uspace/lib/c/include/capa.h

   1 /*
   2  * Copyright (c) 2015 Jiri Svoboda
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup libc
  30  * @{
  31  */
  32 /**
  33  * @file Storage capacity specification.
  34  */
  35
  36 #ifndef _LIBC_CAPA_H_
  37 #define _LIBC_CAPA_H_
  38
  39 #include <errno.h>
  40 #include <stddef.h>
  41 #include <stdint.h>
  42
  43 /** Capacity unit */
  44 typedef enum {
  45         cu_byte = 0,
  46         cu_kbyte,
  47         cu_mbyte,
  48         cu_gbyte,
  49         cu_tbyte,
  50         cu_pbyte,
  51         cu_ebyte,
  52         cu_zbyte,
  53         cu_ybyte
  54 } capa_unit_t;
  55
  56 /** Which of values within the precision of the capacity */
  57 typedef enum {
  58         /** The nominal (middling) value */
  59         cv_nom,
  60         /** The minimum value */
  61         cv_min,
  62         /** The maximum value */
  63         cv_max
  64 } capa_vsel_t;
  65
  66 #define CU_LIMIT (cu_ybyte + 1)
  67
  68 /** Storage capacity.
  69  *
  70  * Storage capacity represents both value and precision.
  71  * It is a decimal floating point value combined with a decimal
  72  * capacity unit. There is an integer mantisa @c m which in combination
  73  * with the number of decimal positions @c dp gives a decimal floating-point
  74  * number. E.g. for m = 1025 and dp = 2 the number is 10.25. If the unit
  75  * cunit = cu_kbyte, the capacity is 10.25 kByte, i.e. 10 250 bytes.
  76  *
  77  * Note that 1.000 kByte is equivalent to 1000 Byte, but 1 kByte is less
  78  * precise.
  79  */
  80 typedef struct {
  81         /** Mantisa */
  82         uint64_t m;
  83         /** Decimal positions */
  84         unsigned dp;
  85         /** Capacity unit */
  86         capa_unit_t cunit;
  87 } capa_spec_t;
  88
  89 extern errno_t capa_format(capa_spec_t *, char **);
  90 extern errno_t capa_parse(const char *, capa_spec_t *);
  91 extern void capa_simplify(capa_spec_t *);
  92 extern void capa_from_blocks(uint64_t, size_t, capa_spec_t *);
  93 extern errno_t capa_to_blocks(capa_spec_t *, capa_vsel_t, size_t, uint64_t *);
  94
  95 #endif
  96
  97 /** @}
  98  */