mirror of
https://github.com/reactos/reactos.git
synced 2024-10-30 11:35:58 +00:00
a7fddf9c07
svn path=/trunk/; revision=29689
272 lines
6.6 KiB
C
272 lines
6.6 KiB
C
/* Written by Krzysztof Kowalczyk (http://blog.kowalczyk.info)
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The author disclaims copyright to this source code. */
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#include "base_util.h"
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#include "tstr_util.h"
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#include "netstr.h"
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/* Implements djb idea of net strings */
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/* Return the number of digits needed to represents a given number in base 10
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string representation.
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*/
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size_t digits_for_number(int num)
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{
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size_t digits = 1;
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/* negative numbers need '-' in front of them */
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if (num < 0) {
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++digits;
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num = -num;
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}
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while (num >= 10)
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{
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++digits;
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num = num / 10;
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}
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return digits;
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}
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/* Netstring format is a safe, easy and mostly human readable format for
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serializing strings (well, any binary data). Netstring format is:
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- a byte length of the data as a string
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- ':' (single character)
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- data
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- ',' (single character)
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e.g. "foo" is encoded as "3:foo,"
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I learned about netstring format from djb (http://cr.yp.to/proto/netstrings.txt)
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*/
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size_t netstr_tstrn_serialized_len_cb(size_t str_len_cch)
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{
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size_t total_len_cch;
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/* 2 is for ':" and ',' */
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total_len_cch = str_len_cch + digits_for_number((int)str_len_cch) + 2;
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return total_len_cch * sizeof(TCHAR);
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}
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/* Return number of bytes needed to serialize string 'str' in netstring format. */
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size_t netstr_tstr_serialized_len_cb(const TCHAR *str)
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{
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size_t str_len_cch;
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if (!str) return 0;
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str_len_cch = tstr_len(str);
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return netstr_tstrn_serialized_len_cb(str_len_cch);
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}
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/* Return number of bytes needed to serialize integer 'num' in netstring format. */
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size_t netstr_int_serialized_len_cb(int num)
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{
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size_t str_len_cch;
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size_t total_len_cch;
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str_len_cch = digits_for_number(num);
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total_len_cch = str_len_cch + digits_for_number((int)str_len_cch) + 2;
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return total_len_cch * sizeof(TCHAR);
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}
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int netstr_tstr_serialize(const TCHAR *str, TCHAR **buf_ptr, size_t *buf_len_cb_ptr)
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{
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char * buf;
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size_t buf_len_cb;
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size_t len_needed_cb;
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TCHAR * num_str;
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size_t str_len_cch;
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size_t len_cb;
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size_t total_len_cb = 0;
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assert(buf_len_cb_ptr);
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if (!buf_len_cb_ptr)
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return FALSE;
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if (!buf_ptr)
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{
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*buf_len_cb_ptr += netstr_tstr_serialized_len_cb(str);
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return TRUE;
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}
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buf = (char*)*buf_ptr;
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assert(buf);
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if (!buf)
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return FALSE;
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buf_len_cb = *buf_len_cb_ptr;
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assert(buf_len_cb > 0);
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if (buf_len_cb <= 0)
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return FALSE;
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len_needed_cb = netstr_tstr_serialized_len_cb(str);
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if (len_needed_cb > buf_len_cb)
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return FALSE;
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str_len_cch = tstr_len(str);
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num_str = tstr_printf(_T("%d:"), str_len_cch);
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if (!num_str)
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return FALSE;
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len_cb = tstr_len(num_str)*sizeof(TCHAR);
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memcpy(buf, num_str, len_cb);
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buf += len_cb;
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total_len_cb += len_cb;
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assert(total_len_cb <= len_needed_cb);
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len_cb = tstr_len(str)*sizeof(TCHAR);
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memcpy(buf, str, len_cb);
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buf += len_cb;
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total_len_cb += len_cb;
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assert(total_len_cb <= len_needed_cb);
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len_cb = sizeof(TCHAR);
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memcpy(buf, _T(","), len_cb);
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buf += len_cb;
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total_len_cb += len_cb;
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assert(total_len_cb == len_needed_cb);
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*buf_len_cb_ptr -= total_len_cb;
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*buf_ptr = (TCHAR*)buf;
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free((void*)num_str);
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return TRUE;
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}
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int netstr_int_serialize(int num, TCHAR **buf_ptr, size_t *buf_len_cb_ptr)
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{
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TCHAR * num_str;
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int f_ok;
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assert(buf_len_cb_ptr);
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if (!buf_len_cb_ptr)
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return FALSE;
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if (!buf_ptr)
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{
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*buf_len_cb_ptr += netstr_int_serialized_len_cb(num);
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return TRUE;
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}
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num_str = tstr_printf(_T("%d"), num);
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if (!num_str)
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return FALSE;
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f_ok = netstr_tstr_serialize(num_str, buf_ptr, buf_len_cb_ptr);
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free((void*)num_str);
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return f_ok;
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}
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/* Parse a netstring number i.e. a list of digits until ':', skipping ':'.
