lib/numberset.h

   1 /* numberset.h */
   2
   3 /*
   4  * Copyright (C) 2012 by Werner Lemberg.
   5  *
   6  * This file is part of the ttfautohint library, and may only be used,
   7  * modified, and distributed under the terms given in `COPYING'.  By
   8  * continuing to use, modify, or distribute this file you indicate that you
   9  * have read `COPYING' and understand and accept it fully.
  10  *
  11  * The file `COPYING' mentioned in the previous paragraph is distributed
  12  * with the ttfautohint library.
  13  */
  14
  15
  16 #ifndef __NUMBERSET_H__
  17 #define __NUMBERSET_H__
  18
  19 #ifdef __cplusplus
  20 extern "C" {
  21 #endif
  22
  23 /*
  24  * A structure defining an integer range, to be used as a linked list.  It
  25  * gets allocated by a successful call to `parse_number_set'.  Use
  26  * `number_set_free' to deallocate it.
  27  */
  28
  29 typedef struct number_range_
  30 {
  31   int start;
  32   int end;
  33
  34   struct number_range_* next;
  35 } number_range;
  36
  37
  38 /*
  39  * Parse a description in string `s' for a set of non-negative integers
  40  * within the limits given by the input parameters `min' and `max', and
  41  * which consists of the following ranges, separated by commas (`n' and `m'
  42  * are non-negative integers):
  43  *
  44  *   -n       min <= x <= n
  45  *   n        x = n; this is a shorthand for `n-n'
  46  *   n-m      n <= x <= m (or  m <= x <= n  if  m < n)
  47  *   m-       m <= x <= max
  48  *   -        min <= x <= max
  49  *
  50  * Superfluous commas are ignored, as is whitespace around numbers, dashes,
  51  * and commas.  The ranges must be ordered, without overlaps.  As a
  52  * consequence, `-n' and `m-' can occur at most once and must be then the
  53  * first and last range, respectively; similarly, `-' cannot be paired with
  54  * any other range.
  55  *
  56  * In the following examples, `min' is 4 and `max' is 12:
  57  *
  58  *   -                ->    4, 5, 6, 7, 8, 9, 10, 11, 12
  59  *   -3, 5-           ->    invalid first range
  60  *   4, 6-8, 10-      ->    4, 6, 7, 8, 10, 11, 12
  61  *   4-8, 6-10        ->    invalid overlapping ranges
  62  *
  63  * In case of success (this is, the number set description in `s' is valid)
  64  * the return value is a pointer to the final zero byte in string `s'.  In
  65  * case of an error, the return value is a pointer to the beginning position
  66  * of the offending range in string `s'.
  67  *
  68  * If the user provides a non-NULL `number_set' value, `number_set_parse'
  69  * stores a linked list of ordered number ranges in `*number_set', allocated
  70  * with `malloc'.  If there is no range at all (for example, an empty string
  71  * or whitespace and commas only) no data gets allocated, and `*number_set'
  72  * is set to NULL.  In case of error, `*number_set' returns an error code;
  73  * you should use the following macros to compare with.
  74  *
  75  *   NUMBERSET_INVALID_CHARACTER   invalid character in description string
  76  *   NUMBERSET_OVERFLOW            numerical overflow
  77  *   NUMBERSET_INVALID_RANGE       invalid range, exceeding `min' or `max'
  78  *   NUMBERSET_OVERLAPPING_RANGES  overlapping ranges
  79  *   NUMBERSET_ALLOCATION_ERROR    allocation error
  80  *
  81  * Note that a negative value for `min' is replaced with zero, and a
  82  * negative value for `max' with the largest representable integer, INT_MAX.
  83  */
  84
  85 #define NUMBERSET_INVALID_CHARACTER (number_range*)-1
  86 #define NUMBERSET_OVERFLOW (number_range*)-2
  87 #define NUMBERSET_INVALID_RANGE (number_range*)-3
  88 #define NUMBERSET_OVERLAPPING_RANGES (number_range*)-4
  89 #define NUMBERSET_ALLOCATION_ERROR (number_range*)-5
  90
  91 const char*
  92 number_set_parse(const char* s,
  93                  number_range** number_set,
  94                  int min,
  95                  int max);
  96
  97
  98 /*
  99  * Free the allocated data in `number_set'.
 100  */
 101
 102 void
 103 number_set_free(number_range* number_set);
 104
 105
 106 /*
 107  * Return a string representation of `number_set', viewed through a
 108  * `window', so to say, spanned up by the parameters `min' and `max'.  After
 109  * use, the string should be deallocated with a call to `free'.  In case of
 110  * an allocation error, the return value is NULL.
 111  *
 112  * Note that a negative value for `min' is replaced with zero, and a
 113  * negative value for `max' with the largest representable integer, INT_MAX.
 114  */
 115
 116 char*
 117 number_set_show(number_range* number_set,
 118                 int min,
 119                 int max);
 120
 121
 122 /*
 123  * Return value 1 if `number' is element of `number_set', zero otherwise.
 124  */
 125
 126 int
 127 number_set_is_element(number_range* number_set,
 128                       int number);
 129
 130 #ifdef __cplusplus
 131 } /* extern "C" */
 132 #endif
 133
 134 #endif /* __NUMBERSET_H__ */
 135
 136 /* end of numberset.h */