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Improvements to the CSV virtual table.

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FossilOrigin-Name: 0406ecbbe75513e342040b71fdd342462222dbb3820486b5f745d7865805c00b
This commit is contained in:
drh
2018-11-16 01:42:26 +00:00
parent 23bfa80c19
commit 6f147c54ef
4 changed files with 164 additions and 46 deletions
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131
ext/misc/csv.c
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@ -19,9 +19,9 @@
** CREATE VIRTUAL TABLE temp.csv USING csv(filename=FILENAME);
** SELECT * FROM csv;
**
** The columns are named "c1", "c2", "c3", ... by default. But the
** application can define its own CREATE TABLE statement as an additional
** parameter. For example:
** The columns are named "c1", "c2", "c3", ... by default. Or the
** application can define its own CREATE TABLE statement using the
** schema= parameter, like this:
**
** CREATE VIRTUAL TABLE temp.csv2 USING csv(
** filename = "../http.log",
@ -32,9 +32,9 @@
** the data= parameter.
**
** If the columns=N parameter is supplied, then the CSV file is assumed to have
** N columns. If the columns parameter is omitted, the CSV file is opened
** as soon as the virtual table is constructed and the first row of the CSV
** is read in order to count the tables.
** N columns. If both the columns= and schema= parameters are omitted, then
** the number and names of the columns is determined by the first line of
** the CSV input.
**
** Some extra debugging features (used for testing virtual tables) are available
** if this module is compiled with -DSQLITE_TEST.
@ -436,6 +436,34 @@ static int csv_boolean(const char *z){
return -1;
}
/* Check to see if the string is of the form: "TAG = BOOLEAN" or just "TAG".
** If it is, set *pValue to be the value of the boolean ("true" if there is
** not "= BOOLEAN" component) and return non-zero. If the input string
** does not begin with TAG, return zero.
*/
static int csv_boolean_parameter(
const char *zTag, /* Tag we are looking for */
int nTag, /* Size of the tag in bytes */
const char *z, /* Input parameter */
int *pValue /* Write boolean value here */
){
int b;
z = csv_skip_whitespace(z);
if( strncmp(zTag, z, nTag)!=0 ) return 0;
z = csv_skip_whitespace(z + nTag);
if( z[0]==0 ){
*pValue = 1;
return 1;
}
if( z[0]!='=' ) return 0;
z = csv_skip_whitespace(z+1);
b = csv_boolean(z);
if( b>=0 ){
*pValue = b;
return 1;
}
return 0;
}
/*
** Parameters:
@ -469,6 +497,7 @@ static int csvtabConnect(
#ifdef SQLITE_TEST
int tstFlags = 0; /* Value for testflags=N parameter */
#endif
int b; /* Value of a boolean parameter */
int nCol = -99; /* Value of the columns= parameter */
CsvReader sRdr; /* A CSV file reader used to store an error
** message and/or to count the number of columns */
@ -493,21 +522,12 @@ static int csvtabConnect(
if( j<sizeof(azParam)/sizeof(azParam[0]) ){
if( sRdr.zErr[0] ) goto csvtab_connect_error;
}else
if( (zValue = csv_parameter("header",6,z))!=0 ){
int x;
if( csv_boolean_parameter("header",6,z,&b) ){
if( bHeader>=0 ){
csv_errmsg(&sRdr, "more than one 'header' parameter");
