diff options
Diffstat (limited to 'strings/my_strchr.c')
| -rw-r--r-- | strings/my_strchr.c | 65 |
1 files changed, 61 insertions, 4 deletions
diff --git a/strings/my_strchr.c b/strings/my_strchr.c index 8c471b1ab3a..5f1d985ba1a 100644 --- a/strings/my_strchr.c +++ b/strings/my_strchr.c @@ -13,6 +13,44 @@ along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#include "strings_def.h" +#include <m_ctype.h> + +#define NEQ(A, B) ((A) != (B)) +#define EQU(A, B) ((A) == (B)) + +/** + Macro for the body of the string scanning. + + @param CS The character set of the string + @param STR Pointer to beginning of string + @param END Pointer to one-after-end of string + @param ACC Pointer to beginning of accept (or reject) string + @param LEN Length of accept (or reject) string + @param CMP is a function-like for doing the comparison of two characters. + */ + +#define SCAN_STRING(CS, STR, END, ACC, LEN, CMP) \ + do { \ + uint mbl; \ + const char *ptr_str, *ptr_acc; \ + const char *acc_end= (ACC) + (LEN); \ + for (ptr_str= (STR) ; ptr_str < (END) ; ptr_str+= mbl) \ + { \ + mbl= my_mbcharlen((CS), *(uchar*)ptr_str); \ + if (mbl < 2) \ + { \ + DBUG_ASSERT(mbl == 1); \ + for (ptr_acc= (ACC) ; ptr_acc < acc_end ; ++ptr_acc) \ + if (CMP(*ptr_acc, *ptr_str)) \ + goto end; \ + } \ + } \ +end: \ + return (size_t) (ptr_str - (STR)); \ + } while (0) + + /* my_strchr(cs, str, end, c) returns a pointer to the first place in str where c (1-byte character) occurs, or NULL if c does not occur @@ -21,10 +59,6 @@ frequently. */ -#include "strings_def.h" -#include <m_ctype.h> - - char *my_strchr(CHARSET_INFO *cs, const char *str, const char *end, pchar c) { @@ -44,3 +78,26 @@ char *my_strchr(CHARSET_INFO *cs, const char *str, const char *end, return(0); } +/** + Calculate the length of the initial segment of 'str' which consists + entirely of characters not in 'reject'. + + @note The reject string points to single-byte characters so it is + only possible to find the first occurrence of a single-byte + character. Multi-byte characters in 'str' are treated as not + matching any character in the reject string. + + @todo should be moved to CHARSET_INFO if it's going to be called + frequently. + + @internal The implementation builds on the assumption that 'str' is long, + while 'reject' is short. So it compares each character in string + with the characters in 'reject' in a tight loop over the characters + in 'reject'. +*/ + +size_t my_strcspn(CHARSET_INFO *cs, const char *str, const char *str_end, + const char *reject) +{ + SCAN_STRING(cs, str, str_end, reject, strlen(reject), EQU); +} |