293 lines
9.4 KiB
C
293 lines
9.4 KiB
C
/*
|
|
** 2022-11-18
|
|
**
|
|
** 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 is a SQLite extension for converting in either direction
|
|
** between a (binary) blob and base64 text. Base64 can transit a
|
|
** sane USASCII channel unmolested. It also plays nicely in CSV or
|
|
** written as TCL brace-enclosed literals or SQL string literals,
|
|
** and can be used unmodified in XML-like documents.
|
|
**
|
|
** This is an independent implementation of conversions specified in
|
|
** RFC 4648, done on the above date by the author (Larry Brasfield)
|
|
** who thereby has the right to put this into the public domain.
|
|
**
|
|
** The conversions meet RFC 4648 requirements, provided that this
|
|
** C source specifies that line-feeds are included in the encoded
|
|
** data to limit visible line lengths to 72 characters and to
|
|
** terminate any encoded blob having non-zero length.
|
|
**
|
|
** Length limitations are not imposed except that the runtime
|
|
** SQLite string or blob length limits are respected. Otherwise,
|
|
** any length binary sequence can be represented and recovered.
|
|
** Generated base64 sequences, with their line-feeds included,
|
|
** can be concatenated; the result converted back to binary will
|
|
** be the concatenation of the represented binary sequences.
|
|
**
|
|
** This SQLite3 extension creates a function, base64(x), which
|
|
** either: converts text x containing base64 to a returned blob;
|
|
** or converts a blob x to returned text containing base64. An
|
|
** error will be thrown for other input argument types.
|
|
**
|
|
** This code relies on UTF-8 encoding only with respect to the
|
|
** meaning of the first 128 (7-bit) codes matching that of USASCII.
|
|
** It will fail miserably if somehow made to try to convert EBCDIC.
|
|
** Because it is table-driven, it could be enhanced to handle that,
|
|
** but the world and SQLite have moved on from that anachronism.
|
|
**
|
|
** To build the extension:
|
|
** Set shell variable SQDIR=<your favorite SQLite checkout directory>
|
|
** *Nix: gcc -O2 -shared -I$SQDIR -fPIC -o base64.so base64.c
|
|
** OSX: gcc -O2 -dynamiclib -fPIC -I$SQDIR -o base64.dylib base64.c
|
|
** Win32: gcc -O2 -shared -I%SQDIR% -o base64.dll base64.c
|
|
** Win32: cl /Os -I%SQDIR% base64.c -link -dll -out:base64.dll
|
|
*/
|
|
|
|
#include <assert.h>
|
|
|
|
#include "sqlite3ext.h"
|
|
|
|
#ifndef deliberate_fall_through
|
|
/* Quiet some compilers about some of our intentional code. */
|
|
# if GCC_VERSION>=7000000
|
|
# define deliberate_fall_through __attribute__((fallthrough));
|
|
# else
|
|
# define deliberate_fall_through
|
|
# endif
|
|
#endif
|
|
|
|
SQLITE_EXTENSION_INIT1;
|
|
|
|
#define PC 0x80 /* pad character */
|
|
#define WS 0x81 /* whitespace */
|
|
#define ND 0x82 /* Not above or digit-value */
|
|
#define PAD_CHAR '='
|
|
|
|
#ifndef U8_TYPEDEF
|
|
typedef unsigned char u8;
|
|
#define U8_TYPEDEF
|
|
#endif
|
|
|
|
/* Decoding table, ASCII (7-bit) value to base 64 digit value or other */
|
|
static const u8 b64DigitValues[128] = {
|
|
/* HT LF VT FF CR */
|
|
ND,ND,ND,ND, ND,ND,ND,ND, ND,WS,WS,WS, WS,WS,ND,ND,
|
|
/* US */
|
|
ND,ND,ND,ND, ND,ND,ND,ND, ND,ND,ND,ND, ND,ND,ND,ND,
|
|
/*sp + / */
|
|
WS,ND,ND,ND, ND,ND,ND,ND, ND,ND,ND,62, ND,ND,ND,63,
|
|
/* 0 1 5 9 = */
|
|
52,53,54,55, 56,57,58,59, 60,61,ND,ND, ND,PC,ND,ND,
|
|
/* A O */
|
|
ND, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
|
|
/* P Z */
|
|
15,16,17,18, 19,20,21,22, 23,24,25,ND, ND,ND,ND,ND,
|
|
/* a o */
|
|
ND,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
|
|
/* p z */
|
|
41,42,43,44, 45,46,47,48, 49,50,51,ND, ND,ND,ND,ND
|
|
};
|
|
|
|
static const char b64Numerals[64+1]
|
|
= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
|
|
#define BX_DV_PROTO(c) \
|
|
((((u8)(c))<0x80)? (u8)(b64DigitValues[(u8)(c)]) : 0x80)
|
|
#define IS_BX_DIGIT(bdp) (((u8)(bdp))<0x80)
|
|
#define IS_BX_WS(bdp) ((bdp)==WS)
|
|
#define IS_BX_PAD(bdp) ((bdp)==PC)
|
|
#define BX_NUMERAL(dv) (b64Numerals[(u8)(dv)])
