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--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   8          Jan Nieuwenhuizen <janneke@gnu.org>
   9 */
  10
  11 #include <math.h>
  12
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <ctype.h>
  16 #include "libc-extension.hh"
  17
  18 char*
  19 strnlwr (char* start ,int n)
  20 {
  21   char * p = start + n;
  22   while (--p >= start)
  23     {
  24       *p = tolower (*p);    /* a macro on some compilers */
  25     }
  26   return start;
  27 }
  28
  29 char*
  30 strnupr (char* start, int n)
  31 {
  32   char * p = start + n;
  33   while (--p >= start)
  34     {
  35       *p = toupper (*p);    /* a macro on some compilers */
  36     }
  37   return start;
  38 }
  39
  40 /*
  41   There are some strange problems with round() on early glibcs.
  42  */
  43 double
  44 my_round (double x)
  45 {
  46   return floor (x -0.5)+ 1.0 ;
  47 }
  48
  49 #ifndef isinf
  50 #if !HAVE_ISINF
  51 int
  52 isinf (double x)
  53 {
  54   return x && ( x == x/ 2) ;
  55 }
  56 #endif
  57 #endif
  58
  59 #if !HAVE_MEMMEM
  60
  61 /** locate a substring. #memmem# finds the first occurrence of
  62   #needle# in #haystack#.  This is not ANSI-C.
  63
  64   The prototype is not in accordance with the Linux Programmer's
  65   Manual v1.15, but it is with /usr/include/string.h   */
  66
  67 Byte *
  68 _memmem (Byte const *haystack, int haystack_len,
  69         Byte const *needle,int needle_len)
  70 {
  71   Byte const * end_haystack = haystack + haystack_len - needle_len + 1;
  72   Byte const * end_needle = needle + needle_len ;
  73
  74   /* Ahhh ... Some minimal lowlevel stuff. This *is* nice; Varation
  75      is the spice of life */
  76   while (haystack < end_haystack)
  77     {
  78       Byte const *subneedle = needle;
  79       Byte const *subhaystack = haystack;
  80       while (subneedle < end_needle)
  81         if (*subneedle++ != *subhaystack++)
  82           goto next;
  83
  84       /* Completed the needle.  Gotcha.  */
  85       return (Byte *) haystack;
  86       next:
  87         haystack++;
  88     }
  89   return 0;
  90 }
  91
  92 void *
  93 memmem (void const *haystack, int haystack_len,
  94         void const *needle,int needle_len)
  95 {
  96   Byte const* haystack_byte_c = (Byte const*)haystack;
  97   Byte const* needle_byte_c = (Byte const*)needle;
  98   return _memmem (haystack_byte_c, haystack_len, needle_byte_c, needle_len);
  99 }
 100
 101 #endif
 102
 103 Byte *
 104 memrchr (Byte const * p, int n, char c)
 105 {
 106   const    Byte * q = p+n;
 107   while (q > p)
 108     {
 109       if (*--q == c)
 110         return (Byte*)q;
 111     }
 112   return 0;
 113 }
 114
 115
 116 template<class T>
 117 inline void
 118 my_swap (T &t1, T &t2, T &tmp)
 119 {
 120   tmp = t1;
 121   t1 = t2;
 122   t2 = tmp;
 123 }
 124
 125 Byte*
 126 strrev (Byte* byte, int length_i)
 127 {
 128   Byte tmp_byte;
 129
 130   Byte* left = byte;
 131   Byte* right = byte + length_i;
 132
 133   while (right > left)
 134     {
 135       my_swap (*right-- , *left++ , tmp_byte);
 136     }
 137   return byte;
 138 }
 139
 140 #if ! HAVE_SNPRINTF
 141 int
 142 snprintf (char *str, size_t, char const *format, ...)
 143 {
 144   va_list ap;
 145   va_start (ap, format);
 146   int i = vsprintf (str, format, ap);
 147   va_end (ap);
 148   return i;
 149 }
 150 #endif
 151
 152 #if ! HAVE_VSNPRINTF
 153 int
 154 vsnprintf (char *str, size_t, char const *format, va_list args)
 155 {
 156   int i = vsprintf (str, format, args);
 157   return i;
 158 }
 159 #endif