mirror of
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234 lines
7.0 KiB
C
234 lines
7.0 KiB
C
/*
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** 2019-10-23
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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******************************************************************************
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**
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** This SQLite extension implements functions that handling RFC-4122 UUIDs
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** Three SQL functions are implemented:
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**
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** uuid() - generate a version 4 UUID as a string
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** uuid_str(X) - convert a UUID X into a well-formed UUID string
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** uuid_blob(X) - convert a UUID X into a 16-byte blob
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**
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** The output from uuid() and uuid_str(X) are always well-formed RFC-4122
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** UUID strings in this format:
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**
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** xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
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**
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** All of the 'x', 'M', and 'N' values are lower-case hexadecimal digits.
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** The M digit indicates the "version". For uuid()-generated UUIDs, the
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** version is always "4" (a random UUID). The upper three bits of N digit
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** are the "variant". This library only supports variant 1 (indicated
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** by values of N between '8' and 'b') as those are overwhelming the most
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** common. Other variants are for legacy compatibility only.
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**
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** The output of uuid_blob(X) is always a 16-byte blob. The UUID input
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** string is converted in network byte order (big-endian) in accordance
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** with RFC-4122 specifications for variant-1 UUIDs. Note that network
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** byte order is *always* used, even if the input self-identifies as a
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** variant-2 UUID.
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**
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** The input X to the uuid_str() and uuid_blob() functions can be either
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** a string or a BLOB. If it is a BLOB it must be exactly 16 bytes in
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** length or else a NULL is returned. If the input is a string it must
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** consist of 32 hexadecimal digits, upper or lower case, optionally
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** surrounded by {...} and with optional "-" characters interposed in the
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** middle. The flexibility of input is inspired by the PostgreSQL
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** implementation of UUID functions that accept in all of the following
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** formats:
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**
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** A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11
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** {a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}
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** a0eebc999c0b4ef8bb6d6bb9bd380a11
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** a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11
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** {a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11}
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**
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** If any of the above inputs are passed into uuid_str(), the output will
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** always be in the canonical RFC-4122 format:
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**
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** a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11
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**
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** If the X input string has too few or too many digits or contains
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** stray characters other than {, }, or -, then NULL is returned.
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*/
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#include "sqlite3ext.h"
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SQLITE_EXTENSION_INIT1
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#include <assert.h>
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#include <string.h>
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#include <ctype.h>
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#if !defined(SQLITE_ASCII) && !defined(SQLITE_EBCDIC)
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# define SQLITE_ASCII 1
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#endif
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/*
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** Translate a single byte of Hex into an integer.
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** This routine only works if h really is a valid hexadecimal
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** character: 0..9a..fA..F
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*/
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static unsigned char sqlite3UuidHexToInt(int h){
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assert( (h>='0' && h<='9') || (h>='a' && h<='f') || (h>='A' && h<='F') );
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#ifdef SQLITE_ASCII
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h += 9*(1&(h>>6));
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#endif
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#ifdef SQLITE_EBCDIC
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h += 9*(1&~(h>>4));
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#endif
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return (unsigned char)(h & 0xf);
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}
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/*
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** Convert a 16-byte BLOB into a well-formed RFC-4122 UUID. The output
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** buffer zStr should be at least 37 bytes in length. The output will
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** be zero-terminated.
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*/
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static void sqlite3UuidBlobToStr(
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const unsigned char *aBlob, /* Input blob */
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unsigned char *zStr /* Write the answer here */
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){
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static const char zDigits[] = "0123456789abcdef";
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int i, k;
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unsigned char x;
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k = 0;
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for(i=0, k=0x550; i<16; i++, k=k>>1){
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if( k&1 ){
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zStr[0] = '-';
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zStr++;
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}
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x = aBlob[i];
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zStr[0] = zDigits[x>>4];
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zStr[1] = zDigits[x&0xf];
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zStr += 2;
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}
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*zStr = 0;
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}
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/*
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** Attempt to parse a zero-terminated input string zStr into a binary
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** UUID. Return 0 on success, or non-zero if the input string is not
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** parsable.
