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Add the delta_parse(DELTA) table-valued function to the fossildelta

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extension.

FossilOrigin-Name: d91fcc267bf1be795dfdb1fbfb40c2aea79ddff247a51d26462136c325b7a6d3
This commit is contained in:
drh
2019-02-19 20:19:51 +00:00
parent 4bec44bdfa
commit 2d441ce3f3
3 changed files with 320 additions and 73 deletions
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ext/misc/fossildelta.c
+313 -66
View File
@@ -134,7 +134,7 @@ static void putInt(unsigned int v, char **pz){
** the integer. The *pLen parameter holds the length of the string
** in *pz and is decremented once for each character in the integer.
*/
static unsigned int getInt(const char **pz, int *pLen){
static unsigned int deltaGetInt(const char **pz, int *pLen){
static const signed char zValue[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
@@ -484,7 +484,7 @@ static int delta_create(
*/
static int delta_output_size(const char *zDelta, int lenDelta){
int size;
size = getInt(&zDelta, &lenDelta);
size = deltaGetInt(&zDelta, &lenDelta);
if( *zDelta!='\n' ){
/* ERROR: size integer not terminated by "\n" */
return -1;
@@ -526,7 +526,7 @@ static int delta_apply(
char *zOrigOut = zOut;
#endif
limit = getInt(&zDelta, &lenDelta);
limit = deltaGetInt(&zDelta, &lenDelta);
if( *zDelta!='\n' ){
/* ERROR: size integer not terminated by "\n" */
return -1;
@@ -534,11 +534,11 @@ static int delta_apply(
zDelta++; lenDelta--;
while( *zDelta && lenDelta>0 ){
unsigned int cnt, ofst;
cnt = getInt(&zDelta, &lenDelta);
cnt = deltaGetInt(&zDelta, &lenDelta);
switch( zDelta[0] ){
case '@': {
zDelta++; lenDelta--;
ofst = getInt(&zDelta, &lenDelta);
ofst = deltaGetInt(&zDelta, &lenDelta);
if( lenDelta>0 && zDelta[0]!=',' ){
/* ERROR: copy command not terminated by ',' */
return -1;
@@ -599,67 +599,6 @@ static int delta_apply(
return -1;
}
/*
** Analyze a delta. Figure out the total number of bytes copied from
** source to target, and the total number of bytes inserted by the delta,
** and return both numbers.
*/
static int delta_analyze(
const char *zDelta, /* Delta to apply to the pattern */
int lenDelta, /* Length of the delta */
int *pnCopy, /* OUT: Number of bytes copied */
int *pnInsert /* OUT: Number of bytes inserted */
){
unsigned int nInsert = 0;
unsigned int nCopy = 0;
(void)getInt(&zDelta, &lenDelta);
if( *zDelta!='\n' ){
/* ERROR: size integer not terminated by "\n" */
return -1;
}
zDelta++; lenDelta--;
while( *zDelta && lenDelta>0 ){
unsigned int cnt;
cnt = getInt(&zDelta, &lenDelta);
switch( zDelta[0] ){
case '@': {
zDelta++; lenDelta--;
(void)getInt(&zDelta, &lenDelta);
if( lenDelta>0 && zDelta[0]!=',' ){
/* ERROR: copy command not terminated by ',' */
return -1;
}
zDelta++; lenDelta--;
nCopy += cnt;
break;
}
case ':': {
zDelta++; lenDelta--;
nInsert += cnt;
if( cnt>lenDelta ){
/* ERROR: insert count exceeds size of delta */
return -1;
}
zDelta += cnt;
lenDelta -= cnt;
break;
}
case ';': {
*pnCopy = nCopy;
*pnInsert = nInsert;
return 0;
}
default: {
/* ERROR: unknown delta operator */
return -1;
}
}
}
/* ERROR: unterminated delta */
return -1;
}
/*
** SQL functions: fossildelta_create(X,Y)
**
@@ -765,6 +704,311 @@ static void deltaOutputSizeFunc(
}
}
/* The deltaparse(DELTA) table-valued function parses the DELTA in
** its input and returns a table that describes that delta.
*/
typedef struct deltaparsevtab_vtab deltaparsevtab_vtab;
typedef struct deltaparsevtab_cursor deltaparsevtab_cursor;
struct deltaparsevtab_vtab {
sqlite3_vtab base; /* Base class - must be first */
/* No additional information needed */
};
struct deltaparsevtab_cursor {
sqlite3_vtab_cursor base; /* Base class - must be first */
char *aDelta; /* The delta being parsed */
int nDelta; /* Number of bytes in the delta */
int iCursor; /* Current cursor location */
int eOp; /* Name of current operator */
unsigned int a1, a2; /* Arguments to current operator */
int iNext; /* Next cursor value */
};
/* Operator names:
*/
static const char *azOp[] = {
"SIZE", "COPY", "INSERT", "CHECKSUM", "ERROR", "EOF"
};
