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a10ae35328
Essentially, the problem is that safemalloc is excruciatingly slow as it checks all allocated blocks for overrun at each memory management primitive, yielding a almost exponential slowdown for the memory management functions (malloc, realloc, free). The overrun check basically consists of verifying some bytes of a block for certain magic keys, which catches some simple forms of overrun. Another minor problem is violation of aliasing rules and that its own internal list of blocks is prone to corruption. Another issue with safemalloc is rather the maintenance cost as the tool has a significant impact on the server code. Given the magnitude of memory debuggers available nowadays, especially those that are provided with the platform malloc implementation, maintenance of a in-house and largely obsolete memory debugger becomes a burden that is not worth the effort due to its slowness and lack of support for detecting more common forms of heap corruption. Since there are third-party tools that can provide the same functionality at a lower or comparable performance cost, the solution is to simply remove safemalloc. Third-party tools can provide the same functionality at a lower or comparable performance cost. The removal of safemalloc also allows a simplification of the malloc wrappers, removing quite a bit of kludge: redefinition of my_malloc, my_free and the removal of the unused second argument of my_free. Since free() always check whether the supplied pointer is null, redudant checks are also removed. Also, this patch adds unit testing for my_malloc and moves my_realloc implementation into the same file as the other memory allocation primitives.
87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
#ifndef GSTREAM_INCLUDED
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#define GSTREAM_INCLUDED
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/* Copyright (C) 2000-2004 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "my_global.h" /* NULL, NullS */
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#include "my_sys.h" /* MY_ALLOW_ZERO_PTR */
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#include "m_ctype.h" /* my_charset_latin1, my_charset_bin */
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typedef struct charset_info_st CHARSET_INFO;
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typedef struct st_mysql_lex_string LEX_STRING;
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class Gis_read_stream
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{
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public:
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enum enum_tok_types
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{
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unknown,
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eostream,
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word,
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numeric,
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l_bra,
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r_bra,
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comma
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};
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Gis_read_stream(CHARSET_INFO *charset, const char *buffer, int size)
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:m_cur(buffer), m_limit(buffer + size), m_err_msg(NULL), m_charset(charset)
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{}
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Gis_read_stream(): m_cur(NullS), m_limit(NullS), m_err_msg(NullS)
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{}
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~Gis_read_stream()
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{
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my_free(m_err_msg);
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}
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enum enum_tok_types get_next_toc_type();
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bool get_next_word(LEX_STRING *);
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bool get_next_number(double *);
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bool check_next_symbol(char);
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inline void skip_space()
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{
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while ((m_cur < m_limit) && my_isspace(&my_charset_latin1, *m_cur))
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m_cur++;
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}
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/* Skip next character, if match. Return 1 if no match */
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inline bool skip_char(char skip)
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{
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skip_space();
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if ((m_cur >= m_limit) || *m_cur != skip)
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return 1; /* Didn't find char */
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m_cur++;
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return 0;
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}
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void set_error_msg(const char *msg);
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// caller should free this pointer
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char *get_error_msg()
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{
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char *err_msg = m_err_msg;
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m_err_msg= NullS;
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return err_msg;
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}
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protected:
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const char *m_cur;
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const char *m_limit;
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char *m_err_msg;
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CHARSET_INFO *m_charset;
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};
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#endif /* GSTREAM_INCLUDED */
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