/*
* Copyright (C) 2015, 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
* Copyright (C) 2007-2008 Sourcefire, Inc.
*
* Authors: Tomasz Kojm, Nigel Horne, Török Edvin
*
* Acknowledgements: cli_strcasestr() contains a public domain code from:
* http://unixpapa.com/incnote/string.html
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif
#include "str.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#include <ctype.h>
#include <sys/types.h>
#include "clamav.h"
#include "others.h"
#include "matcher.h"
#include "cltypes.h"
#include "jsparse/textbuf.h"
static const int hex_chars[256] = {
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1, -1,-1,-1,-1,
-1,10,11,12, 13,14,15,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,10,11,12, 13,14,15,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
};
static inline int cli_hex2int(const char c)
{
return hex_chars[(const unsigned char)c];
}
int cli_realhex2ui(const char *hex, uint16_t *ptr, unsigned int len) {
uint16_t val;
unsigned int i;
int c;
for(i = 0; i < len; i += 2) {
val = 0;
if(hex[i] == '?' && hex[i + 1] == '?') {
val |= CLI_MATCH_IGNORE;
} else if(hex[i + 1] == '?') {
if((c = cli_hex2int(hex[i])) >= 0) {
val = c << 4;
} else {
return 0;
}
val |= CLI_MATCH_NIBBLE_HIGH;
} else if(hex[i] == '?') {
if((c = cli_hex2int(hex[i + 1])) >= 0) {
val = c;
} else {
return 0;
}
val |= CLI_MATCH_NIBBLE_LOW;
} else if(hex[i] == '(') {
val |= CLI_MATCH_SPECIAL;
} else {
if((c = cli_hex2int(hex[i])) >= 0) {
val = c;
if((c = cli_hex2int(hex[i+1])) >= 0) {
val = (val << 4) + c;
} else {
return 0;
}
} else {
return 0;
}
}
*ptr++ = val;
}
return 1;
}
uint16_t *cli_hex2ui(const char *hex)
{
uint16_t *str;
unsigned int len;
len = strlen(hex);
if(len % 2 != 0) {
cli_errmsg("cli_hex2ui(): Malformed hexstring: %s (length: %u)\n", hex, len);
return NULL;
}
str = cli_calloc((len / 2) + 1, sizeof(uint16_t));
if(!str)
return NULL;
if(cli_realhex2ui(hex, str, len))
return str;
free(str);
return NULL;
}
char *cli_hex2str(const char *hex)
{
char *str;
size_t len;
len = strlen(hex);
if(len % 2 != 0) {
cli_errmsg("cli_hex2str(): Malformed hexstring: %s (length: %u)\n", hex, (unsigned)len);
return NULL;
}
str = cli_calloc((len / 2) + 1, sizeof(char));
if(!str)
return NULL;
if (cli_hex2str_to(hex, str, len) == -1) {
free(str);
return NULL;
}
return str;
}
int cli_hex2str_to(const char *hex, char *ptr, size_t len)
{
size_t i;
int c;
char val;
for(i = 0; i < len; i += 2) {
if((c = cli_hex2int(hex[i])) >= 0) {
val = c;
if((c = cli_hex2int(hex[i+1])) >= 0) {
val = (val << 4) + c;
} else {
return -1;
}
} else {
return -1;
}
*ptr++ = val;
}
return 0;
}
int cli_hex2num(const char *hex)
{
int hexval, ret = 0, len, i;
len = strlen(hex);
if(len % 2 != 0) {
cli_errmsg("cli_hex2num(): Malformed hexstring: %s (length: %d)\n", hex, len);
return -1;
}
for(i = 0; i < len; i++) {
if((hexval = cli_hex2int(hex[i])) < 0)
break;
ret = (ret << 4) | hexval;
}
return ret;
}
int cli_xtoi(const char *hex)
{
int len, val, i;
char * hexbuf;
len = strlen(hex);
if(len % 2 == 0)
return cli_hex2num(hex);
hexbuf = cli_calloc(len+2, sizeof(char));
if (hexbuf == NULL) {
cli_errmsg("cli_xtoi(): cli_malloc fails.\n");
return -1;
}
