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kwlookup.c File Reference
#include "c.h"
#include "common/kwlookup.h"
Include dependency graph for kwlookup.c:

Go to the source code of this file.

Functions

int ScanKeywordLookup (const char *str, const ScanKeywordList *keywords)
 

Function Documentation

◆ ScanKeywordLookup()

int ScanKeywordLookup ( const char *  str,
const ScanKeywordList keywords 
)

Definition at line 38 of file kwlookup.c.

40{
41 size_t len;
42 int h;
43 const char *kw;
44
45 /*
46 * Reject immediately if too long to be any keyword. This saves useless
47 * hashing and downcasing work on long strings.
48 */
49 len = strlen(str);
50 if (len > keywords->max_kw_len)
51 return -1;
52
53 /*
54 * Compute the hash function. We assume it was generated to produce
55 * case-insensitive results. Since it's a perfect hash, we need only
56 * match to the specific keyword it identifies.
57 */
58 h = keywords->hash(str, len);
59
60 /* An out-of-range result implies no match */
61 if (h < 0 || h >= keywords->num_keywords)
62 return -1;
63
64 /*
65 * Compare character-by-character to see if we have a match, applying an
66 * ASCII-only downcasing to the input characters. We must not use
67 * tolower() since it may produce the wrong translation in some locales
68 * (eg, Turkish).
69 */
70 kw = GetScanKeyword(h, keywords);
71 while (*str != '\0')
72 {
73 char ch = *str++;
74
75 if (ch >= 'A' && ch <= 'Z')
76 ch += 'a' - 'A';
77 if (ch != *kw++)
78 return -1;
79 }
80 if (*kw != '\0')
81 return -1;
82
83 /* Success! */
84 return h;
85}
const char * str
static const JsonPathKeyword keywords[]
static const char * GetScanKeyword(int n, const ScanKeywordList *keywords)
Definition: kwlookup.h:39
const void size_t len

References GetScanKeyword(), keywords, len, and str.

Referenced by fmtId(), plpgsql_yylex(), quote_identifier(), and ScanECPGKeywordLookup().