4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
11 *************************************************************************
12 ** This file contains the sqlite3_get_table() and sqlite3_free_table()
13 ** interface routines. These are just wrappers around the main
14 ** interface routine of sqlite3_exec().
16 ** These routines are in a separate files so that they will not be linked
17 ** if they are not used.
19 #include "sqliteInt.h"
23 #ifndef SQLITE_OMIT_GET_TABLE
26 ** This structure is used to pass data from sqlite3_get_table() through
27 ** to the callback function is uses to build the result.
29 typedef struct TabResult {
30 char **azResult; /* Accumulated output */
31 char *zErrMsg; /* Error message text, if an error occurs */
32 int nAlloc; /* Slots allocated for azResult[] */
33 int nRow; /* Number of rows in the result */
34 int nColumn; /* Number of columns in the result */
35 int nData; /* Slots used in azResult[]. (nRow+1)*nColumn */
36 int rc; /* Return code from sqlite3_exec() */
40 ** This routine is called once for each row in the result table. Its job
41 ** is to fill in the TabResult structure appropriately, allocating new
42 ** memory as necessary.
44 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
45 TabResult *p = (TabResult*)pArg; /* Result accumulator */
46 int need; /* Slots needed in p->azResult[] */
47 int i; /* Loop counter */
48 char *z; /* A single column of result */
50 /* Make sure there is enough space in p->azResult to hold everything
51 ** we need to remember from this invocation of the callback.
53 if( p->nRow==0 && argv!=0 ){
58 if( p->nData + need > p->nAlloc ){
60 p->nAlloc = p->nAlloc*2 + need;
61 azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc );
62 if( azNew==0 ) goto malloc_failed;
66 /* If this is the first row, then generate an extra row containing
67 ** the names of all columns.
71 for(i=0; i<nCol; i++){
72 z = sqlite3_mprintf("%s", colv[i]);
73 if( z==0 ) goto malloc_failed;
74 p->azResult[p->nData++] = z;
76 }else if( p->nColumn!=nCol ){
77 sqlite3_free(p->zErrMsg);
78 p->zErrMsg = sqlite3_mprintf(
79 "sqlite3_get_table() called with two or more incompatible queries"
85 /* Copy over the row data
88 for(i=0; i<nCol; i++){
92 int n = sqlite3Strlen30(argv[i])+1;
93 z = sqlite3_malloc( n );
94 if( z==0 ) goto malloc_failed;
95 memcpy(z, argv[i], n);
97 p->azResult[p->nData++] = z;
104 p->rc = SQLITE_NOMEM;
109 ** Query the database. But instead of invoking a callback for each row,
110 ** malloc() for space to hold the result and return the entire results
111 ** at the conclusion of the call.
113 ** The result that is written to ***pazResult is held in memory obtained
114 ** from malloc(). But the caller cannot free this memory directly.
115 ** Instead, the entire table should be passed to sqlite3_free_table() when
116 ** the calling procedure is finished using it.
118 int sqlite3_get_table(
119 sqlite3 *db, /* The database on which the SQL executes */
120 const char *zSql, /* The SQL to be executed */
121 char ***pazResult, /* Write the result table here */
122 int *pnRow, /* Write the number of rows in the result here */
123 int *pnColumn, /* Write the number of columns of result here */
124 char **pzErrMsg /* Write error messages here */
130 if( pnColumn ) *pnColumn = 0;
131 if( pnRow ) *pnRow = 0;
132 if( pzErrMsg ) *pzErrMsg = 0;
139 res.azResult = sqlite3_malloc(sizeof(char*)*res.nAlloc );
140 if( res.azResult==0 ){
141 db->errCode = SQLITE_NOMEM;
145 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg);
146 assert( sizeof(res.azResult[0])>= sizeof(res.nData) );
147 res.azResult[0] = SQLITE_INT_TO_PTR(res.nData);
148 if( (rc&0xff)==SQLITE_ABORT ){
149 sqlite3_free_table(&res.azResult[1]);
152 sqlite3_free(*pzErrMsg);
153 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg);
155 sqlite3_free(res.zErrMsg);
157 db->errCode = res.rc; /* Assume 32-bit assignment is atomic */
160 sqlite3_free(res.zErrMsg);
162 sqlite3_free_table(&res.azResult[1]);
165 if( res.nAlloc>res.nData ){
167 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*res.nData );
169 sqlite3_free_table(&res.azResult[1]);
170 db->errCode = SQLITE_NOMEM;
173 res.azResult = azNew;
175 *pazResult = &res.azResult[1];
176 if( pnColumn ) *pnColumn = res.nColumn;
177 if( pnRow ) *pnRow = res.nRow;
182 ** This routine frees the space the sqlite3_get_table() malloced.
184 void sqlite3_free_table(
185 char **azResult /* Result returned from from sqlite3_get_table() */
190 assert( azResult!=0 );
191 n = SQLITE_PTR_TO_INT(azResult[0]);
192 for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); }
193 sqlite3_free(azResult);
197 #endif /* SQLITE_OMIT_GET_TABLE */