goto csvtab_connect_error;
}
x = csv_boolean(zValue);
if( x==1 ){
bHeader = 1;
}else if( x==0 ){
bHeader = 0;
}else{
csv_errmsg(&sRdr, "unrecognized argument to 'header': %s", zValue);
goto csvtab_connect_error;
}
bHeader = b;
}else
#ifdef SQLITE_TEST
if( (zValue = csv_parameter("testflags",9,z))!=0 ){
@ -521,53 +541,94 @@ static int csvtabConnect(
}
nCol = atoi(zValue);
if( nCol<=0 ){
csv_errmsg(&sRdr, "must have at least one column");
csv_errmsg(&sRdr, "column= value must be positive");
goto csvtab_connect_error;
}
}else
{
csv_errmsg(&sRdr, "unrecognized parameter '%s'", z);
csv_errmsg(&sRdr, "bad parameter: '%s'", z);
goto csvtab_connect_error;
}
}
if( (CSV_FILENAME==0)==(CSV_DATA==0) ){
csv_errmsg(&sRdr, "must either filename= or data= but not both");
csv_errmsg(&sRdr, "must specify either filename= or data= but not both");
goto csvtab_connect_error;
}
if( nCol<=0 && csv_reader_open(&sRdr, CSV_FILENAME, CSV_DATA) ){
if( (nCol<=0 || bHeader==1)
&& csv_reader_open(&sRdr, CSV_FILENAME, CSV_DATA)
){
goto csvtab_connect_error;
}
pNew = sqlite3_malloc( sizeof(*pNew) );
*ppVtab = (sqlite3_vtab*)pNew;
if( pNew==0 ) goto csvtab_connect_oom;
memset(pNew, 0, sizeof(*pNew));
if( nCol>0 ){
if( CSV_SCHEMA==0 ){
sqlite3_str *pStr = sqlite3_str_new(0);
char *zSep = "";
int iCol = 0;
sqlite3_str_appendf(pStr, "CREATE TABLE x(");
if( nCol<0 && bHeader<1 ){
nCol = 0;
do{
csv_read_one_field(&sRdr);
nCol++;
}while( sRdr.cTerm==',' );
}
if( nCol>0 && bHeader<1 ){
for(iCol=0; iCol<nCol; iCol++){
sqlite3_str_appendf(pStr, "%sc%d TEXT", zSep, iCol);
zSep = ",";
}
}else{
do{
char *z = csv_read_one_field(&sRdr);
if( (nCol>0 && iCol<nCol) || (nCol<0 && bHeader) ){
sqlite3_str_appendf(pStr,"%s\"%w\" TEXT", zSep, z);
zSep = ",";
iCol++;
}
}while( sRdr.cTerm==',' );
if( nCol<0 ){
nCol = iCol;
}else{
while( iCol<nCol ){
sqlite3_str_appendf(pStr,"%sc%d TEXT", zSep, ++iCol);
zSep = ",";
}
}
}
pNew->nCol = nCol;
}else{
sqlite3_str_appendf(pStr, ")");
CSV_SCHEMA = sqlite3_str_finish(pStr);
if( CSV_SCHEMA==0 ) goto csvtab_connect_oom;
}else if( nCol<0 ){
do{
csv_read_one_field(&sRdr);
pNew->nCol++;
}while( sRdr.cTerm==',' );
}else{
pNew->nCol = nCol;
}
pNew->zFilename = CSV_FILENAME; CSV_FILENAME = 0;
pNew->zData = CSV_DATA; CSV_DATA = 0;
#ifdef SQLITE_TEST
pNew->tstFlags = tstFlags;
#endif
pNew->iStart = bHeader==1 ? ftell(sRdr.in) : 0;
csv_reader_reset(&sRdr);
if( CSV_SCHEMA==0 ){
char *zSep = "";
CSV_SCHEMA = sqlite3_mprintf("CREATE TABLE x(");
if( CSV_SCHEMA==0 ) goto csvtab_connect_oom;
for(i=0; i<pNew->nCol; i++){
CSV_SCHEMA = sqlite3_mprintf("%z%sc%d TEXT",CSV_SCHEMA, zSep, i);
zSep = ",";
}
CSV_SCHEMA = sqlite3_mprintf("%z);", CSV_SCHEMA);
if( bHeader!=1 ){
pNew->iStart = 0;
}else if( pNew->zData ){
pNew->iStart = (int)sRdr.iIn;
}else{
pNew->iStart = ftell(sRdr.in);
}
csv_reader_reset(&sRdr);
rc = sqlite3_declare_vtab(db, CSV_SCHEMA);
if( rc ) goto csvtab_connect_error;
if( rc ){
csv_errmsg(&sRdr, "bad schema: '%s' - %s", CSV_SCHEMA, sqlite3_errmsg(db));
goto csvtab_connect_error;
}
for(i=0; i<sizeof(azPValue)/sizeof(azPValue[0]); i++){
sqlite3_free(azPValue[i]);
}