for(i = 0; i < len; i++)
hexbuf[i+1] = hex[i];
val = cli_hex2num(hexbuf);
free(hexbuf);
return val;
}
char *cli_str2hex(const char *string, unsigned int len)
{
char *hexstr;
char HEX[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f' };
unsigned int i, j;
if((hexstr = (char *) cli_calloc(2 * len + 1, sizeof(char))) == NULL)
return NULL;
for(i = 0, j = 0; i < len; i++, j += 2) {
hexstr[j] = HEX[(string[i] >> 4) & 0xf];
hexstr[j + 1] = HEX[string[i] & 0xf];
}
return hexstr;
}
char *cli_utf16toascii(const char *str, unsigned int length)
{
char *decoded;
unsigned int i, j;
if(length < 2) {
cli_dbgmsg("cli_utf16toascii: length < 2\n");
return NULL;
}
if(length % 2)
length--;
if(!(decoded = cli_calloc(length / 2 + 1, sizeof(char))))
return NULL;
for(i = 0, j = 0; i < length; i += 2, j++) {
decoded[j] = str[i + 1] << 4;
decoded[j] += str[i];
}
return decoded;
}
int cli_strbcasestr(const char *haystack, const char *needle)
{
const char *pt = haystack;
int i, j;
i = strlen(haystack);
j = strlen(needle);
if(i < j)
return 0;
pt += i - j;
return !strcasecmp(pt, needle);
}
/*
* Remove trailing NL and CR characters from the end of the given string.
* Return the new length of the string (ala strlen)
*/
int
cli_chomp(char *string)
{
int l;
if(string == NULL)
return -1;
l = strlen(string);
if(l == 0)
return 0;
--l;
while((l >= 0) && ((string[l] == '\n') || (string[l] == '\r')))
string[l--] = '\0';
return l + 1;
}
/*
* char *cli_strok(const char *line, int fieldno, char *delim)
* Return a copy of field <fieldno> from the string <line>, where
* fields are delimited by any char from <delim>, or NULL if <line>
* doesn't have <fieldno> fields or not enough memory is available.
* The caller has to free() the result afterwards.
*/
char *cli_strtok(const char *line, int fieldno, const char *delim)
{
int counter = 0, i, j;
char *buffer = NULL;
/* step to arg # <fieldno> */
for (i=0; line[i] && counter != fieldno; i++) {
if (strchr(delim, line[i])) {
counter++;
while(line[i+1] && strchr(delim, line[i+1])) {
i++;
}
}
}
if (!line[i]) {
/* end of buffer before field reached */
return NULL;
}
for (j=i; line[j]; j++) {
if (strchr(delim, line[j])) {
break;
}
}
if (i == j) {
return NULL;
}
buffer = cli_malloc(j-i+1);
if(!buffer) {
cli_errmsg("cli_strtok: Unable to allocate memory for buffer\n");
return NULL;
}
strncpy(buffer, line+i, j-i);
buffer[j-i] = '\0';
return buffer;
}
/*
* Like cli_strtok, but this puts the output into a given argument, rather
* than allocating fresh memory
* Returns NULL for error, or a pointer to output
* njh@bandsman.co.uk
*/
char *cli_strtokbuf(const char *input, int fieldno, const char *delim, char *output)
{
int counter = 0, i, j;
/* step to arg # <fieldno> */
for (i=0; input[i] && counter != fieldno; i++) {
if (strchr(delim, input[i])) {
counter++;
while(input[i+1] && strchr(delim, input[i+1])) {
i++;
}
}
}
if (input[i] == '\0') {
/* end of buffer before field reached */
return NULL;
}
for (j=i; input[j]; j++) {
if (strchr(delim, input[j])) {
break;
}
}
if (i == j) {
return NULL;
}
strncpy(output, input+i, j-i);
output[j-i] = '\0';
return output;
}
const char *cli_memstr(const char *haystack, unsigned int hs, const char *needle, unsigned int ns)
