1 files changed, 344 insertions, 0 deletions
diff --git a/src/bin/psql/stringutils.c b/src/bin/psql/stringutils.c
new file mode 100644
index 0000000..c96b2fe
--- /dev/null
+++ b/src/bin/psql/stringutils.c
@@ -0,0 +1,344 @@
+/*
+ * psql - the PostgreSQL interactive terminal
+ *
+ * Copyright (c) 2000-2020, PostgreSQL Global Development Group
+ *
+ * src/bin/psql/stringutils.c
+ */
+#include "postgres_fe.h"
+
+#include <ctype.h>
+
+#include "common.h"
+#include "stringutils.h"
+
+#define PQmblenBounded(s, e)  strnlen(s, PQmblen(s, e))
+
+
+/*
+ * Replacement for strtok() (a.k.a. poor man's flex)
+ *
+ * Splits a string into tokens, returning one token per call, then NULL
+ * when no more tokens exist in the given string.
+ *
+ * The calling convention is similar to that of strtok, but with more
+ * frammishes.
+ *
+ * s -			string to parse, if NULL continue parsing the last string
+ * whitespace - set of whitespace characters that separate tokens
+ * delim -		set of non-whitespace separator characters (or NULL)
+ * quote -		set of characters that can quote a token (NULL if none)
+ * escape -		character that can quote quotes (0 if none)
+ * e_strings -	if true, treat E'...' syntax as a valid token
+ * del_quotes - if true, strip quotes from the returned token, else return
+ *				it exactly as found in the string
+ * encoding -	the active character-set encoding
+ *
+ * Characters in 'delim', if any, will be returned as single-character
+ * tokens unless part of a quoted token.
+ *
+ * Double occurrences of the quoting character are always taken to represent
+ * a single quote character in the data.  If escape isn't 0, then escape
+ * followed by anything (except \0) is a data character too.
+ *
+ * The combination of e_strings and del_quotes both true is not currently
+ * handled.  This could be fixed but it's not needed anywhere at the moment.
+ *
+ * Note that the string s is _not_ overwritten in this implementation.
+ *
+ * NB: it's okay to vary delim, quote, and escape from one call to the
+ * next on a single source string, but changing whitespace is a bad idea
+ * since you might lose data.
+ */
+char *
+strtokx(const char *s,
+		const char *whitespace,
+		const char *delim,
+		const char *quote,
+		char escape,
+		bool e_strings,
+		bool del_quotes,
+		int encoding)
+{
+	static char *storage = NULL;	/* store the local copy of the users
+									 * string here */
+	static char *string = NULL; /* pointer into storage where to continue on
+								 * next call */
+
+	/* variously abused variables: */
+	unsigned int offset;
+	char	   *start;
+	char	   *p;
+
+	if (s)
+	{
+		free(storage);
+
+		/*
+		 * We may need extra space to insert delimiter nulls for adjacent
+		 * tokens.  2X the space is a gross overestimate, but it's unlikely
+		 * that this code will be used on huge strings anyway.
+		 */
+		storage = pg_malloc(2 * strlen(s) + 1);
+		strcpy(storage, s);
+		string = storage;
+	}
+
+	if (!storage)
+		return NULL;
+
+	/* skip leading whitespace */
+	offset = strspn(string, whitespace);
+	start = &string[offset];
+
+	/* end of string reached? */
+	if (*start == '\0')
+	{
+		/* technically we don't need to free here, but we're nice */
+		free(storage);
+		storage = NULL;
+		string = NULL;
+		return NULL;
+	}
+
+	/* test if delimiter character */
+	if (delim && strchr(delim, *start))
+	{
+		/*
+		 * If not at end of string, we need to insert a null to terminate the
+		 * returned token.  We can just overwrite the next character if it
+		 * happens to be in the whitespace set ... otherwise move over the
+		 * rest of the string to make room.  (This is why we allocated extra
+		 * space above).
+		 */
+		p = start + 1;
+		if (*p != '\0')
+		{
+			if (!strchr(whitespace, *p))
+				memmove(p + 1, p, strlen(p) + 1);
+			*p = '\0';
+			string = p + 1;
+		}
+		else
+		{
+			/* at end of string, so no extra work */
+			string = p;
+		}
+
+		return start;
+	}
+
+	/* check for E string */
+	p = start;
+	if (e_strings &&
+		(*p == 'E' || *p == 'e') &&
+		p[1] == '\'')
+	{
+		quote = "'";
+		escape = '\\';			/* if std strings before, not any more */
+		p++;
+	}
+
+	/* test if quoting character */
+	if (quote && strchr(quote, *p))
+	{
+		/* okay, we have a quoted token, now scan for the closer */
+		char		thisquote = *p++;
+
+		for (; *p; p += PQmblenBounded(p, encoding))
+		{
+			if (*p == escape && p[1] != '\0')
+				p++;			/* process escaped anything */
+			else if (*p == thisquote && p[1] == thisquote)
+				p++;			/* process doubled quote */
+			else if (*p == thisquote)
+			{
+				p++;			/* skip trailing quote */
+				break;
+			}
+		}
+
+		/*
+		 * If not at end of string, we need to insert a null to terminate the
+		 * returned token.  See notes above.