#define DELTAPARSE_OP_SIZE 0
#define DELTAPARSE_OP_COPY 1
#define DELTAPARSE_OP_INSERT 2
#define DELTAPARSE_OP_CHECKSUM 3
#define DELTAPARSE_OP_ERROR 4
#define DELTAPARSE_OP_EOF 5
/*
** The deltaparsevtabConnect() method is invoked to create a new
** deltaparse virtual table.
**
** Think of this routine as the constructor for deltaparsevtab_vtab objects.
**
** All this routine needs to do is:
**
** (1) Allocate the deltaparsevtab_vtab object and initialize all fields.
**
** (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the
** result set of queries against the virtual table will look like.
*/
static int deltaparsevtabConnect(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
deltaparsevtab_vtab *pNew;
int rc;
rc = sqlite3_declare_vtab(db,
"CREATE TABLE x(op,a1,a2,delta HIDDEN)"
);
/* For convenience, define symbolic names for the index to each column. */
#define DELTAPARSEVTAB_OP 0
#define DELTAPARSEVTAB_A1 1
#define DELTAPARSEVTAB_A2 2
#define DELTAPARSEVTAB_DELTA 3
if( rc==SQLITE_OK ){
pNew = sqlite3_malloc64( sizeof(*pNew) );
*ppVtab = (sqlite3_vtab*)pNew;
if( pNew==0 ) return SQLITE_NOMEM;
memset(pNew, 0, sizeof(*pNew));
}
return rc;
}
/*
** This method is the destructor for deltaparsevtab_vtab objects.
*/
static int deltaparsevtabDisconnect(sqlite3_vtab *pVtab){
deltaparsevtab_vtab *p = (deltaparsevtab_vtab*)pVtab;
sqlite3_free(p);
return SQLITE_OK;
}
/*
** Constructor for a new deltaparsevtab_cursor object.
*/
static int deltaparsevtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
deltaparsevtab_cursor *pCur;
pCur = sqlite3_malloc( sizeof(*pCur) );
if( pCur==0 ) return SQLITE_NOMEM;
memset(pCur, 0, sizeof(*pCur));
*ppCursor = &pCur->base;
return SQLITE_OK;
}
/*
** Destructor for a deltaparsevtab_cursor.
*/
static int deltaparsevtabClose(sqlite3_vtab_cursor *cur){
deltaparsevtab_cursor *pCur = (deltaparsevtab_cursor*)cur;
sqlite3_free(pCur);
return SQLITE_OK;
}
/*
** Advance a deltaparsevtab_cursor to its next row of output.
*/
static int deltaparsevtabNext(sqlite3_vtab_cursor *cur){
deltaparsevtab_cursor *pCur = (deltaparsevtab_cursor*)cur;
const char *z;
int i = 0;
pCur->iCursor = pCur->iNext;
z = pCur->aDelta + pCur->iCursor;
pCur->a1 = deltaGetInt(&z, &i);
switch( z[0] ){
case '@': {
z++;
pCur->a2 = deltaGetInt(&z, &i);
pCur->eOp = DELTAPARSE_OP_COPY;
pCur->iNext = (int)(&z[1] - pCur->aDelta);
break;
}
case ':': {
z++;
pCur->a2 = (unsigned int)(z - pCur->aDelta);
pCur->eOp = DELTAPARSE_OP_INSERT;
pCur->iNext = (int)(&z[pCur->a1] - pCur->aDelta);
break;
}
case ';': {
pCur->eOp = DELTAPARSE_OP_CHECKSUM;
pCur->iNext = pCur->nDelta;
break;
}
default: {
if( pCur->iNext==pCur->nDelta ){
pCur->eOp = DELTAPARSE_OP_EOF;
}else{
pCur->eOp = DELTAPARSE_OP_ERROR;
pCur->iNext = pCur->nDelta;
}
break;
}
}
return SQLITE_OK;
}
/*
** Return values of columns for the row at which the deltaparsevtab_cursor
** is currently pointing.
*/
static int deltaparsevtabColumn(
sqlite3_vtab_cursor *cur, /* The cursor */
sqlite3_context *ctx, /* First argument to sqlite3_result_...() */
int i /* Which column to return */
){
deltaparsevtab_cursor *pCur = (deltaparsevtab_cursor*)cur;
switch( i ){
case DELTAPARSEVTAB_OP: {
sqlite3_result_text(ctx, azOp[pCur->eOp], -1, SQLITE_STATIC);
break;
}
case DELTAPARSEVTAB_A1: {
sqlite3_result_int(ctx, pCur->a1);
break;
}
case DELTAPARSEVTAB_A2: {
if( pCur->eOp==DELTAPARSE_OP_COPY ){
sqlite3_result_int(ctx, pCur->a2);
}else if( pCur->eOp==DELTAPARSE_OP_INSERT ){
sqlite3_result_blob(ctx, pCur->aDelta+pCur->a2, pCur->a1,
SQLITE_TRANSIENT);
}
break;
}
case DELTAPARSEVTAB_DELTA: {
sqlite3_result_blob(ctx, pCur->aDelta, pCur->nDelta, SQLITE_TRANSIENT);
break;
}
}
return SQLITE_OK;
