sqlite源码剖析(2)
声明：本SQLite源码剖析系列为刘兴(http://deepfuture.iyunv.com/)原创，未经笔者授权，任何人和机构不能转载/*
** The maximum number of opcodes in a VDBE program.
** Not currently enforced.
*/
//VDBE程序的最大操作码数目
#ifndef SQLITE_MAX_VDBE_OP
# define SQLITE_MAX_VDBE_OP 25000
#endif
/*
** The maximum number of arguments to an SQL function.
*/
//SQL函数的最大参数数目
#ifndef SQLITE_MAX_FUNCTION_ARG
# define SQLITE_MAX_FUNCTION_ARG 127
#endif
/*
** The maximum number of in-memory pages to use for the main database
** table and for temporary tables. The SQLITE_DEFAULT_CACHE_SIZE
*/
//主数据库表和临时表的最大内存大小
#ifndef SQLITE_DEFAULT_CACHE_SIZE
# define SQLITE_DEFAULT_CACHE_SIZE 2000
#endif
#ifndef SQLITE_DEFAULT_TEMP_CACHE_SIZE
# define SQLITE_DEFAULT_TEMP_CACHE_SIZE 500
#endif
/*
** The maximum number of attached databases. This must be between 0
** and 30. The upper bound on 30 is because a 32-bit integer bitmap
** is used internally to track attached databases.
*/
//附加数据库的数目
#ifndef SQLITE_MAX_ATTACHED
# define SQLITE_MAX_ATTACHED 10
#endif
/*
** The maximum value of a ?nnn wildcard that the parser will accept.
*/
//解析器接受的匹配符参数最大值
#ifndef SQLITE_MAX_VARIABLE_NUMBER
# define SQLITE_MAX_VARIABLE_NUMBER 999
#endif
/* Maximum page size. The upper bound on this value is 32768. This a limit
** imposed by the necessity of storing the value in a 2-byte unsigned integer
** and the fact that the page size must be a power of 2.
**
** If this limit is changed, then the compiled library is technically
** incompatible with an SQLite library compiled with a different limit. If
** a process operating on a database with a page-size of 65536 bytes
** crashes, then an instance of SQLite compiled with the default page-size
** limit will not be able to rollback the aborted transaction. This could
** lead to database corruption.
*/
//最大页面大小
#ifndef SQLITE_MAX_PAGE_SIZE
# define SQLITE_MAX_PAGE_SIZE 32768
#endif
/*
** The default size of a database page.
*/
//数据库页面的默认大小
#ifndef SQLITE_DEFAULT_PAGE_SIZE
# define SQLITE_DEFAULT_PAGE_SIZE 1024
#endif
#if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
# undef SQLITE_DEFAULT_PAGE_SIZE
# define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
#endif
/*
** Ordinarily, if no value is explicitly provided, SQLite creates databases
** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
** device characteristics (sector-size and atomic write() support),
** SQLite may choose a larger value. This constant is the maximum value
** SQLite will choose on its own.
*/
//数据库页面的最大默认大小
#ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE
# define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192
#endif
#if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
# undef SQLITE_MAX_DEFAULT_PAGE_SIZE
# define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
#endif
/*
** Maximum number of pages in one database file.
**
** This is really just the default value for the max_page_count pragma.
** This value can be lowered (or raised) at run-time using that the
** max_page_count macro.
*/
//单个数据库文件的最大页数数
#ifndef SQLITE_MAX_PAGE_COUNT
# define SQLITE_MAX_PAGE_COUNT 1073741823
#endif
/*
** Maximum length (in bytes) of the pattern in a LIKE or GLOB
** operator.
*/
// LIKE or GLOB模式的最大长度（字节）
#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
#endif
/*
** Maximum depth of recursion for triggers.
**
** A value of 1 means that a trigger program will not be able to itself
** fire any triggers. A value of 0 means that no trigger programs at all
** may be executed.
*/