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*/
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static int sqlite3UuidStrToBlob(
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const unsigned char *zStr, /* Input string */
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unsigned char *aBlob /* Write results here */
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){
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int i;
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if( zStr[0]=='{' ) zStr++;
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for(i=0; i<16; i++){
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if( zStr[0]=='-' ) zStr++;
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if( isxdigit(zStr[0]) && isxdigit(zStr[1]) ){
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aBlob[i] = (sqlite3UuidHexToInt(zStr[0])<<4)
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+ sqlite3UuidHexToInt(zStr[1]);
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zStr += 2;
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}else{
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return 1;
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}
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}
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if( zStr[0]=='}' ) zStr++;
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return zStr[0]!=0;
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}
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/*
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** Render sqlite3_value pIn as a 16-byte UUID blob. Return a pointer
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** to the blob, or NULL if the input is not well-formed.
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*/
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static const unsigned char *sqlite3UuidInputToBlob(
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sqlite3_value *pIn, /* Input text */
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unsigned char *pBuf /* output buffer */
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){
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switch( sqlite3_value_type(pIn) ){
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case SQLITE_TEXT: {
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const unsigned char *z = sqlite3_value_text(pIn);
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if( sqlite3UuidStrToBlob(z, pBuf) ) return 0;
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return pBuf;
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}
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case SQLITE_BLOB: {
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int n = sqlite3_value_bytes(pIn);
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return n==16 ? sqlite3_value_blob(pIn) : 0;
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}
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default: {
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return 0;
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}
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}
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}
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/* Implementation of uuid() */
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static void sqlite3UuidFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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unsigned char aBlob[16];
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unsigned char zStr[37];
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(void)argc;
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(void)argv;
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sqlite3_randomness(16, aBlob);
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aBlob[6] = (aBlob[6]&0x0f) + 0x40;
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aBlob[8] = (aBlob[8]&0x3f) + 0x80;
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sqlite3UuidBlobToStr(aBlob, zStr);
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sqlite3_result_text(context, (char*)zStr, 36, SQLITE_TRANSIENT);
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}
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/* Implementation of uuid_str() */
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static void sqlite3UuidStrFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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unsigned char aBlob[16];
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unsigned char zStr[37];
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const unsigned char *pBlob;
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(void)argc;
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pBlob = sqlite3UuidInputToBlob(argv[0], aBlob);
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if( pBlob==0 ) return;
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sqlite3UuidBlobToStr(pBlob, zStr);
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sqlite3_result_text(context, (char*)zStr, 36, SQLITE_TRANSIENT);
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}
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/* Implementation of uuid_blob() */
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static void sqlite3UuidBlobFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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unsigned char aBlob[16];
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const unsigned char *pBlob;
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(void)argc;
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pBlob = sqlite3UuidInputToBlob(argv[0], aBlob);
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if( pBlob==0 ) return;
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sqlite3_result_blob(context, pBlob, 16, SQLITE_TRANSIENT);
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}
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#ifdef _WIN32
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__declspec(dllexport)
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#endif
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int sqlite3_uuid_init(
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sqlite3 *db,
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char **pzErrMsg,
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const sqlite3_api_routines *pApi
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){
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int rc = SQLITE_OK;
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SQLITE_EXTENSION_INIT2(pApi);
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(void)pzErrMsg; /* Unused parameter */
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rc = sqlite3_create_function(db, "uuid", 0, SQLITE_UTF8|SQLITE_INNOCUOUS, 0,
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sqlite3UuidFunc, 0, 0);
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if( rc==SQLITE_OK ){
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rc = sqlite3_create_function(db, "uuid_str", 1,
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SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
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0, sqlite3UuidStrFunc, 0, 0);
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}
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if( rc==SQLITE_OK ){
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rc = sqlite3_create_function(db, "uuid_blob", 1,
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SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
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0, sqlite3UuidBlobFunc, 0, 0);
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}
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return rc;
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}
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