{
unsigned int i, s1, s2;
if(!hs || !ns || hs < ns)
return NULL;
if(needle == haystack)
return haystack;
if(ns == 1)
return memchr(haystack, needle[0], hs);
if(needle[0] == needle[1]) {
s1 = 2;
s2 = 1;
} else {
s1 = 1;
s2 = 2;
}
for(i = 0; i <= hs - ns; ) {
if(needle[1] != haystack[i + 1]) {
i += s1;
} else {
if((needle[0] == haystack[i]) && !memcmp(needle + 2, haystack + i + 2, ns - 2))
return &haystack[i];
i += s2;
}
}
return NULL;
}
char *cli_strrcpy(char *dest, const char *source) /* by NJH */
{
if(!dest || !source) {
cli_errmsg("cli_strrcpy: NULL argument\n");
return NULL;
}
while((*dest++ = *source++));
return --dest;
}
#ifndef HAVE_STRCASESTR
const char* cli_strcasestr(const char* a, const char *b)
{
size_t l;
char f[3];
const size_t strlen_a = strlen(a);
const size_t strlen_b = strlen(b);
f[0] = tolower(*b);
f[1] = toupper(*b);
f[2] = '\0';
for (l = strcspn(a, f); l != strlen_a; l += strcspn(a + l + 1, f) + 1)
if (strncasecmp(a + l, b, strlen_b) == 0)
return(a + l);
return(NULL);
}
#endif
#if !defined(HAVE_STRNLEN) || defined(HAVE_STRNI)
size_t cli_strnlen(const char *s, size_t n)
{
size_t i = 0;
for(; (i < n) && s[i] != '\0'; ++i);
return i;
}
#endif
#if !defined(HAVE_STRNDUP) || defined(HAVE_STRNI)
char *cli_strndup(const char *s, size_t n)
{
char *alloc;
size_t len;
if(!s) {
return NULL;
}
len = cli_strnlen(s, n);
alloc = malloc(len+1);
if(!alloc) {
return NULL;
} else
memcpy(alloc, s, len);
alloc[len] = '\0';
return alloc;
}
#endif
size_t cli_strtokenize(char *buffer, const char delim, const size_t token_count, const char **tokens)
{
size_t tokens_found, i;
for(tokens_found = 0; tokens_found < token_count; ) {
tokens[tokens_found++] = buffer;
buffer = strchr(buffer, delim);
if(buffer) {
*buffer++ = '\0';
} else {
i = tokens_found;
while(i < token_count)
tokens[i++] = NULL;
return tokens_found;
}
}
return tokens_found;
}
/**
* @brief The strntol() function converts the string in str to a long value.
* Modifications made to validate the length of the string for non-null term strings.
*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* @param nptr Pointer to start of string.
* @param n Max length of buffer in bytes.
* @param[out] endptr [optional] If endptr is not NULL, strtol() stores the address
* of the first invalid character in *endptr. If there were no digits
* at all, however, strtol() stores the
* original value of str in *endptr.
* Nota Bene: If the buffer is non-null terminated and the number
* comprises the entire buffer, endptr will point past the end of
* the buffer, and the caller should check if endptr >= nptr + n.
*
* @param int The conversion is done according to the given base, which must be
* between 2 and 36 inclusive, or be the special value 0.
* @return long The signed long value.
*/
static
long cli_strntol(const char *nptr, size_t n, char **endptr, register int base)
{
register const char *s = nptr;
register unsigned long acc;
register int c;
register unsigned long cutoff;
register int neg = 0, any, cutlim;
if (0 == n) {
return 0;
}
/*
* Skip white space and pick up leading +/- sign if any.
* If base is 0, allow 0x for hex and 0 for octal, else
* assume decimal; if base is already 16, allow 0x.