//触发器程序的递归深度
#ifndef SQLITE_MAX_TRIGGER_DEPTH
# define SQLITE_MAX_TRIGGER_DEPTH 1000
#endif
//SQLITE限制参数定义完毕
/************** End of sqliteLimit.h *****************************************/
/************** Continuing where we left off in sqliteInt.h ******************/
//禁止Borland编译器的讨厌的警告
/* Disable nuisance warnings on Borland compilers */
#if defined(__BORLANDC__)
#pragma warn -rch /* unreachable code */
#pragma warn -ccc /* Condition is always true or false */
#pragma warn -aus /* Assigned value is never used */
#pragma warn -csu /* Comparing signed and unsigned */
#pragma warn -spa /* Suspicious pointer arithmetic */
#endif
//定义为GNU源码
/* Needed for various definitions... */
#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
/*
** Include standard header files as necessary
*/
//包含必要的头文件
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif
/*
** The number of samples of an index that SQLite takes in order to
** construct a histogram of the table content when running ANALYZE
** and with SQLITE_ENABLE_STAT2
*/
//索引样本数
#define SQLITE_INDEX_SAMPLES 10
/*
** The following macros are used to cast pointers to integers and
** integers to pointers. The way you do this varies from one compiler
** to the next, so we have developed the following set of #if statements
** to generate appropriate macros for a wide range of compilers.
**
** The correct "ANSI" way to do this is to use the intptr_t type.
** Unfortunately, that typedef is not available on all compilers, or
** if it is available, it requires an #include of specific headers
** that very from one machine to the next.
**
** Ticket #3860: The llvm-gcc-4.2 compiler from Apple chokes on
** the ((void*)&((char*)0)) construct. But MSVC chokes on ((void*)(X)).
** So we have to define the macros in different ways depending on the
** compiler.
*/
//下列宏完成指针转整数和整数转指针
#if defined(__PTRDIFF_TYPE__) /* This case should work for GCC */
# define SQLITE_INT_TO_PTR(X) ((void*)(__PTRDIFF_TYPE__)(X))
# define SQLITE_PTR_TO_INT(X) ((int)(__PTRDIFF_TYPE__)(X))
#elif !defined(__GNUC__) /* Works for compilers other than LLVM */
# define SQLITE_INT_TO_PTR(X) ((void*)&((char*)0))
# define SQLITE_PTR_TO_INT(X) ((int)(((char*)X)-(char*)0))
#elif defined(HAVE_STDINT_H) /* Use this case if we have ANSI headers */
# define SQLITE_INT_TO_PTR(X) ((void*)(intptr_t)(X))
# define SQLITE_PTR_TO_INT(X) ((int)(intptr_t)(X))
#else /* Generates a warning - but it always works */
# define SQLITE_INT_TO_PTR(X) ((void*)(X))
# define SQLITE_PTR_TO_INT(X) ((int)(X))
#endif
/*
** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.
** Older versions of SQLite used an optional THREADSAFE macro.
** We support that for legacy
*/
// SQLITE_THREADSAFE线程安全宏被定义为0或1,
#if !defined(SQLITE_THREADSAFE)
#if defined(THREADSAFE)
# define SQLITE_THREADSAFE THREADSAFE
#else
# define SQLITE_THREADSAFE 1
#endif
#endif
/*
** The SQLITE_DEFAULT_MEMSTATUS macro must be defined as either 0 or 1.
** It determines whether or not the features related to
** SQLITE_CONFIG_MEMSTATUS are available by default or not. This value can
** be overridden at runtime using the sqlite3_config() API.
*/
// SQLITE_DEFAULT_MEMSTATUS宏被定义为0或1，在运行时可使
//用sqlite3_config() API修改该值
#if !defined(SQLITE_DEFAULT_MEMSTATUS)
# define SQLITE_DEFAULT_MEMSTATUS 1
#endif
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