mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-27 18:12:02 +00:00
98 lines
3.3 KiB
C++
98 lines
3.3 KiB
C++
// Copyright 1999-2005 The RE2 Authors. All Rights Reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
#include "util/util.h"
|
|
#include "re2/stringpiece.h"
|
|
|
|
namespace re2 {
|
|
|
|
// ----------------------------------------------------------------------
|
|
// CEscapeString()
|
|
// Copies 'src' to 'dest', escaping dangerous characters using
|
|
// C-style escape sequences. 'src' and 'dest' should not overlap.
|
|
// Returns the number of bytes written to 'dest' (not including the \0)
|
|
// or -1 if there was insufficient space.
|
|
// ----------------------------------------------------------------------
|
|
int CEscapeString(const char* src, int src_len, char* dest,
|
|
int dest_len) {
|
|
const char* src_end = src + src_len;
|
|
int used = 0;
|
|
|
|
for (; src < src_end; src++) {
|
|
if (dest_len - used < 2) // Need space for two letter escape
|
|
return -1;
|
|
|
|
unsigned char c = *src;
|
|
switch (c) {
|
|
case '\n': dest[used++] = '\\'; dest[used++] = 'n'; break;
|
|
case '\r': dest[used++] = '\\'; dest[used++] = 'r'; break;
|
|
case '\t': dest[used++] = '\\'; dest[used++] = 't'; break;
|
|
case '\"': dest[used++] = '\\'; dest[used++] = '\"'; break;
|
|
case '\'': dest[used++] = '\\'; dest[used++] = '\''; break;
|
|
case '\\': dest[used++] = '\\'; dest[used++] = '\\'; break;
|
|
default:
|
|
// Note that if we emit \xNN and the src character after that is a hex
|
|
// digit then that digit must be escaped too to prevent it being
|
|
// interpreted as part of the character code by C.
|
|
if (c < ' ' || c > '~') {
|
|
if (dest_len - used < 4) // need space for 4 letter escape
|
|
return -1;
|
|
sprintf(dest + used, "\\%03o", c);
|
|
used += 4;
|
|
} else {
|
|
dest[used++] = c; break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (dest_len - used < 1) // make sure that there is room for \0
|
|
return -1;
|
|
|
|
dest[used] = '\0'; // doesn't count towards return value though
|
|
return used;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------
|
|
// CEscape()
|
|
// Copies 'src' to result, escaping dangerous characters using
|
|
// C-style escape sequences. 'src' and 'dest' should not overlap.
|
|
// ----------------------------------------------------------------------
|
|
string CEscape(const StringPiece& src) {
|
|
const int dest_length = src.size() * 4 + 1; // Maximum possible expansion
|
|
char* dest = new char[dest_length];
|
|
const int len = CEscapeString(src.data(), src.size(),
|
|
dest, dest_length);
|
|
string s = string(dest, len);
|
|
delete[] dest;
|
|
return s;
|
|
}
|
|
|
|
string PrefixSuccessor(const StringPiece& prefix) {
|
|
// We can increment the last character in the string and be done
|
|
// unless that character is 255, in which case we have to erase the
|
|
// last character and increment the previous character, unless that
|
|
// is 255, etc. If the string is empty or consists entirely of
|
|
// 255's, we just return the empty string.
|
|
bool done = false;
|
|
string limit(prefix.data(), prefix.size());
|
|
int index = limit.length() - 1;
|
|
while (!done && index >= 0) {
|
|
if ((limit[index]&255) == 255) {
|
|
limit.erase(index);
|
|
index--;
|
|
} else {
|
|
limit[index]++;
|
|
done = true;
|
|
}
|
|
}
|
|
if (!done) {
|
|
return "";
|
|
} else {
|
|
return limit;
|
|
}
|
|
}
|
|
|
|
} // namespace re2
|