flower/libc-extension.cc

   1 /*
   2   libc-extension.cc --  compensate for lacking libc functions.
   3
   4   source file of the flowerlib
   5
   6   (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7   Jan Nieuwenhuizen <janneke@gnu.org>
   8 */
   9
  10 #include <cmath>
  11 #include <cstdio>
  12 #include <cstring>
  13 #include <cctype>
  14 #include <cassert>
  15
  16 using namespace std;
  17
  18 #include "libc-extension.hh"
  19
  20 char *
  21 strnlwr (char *start, int n)
  22 {
  23   char *p = start + n;
  24   while (--p >= start)
  25     {
  26       *p = tolower (*p);    /* a macro on some compilers */
  27     }
  28   return start;
  29 }
  30
  31 char *
  32 strnupr (char *start, int n)
  33 {
  34   char *p = start + n;
  35   while (--p >= start)
  36     {
  37       *p = toupper (*p);    /* a macro on some compilers */
  38     }
  39   return start;
  40 }
  41
  42 #if !HAVE_MEMMEM
  43
  44 /** locate a substring. #memmem# finds the first occurrence of
  45     #needle# in #haystack#.  This is not ANSI-C.
  46
  47     The prototype is not in accordance with the Linux Programmer's
  48     Manual v1.15, but it is with /usr/include/string.h   */
  49
  50 unsigned char *
  51 _memmem (unsigned char const *haystack, int haystack_len,
  52          unsigned char const *needle, int needle_len)
  53 {
  54   unsigned char const *end_haystack = haystack + haystack_len - needle_len + 1;
  55   unsigned char const *end_needle = needle + needle_len;
  56
  57   /* Ahhh ... Some minimal lowlevel stuff. This *is* nice; Varation
  58      is the spice of life */
  59   while (haystack < end_haystack)
  60     {
  61       unsigned char const *subneedle = needle;
  62       unsigned char const *subhaystack = haystack;
  63       while (subneedle < end_needle)
  64         if (*subneedle++ != *subhaystack++)
  65           goto next;
  66
  67       /* Completed the needle.  Gotcha.  */
  68       return (unsigned char *) haystack;
  69     next:
  70       haystack++;
  71     }
  72   return 0;
  73 }
  74
  75 void *
  76 memmem (void const *haystack, int haystack_len,
  77         void const *needle, int needle_len)
  78 {
  79   unsigned char const *haystack_byte_c = (unsigned char const *)haystack;
  80   unsigned char const *needle_byte_c = (unsigned char const *)needle;
  81   return _memmem (haystack_byte_c, haystack_len, needle_byte_c, needle_len);
  82 }
  83
  84 #endif
  85
  86 unsigned char *
  87 memrchr (unsigned char const *p, int n, char c)
  88 {
  89   const unsigned char *q = p + n;
  90   while (q > p)
  91     {
  92       if (*--q == c)
  93         return (unsigned char *)q;
  94     }
  95   return 0;
  96 }
  97
  98 template<class T>
  99 inline void
 100 my_swap (T &t1, T &t2, T &tmp)
 101 {
 102   tmp = t1;
 103   t1 = t2;
 104   t2 = tmp;
 105 }
 106
 107 unsigned char *
 108 memrev (unsigned char *byte, int length)
 109 {
 110   unsigned char tmp_byte;
 111   unsigned char *left = byte;
 112   unsigned char *right = byte + length;
 113
 114   while (right > left)
 115     my_swap (*right--, *left++, tmp_byte);
 116   return byte;
 117 }
 118
 119 /*
 120   There are some strange problems with round() on early glibcs.
 121 */
 122 double
 123 my_round (double x)
 124 {
 125   return floor (x -0.5)+ 1.0;
 126 }
 127
 128 /* namespace std { */
 129
 130 #ifndef isinf
 131 #if !HAVE_ISINF
 132 int
 133 isinf (double x)
 134 {
 135   return x && (x == x/ 2);
 136 }
 137 #endif
 138 #endif
 139
 140 #if ! HAVE_SNPRINTF
 141 int
 142 snprintf (char *str, size_t n, char const *format, ...)
 143 {
 144   va_list ap;
 145   va_start (ap, format);
 146   int i = vsprintf (str, format, ap);
 147   if (i > 0 && (unsigned) i > n)
 148     assert (false);
 149   va_end (ap);
 150   return i;
 151 }
 152 #endif
 153
 154 #if ! HAVE_VSNPRINTF
 155 int
 156 vsnprintf (char *str, size_t n, char const *format, va_list args)
 157 {
 158   int i = vsprintf (str, format, args);
 159   if (i > 0 && (unsigned) i > n)
 160     assert (false);
 161   return i;
 162 }
 163 #endif
 164
 165 /* } namespace std */