:-) (CVS 147)

FossilOrigin-Name: e11f7527f9187e8902db84069baad0d3b7e17ad0

src/table.c

@@ -0,0 +1,163 @@
+/*
+** This file contains the sqlite_get_table() and sqlite_free_table()
+** interface routines.  These are just wrappers around the main
+** interface routine of sqlite_exec().
+**
+** This routines are in a separate files to that they will not be linked
+** if they are not used.
+*/
+#include <stdlib.h>
+#include "sqlite.h"
+
+/*
+** This structure is used to pass data from sqlite_get_table() through
+** to the callback function is uses to build the result.
+*/
+typedef struct TabResult {
+  char **azResult;
+  int nResult;
+  int nAlloc;
+  int nRow;
+  int nColumn;
+  int nData;
+  int rc;
+} TabResult;
+
+/*
+** This routine is called once for each row in the result table.  Its job
+** is to fill in the TabResult structure appropriately, allocating new
+** memory as necessary.
+*/
+static int sqlite_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
+  TabResult *p = (TabResult*)pArg;
+  int need;
+  int i, len;
+  char *z, *zVal;
+
+  /* Make sure there is enough space in p->azResult to hold everything
+  ** we need to remember from this invocation of the callback.
+  */
+  if( p->nRow==0 ){
+    p->nColumn = nCol;
+    need = nCol*2;
+  }else{
+    need = nCol;
+  }
+  if( p->nData + need >= p->nAlloc ){
+    p->nAlloc = p->nAlloc*2 + need + 1;
+    p->azResult = realloc( p->azResult, sizeof(char*)*p->nAlloc );
+    if( p->azResult==0 ){
+      p->rc = SQLITE_NOMEM;
+      return 1;
+    }
+  }
+
+  /* If this is the first row, then generate an extra row containing
+  ** the names of all columns.
+  */
+  if( p->nRow==0 ){
+    for(i=0; i<nCol; i++){
+      if( colv[i]==0 ){
+        z = 0;
+      }else{
+        z = malloc( strlen(colv[i])+1 );
+        if( z==0 ){
+          p->rc = SQLITE_NOMEM;
+          return 1;
+        }
+        strcpy(z, colv[i]);
+      }
+      p->azResult[p->nData++] = z;
+    }
+  }
+
+  /* Copy over the row data
+  */
+  for(i=0; i<nCol; i++){
+    if( argv[i]==0 ){
+      z = 0;
+    }else{
+      z = malloc( strlen(argv[i])+1 );
+      if( z==0 ){
+        p->rc = SQLITE_NOMEM;
+        return 1;
+      }
+      strcpy(z, argv[i]);
+    }
+    p->azResult[p->nData++] = z;
+  }
+  p->nRow++;
+  return 0;
+}
+
+/*
+** Query the database.  But instead of invoking a callback for each row,
+** malloc() for space to hold the result and return the entire results
+** at the conclusion of the call.
+**
+** The result that is written to ***pazResult is held in memory obtained
+** from malloc().  But the caller cannot free this memory directly.  
+** Instead, the entire table should be passed to sqlite_free_table() when
+** the calling procedure is finished using it.
+*/
+int sqlite_get_table(
+  sqlite *db,                 /* The database on which the SQL executes */
+  char *zSql,                 /* The SQL to be executed */
+  char ***pazResult,          /* Write the result table here */
+  int *pnRow,                 /* Write the number of rows in the result here */
+  int *pnColumn,              /* Write the number of columns of result here */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc;
+  TabResult res;
+  if( pazResult==0 ){ return SQLITE_ERROR; }
+  *pazResult = 0;
+  if( pnColumn ) *pnColumn = 0;
+  if( pnRow ) *pnRow = 0;
+  res.nResult = 0;
+  res.nRow = 0;
+  res.nColumn = 0;
+  res.nData = 1;
+  res.nAlloc = 200;
+  res.rc = SQLITE_OK;
+  res.azResult = malloc( sizeof(char*)*res.nAlloc );
+  if( res.azResult==0 ){
+    return SQLITE_NOMEM;
+  }
+  res.azResult[0] = 0;
+  rc = sqlite_exec(db, zSql, sqlite_get_table_cb, &res, pzErrMsg);
+  if( res.azResult ){
+    res.azResult[0] = (char*)res.nData;
+  }
+  if( rc==SQLITE_ABORT ){
+    sqlite_free_table(&res.azResult[1]);
+    return res.rc;
+  }
+  if( rc!=SQLITE_OK ){
+    sqlite_free_table(&res.azResult[1]);
+    return rc;
+  }
+  if( res.nAlloc>res.nData ){
+    res.azResult = realloc( res.azResult, sizeof(char*)*(res.nData+1) );
+    if( res.azResult==0 ) return SQLITE_NOMEM;
+  }
+  *pazResult = &res.azResult[1];
+  if( pnColumn ) *pnColumn = res.nColumn;
+  if( pnRow ) *pnRow = res.nRow;
+  return rc;
+}
+
+/*
+** This routine frees the space the sqlite_get_table() malloced.
+*/
+void sqlite_free_table(
+  char **azResult             /* Result returned from from sqlite_get_table() */
+){
+  if( azResult ){
+    int i, n;
+    azResult--;
+    n = (int)azResult[0];
+    for(i=1; i<n; i++){ if( azResult[i] ) free(azResult[i]); }
+    free(azResult);
+  }
+}