Quelle sql_digest.h Sprache: C

/* Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; version 2 of the License.

  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,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

#ifndef SQL_DIGEST_H
#define SQL_DIGEST_H

#include <string.h>
class String;

#define MAX_DIGEST_STORAGE_SIZE (1024*1024)

#define DIGEST_HASH_SIZE 16

/**
  Structure to store token count/array for a statement
  on which digest is to be calculated.
*/
struct sql_digest_storage
{
  bool m_full;
  uint m_byte_count;
  unsigned char m_hash[DIGEST_HASH_SIZE];
  /** Character set number. */
  uint m_charset_number;
  /**
    Token array.
    Token array is an array of bytes to store tokens received during parsing.
    Following is the way token array is formed.
    ... <non-id-token> <non-id-token> <id-token&</span>gt; <id_len> <id_text> ...
    For Example:
    SELECT * FROM T1;
    <SELECT_TOKEN> <*> <FROM_TOKEN> &an>lt;ID_TOKEN> <2> <T1>

    @note Only the first @c m_byte_count bytes are initialized,
      out of @c m_token_array_length.
  */
  unsigned char *m_token_array;
  /* Length of the token array to be considered for DIGEST_TEXT calculation. */
  uint m_token_array_length;

  sql_digest_storage()
  {
    reset(NULL, 0);
  }

  inline void reset(unsigned char *token_array, size_t length)
  {
    m_token_array= token_array;
    m_token_array_length= (uint)length;
    reset();
  }

  inline void reset()
  {
    m_full= false;
    m_byte_count= 0;
    m_charset_number= 0;
    memset(m_hash, 0, DIGEST_HASH_SIZE);
  }

  inline bool is_empty()
  {
    return (m_byte_count == 0);
  }

  inline void copy(const sql_digest_storage *from)
  {
    /*
      Keep in mind this is a dirty copy of something that may change,
      as the thread producing the digest is executing concurrently,
      without any lock enforced.
    */
    uint byte_count_copy= m_token_array_length < from->m_byte_count ?
                          m_token_array_length : from->m_byte_count;

    if (byte_count_copy > 0)
    {
      m_full= from->m_full;
      m_byte_count= byte_count_copy;
      m_charset_number= from->m_charset_number;
      memcpy(m_token_array, from->m_token_array, m_byte_count);
      memcpy(m_hash, from->m_hash, DIGEST_HASH_SIZE);
    }
    else
    {
      m_full= false;
      m_byte_count= 0;
      m_charset_number= 0;
    }
  }
};
typedef struct sql_digest_storage sql_digest_storage;

/**
  Compute a digest hash.
  @param digest_storage The digest
  @param [out] hash The computed digest hash. This parameter is a buffer of size @c DIGEST_HASH_SIZE.
*/
void compute_digest_hash(const sql_digest_storage *digest_storage, unsigned char *hash);

/**
  Compute a digest text.
  A 'digest text' is a textual representation of a query,
  where:
  - comments are removed,
  - non significant spaces are removed,
  - literal values are replaced with a special '?' marker,
  - lists of values are collapsed using a shorter notation
  @param digest_storage The digest
  @param [out] digest_text
  @param digest_text_length Size of @c digest_text.
  @param [out] truncated true if the text representation was truncated
*/
void compute_digest_text(const sql_digest_storage *digest_storage,
                         String *digest_text);

#endif

Messung V0.5 in Prozent

¤ Dauer der Verarbeitung: 0.11 Sekunden (vorverarbeitet am 2026-10-08) ¤

Wurzel

Suchen

PVS Prover

Isabelle Prover

NIST Cobol Testsuite

Cephes Mathematical Library

Vienna Development Method

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.