*/
do {
c = *s;
} while (isspace(c) && (++s < nptr + n));
if (s >= nptr + n) {
return 0;
}
if (c == '-') {
neg = 1;
c = *s++;
if (s >= nptr + n)
return 0;
} else if (c == '+') {
c = *s++;
if (s >= nptr + n)
return 0;
}
if (base == 0 || base == 16) {
if (c == '0' && (*s == 'x' || *s == 'X')) {
if (s + 2 >= nptr + n) {
return 0;
}
c = s[1];
s += 2;
base = 16;
}
}
if (base == 0)
base = c == '0' ? 8 : 10;
/*
* Compute the cutoff value between legal numbers and illegal
* numbers. That is the largest legal value, divided by the
* base. An input number that is greater than this value, if
* followed by a legal input character, is too big. One that
* is equal to this value may be valid or not; the limit
* between valid and invalid numbers is then based on the last
* digit. For instance, if the range for longs is
* [-2147483648..2147483647] and the input base is 10,
* cutoff will be set to 214748364 and cutlim to either
* 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
* a value > 214748364, or equal but the next digit is > 7 (or 8),
* the number is too big, and we will return a range error.
*
* Set any if any `digits' consumed; make it negative to indicate
* overflow.
*/
cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
cutlim = cutoff % (unsigned long)base;
cutoff /= (unsigned long)base;
for (acc = 0, any = 0; s < nptr + n; s++) {
c = *s;
if (isdigit(c))
c -= '0';
else if (isalpha(c))
c -= isupper(c) ? 'A' - 10 : 'a' - 10;
else
break;
if (c >= base)
break;
if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
any = -1;
else {
any = 1;
acc *= base;
acc += c;
}
}
if (any < 0) {
acc = neg ? LONG_MIN : LONG_MAX;
errno = ERANGE;
} else if (neg)
acc = -acc;
if (endptr != 0)
*endptr = (char *) (any ? s : nptr);
return (acc);
}
/**
* @brief The strntol() function converts the string in str to a long value.
*
* Wrapper for cli_strntol() that provides incentive to check for failure.
*
* @param buf Pointer to start of string.
* @param buf_size Max length of buffer to convert to integer.
* @param fail_at_nondigit If 1, fail out if the a non-digit character is found before the end of the buffer.
* If 0, non-digit character represents end of number and is not a failure.
* @param base The conversion is done according to the given base, which must be
* between 2 and 36 inclusive, or be the special value 0.
* @param[out] result Long integer value of ascii number.
* @return CL_SUCCESS Success
* @return CL_EPARSE Failure
*/
int cli_strntol_wrap(const char *buf, size_t buf_size, int fail_at_nondigit, int base, long *result)
{
char *endptr = NULL;
long num;
if (buf_size == 0 || !buf || !result) {
/* invalid parameter */
return CL_EPARSE;
}
errno = 0;
num = cli_strntol(buf, buf_size, &endptr, base);
if ((num == LONG_MIN || num == LONG_MAX) && errno == ERANGE) {
/* under- or overflow */
return CL_EPARSE;
}
if (endptr == buf) {
/* no digits */
return CL_EPARSE;
}
if (fail_at_nondigit && (endptr < (buf + buf_size)) && (*endptr != '\0')) {