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Returns FALSE if there's an error parsing (string doesn't follow the format) */
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static int netstr_get_str_len(const TCHAR **str_ptr, size_t *str_len_cb_ptr, int *num_out)
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{
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int num = 0;
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const TCHAR * tmp;
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size_t str_len_cb;
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TCHAR c;
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int digit = 0;
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assert(str_ptr);
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if (!str_ptr)
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return FALSE;
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assert(str_len_cb_ptr);
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if (!str_len_cb_ptr)
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return FALSE;
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assert(num_out);
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if (!num_out)
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return FALSE;
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tmp = *str_ptr;
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assert(tmp);
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if (!tmp)
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return FALSE;
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str_len_cb = *str_len_cb_ptr;
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assert(str_len_cb > 0);
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if (str_len_cb <= 0)
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return FALSE;
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for (;;) {
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str_len_cb -= sizeof(TCHAR);
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if (str_len_cb < 0)
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return FALSE;
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c = *tmp++;
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if (_T(':') == c)
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break;
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if ( (c >= _T('0')) && (c <= _T('9')) )
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digit = (int)c - _T('0');
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else
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return FALSE;
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num = (num * 10) + digit;
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}
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if (str_len_cb == *str_len_cb_ptr)
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return FALSE;
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*str_ptr = tmp;
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*str_len_cb_ptr = str_len_cb;
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*num_out = num;
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return TRUE;
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}
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int netstr_valid_separator(TCHAR c)
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{
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if (c == _T(','))
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return TRUE;
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return FALSE;
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}
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int netstr_parse_str(const TCHAR **str_ptr, size_t *str_len_cb_ptr, const TCHAR **str_out, size_t *str_len_cch_out)
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{
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int f_ok;
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size_t str_len_cch;
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size_t str_len_cb;
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const TCHAR * str;
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const TCHAR * str_copy;
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int num;
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f_ok = netstr_get_str_len(str_ptr, str_len_cb_ptr, &num);
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if (!f_ok)
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return FALSE;
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assert(num >= 0);
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str_len_cch = (size_t)num;
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str_len_cb = (str_len_cch+1)*sizeof(TCHAR);
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if (str_len_cb > *str_len_cb_ptr)
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return FALSE;
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str = *str_ptr;
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if (!netstr_valid_separator(str[str_len_cch]))
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return FALSE;
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str_copy = (const TCHAR*)tstr_dupn(str, str_len_cch);
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if (!str_copy)
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return FALSE;
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*str_out = str_copy;
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*str_len_cch_out = str_len_cch;
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*str_ptr = str + str_len_cch + 1;
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*str_len_cb_ptr -= str_len_cb ;
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return TRUE;
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}
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int netstr_parse_int(const TCHAR **str_ptr, size_t *str_len_cb_ptr, int *int_out)
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{
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const TCHAR * str = NULL;
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const TCHAR * tmp;
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TCHAR c;
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size_t str_len_cch;
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int f_ok;
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int num = 0;
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int digit = 0;
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f_ok = netstr_parse_str(str_ptr, str_len_cb_ptr, &str, &str_len_cch);
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if (!f_ok)
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return FALSE;
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tmp = str;
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while (*tmp) {
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c = *tmp++;
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if ( (c >= _T('0')) && (c <= _T('9')) )
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digit = (int)c - _T('0');
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else
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goto Error;
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num = (num * 10) + digit;
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}
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*int_out = num;
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free((void*)str);
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return TRUE;
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Error:
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free((void*)str);
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return FALSE;
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}
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