Combine the internal btree functions BtreePutData() and getPayload(). (CVS 3901)

FossilOrigin-Name: a100a5304b0e7cbbdb6dac71a39c78eb71d44a03

manifest

@@ -1,5 +1,5 @@
-C More\sfixes\sand\simprovements\sto\sthe\szeroblob()\smechanism.\s(CVS\s3900)
+C Combine\sthe\sinternal\sbtree\sfunctions\sBtreePutData()\sand\sgetPayload().\s(CVS\s3901)
-D 2007-05-02T16:51:59
+D 2007-05-02T17:48:46
 F Makefile.in 8cab54f7c9f5af8f22fd97ddf1ecfd1e1860de62
 F Makefile.linux-gcc 2d8574d1ba75f129aba2019f0b959db380a90935
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -59,7 +59,7 @@ F src/alter.c 2c79ec40f65e33deaf90ca493422c74586e481a3
 F src/analyze.c 4bbf5ddf9680587c6d4917e02e378b6037be3651
 F src/attach.c a16ada4a4654a0d126b8223ec9494ebb81bc5c3c
 F src/auth.c 902f4722661c796b97f007d9606bd7529c02597f
-F src/btree.c 4efb50fa388aa1678eb9cce5e5fc6fa8247406b2
+F src/btree.c ecd0a02c8f867509b5439379208f0ee4d801389e
 F src/btree.h 2c187d60cf76d74c2b4767294d6b5fa267037ff0
 F src/build.c 02e01ec7907c7d947ab3041fda0e81eaed05db42
 F src/callback.c 6414ed32d55859d0f65067aa5b88d2da27b3af9e
@@ -471,7 +471,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 349f1ea7895f06c40affc985a13aa6686dfdea07
+P 83ab25014e890b1cc6ea08ca1ebeeee0078da466
-R c40994429188bdd3545336b5231dc204
+R 6382007c866ff2246040af323c0a9f53
-U drh
+U danielk1977
-Z 278e5bf758bcf3f514d6f2d4595a443f
+Z 54f827912c39196d14fa4e08648aa7ab

manifest.uuid

@@ -1 +1 @@
-83ab25014e890b1cc6ea08ca1ebeeee0078da466
+a100a5304b0e7cbbdb6dac71a39c78eb71d44a03

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.366 2007/05/02 16:48:37 danielk1977 Exp $
+** $Id: btree.c,v 1.367 2007/05/02 17:48:46 danielk1977 Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
@@ -3139,20 +3139,28 @@ static int getOverflowPage(
 
 
 /*
-** Read payload information from the entry that the pCur cursor is
+** This function is used to read or overwrite payload information
-** pointing to.  Begin reading the payload at "offset" and read
+** for the entry that the pCur cursor is pointing to. If the eOp
-** a total of "amt" bytes.  Put the result in zBuf.
+** parameter is 0, this is a read operation (data copied into
+** buffer pBuf). If it is non-zero, a write (data copied from
+** buffer pBuf).
+**
+** A total of "amt" bytes are read or written beginning at "offset".
+** Data is read to or from the buffer pBuf.
 **
 ** This routine does not make a distinction between key and data.
-** It just reads bytes from the payload area.  Data might appear
+** It just reads or writes bytes from the payload area.  Data might 
-** on the main page or be scattered out on multiple overflow pages.
+** appear on the main page or be scattered out on multiple overflow 
+** pages.
 */
-static int getPayload(
+#define getPayload(a,b,c,d,e) accessPayload(a,b,c,d,e,0)
+static int accessPayload(
   BtCursor *pCur,      /* Cursor pointing to entry to read from */
   int offset,          /* Begin reading this far into payload */
   int amt,             /* Read this many bytes */
   unsigned char *pBuf, /* Write the bytes into this buffer */ 
-  int skipKey          /* offset begins at data if this is true */
+  int skipKey,         /* offset begins at data if this is true */
+  int eOp              /* zero to read. non-zero to write. */
 ){
   unsigned char *aPayload;
   Pgno nextPage;
@@ -3187,7 +3195,17 @@ static int getPayload(
     if( a+offset>pCur->info.nLocal ){
       a = pCur->info.nLocal - offset;
     }
-    memcpy(pBuf, &aPayload[offset], a);
+    if( eOp ){
+      /* A write operation. */
+      rc = sqlite3PagerWrite(pPage->pDbPage);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      memcpy(&aPayload[offset], pBuf, a);
+    }else{
+      /* A read operation */
+      memcpy(pBuf, &aPayload[offset], a);
+    }
     if( a==amt ){
       return SQLITE_OK;
     }
@@ -3232,8 +3250,8 @@ static int getPayload(
         }
 #endif
       }else{
-        /* Need to read this page properly, to obtain data to copy into
+        /* Need to read this page properly. It contains some of the
-        ** the caller's buffer.
+        ** range of data that is being read (eOp==0) or written (eOp!=0).
         */
         DbPage *pDbPage;
         int a = amt;
@@ -3246,7 +3264,18 @@ static int getPayload(
         if( a + offset > ovflSize ){
           a = ovflSize - offset;
         }
-        memcpy(pBuf, &aPayload[offset+4], a);
+        if( eOp ){
+          /* A write operation. */
+          rc = sqlite3PagerWrite(pPage->pDbPage);
+          if( rc!=SQLITE_OK ){
+            sqlite3PagerUnref(pDbPage);
+            return rc;
+          }
+          memcpy(&aPayload[offset+4], pBuf, a);
+        }else{
+          /* A read operation */
+          memcpy(pBuf, &aPayload[offset+4], a);
+        }
         offset = 0;
         amt -= a;
         pBuf += a;
@@ -6942,7 +6971,7 @@ int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, const void *z){
   **   (d) the cursor points at a valid row of an intKey table.
   */
   if( pBt->inTransaction!=TRANS_WRITE ){
-    /* Must start a transaction before doing an insert */
+    /* Must start a transaction before writing to a blob */
     return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
   }
   assert( !pBt->readOnly );
@@ -6956,94 +6985,7 @@ int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, const void *z){
     return SQLITE_ERROR;
   }
 