|
|
/* Width of base64 lines. Should be an integer multiple of 4. */
|
|
#define B64_DARK_MAX 72
|
|
|
|
/* Encode a byte buffer into base64 text with linefeeds appended to limit
|
|
** encoded group lengths to B64_DARK_MAX or to terminate the last group.
|
|
*/
|
|
static char* toBase64( u8 *pIn, int nbIn, char *pOut ){
|
|
int nCol = 0;
|
|
while( nbIn >= 3 ){
|
|
/* Do the bit-shuffle, exploiting unsigned input to avoid masking. */
|
|
pOut[0] = BX_NUMERAL(pIn[0]>>2);
|
|
pOut[1] = BX_NUMERAL(((pIn[0]<<4)|(pIn[1]>>4))&0x3f);
|
|
pOut[2] = BX_NUMERAL(((pIn[1]&0xf)<<2)|(pIn[2]>>6));
|
|
pOut[3] = BX_NUMERAL(pIn[2]&0x3f);
|
|
pOut += 4;
|
|
nbIn -= 3;
|
|
pIn += 3;
|
|
if( (nCol += 4)>=B64_DARK_MAX || nbIn<=0 ){
|
|
*pOut++ = '\n';
|
|
nCol = 0;
|
|
}
|
|
}
|
|
if( nbIn > 0 ){
|
|
signed char nco = nbIn+1;
|
|
int nbe;
|
|
unsigned long qv = *pIn++;
|
|
for( nbe=1; nbe<3; ++nbe ){
|
|
qv <<= 8;
|
|
if( nbe<nbIn ) qv |= *pIn++;
|
|
}
|
|
for( nbe=3; nbe>=0; --nbe ){
|
|
char ce = (nbe<nco)? BX_NUMERAL((u8)(qv & 0x3f)) : PAD_CHAR;
|
|
qv >>= 6;
|
|
pOut[nbe] = ce;
|
|
}
|
|
pOut += 4;
|
|
*pOut++ = '\n';
|
|
}
|
|
*pOut = 0;
|
|
return pOut;
|
|
}
|
|
|
|
/* Skip over text which is not base64 numeral(s). */
|
|
static char * skipNonB64( char *s, int nc ){
|
|
char c;
|
|
while( nc-- > 0 && (c = *s) && !IS_BX_DIGIT(BX_DV_PROTO(c)) ) ++s;
|
|
return s;
|
|
}
|
|
|
|
/* Decode base64 text into a byte buffer. */
|
|
static u8* fromBase64( char *pIn, int ncIn, u8 *pOut ){
|
|
if( ncIn>0 && pIn[ncIn-1]=='\n' ) --ncIn;
|
|
while( ncIn>0 && *pIn!=PAD_CHAR ){
|
|
static signed char nboi[] = { 0, 0, 1, 2, 3 };
|
|
char *pUse = skipNonB64(pIn, ncIn);
|
|
unsigned long qv = 0L;
|
|
int nti, nbo, nac;
|
|
ncIn -= (pUse - pIn);
|
|
pIn = pUse;
|
|
nti = (ncIn>4)? 4 : ncIn;
|
|
ncIn -= nti;
|
|
nbo = nboi[nti];
|
|
if( nbo==0 ) break;
|
|
for( nac=0; nac<4; ++nac ){
|
|
char c = (nac<nti)? *pIn++ : b64Numerals[0];
|
|
u8 bdp = BX_DV_PROTO(c);
|
|
switch( bdp ){
|
|
case ND:
|
|
/* Treat dark non-digits as pad, but they terminate decode too. */
|
|
ncIn = 0;
|
|
deliberate_fall_through;
|
|
case WS:
|
|
/* Treat whitespace as pad and terminate this group.*/
|
|
nti = nac;
|
|
deliberate_fall_through;
|
|
case PC:
|
|
bdp = 0;
|
|
--nbo;
|
|
deliberate_fall_through;
|
|
default: /* bdp is the digit value. */
|
|
qv = qv<<6 | bdp;
|
|
break;
|
|
}
|
|
}
|
|
switch( nbo ){
|
|
case 3:
|
|
pOut[2] = (qv) & 0xff;
|
|
case 2:
|
|
pOut[1] = (qv>>8) & 0xff;
|
|
case 1:
|
|
pOut[0] = (qv>>16) & 0xff;
|
|
}
|
|
pOut += nbo;
|
|
}
|
|
return pOut;
|
|
}
|
|
|
|
/* This function does the work for the SQLite base64(x) UDF. */
|
|
static void base64(sqlite3_context *context, int na, sqlite3_value *av[]){
