release/src/router/mysql/strings/my_strchr.c

   1 /* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
  15 */
  16
  17 #include <my_global.h>
  18 #include "m_string.h"
  19 #include "m_ctype.h"
  20
  21 #define NEQ(A, B) ((A) != (B))
  22 #define EQU(A, B) ((A) == (B))
  23
  24 /**
  25   Macro for the body of the string scanning.
  26
  27   @param CS  The character set of the string
  28   @param STR Pointer to beginning of string
  29   @param END Pointer to one-after-end of string
  30   @param ACC Pointer to beginning of accept (or reject) string
  31   @param LEN Length of accept (or reject) string
  32   @param CMP is a function-like for doing the comparison of two characters.
  33  */
  34
  35 #define SCAN_STRING(CS, STR, END, ACC, LEN, CMP)                        \
  36   do {                                                                  \
  37     uint mbl;                                                           \
  38     const char *ptr_str, *ptr_acc;                                      \
  39     const char *acc_end= (ACC) + (LEN);                                 \
  40     for (ptr_str= (STR) ; ptr_str < (END) ; ptr_str+= mbl)              \
  41     {                                                                   \
  42       mbl= my_mbcharlen((CS), *(uchar*)ptr_str);                        \
  43       if (mbl < 2)                                                      \
  44       {                                                                 \
  45         DBUG_ASSERT(mbl == 1);                                          \
  46         for (ptr_acc= (ACC) ; ptr_acc < acc_end ; ++ptr_acc)            \
  47           if (CMP(*ptr_acc, *ptr_str))                                  \
  48             goto end;                                                   \
  49       }                                                                 \
  50     }                                                                   \
  51 end:                                                                    \
  52     return (size_t) (ptr_str - (STR));                                  \
  53   } while (0)
  54
  55
  56 /*
  57   my_strchr(cs, str, end, c) returns a pointer to the first place in
  58   str where c (1-byte character) occurs, or NULL if c does not occur
  59   in str. This function is multi-byte safe.
  60   TODO: should be moved to CHARSET_INFO if it's going to be called
  61   frequently.
  62 */
  63
  64 char *my_strchr(CHARSET_INFO *cs, const char *str, const char *end,
  65                 pchar c)
  66 {
  67   uint mbl;
  68   while (str < end)
  69   {
  70     mbl= my_mbcharlen(cs, *(uchar *)str);
  71     if (mbl < 2)
  72     {
  73       if (*str == c)
  74         return((char *)str);
  75       str++;
  76     }
  77     else
  78       str+= mbl;
  79   }
  80   return(0);
  81 }
  82
  83 /**
  84   Calculate the length of the initial segment of 'str' which consists
  85   entirely of characters not in 'reject'.
  86
  87   @note The reject string points to single-byte characters so it is
  88   only possible to find the first occurrence of a single-byte
  89   character.  Multi-byte characters in 'str' are treated as not
  90   matching any character in the reject string.
  91
  92   @todo should be moved to CHARSET_INFO if it's going to be called
  93   frequently.
  94
  95   @internal The implementation builds on the assumption that 'str' is long,
  96   while 'reject' is short. So it compares each character in string
  97   with the characters in 'reject' in a tight loop over the characters
  98   in 'reject'.
  99 */
 100
 101 size_t my_strcspn(CHARSET_INFO *cs, const char *str, const char *str_end,
 102                   const char *reject)
 103 {
 104   SCAN_STRING(cs, str, str_end, reject, strlen(reject), EQU);
 105 }