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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2011 New Dream Network
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include "common/utf8.h"
#include <string.h>
static int high_bits_set(int c)
{
int ret = 0;
while (1) {
if ((c & 0x80) != 0x080)
break;
c <<= 1;
++ret;
}
return ret;
}
/* Encode a 31-bit UTF8 code point to 'buf'.
* Assumes buf is of size MAX_UTF8_SZ
* Returns -1 on failure; number of bytes in the encoded value otherwise.
*/
int encode_utf8(unsigned long u, unsigned char *buf)
{
static const unsigned long max_val[MAX_UTF8_SZ] = {
0x0000007ful, 0x000007fful, 0x0000fffful,
0x001ffffful, 0x03fffffful, 0x7ffffffful
};
static const int MAX_VAL_SZ = sizeof(max_val)/sizeof(max_val[0]);
int i;
for (i = 0; i < MAX_VAL_SZ; ++i) {
if (u <= max_val[i])
break;
}
if (i == MAX_VAL_SZ) {
// This code point is too big to encode.
return -1;
}
if (i == 0) {
buf[0] = u;
}
else {
signed int j;
for (j = i; j > 0; --j) {
buf[j] = 0x80 | (u & 0x3f);
u >>= 6;
}
unsigned char mask = ~(0xFF >> (i + 1));
buf[0] = mask | u;
}
return i + 1;
}
/*
* Decode a UTF8 character from an array of bytes. Return character code.
* Upon error, return INVALID_UTF8_CHAR.
*/
unsigned long decode_utf8(unsigned char *buf, int nbytes)
{
unsigned long code;
int i, j;
if (nbytes <= 0)
return INVALID_UTF8_CHAR;
if (nbytes == 1) {
if (buf[0] >= 0x80)
return INVALID_UTF8_CHAR;
return buf[0];
}
i = high_bits_set(buf[0]);
if (i != nbytes)
return INVALID_UTF8_CHAR;
code = buf[0] & (0xff >> i);
for (j = 1; j < nbytes; ++j) {
if ((buf[j] & 0xc0) != 0x80)
return INVALID_UTF8_CHAR;
code = (code << 6) | (buf[j] & 0x3f);
}
// Check for invalid code points
if (code == 0xFFFE)
return INVALID_UTF8_CHAR;
if (code == 0xFFFF)
return INVALID_UTF8_CHAR;
if (code >= 0xD800 && code <= 0xDFFF)
return INVALID_UTF8_CHAR;
return code;
}
int check_utf8(const char *buf, int len)
{
unsigned char u[MAX_UTF8_SZ];
int enc_len = 0;
int i = 0;
while (1) {
unsigned int c = buf[i];
if (i >= len || c < 0x80 || (c & 0xC0) != 0x80) {
// the start of a new character. Process what we have
// in the buffer.
if (enc_len > 0) {
int re_encoded_len;
unsigned char re_encoded[MAX_UTF8_SZ];
unsigned long code = decode_utf8(u, enc_len);
if (code == INVALID_UTF8_CHAR) {
//printf("decoded to invalid utf8");
return i + 1;
}
re_encoded_len = encode_utf8(code, re_encoded);
if (enc_len != re_encoded_len) {
//printf("originally encoded as %d bytes, "
// "but was re-encoded to %d!\n",
// enc_len, re_encoded_len);
return i + 1;
}
if (memcmp(u, re_encoded, enc_len) != 0) {
//printf("re-encoded to a different "
// "byte stream!");
return i + 1;
}
//printf("code_point %lu\n", code);
}
enc_len = 0;
if (i >= len)
break;
// start collecting again?
if (c >= 0x80)
u[enc_len++] = c;
} else {
if (enc_len == MAX_UTF8_SZ) {
//printf("too many enc_len in utf character!\n");
return i + 1;
}
//printf("continuation byte...\n");
u[enc_len++] = c;
}
++i;
}
return 0;
}
int check_utf8_cstr(const char *buf)
{
return check_utf8(buf, strlen(buf));
}
int is_control_character(int c)
{
return (((c != 0) && (c < 0x20)) || (c == 0x7f));
}
int check_for_control_characters(const char *buf, int len)
{
int i;
for (i = 0; i < len; ++i) {
if (is_control_character((int)(unsigned char)buf[i])) {
return i + 1;
}
}
return 0;
}
int check_for_control_characters_cstr(const char *buf)
{
return check_for_control_characters(buf, strlen(buf));
}
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