MySQL  8.0.27
Source Code Documentation
gen_lex_hash.cc File Reference
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <set>
#include <utility>
#include "my_inttypes.h"
#include "sql/lex.h"
#include "sql/lex_symbol.h"
#include "template_utils.h"
#include "welcome_copyright_notice.h"

Classes

struct  hash_lex_struct
 
class  hash_map_info
 

Macros

#define NO_YACC_SYMBOLS
 

Functions

static bool check_duplicates (uint group_mask)
 
static void insert_into_hash (hash_lex_struct *root, const char *name, int len_from_begin, int index)
 
int main (int, char **)
 

Detailed Description

Algorithm implemented from a description in
"The Art of Computer Programming" by Donald E. Knuth
Volume 3 "Sorting and searching",
chapter 6.3 "Digital searching"

as illustration of data structures, imagine next table:

static SYMBOL symbols[] = {
  { "ADD",              SYM(ADD),0,0},
  { "AND",              SYM(AND),0,0},
  { "DAY",              SYM(DAY_SYM),0,0},
};

for this structure, presented program generate next searching-structure:

+-----------+-+-+-+
|       len |1|2|3|
+-----------+-+-+-+
|first_char |0|0|a|
|last_char  |0|0|d|
|link       |0|0|+|
                 |
                 V
       +----------+-+-+-+--+
       |    1 char|a|b|c|d |
       +----------+-+-+-+--+
       |first_char|d|0|0|0 |
       |last_char |n|0|0|-1|
       |link      |+|0|0|+ |
                   |     |
                   |     V
                   |  symbols[2] ( "DAY" )
                   V
+----------+--+-+-+-+-+-+-+-+-+-+--+
|    2 char|d |e|f|j|h|i|j|k|l|m|n |
+----------+--+-+-+-+-+-+-+-+-+-+--+
|first_char|0 |0|0|0|0|0|0|0|0|0|0 |
|last_char |-1|0|0|0|0|0|0|0|0|0|-1|
|link      |+ |0|0|0|0|0|0|0|0|0|+ |
            |                    |
            V                    V
         symbols[0] ( "ADD" )  symbols[1] ( "AND" )

for optimization, link is the 16-bit index in 'symbols'
or search-array..

So, we can read full search-structure as 32-bit word

Macro Definition Documentation

◆ NO_YACC_SYMBOLS

#define NO_YACC_SYMBOLS

Function Documentation

◆ check_duplicates()

bool check_duplicates ( uint  group_mask)
static

◆ insert_into_hash()

static void insert_into_hash ( hash_lex_struct root,
const char *  name,
int  len_from_begin,
int  index 
)
static

◆ main()

int main ( int  ,
char **   
)