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| 1 /* |
| 2 ** 2001 September 15 |
| 3 ** |
| 4 ** The author disclaims copyright to this source code. In place of |
| 5 ** a legal notice, here is a blessing: |
| 6 ** |
| 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. |
| 10 ** |
| 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(). |
| 15 ** |
| 16 ** These routines are in a separate files so that they will not be linked |
| 17 ** if they are not used. |
| 18 */ |
| 19 #include "sqliteInt.h" |
| 20 #include <stdlib.h> |
| 21 #include <string.h> |
| 22 |
| 23 #ifndef SQLITE_OMIT_GET_TABLE |
| 24 |
| 25 /* |
| 26 ** This structure is used to pass data from sqlite3_get_table() through |
| 27 ** to the callback function is uses to build the result. |
| 28 */ |
| 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() */ |
| 37 } TabResult; |
| 38 |
| 39 /* |
| 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. |
| 43 */ |
| 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 */ |
| 49 |
| 50 /* Make sure there is enough space in p->azResult to hold everything |
| 51 ** we need to remember from this invocation of the callback. |
| 52 */ |
| 53 if( p->nRow==0 && argv!=0 ){ |
| 54 need = nCol*2; |
| 55 }else{ |
| 56 need = nCol; |
| 57 } |
| 58 if( p->nData + need > p->nAlloc ){ |
| 59 char **azNew; |
| 60 p->nAlloc = p->nAlloc*2 + need; |
| 61 azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc ); |
| 62 if( azNew==0 ) goto malloc_failed; |
| 63 p->azResult = azNew; |
| 64 } |
| 65 |
| 66 /* If this is the first row, then generate an extra row containing |
| 67 ** the names of all columns. |
| 68 */ |
| 69 if( p->nRow==0 ){ |
| 70 p->nColumn = nCol; |
| 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; |
| 75 } |
| 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" |
| 80 ); |
| 81 p->rc = SQLITE_ERROR; |
| 82 return 1; |
| 83 } |
| 84 |
| 85 /* Copy over the row data |
| 86 */ |
| 87 if( argv!=0 ){ |
| 88 for(i=0; i<nCol; i++){ |
| 89 if( argv[i]==0 ){ |
| 90 z = 0; |
| 91 }else{ |
| 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); |
| 96 } |
| 97 p->azResult[p->nData++] = z; |
| 98 } |
| 99 p->nRow++; |
| 100 } |
| 101 return 0; |
| 102 |
| 103 malloc_failed: |
| 104 p->rc = SQLITE_NOMEM; |
| 105 return 1; |
| 106 } |
| 107 |
| 108 /* |
| 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. |
| 112 ** |
| 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. |
| 117 */ |
| 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 */ |
| 125 ){ |
| 126 int rc; |
| 127 TabResult res; |
| 128 |
| 129 *pazResult = 0; |
| 130 if( pnColumn ) *pnColumn = 0; |
| 131 if( pnRow ) *pnRow = 0; |
| 132 if( pzErrMsg ) *pzErrMsg = 0; |
| 133 res.zErrMsg = 0; |
| 134 res.nRow = 0; |
| 135 res.nColumn = 0; |
| 136 res.nData = 1; |
| 137 res.nAlloc = 20; |
| 138 res.rc = SQLITE_OK; |
| 139 res.azResult = sqlite3_malloc(sizeof(char*)*res.nAlloc ); |
| 140 if( res.azResult==0 ){ |
| 141 db->errCode = SQLITE_NOMEM; |
| 142 return SQLITE_NOMEM; |
| 143 } |
| 144 res.azResult[0] = 0; |
| 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]); |
| 150 if( res.zErrMsg ){ |
| 151 if( pzErrMsg ){ |
| 152 sqlite3_free(*pzErrMsg); |
| 153 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg); |
| 154 } |
| 155 sqlite3_free(res.zErrMsg); |
| 156 } |
| 157 db->errCode = res.rc; /* Assume 32-bit assignment is atomic */ |
| 158 return res.rc; |
| 159 } |
| 160 sqlite3_free(res.zErrMsg); |
| 161 if( rc!=SQLITE_OK ){ |
| 162 sqlite3_free_table(&res.azResult[1]); |
| 163 return rc; |
| 164 } |
| 165 if( res.nAlloc>res.nData ){ |
| 166 char **azNew; |
| 167 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*res.nData ); |
| 168 if( azNew==0 ){ |
| 169 sqlite3_free_table(&res.azResult[1]); |
| 170 db->errCode = SQLITE_NOMEM; |
| 171 return SQLITE_NOMEM; |
| 172 } |
| 173 res.azResult = azNew; |
| 174 } |
| 175 *pazResult = &res.azResult[1]; |
| 176 if( pnColumn ) *pnColumn = res.nColumn; |
| 177 if( pnRow ) *pnRow = res.nRow; |
| 178 return rc; |
| 179 } |
| 180 |
| 181 /* |
| 182 ** This routine frees the space the sqlite3_get_table() malloced. |
| 183 */ |
| 184 void sqlite3_free_table( |
| 185 char **azResult /* Result returned from from sqlite3_get_table() */ |
| 186 ){ |
| 187 if( azResult ){ |
| 188 int i, n; |
| 189 azResult--; |
| 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); |
| 194 } |
| 195 } |
| 196 |
| 197 #endif /* SQLITE_OMIT_GET_TABLE */ |
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