flower/libc-extension.cc

   1 /*
   2   libc-extension.cc --  compensate for lacking libc functions.
   3
   4
   5   source file of the flowerlib
   6
   7   (c)  1997--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   8          Jan Nieuwenhuizen <janneke@gnu.org>
   9 */
  10
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <ctype.h>
  14 #include "libc-extension.hh"
  15
  16 /*
  17   urg: why soo wierd?
  18  */
  19 char*
  20 strnlwr (char* start ,int n)
  21 {
  22   char * p = start + n;
  23   while (--p >= start)
  24     {
  25       *p = tolower (*p);    /* a macro on some compilers */
  26     }
  27   return start;
  28 }
  29
  30 char*
  31 strnupr (char* start, int n)
  32 {
  33   char * p = start + n;
  34   while (--p >= start)
  35     {
  36       *p = toupper (*p);    /* a macro on some compilers */
  37     }
  38   return start;
  39 }
  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 Byte *
  51 _memmem (Byte const *haystack, int haystack_len,
  52         Byte const *needle,int needle_len)
  53 {
  54   Byte const * end_haystack = haystack + haystack_len - needle_len + 1;
  55   Byte 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       Byte const *subneedle = needle;
  62       Byte const *subhaystack = haystack;
  63       while (subneedle < end_needle)
  64         if (*subneedle++ != *subhaystack++)
  65           goto next;
  66
  67       // completed the needle. Gotcha.
  68       return (Byte *) 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   Byte const* haystack_byte_c = (Byte const*)haystack;
  80   Byte const* needle_byte_c = (Byte const*)needle;
  81   return _memmem (haystack_byte_c, haystack_len, needle_byte_c, needle_len);
  82 }
  83
  84 #endif
  85
  86 Byte *
  87 memrchr (Byte const * p, int n, char c)
  88 {
  89   const    Byte * q = p+n;
  90   while (q > p)
  91     {
  92       if (*--q == c)
  93         return (Byte*)q;
  94     }
  95   return 0;
  96 }
  97
  98
  99 template<class T>
 100 inline void
 101 my_swap (T &t1, T &t2, T &tmp)
 102 {
 103   tmp = t1;
 104   t1 = t2;
 105   t2 = tmp;
 106 }
 107
 108 Byte*
 109 strrev (Byte* byte, int length_i)
 110 {
 111   Byte tmp_byte;
 112
 113   Byte* left = byte;
 114   Byte* right = byte + length_i;
 115
 116   while (right > left)
 117     {
 118       my_swap (*right-- , *left++ , tmp_byte);
 119     }
 120   return byte;
 121 }
 122
 123 #if ! HAVE_SNPRINTF
 124 int
 125 snprintf (char *str, size_t, char const *format, ...)
 126 {
 127   va_list ap;
 128   va_start (ap, format);
 129   int i = vsprintf (str, format, ap);
 130   va_end (ap);
 131   return i;
 132 }
 133 #endif
 134
 135 #if ! HAVE_VSNPRINTF
 136 int
 137 vsnprintf (char *str, size_t, char const *format, va_list args)
 138 {
 139   int i = vsprintf (str, format, args);
 140   return i;
 141 }
 142 #endif
 143
 144
 145 #if !HAVE_ISINF
 146 int
 147 isinf (double x)
 148 {
 149   return x && ( x == x/ 2) ;
 150 }
 151
 152 #endif