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/*
* stringutil.c - some tools for string handling
*
* Copyright (c) 2007 Marko Kreen, Skype Technologies OÜ
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <postgres.h>
#include <lib/stringinfo.h>
#include <mb/pg_wchar.h>
#include <parser/keywords.h>
#include <utils/memutils.h>
#include "stringutil.h"
#ifndef SET_VARSIZE
#define SET_VARSIZE(x, len) VARATT_SIZEP(x) = len
#endif
StringInfo pgq_init_varbuf(void)
{
StringInfo buf;
buf = makeStringInfo();
appendStringInfoString(buf, "XXXX");
return buf;
}
Datum pgq_finish_varbuf(StringInfo buf)
{
if (!buf) return (Datum)0;
SET_VARSIZE(buf->data, buf->len);
return PointerGetDatum(buf->data);
}
/*
* Find a string in comma-separated list.
*
* It does not support space inside tokens.
*/
bool pgq_strlist_contains(const char *liststr, const char *str)
{
int c, len = strlen(str);
const char *p, *listpos = liststr;
loop:
/* find string fragment, later check if actual token */
p = strstr(listpos, str);
if (p == NULL)
return false;
/* move listpos further */
listpos = p + len;
/* survive len=0 and avoid unneccesary compare */
if (*listpos)
listpos++;
/* check previous symbol */
if (p > liststr) {
c = *(p - 1);
if (!isspace(c) && c != ',')
goto loop;
}
/* check following symbol */
c = p[len];
if (c != 0 && !isspace(c) && c != ',')
goto loop;
return true;
}
/*
* quoting
*/
static int pgq_urlencode(char *dst, const uint8 *src, int srclen)
{
static const char hextbl[] = "0123456789abcdef";
const uint8 *end = src + srclen;
char *p = dst;
while (src < end) {
unsigned c = *src++;
if (c == ' ') {
*p++ = '+';
} else if ((c >= '0' && c <= '9')
|| (c >= 'A' && c <= 'Z')
|| (c >= 'a' && c <= 'z')
|| c == '_' || c == '.' || c == '-') {
*p++ = c;
} else {
*p++ = '%';
*p++ = hextbl[c >> 4];
*p++ = hextbl[c & 15];
}
}
return p - dst;
}
static int pgq_quote_literal(char *dst, const uint8 *src, int srclen)
{
const uint8 *cp1 = src, *src_end = src + srclen;
char *cp2 = dst;
bool is_ext = false;
*cp2++ = '\'';
while (cp1 < src_end) {
int wl = pg_mblen((const char *)cp1);
if (wl != 1) {
while (wl-- > 0 && cp1 < src_end)
*cp2++ = *cp1++;
continue;
}
if (*cp1 == '\'') {
*cp2++ = '\'';
} else if (*cp1 == '\\') {
if (!is_ext) {
/* make room for 'E' */
memmove(dst + 1, dst, cp2 - dst);
*dst = 'E';
is_ext = true;
cp2++;
}
*cp2++ = '\\';
}
*cp2++ = *cp1++;
}
*cp2++ = '\'';
return cp2 - dst;
}
/* check if ident is keyword that needs quoting */
static bool is_keyword(const char *ident)
{
const ScanKeyword *kw;
/* do the lookup */
#if PG_VERSION_NUM >= 80500
kw = ScanKeywordLookup(ident, ScanKeywords, NumScanKeywords);
#else
kw = ScanKeywordLookup(ident);
#endif
/* unreserved? */
#if PG_VERSION_NUM >= 80300
if (kw && kw->category == UNRESERVED_KEYWORD)
return false;
#endif
/* found anything? */
return kw != NULL;
}
/*
* pgq_quote_ident - Quote an identifier only if needed
*/
static int pgq_quote_ident(char *dst, const uint8 *src, int srclen)
{
/*
* Can avoid quoting if ident starts with a lowercase letter or
* underscore and contains only lowercase letters, digits, and
* underscores, *and* is not any SQL keyword. Otherwise, supply
* quotes.
*/
int nquotes = 0;
bool safe;
const char *ptr;
char *optr;
char ident[NAMEDATALEN + 1];
/* expect idents be not bigger than NAMEDATALEN */
if (srclen > NAMEDATALEN)
srclen = NAMEDATALEN;
memcpy(ident, src, srclen);
ident[srclen] = 0;
/*
* would like to use <ctype.h> macros here, but they might yield
* unwanted locale-specific results...
*/
safe = ((ident[0] >= 'a' && ident[0] <= 'z') || ident[0] == '_');
for (ptr = ident; *ptr; ptr++) {
char ch = *ptr;
if ((ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9') || (ch == '_'))
continue; /* okay */
safe = false;
if (ch == '"')
nquotes++;
}
if (safe) {
if (is_keyword(ident))
safe = false;
}
optr = dst;
if (!safe)
*optr++ = '"';
for (ptr = ident; *ptr; ptr++) {
char ch = *ptr;
if (ch == '"')
*optr++ = '"';
*optr++ = ch;
}
if (!safe)
*optr++ = '"';
return optr - dst;
}
static char *start_append(StringInfo buf, int alloc_len)
{
enlargeStringInfo(buf, alloc_len);
return buf->data + buf->len;
}
static void finish_append(StringInfo buf, int final_len)
{
if (buf->len + final_len > buf->maxlen)
elog(FATAL, "buffer overflow");
buf->len += final_len;
}
static void tbuf_encode_data(StringInfo buf, const uint8 *data, int len, enum PgqEncode encoding)
{
int dlen = 0;
char *dst;
switch (encoding) {
case TBUF_QUOTE_LITERAL:
dst = start_append(buf, len * 2 + 3);
dlen = pgq_quote_literal(dst, data, len);
break;
case TBUF_QUOTE_IDENT:
dst = start_append(buf, len * 2 + 2);
dlen = pgq_quote_ident(dst, data, len);
break;
case TBUF_QUOTE_URLENC:
dst = start_append(buf, len * 3 + 2);
dlen = pgq_urlencode(dst, data, len);
break;
default:
elog(ERROR, "bad encoding");
}
finish_append(buf, dlen);
}
void pgq_encode_cstring(StringInfo tbuf, const char *str, enum PgqEncode encoding)
{
if (str == NULL)
elog(ERROR, "tbuf_encode_cstring: NULL");
tbuf_encode_data(tbuf, (const uint8 *)str, strlen(str), encoding);
}
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