/* non-digit encountered */
return CL_EPARSE;
}
/* success */
*result = num;
return CL_SUCCESS;
}
size_t cli_ldbtokenize(char *buffer, const char delim, const size_t token_count, const char **tokens, int token_skip)
{
size_t tokens_found, i;
int within_pcre = 0;
for(tokens_found = 0; tokens_found < token_count; ) {
tokens[tokens_found++] = buffer;
while (*buffer != '\0') {
if (!within_pcre && (*buffer == delim))
break;
else if ((tokens_found > token_skip) && (*(buffer-1) != '\\') && (*buffer == '/'))
within_pcre = !within_pcre;
buffer++;
}
if(*buffer != '\0') {
*buffer++ = '\0';
} else {
i = tokens_found;
while(i < token_count)
tokens[i++] = NULL;
return tokens_found;
}
}
return tokens_found;
}
int cli_isnumber(const char *str)
{
while(*str)
if(!strchr("0123456789", *str++))
return 0;
return 1;
}
/* encodes the unicode character as utf-8 */
static inline size_t output_utf8(uint16_t u, unsigned char* dst)
{
if(!u) {
*dst = 0x1; /* don't add \0, add \1 instead */
return 1;
}
if(u < 0x80) {
*dst = u&0xff;
return 1;
}
if(u < 0x800) {
*dst++ = 0xc0 | (u>>6); /* 110yyyyy */
*dst = 0x80 | (u & 0x3f); /* 10zzzzzz */
return 2;
}
/* u < 0x10000 because we only handle utf-16,
* values in range 0xd800 - 0xdfff aren't valid, but we don't check for
* that*/
*dst++ = 0xe0 | (u>>12); /* 1110xxxx */
*dst++ = 0x80 | ((u>>6)&0x3f); /* 10yyyyyy */
*dst = 0x80 | (u & 0x3f); /* 10zzzzzz */
return 3;
}
/* javascript-like unescape() function */
char *cli_unescape(const char *str)
{
char *R;
size_t k, i=0;
const size_t len = strlen(str);
/* unescaped string is at most as long as original,
* it will usually be shorter */
R = cli_malloc(len + 1);
if(!R) {
cli_errmsg("cli_unescape: Unable to allocate memory for string\n");
return NULL;
}
for(k=0;k < len;k++) {
unsigned char c = str[k];
if (str[k] == '%') {
if(k+5 >= len || str[k+1] != 'u' || !isxdigit(str[k+2]) || !isxdigit(str[k+3])
|| !isxdigit(str[k+4]) || !isxdigit(str[k+5])) {
if(k+2 < len && isxdigit(str[k+1]) && isxdigit(str[k+2])) {
c = (cli_hex2int(str[k+1])<<4) | cli_hex2int(str[k+2]);
k += 2;
}
} else {
uint16_t u = (cli_hex2int(str[k+2])<<12) | (cli_hex2int(str[k+3])<<8) |
(cli_hex2int(str[k+4])<<4) | cli_hex2int(str[k+5]);
i += output_utf8(u, (unsigned char*)&R[i]);
k += 5;
continue;
}
}
if(!c) c = 1; /* don't add \0 */
R[i++] = c;
}
R[i++] = '\0';
R = cli_realloc2(R, i);
return R;
}
/* handle javascript's escape sequences inside strings */
int cli_textbuffer_append_normalize(struct text_buffer *buf, const char *str, size_t len)
{
size_t i;
for(i=0;i < len;i++) {
char c = str[i];
if (c == '\\' && i+1 < len) {
i++;
switch (str[i]) {
case '0':
c = 0;
break;
case 'b':
c = 8;
break;
case 't':
c = 9;
break;
case 'n':
c = 10;
break;
case 'v':
c = 11;
break;
case 'f':
c = 12;
break;
case 'r':
c=13;
break;
case 'x':
if(i+2 < len)
c = (cli_hex2int(str[i+1])<<4)|cli_hex2int(str[i+2]);
i += 2;
break;
case 'u':
if(i+4 < len) {
uint16_t u = (cli_hex2int(str[i+1])<<12) | (cli_hex2int(str[i+2])<<8) |