+		 */
+		if (*p != '\0')
+		{
+			if (!strchr(whitespace, *p))
+				memmove(p + 1, p, strlen(p) + 1);
+			*p = '\0';
+			string = p + 1;
+		}
+		else
+		{
+			/* at end of string, so no extra work */
+			string = p;
+		}
+
+		/* Clean up the token if caller wants that */
+		if (del_quotes)
+			strip_quotes(start, thisquote, escape, encoding);
+
+		return start;
+	}
+
+	/*
+	 * Otherwise no quoting character.  Scan till next whitespace, delimiter
+	 * or quote.  NB: at this point, *start is known not to be '\0',
+	 * whitespace, delim, or quote, so we will consume at least one character.
+	 */
+	offset = strcspn(start, whitespace);
+
+	if (delim)
+	{
+		unsigned int offset2 = strcspn(start, delim);
+
+		if (offset > offset2)
+			offset = offset2;
+	}
+
+	if (quote)
+	{
+		unsigned int offset2 = strcspn(start, quote);
+
+		if (offset > offset2)
+			offset = offset2;
+	}
+
+	p = start + offset;
+
+	/*
+	 * If not at end of string, we need to insert a null to terminate the
+	 * returned token.  See notes above.
+	 */
+	if (*p != '\0')
+	{
+		if (!strchr(whitespace, *p))
+			memmove(p + 1, p, strlen(p) + 1);
+		*p = '\0';
+		string = p + 1;
+	}
+	else
+	{
+		/* at end of string, so no extra work */
+		string = p;
+	}
+
+	return start;
+}
+
+
+/*
+ * strip_quotes
+ *
+ * Remove quotes from the string at *source.  Leading and trailing occurrences
+ * of 'quote' are removed; embedded double occurrences of 'quote' are reduced
+ * to single occurrences; if 'escape' is not 0 then 'escape' removes special
+ * significance of next character.
+ *
+ * Note that the source string is overwritten in-place.
+ */
+void
+strip_quotes(char *source, char quote, char escape, int encoding)
+{
+	char	   *src;
+	char	   *dst;
+
+	Assert(source != NULL);
+	Assert(quote != '\0');
+
+	src = dst = source;
+
+	if (*src && *src == quote)
+		src++;					/* skip leading quote */
+
+	while (*src)
+	{
+		char		c = *src;
+		int			i;
+
+		if (c == quote && src[1] == '\0')
+			break;				/* skip trailing quote */
+		else if (c == quote && src[1] == quote)
+			src++;				/* process doubled quote */
+		else if (c == escape && src[1] != '\0')
+			src++;				/* process escaped character */
+
+		i = PQmblenBounded(src, encoding);
+		while (i--)
+			*dst++ = *src++;
+	}
+
+	*dst = '\0';
+}
+
+
+/*
+ * quote_if_needed
+ *
+ * Opposite of strip_quotes().  If "source" denotes itself literally without
+ * quoting or escaping, returns NULL.  Otherwise, returns a malloc'd copy with
+ * quoting and escaping applied:
+ *
+ * source -			string to parse
+ * entails_quote -	any of these present?  need outer quotes
+ * quote -			doubled within string, affixed to both ends
+ * escape -			doubled within string
+ * force_quote -	if true, quote the output even if it doesn't "need" it
+ * encoding -		the active character-set encoding
+ *
+ * Do not use this as a substitute for PQescapeStringConn().  Use it for
+ * strings to be parsed by strtokx() or psql_scan_slash_option().
+ */
+char *
+quote_if_needed(const char *source, const char *entails_quote,
+				char quote, char escape, bool force_quote,
+				int encoding)
+{
+	const char *src;
+	char	   *ret;
+	char	   *dst;
+	bool		need_quotes = force_quote;
+
+	Assert(source != NULL);
+	Assert(quote != '\0');
+
+	src = source;
+	dst = ret = pg_malloc(2 * strlen(src) + 3); /* excess */
+
+	*dst++ = quote;
+
+	while (*src)
+	{
+		char		c = *src;
+		int			i;
+
+		if (c == quote)
+		{
+			need_quotes = true;
+			*dst++ = quote;
+		}
+		else if (c == escape)
+		{
+			need_quotes = true;
+			*dst++ = escape;
+		}
+		else if (strchr(entails_quote, c))
+			need_quotes = true;
+
+		i = PQmblenBounded(src, encoding);
+		while (i--)
+			*dst++ = *src++;
+	}
+
+	*dst++ = quote;
+	*dst = '\0';
+
+	if (!need_quotes)
+	{
+		free(ret);
+		ret = NULL;
+	}
+
+	return ret;
+}