-  /* Parse the cell-info. Check that the cell-data area is large
+  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 0, 1);
-  ** enough for the proposed write operation.
-  */
-  getCellInfo(pCsr);
-  pInfo = &pCsr->info;
-  if( pInfo->nData<(offset+amt) ){
-    return SQLITE_ERROR;
-  }
-  ovflSize = pBt->usableSize - 4;
-
-  assert(pCsr->cacheOverflow);
-  if( !pCsr->aOverflow ){
-    int nOverflow = (pInfo->nPayload - pInfo->nLocal + ovflSize - 1)/ovflSize;
-    pCsr->aOverflow = (Pgno *)sqliteMalloc(sizeof(Pgno)*nOverflow);
-    if( nOverflow && !pCsr->aOverflow ){
-      return SQLITE_NOMEM;
-    }
-  }
-
-  if( pInfo->nLocal>iOffset ){
-    /* In this case data must be written to the b-tree page. */
-    int iWrite = pInfo->nLocal - offset;
-    if( iWrite>iRem ){
-      iWrite = iRem;
-    }
-    rc = sqlite3PagerWrite(pCsr->pPage->pDbPage);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
-    memcpy(&pInfo->pCell[iOffset+pInfo->nHeader], zRem, iWrite);
-
-    zRem += iWrite;
-    iRem -= iWrite;
-  }
-  iOffset = ((iOffset<pInfo->nLocal)?0:(iOffset-pInfo->nLocal));
-
-  assert(pInfo->iOverflow>0 || iRem==0);
-  if( iRem>0 ){
-    if( pCsr->aOverflow[iOffset/ovflSize] ){
-      iIdx = iOffset/ovflSize;
-      iOvfl = pCsr->aOverflow[iIdx];
-      iOffset = iOffset%ovflSize;
-    }else{
-      iOvfl = get4byte(&pInfo->pCell[pInfo->iOverflow]);
-    }
-    for(iIdx++; iRem>0; iIdx++){
-      if( iOffset>ovflSize ){
-        /* The only reason to read this page is to obtain the page
-        ** number for the next page in the overflow chain. So try
-        ** the getOverflowPage() shortcut.  */
-        rc = getOverflowPage(pBt, iOvfl, 0, &iOvfl);
-        if( rc!=SQLITE_OK ){
-          return rc;
-        }
-        iOffset -= ovflSize;
-        pCsr->aOverflow[iIdx] = iOvfl;
-      }else{
-        int iWrite = ovflSize - iOffset;
-        DbPage *pOvfl;          /* The overflow page. */
-        u8 *aData;              /* Page data */
-  
-        rc = sqlite3PagerGet(pBt->pPager, iOvfl, &pOvfl);
-        if( rc!=SQLITE_OK ){
-          return rc;
-        }
-        rc = sqlite3PagerWrite(pOvfl);
-        if( rc!=SQLITE_OK ){
-          sqlite3PagerUnref(pOvfl);
-          return rc;
-        }
-  
-        aData = sqlite3PagerGetData(pOvfl);
-        iOvfl = get4byte(aData);
-        pCsr->aOverflow[iIdx] = iOvfl;
-        if( iWrite>iRem ){
-          iWrite = iRem;
-        }
-        memcpy(&aData[iOffset+4], zRem, iWrite);
-        sqlite3PagerUnref(pOvfl);
-  
-        zRem += iWrite;
-        iRem -= iWrite;
-        iOffset = ((iOffset<ovflSize)?0:(iOffset-ovflSize));
-      }
-    }
-  }
-
-  return SQLITE_OK;
 }
 
 /*