greenplumn c_keywords 源码
greenplumn c_keywords 代码
文件路径：/src/interfaces/ecpg/preproc/c_keywords.c
/*-------------------------------------------------------------------------
*
* c_keywords.c
* lexical token lookup for reserved words in postgres embedded SQL
*
* src/interfaces/ecpg/preproc/c_keywords.c
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include "preproc_extern.h"
#include "preproc.h"
/* ScanKeywordList lookup data for C keywords */
#include "c_kwlist_d.h"
/* Token codes for C keywords */
#define PG_KEYWORD(kwname, value) value,
static const uint16 ScanCKeywordTokens[] = {
#include "c_kwlist.h"
};
#undef PG_KEYWORD
/*
* ScanCKeywordLookup - see if a given word is a keyword
*
* Returns the token value of the keyword, or -1 if no match.
*
* Do a hash search using plain strcmp() comparison. This is much like
* ScanKeywordLookup(), except we want case-sensitive matching.
*/
int
ScanCKeywordLookup(const char *str)
{
size_t len;
int h;
const char *kw;
/*
* Reject immediately if too long to be any keyword. This saves useless
* hashing work on long strings.
*/
len = strlen(str);
if (len > ScanCKeywords.max_kw_len)
return -1;
/*
* Compute the hash function. Since it's a perfect hash, we need only
* match to the specific keyword it identifies.
*/
h = ScanCKeywords_hash_func(str, len);
/* An out-of-range result implies no match */
if (h < 0 || h >= ScanCKeywords.num_keywords)
return -1;
kw = GetScanKeyword(h, &ScanCKeywords);
if (strcmp(kw, str) == 0)
return ScanCKeywordTokens[h];
return -1;
}
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