|
|
int nb, nc, nv = sqlite3_value_bytes(av[0]);
|
|
int nvMax = sqlite3_limit(sqlite3_context_db_handle(context),
|
|
SQLITE_LIMIT_LENGTH, -1);
|
|
char *cBuf;
|
|
u8 *bBuf;
|
|
assert(na==1);
|
|
switch( sqlite3_value_type(av[0]) ){
|
|
case SQLITE_BLOB:
|
|
nb = nv;
|
|
nc = 4*(nv+2/3); /* quads needed */
|
|
nc += (nc+(B64_DARK_MAX-1))/B64_DARK_MAX + 1; /* LFs and a 0-terminator */
|
|
if( nvMax < nc ){
|
|
sqlite3_result_error(context, "blob expanded to base64 too big", -1);
|
|
return;
|
|
}
|
|
bBuf = (u8*)sqlite3_value_blob(av[0]);
|
|
if( !bBuf ){
|
|
if( SQLITE_NOMEM==sqlite3_errcode(sqlite3_context_db_handle(context)) ){
|
|
goto memFail;
|
|
}
|
|
sqlite3_result_text(context,"",-1,SQLITE_STATIC);
|
|
break;
|
|
}
|
|
cBuf = sqlite3_malloc(nc);
|
|
if( !cBuf ) goto memFail;
|
|
nc = (int)(toBase64(bBuf, nb, cBuf) - cBuf);
|
|
sqlite3_result_text(context, cBuf, nc, sqlite3_free);
|
|
break;
|
|
case SQLITE_TEXT:
|
|
nc = nv;
|
|
nb = 3*((nv+3)/4); /* may overestimate due to LF and padding */
|
|
if( nvMax < nb ){
|
|
sqlite3_result_error(context, "blob from base64 may be too big", -1);
|
|
return;
|
|
}else if( nb<1 ){
|
|
nb = 1;
|
|
}
|
|
cBuf = (char *)sqlite3_value_text(av[0]);
|
|
if( !cBuf ){
|
|
if( SQLITE_NOMEM==sqlite3_errcode(sqlite3_context_db_handle(context)) ){
|
|
goto memFail;
|
|
}
|
|
sqlite3_result_zeroblob(context, 0);
|
|
break;
|
|
}
|
|
bBuf = sqlite3_malloc(nb);
|
|
if( !bBuf ) goto memFail;
|
|
nb = (int)(fromBase64(cBuf, nc, bBuf) - bBuf);
|
|
sqlite3_result_blob(context, bBuf, nb, sqlite3_free);
|
|
break;
|
|
default:
|
|
sqlite3_result_error(context, "base64 accepts only blob or text", -1);
|
|
return;
|
|
}
|
|
return;
|
|
memFail:
|
|
sqlite3_result_error(context, "base64 OOM", -1);
|
|
}
|
|
|
|
/*
|
|
** Establish linkage to running SQLite library.
|
|
*/
|
|
#ifndef SQLITE_SHELL_EXTFUNCS
|
|
#ifdef _WIN32
|
|
__declspec(dllexport)
|
|
#endif
|
|
int sqlite3_base_init
|
|
#else
|
|
static int sqlite3_base64_init
|
|
#endif
|
|
(sqlite3 *db, char **pzErr, const sqlite3_api_routines *pApi){
|
|
SQLITE_EXTENSION_INIT2(pApi);
|
|
(void)pzErr;
|
|
return sqlite3_create_function
|
|
(db, "base64", 1,
|
|
SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS|SQLITE_DIRECTONLY|SQLITE_UTF8,
|
|
0, base64, 0, 0);
|
|
}
|
|
|
|
/*
|
|
** Define some macros to allow this extension to be built into the shell
|
|
** conveniently, in conjunction with use of SQLITE_SHELL_EXTFUNCS. This
|
|
** allows shell.c, as distributed, to have this extension built in.
|
|
*/
|
|
#define BASE64_INIT(db) sqlite3_base64_init(db, 0, 0)
|
|
#define BASE64_EXPOSE(db, pzErr) /* Not needed, ..._init() does this. */
|