}
/*
** Return the rowid for the current row. In this implementation, the
** rowid is the same as the output value.
*/
static int deltaparsevtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
deltaparsevtab_cursor *pCur = (deltaparsevtab_cursor*)cur;
*pRowid = pCur->iCursor;
return SQLITE_OK;
}
/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int deltaparsevtabEof(sqlite3_vtab_cursor *cur){
deltaparsevtab_cursor *pCur = (deltaparsevtab_cursor*)cur;
return pCur->eOp==DELTAPARSE_OP_EOF;
}
/*
** This method is called to "rewind" the deltaparsevtab_cursor object back
** to the first row of output. This method is always called at least
** once prior to any call to deltaparsevtabColumn() or deltaparsevtabRowid() or
** deltaparsevtabEof().
*/
static int deltaparsevtabFilter(
sqlite3_vtab_cursor *pVtabCursor,
int idxNum, const char *idxStr,
int argc, sqlite3_value **argv
){
deltaparsevtab_cursor *pCur = (deltaparsevtab_cursor *)pVtabCursor;
const char *a;
int i = 0;
pCur->eOp = DELTAPARSE_OP_ERROR;
if( idxNum!=1 ){
return SQLITE_OK;
}
pCur->nDelta = sqlite3_value_bytes(argv[0]);
a = (const char*)sqlite3_value_blob(argv[0]);
if( pCur->nDelta==0 || a==0 ){
return SQLITE_OK;
}
pCur->aDelta = sqlite3_malloc64( pCur->nDelta+1 );
if( pCur->aDelta==0 ){
pCur->nDelta = 0;
return SQLITE_NOMEM;
}
memcpy(pCur->aDelta, a, pCur->nDelta);
pCur->aDelta[pCur->nDelta] = 0;
a = pCur->aDelta;
pCur->eOp = DELTAPARSE_OP_SIZE;
pCur->a1 = deltaGetInt(&a, &i);
if( a[0]!='\n' ){
pCur->eOp = DELTAPARSE_OP_ERROR;
pCur->a1 = pCur->a2 = 0;
pCur->iNext = pCur->nDelta;
return SQLITE_OK;
}
a++;
pCur->iNext = (unsigned int)(a - pCur->aDelta);
return SQLITE_OK;
}
/*
** SQLite will invoke this method one or more times while planning a query
** that uses the virtual table. This routine needs to create
** a query plan for each invocation and compute an estimated cost for that
** plan.
*/
static int deltaparsevtabBestIndex(
sqlite3_vtab *tab,
sqlite3_index_info *pIdxInfo
){
int i;
for(i=0; i<pIdxInfo->nConstraint; i++){
if( pIdxInfo->aConstraint[i].iColumn != DELTAPARSEVTAB_DELTA ) continue;
if( pIdxInfo->aConstraint[i].usable==0 ) continue;
if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
pIdxInfo->aConstraintUsage[i].argvIndex = 1;
pIdxInfo->aConstraintUsage[i].omit = 1;
pIdxInfo->estimatedCost = (double)1;
pIdxInfo->estimatedRows = 10;
pIdxInfo->idxNum = 1;
return SQLITE_OK;
}
pIdxInfo->idxNum = 0;
pIdxInfo->estimatedCost = (double)0x7fffffff;
pIdxInfo->estimatedRows = 0x7fffffff;
return SQLITE_OK;
}
/*
** This following structure defines all the methods for the
** virtual table.
*/
static sqlite3_module deltaparsevtabModule = {
/* iVersion */ 0,
/* xCreate */ 0,
/* xConnect */ deltaparsevtabConnect,
/* xBestIndex */ deltaparsevtabBestIndex,
/* xDisconnect */ deltaparsevtabDisconnect,
/* xDestroy */ 0,
/* xOpen */ deltaparsevtabOpen,
/* xClose */ deltaparsevtabClose,
/* xFilter */ deltaparsevtabFilter,
/* xNext */ deltaparsevtabNext,
/* xEof */ deltaparsevtabEof,
/* xColumn */ deltaparsevtabColumn,
/* xRowid */ deltaparsevtabRowid,
/* xUpdate */ 0,
/* xBegin */ 0,
/* xSync */ 0,
/* xCommit */ 0,
/* xRollback */ 0,
/* xFindMethod */ 0,
/* xRename */ 0,
/* xSavepoint */ 0,
/* xRelease */ 0,
/* xRollbackTo */ 0,
/* xShadowName */ 0
};
#ifdef _WIN32
__declspec(dllexport)
@@ -787,5 +1031,8 @@ int sqlite3_fossildelta_init(
rc = sqlite3_create_function(db, "delta_output_size", 1, SQLITE_UTF8, 0,
deltaOutputSizeFunc, 0, 0);
}
if( rc==SQLITE_OK ){
rc = sqlite3_create_module(db, "delta_parse", &deltaparsevtabModule, 0);
}
return rc;
}