MDEV-8360 Clean-up CHARSET_INFO: strnncollsp: diff_if_only_endspace_difference

- Removing the "diff_if_only_endspace_difference" argument from
  MY_COLLATION_HANDLER::strnncollsp(), my_strnncollsp_simple(),
  as well as in the function template MY_FUNCTION_NAME(strnncollsp)
  in strcoll.ic

- Removing the "diff_if_only_space_different" from ha_compare_text(),
  hp_rec_key_cmp().

- Adding a new function my_strnncollsp_padspace_bin() and reusing
  it instead of duplicate code pieces in my_strnncollsp_8bit_bin(),
  my_strnncollsp_latin1_de(), my_strnncollsp_tis620(),
  my_strnncollsp_utf8_cs().

- Adding more tests for better coverage of the trailing space handling.

- Removing the unused definition of HA_END_SPACE_ARE_EQUAL

3 files changed, 15 insertions, 10 deletions

diff --git a/include/m_ctype.h b/include/m_ctype.h
index 615ee6ac1c6..d22a0b1f987 100644
--- a/include/m_ctype.h
+++ b/include/m_ctype.h
@@ -325,8 +325,7 @@ struct my_collation_handler_st
   int     (*strnncoll)(CHARSET_INFO *,
 		       const uchar *, size_t, const uchar *, size_t, my_bool);
   int     (*strnncollsp)(CHARSET_INFO *,
-                         const uchar *, size_t, const uchar *, size_t,
-                         my_bool diff_if_only_endspace_difference);
+                         const uchar *, size_t, const uchar *, size_t);
   size_t     (*strnxfrm)(CHARSET_INFO *,
                          uchar *dst, size_t dstlen, uint nweights,
                          const uchar *src, size_t srclen, uint flags);
@@ -644,8 +643,7 @@ extern int  my_strnncoll_simple(CHARSET_INFO *, const uchar *, size_t,
 				const uchar *, size_t, my_bool);
 
 extern int  my_strnncollsp_simple(CHARSET_INFO *, const uchar *, size_t,
-                                  const uchar *, size_t,
-                                  my_bool diff_if_only_endspace_difference);
+                                  const uchar *, size_t);
 
 extern void my_hash_sort_simple(CHARSET_INFO *cs,
 				const uchar *key, size_t len,
@@ -654,6 +652,17 @@ extern void my_hash_sort_bin(CHARSET_INFO *cs,
                              const uchar *key, size_t len, ulong *nr1,
                              ulong *nr2);
 
+/**
+  Compare a string to an array of spaces, for PAD SPACE comparison.
+  The function iterates through the string and compares every byte to 0x20.
+  @param       - the string
+  @param       - its length
+  @return <0   - if a byte less than 0x20 was found in the string.
+  @return  0   - if all bytes in the string were 0x20, or if length was 0.
+  @return >0   - if a byte greater than 0x20 was found in the string.
+*/
+extern int my_strnncollsp_padspace_bin(const uchar *str, size_t length);
+
 extern size_t my_lengthsp_8bit(CHARSET_INFO *cs, const char *ptr, size_t length);
 
 extern uint my_instr_simple(CHARSET_INFO *,
diff --git a/include/my_base.h b/include/my_base.h
index 8b546edac43..1317639c528 100644
--- a/include/my_base.h
+++ b/include/my_base.h
@@ -298,11 +298,7 @@ enum ha_base_keytype {
 #define HA_SWAP_KEY		 64
 #define HA_REVERSE_SORT		 128	/* Sort key in reverse order */
 #define HA_NO_SORT               256 /* do not bother sorting on this keyseg */
-/*
-  End space in unique/varchar are considered equal. (Like 'a' and 'a ')
-  Only needed for internal temporary tables.
-*/
-#define HA_END_SPACE_ARE_EQUAL	 512
+
 #define HA_BIT_PART		1024
 #define HA_CAN_MEMCMP           2048 /* internal, never stored in frm */
 
diff --git a/include/my_compare.h b/include/my_compare.h
index 0db22b593f4..6b76483074b 100644
--- a/include/my_compare.h
+++ b/include/my_compare.h
@@ -108,7 +108,7 @@ typedef struct st_HA_KEYSEG		/* Key-portion */
   set_rec_bits(0, bit_ptr, bit_ofs, bit_len)
 
 extern int ha_compare_text(CHARSET_INFO *, const uchar *, uint,
-                           const uchar *, uint , my_bool, my_bool);
+                           const uchar *, uint , my_bool);
 extern int ha_key_cmp(HA_KEYSEG *keyseg, const uchar *a,
 		      const uchar *b, uint key_length, uint nextflag,
 		      uint *diff_pos);