sqlite 扩展函数(源码)

/****************************************************************************** ** This file is an amalgamation of many separate C source files from SQLite ** version 3.7.3. By combining all the individual C code files into this ** single large file, the entire code can be compiled as a one translation ** unit. This allows many compilers to do optimizations that would not be ** possible if the files were compiled separately. Performance improvements ** of 5% are more are commonly seen when SQLite is compiled as a single ** translation unit. ** ** This file is all you need to compile SQLite. To use SQLite in other ** programs, you need this file and the "sqlite3.h" header file that defines ** the programming interface to the SQLite library. (If you do not have ** the "sqlite3.h" header file at hand, you will find a copy embedded within ** the text of this file. Search for "Begin file sqlite3.h" to find the start ** of the embedded sqlite3.h header file.) Additional code files may be needed ** if you want a wrapper to interface SQLite with your choice of programming ** language. The code for the "sqlite3" command-line shell is also in a ** separate file. This file contains only code for the core SQLite library. */ #define SQLITE_CORE 1 #define SQLITE_AMALGAMATION 1 #ifndef SQLITE_PRIVATE # define SQLITE_PRIVATE static #endif #ifndef SQLITE_API # define SQLITE_API #endif /************** Begin file sqliteInt.h ***************************************/ /* ** 2001 September 15 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** Internal interface definitions for SQLite. ** */ #ifndef _SQLITEINT_H_ #define _SQLITEINT_H_ /* ** These #defines should enable >2GB file support on POSIX if the ** underlying operating system supports it. If the OS lacks ** large file support, or if the OS is windows, these should be no-ops. ** ** Ticket #2739: The _LARGEFILE_SOURCE macro must appear before any ** system #includes. Hence, this block of code must be the very first ** code in all source files. ** ** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch ** on the compiler command line. This is necessary if you are compiling ** on a recent machine (ex: Red Hat 7.2) but you want your code to work ** on an older machine (ex: Red Hat 6.0). If you compile on Red Hat 7.2 ** without this option, LFS is enable. But LFS does not exist in the kernel ** in Red Hat 6.0, so the code won't work. Hence, for maximum binary ** portability you should omit LFS. ** ** Similar is true for Mac OS X. LFS is only supported on Mac OS X 9 and later. */ #ifndef SQLITE_DISABLE_LFS # define _LARGE_FILE 1 # ifndef _FILE_OFFSET_BITS # define _FILE_OFFSET_BITS 64 # endif # define _LARGEFILE_SOURCE 1 #endif /* ** Include the configuration header output by 'configure' if we're using the ** autoconf-based build */ #ifdef _HAVE_SQLITE_CONFIG_H #include "config.h" #endif /************** Include sqliteLimit.h in the middle of sqliteInt.h ***********/ /************** Begin file sqliteLimit.h *************************************/ /* ** 2007 May 7 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** ** This file defines various limits of what SQLite can process. */ /* ** The maximum length of a TEXT or BLOB in bytes. This also ** limits the size of a row in a table or index. ** ** The hard limit is the ability of a 32-bit signed integer ** to count the size: 2^31-1 or 2147483647. */ #ifndef SQLITE_MAX_LENGTH # define SQLITE_MAX_LENGTH 1000000000 #endif /* ** This is the maximum number of ** ** * Columns in a table ** * Columns in an index ** * Columns in a view ** * Terms in the SET clause of an UPDATE statement ** * Terms in the result set of a SELECT statement ** * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement. ** * Terms in the VALUES clause of an INSERT statement ** ** The hard upper limit here is 32676. Most database people will ** tell you that in a well-normalized database, you usually should ** not have more than a dozen or so columns in any table. And if ** that is the case, there is no point in having more than a few ** dozen values in any of the other situations described above. */ #ifndef SQLITE_MAX_COLUMN # define SQLITE_MAX_COLUMN 2000 #endif /* ** The maximum length of a single SQL statement in bytes. ** ** It used to be the case that setting this value to zero would ** turn the limit off. That is no longer true. It is not possible ** to turn this limit off. */ #ifndef SQLITE_MAX_SQL_LENGTH # define SQLITE_MAX_SQL_LENGTH 1000000000 #endif /* ** The maximum depth of an expression tree. This is limited to ** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might ** want to place more severe limits on the complexity of an ** expression. ** ** A value of 0 used to mean that the limit was not enforced. ** But that is no longer true. The limit is now strictly enforced ** at all times. */ #ifndef SQLITE_MAX_EXPR_DEPTH # define SQLITE_MAX_EXPR_DEPTH 1000 #endif /* ** The maximum number of terms in a compound SELECT statement. ** The code generator for compound SELECT statements does one ** level of recursion for each term. A stack overflow can result ** if the number of terms is too large. In practice, most SQL ** never has more than 3 or 4 terms. Use a value of 0 to disable ** any limit on the number of terms in a compount SELECT. */ #ifndef SQLITE_MAX_COMPOUND_SELECT # define SQLITE_MAX_COMPOUND_SELECT 500 #endif /* ** The maximum number of opcodes in a VDBE program. ** Not currently enforced. */ #ifndef SQLITE_MAX_VDBE_OP # define SQLITE_MAX_VDBE_OP 25000 #endif /* ** The maximum number of arguments to an SQL function. */ #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 */ #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 default number of frames to accumulate in the log file before ** checkpointing the database in WAL mode. */ #ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT # define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 1000 #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. */ #ifndef SQLITE_MAX_ATTACHED # define SQLITE_MAX_ATTACHED 10 #endif /* ** The maximum value of a ?nnn wildcard that the parser will accept. */ #ifndef SQLITE_MAX_VARIABLE_NUMBER # define SQLITE_MAX_VARIABLE_NUMBER 999 #endif /* Maximum page size. The upper bound on this value is 65536. This a limit ** imposed by the use of 16-bit offsets within each page. ** ** Earlier versions of SQLite allowed the user to change this value at ** compile time. This is no longer permitted, on the grounds that it creates ** a library that 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. */ #ifdef SQLITE_MAX_PAGE_SIZE # undef S