.h>              /* for ERANGE */
  29 #include <glib.h>               /* for g* types, etc. */
  30
  31 #ifdef HAVE_STDINT_H
  32 #include <stdint.h>             /* for SIZE_MAX */
  33 #endif
  34
  35 #if __APPLE__ || __BSD__
  36 #define MPH_ON_BSD
  37 #endif
  38
  39 typedef    gint64 mph_blkcnt_t;
  40 typedef    gint64 mph_blksize_t;
  41 typedef   guint64 mph_dev_t;
  42 typedef   guint64 mph_ino_t;
  43 typedef   guint64 mph_nlink_t;
  44 typedef    gint64 mph_off_t;
  45 typedef   guint64 mph_size_t;
  46 typedef    gint64 mph_ssize_t;
  47 typedef    gint32 mph_pid_t;
  48 typedef   guint32 mph_gid_t;
  49 typedef   guint32 mph_uid_t;
  50 typedef    gint64 mph_time_t;
  51 typedef    gint64 mph_clock_t;
  52
  53 #ifdef HAVE_LARGE_FILE_SUPPORT
  54 #define MPH_OFF_T_MAX G_MAXINT64
  55 #define MPH_OFF_T_MIN G_MININT64
  56 #else
  57 #define MPH_OFF_T_MAX G_MAXINT32
  58 #define MPH_OFF_T_MIN G_MININT32
  59 #endif
  60
  61 #ifdef SIZE_MAX
  62 #define MPH_SIZE_T_MAX SIZE_MAX
  63 #elif SIZEOF_SIZE_T == 8
  64 #define MPH_SIZE_T_MAX  G_MAXUINT64
  65 #elif SIZEOF_SIZE_T == 4
  66 #define MPH_SIZE_T_MAX  G_MAXUINT32
  67 #else
  68 #error "sizeof(size_t) is unknown!"
  69 #endif
  70
  71 #define _mph_return_val_if_cb_(val, ret, cb) G_STMT_START{ \
  72         if (cb (val)) { \
  73                 errno = EOVERFLOW; \
  74                 return ret; \
  75         }}G_STMT_END
  76
  77 #define mph_have_long_overflow(var) ((var) > LONG_MAX || (var) < LONG_MIN)
  78
  79 #define mph_return_val_if_long_overflow(var, ret) \
  80         _mph_return_val_if_cb_(var, ret, mph_have_long_overflow)
  81
  82 #define mph_return_if_long_overflow(var) mph_return_val_if_long_overflow(var, -1)
  83
  84 #define mph_have_ulong_overflow(var) ((var) > ULONG_MAX)
  85
  86 #define mph_return_val_if_ulong_overflow(var, ret) \
  87         _mph_return_val_if_cb_(var, ret, mph_have_ulong_overflow)
  88
  89 #define mph_return_if_ulong_overflow(var) mph_return_val_if_ulong_overflow(var, -1)
  90
  91 #define mph_have_size_t_overflow(var) ((var) > MPH_SIZE_T_MAX)
  92
  93 #define mph_return_val_if_size_t_overflow(var, ret) \
  94         _mph_return_val_if_cb_(var, ret, mph_have_size_t_overflow)
  95
  96 #define mph_return_if_size_t_overflow(var) mph_return_val_if_size_t_overflow(var, -1)
  97
  98 #define mph_have_off_t_overflow(var) \
  99         (((var) < MPH_OFF_T_MIN) || ((var) > MPH_OFF_T_MAX))
 100
 101 #define mph_return_val_if_off_t_overflow(var, ret) \
 102         _mph_return_val_if_cb_(var, ret, mph_have_off_t_overflow)
 103
 104 #define mph_return_if_off_t_overflow(var) mph_return_val_if_size_t_overflow(var, -1)
 105
 106 #define mph_return_if_time_t_overflow(var) mph_return_if_long_overflow(var)
 107
 108 /*
 109  * Helper function for functions which use ERANGE (such as getpwnam_r and
 110  * getgrnam_r).  These functions accept buffers which are dynamically
 111  * allocated so that they're only as large as necessary.  However, Linux and
 112  * Mac OS X differ on how to signal an error value.
 113  *
 114  * Linux returns the error value directly, while Mac OS X is more traditional,
 115  * returning -1 and setting errno accordingly.
 116  *
 117  * Unify the checking in one place.
 118  */
 119 static inline int
 120 recheck_range (int ret)
 121 {
 122         if (ret == ERANGE)
 123                 return 1;
 124         if (ret == -1)
 125                 return errno == ERANGE;
 126         return 0;
 127 }
 128
 129 #endif /* ndef INC_mph_H */
 130
 131 /*
 132  * vim: noexpandtab
 133  */