1 files changed, 114 insertions, 0 deletions
diff --git a/src/common/keywords.c b/src/common/keywords.c
new file mode 100644
index 00000000000..485dd02e89d
--- /dev/null
+++ b/src/common/keywords.c
@@ -0,0 +1,114 @@
+/*-------------------------------------------------------------------------
+ *
+ * keywords.c
+ *	  lexical token lookup for key words in PostgreSQL
+ *
+ *
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/common/keywords.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef FRONTEND
+#include "postgres.h"
+#else
+#include "postgres_fe.h"
+#endif
+
+#ifndef FRONTEND
+
+#include "parser/gramparse.h"
+
+#define PG_KEYWORD(a,b,c) {a,b,c},
+
+#else
+
+#include "common/keywords.h"
+
+/*
+ * We don't need the token number for frontend uses, so leave it out to avoid
+ * requiring backend headers that won't compile cleanly here.
+ */
+#define PG_KEYWORD(a,b,c) {a,0,c},
+
+#endif   /* FRONTEND */
+
+
+const ScanKeyword ScanKeywords[] = {
+#include "parser/kwlist.h"
+};
+
+const int	NumScanKeywords = lengthof(ScanKeywords);
+
+
+/*
+ * ScanKeywordLookup - see if a given word is a keyword
+ *
+ * The table to be searched is passed explicitly, so that this can be used
+ * to search keyword lists other than the standard list appearing above.
+ *
+ * Returns a pointer to the ScanKeyword table entry, or NULL if no match.
+ *
+ * The match is done case-insensitively.  Note that we deliberately use a
+ * dumbed-down case conversion that will only translate 'A'-'Z' into 'a'-'z',
+ * even if we are in a locale where tolower() would produce more or different
+ * translations.  This is to conform to the SQL99 spec, which says that
+ * keywords are to be matched in this way even though non-keyword identifiers
+ * receive a different case-normalization mapping.
+ */
+const ScanKeyword *
+ScanKeywordLookup(const char *text,
+				  const ScanKeyword *keywords,
+				  int num_keywords)
+{
+	int			len,
+				i;
+	char		word[NAMEDATALEN];
+	const ScanKeyword *low;
+	const ScanKeyword *high;
+
+	len = strlen(text);
+	/* We assume all keywords are shorter than NAMEDATALEN. */
+	if (len >= NAMEDATALEN)
+		return NULL;
+
+	/*
+	 * Apply an ASCII-only downcasing.  We must not use tolower() since it may
+	 * produce the wrong translation in some locales (eg, Turkish).
+	 */
+	for (i = 0; i < len; i++)
+	{
+		char		ch = text[i];
+
+		if (ch >= 'A' && ch <= 'Z')
+			ch += 'a' - 'A';
+		word[i] = ch;
+	}
+	word[len] = '\0';
+
+	/*
+	 * Now do a binary search using plain strcmp() comparison.
+	 */
+	low = keywords;
+	high = keywords + (num_keywords - 1);
+	while (low <= high)
+	{
+		const ScanKeyword *middle;
+		int			difference;
+
+		middle = low + (high - low) / 2;
+		difference = strcmp(middle->name, word);
+		if (difference == 0)
+			return middle;
+		else if (difference < 0)
+			low = middle + 1;
+		else
+			high = middle - 1;
+	}
+
+	return NULL;
+}