(cli_hex2int(str[i+3])<<4) | cli_hex2int(str[i+4]);
if(textbuffer_ensure_capacity(buf, 4) == -1)
return -1;
buf->pos += output_utf8(u, (unsigned char*)&buf->data[buf->pos]);
i += 4;
continue;
}
break;
default:
c = str[i];
break;
}
}
if(!c) c = 1; /* we don't insert \0 */
if(textbuffer_putc(buf, c) == -1)
return -1;
}
return 0;
}
int cli_hexnibbles(char *str, int len)
{
int i;
for(i=0; i<len; i++) {
int c = cli_hex2int(str[i]);
if(c<0) return 1;
str[i] = c;
}
return 0;
}
char *cli_utf16_to_utf8(const char *utf16, size_t length, utf16_type type)
{
/* utf8 -
* 4 bytes for utf16 high+low surrogate (4 bytes input)
* 3 bytes for utf16 otherwise (2 bytes input) */
size_t i, j;
size_t needed = length * 3/2 + 2;
char *s2;
if (length < 2)
return cli_strdup("");
if (length % 2) {
cli_warnmsg("utf16 length is not multiple of two: %lu\n", (long)length);
length--;
}
s2 = cli_malloc(needed);
if (!s2)
return NULL;
i = 0;
if((utf16[0] == '\xff' && utf16[1] == '\xfe') || (utf16[0] == '\xfe' && utf16[1] == '\xff')) {
i += 2;
if(type == UTF16_BOM)
type = (utf16[0] == '\xff') ? UTF16_LE : UTF16_BE;
} else if(type == UTF16_BOM)
type = UTF16_BE;
for (j=0;i<length && j<needed;i += 2) {
uint16_t c = cli_readint16(&utf16[i]);
if(type == UTF16_BE)
c = cbswap16(c);
if (c < 0x80) {
s2[j++] = c;
} else if (c < 0x800) {
s2[j] = 0xc0 | (c >>6);
s2[j+1] = 0x80 | (c&0x3f);
j += 2;
} else if (c < 0xd800 || c >= 0xe000) {
s2[j] = 0xe0 | (c >> 12);
s2[j+1] = 0x80 | ((c >> 6) & 0x3f);
s2[j+2] = 0x80 | (c & 0x3f);
j += 3;
} else if (c < 0xdc00 && i+3 < length) {
uint16_t c2;
/* UTF16 high+low surrogate */
c = c - 0xd800 + 0x40;
c2 = i+3 < length ? cli_readint16(&utf16[i+2]) : 0;
c2 -= 0xdc00;
s2[j] = 0xf0 | (c >> 8);
s2[j+1] = 0x80 | ((c >> 2) & 0x3f);
s2[j+2] = 0x80 | ((c&3) << 4) | (c2 >> 6);
s2[j+3] = 0x80 | (c2 & 0x3f);
j += 4;
i += 2;
} else {
cli_dbgmsg("UTF16 surrogate encountered at wrong pos\n");
/* invalid char */
s2[j++] = 0xef;
s2[j++] = 0xbf;
s2[j++] = 0xbd;
}
}
if (j >= needed)
j = needed-1;
s2[j] = '\0';
return s2;
}
int cli_isutf8(const char *buf, unsigned int len)
{
unsigned int i, j;
for(i = 0; i < len; i++) {
if((buf[i] & 0x80) == 0) { /* 0xxxxxxx is plain ASCII */
continue;
} else if((buf[i] & 0x40) == 0) { /* 10xxxxxx never 1st byte */
return 0;
} else {
unsigned int following;
if((buf[i] & 0x20) == 0) { /* 110xxxxx */
/* c = buf[i] & 0x1f; */
following = 1;
} else if((buf[i] & 0x10) == 0) { /* 1110xxxx */
/* c = buf[i] & 0x0f; */
following = 2;
} else if((buf[i] & 0x08) == 0) { /* 11110xxx */
/* c = buf[i] & 0x07; */
following = 3;
} else if((buf[i] & 0x04) == 0) { /* 111110xx */
/* c = buf[i] & 0x03; */
following = 4;
} else if((buf[i] & 0x02) == 0) { /* 1111110x */
/* c = buf[i] & 0x01; */
following = 5;
} else {
return 0;
}
for(j = 0; j < following; j++) {
if(++i >= len)
return 0;
if((buf[i] & 0x80) == 0 || (buf[i] & 0x40))
return 0;
/* c = (c << 6) + (buf[i] & 0x3f); */
}
}
}
return 1;
}