161 lines
3.6 KiB
C
161 lines
3.6 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997, 1998
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* Sleepycat Software. All rights reserved.
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*/
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#include "config.h"
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#ifndef lint
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static const char sccsid[] = "@(#)db_ret.c 10.13 (Sleepycat) 5/7/98";
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#endif /* not lint */
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#include <errno.h>
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#include <string.h>
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#endif
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#include "db_int.h"
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#include "db_page.h"
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#include "btree.h"
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#include "db_am.h"
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/*
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* __db_ret --
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* Build return DBT.
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*
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* PUBLIC: int __db_ret __P((DB *,
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* PUBLIC: PAGE *, u_int32_t, DBT *, void **, u_int32_t *));
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*/
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int
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__db_ret(dbp, h, indx, dbt, memp, memsize)
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DB *dbp;
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PAGE *h;
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u_int32_t indx;
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DBT *dbt;
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void **memp;
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u_int32_t *memsize;
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{
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BKEYDATA *bk;
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HOFFPAGE ho;
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BOVERFLOW *bo;
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u_int32_t len;
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u_int8_t *hk;
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void *data;
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switch (TYPE(h)) {
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case P_HASH:
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hk = P_ENTRY(h, indx);
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if (HPAGE_PTYPE(hk) == H_OFFPAGE) {
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memcpy(&ho, hk, sizeof(HOFFPAGE));
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return (__db_goff(dbp, dbt,
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ho.tlen, ho.pgno, memp, memsize));
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}
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len = LEN_HKEYDATA(h, dbp->pgsize, indx);
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data = HKEYDATA_DATA(hk);
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break;
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case P_DUPLICATE:
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case P_LBTREE:
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case P_LRECNO:
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bk = GET_BKEYDATA(h, indx);
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if (B_TYPE(bk->type) == B_OVERFLOW) {
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bo = (BOVERFLOW *)bk;
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return (__db_goff(dbp, dbt,
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bo->tlen, bo->pgno, memp, memsize));
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}
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len = bk->len;
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data = bk->data;
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break;
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default:
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return (__db_pgfmt(dbp, h->pgno));
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}
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return (__db_retcopy(dbt, data, len, memp, memsize,
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F_ISSET(dbt, DB_DBT_INTERNAL) ? NULL : dbp->db_malloc));
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}
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/*
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* __db_retcopy --
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* Copy the returned data into the user's DBT, handling special flags.
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*
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* PUBLIC: int __db_retcopy __P((DBT *,
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* PUBLIC: void *, u_int32_t, void **, u_int32_t *, void *(*)(size_t)));
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*/
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int
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__db_retcopy(dbt, data, len, memp, memsize, db_malloc)
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DBT *dbt;
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void *data;
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u_int32_t len;
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void **memp;
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u_int32_t *memsize;
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void *(*db_malloc) __P((size_t));
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{
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/* If returning a partial record, reset the length. */
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if (F_ISSET(dbt, DB_DBT_PARTIAL)) {
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data = (u_int8_t *)data + dbt->doff;
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if (len > dbt->doff) {
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len -= dbt->doff;
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if (len > dbt->dlen)
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len = dbt->dlen;
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} else
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len = 0;
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}
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/*
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* Return the length of the returned record in the DBT size field.
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* This satisfies the requirement that if we're using user memory
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* and insufficient memory was provided, return the amount necessary
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* in the size field.
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*/
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dbt->size = len;
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/*
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* Allocate memory to be owned by the application: DB_DBT_MALLOC.
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*
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* !!!
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* We always allocate memory, even if we're copying out 0 bytes. This
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* guarantees consistency, i.e., the application can always free memory
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* without concern as to how many bytes of the record were requested.
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*
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* XXX
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* Never allocate 0 bytes, it's known to make malloc/realloc unhappy.
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*
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* Use the memory specified by the application: DB_DBT_USERMEM.
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*
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* !!!
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* If the length we're going to copy is 0, the application-supplied
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* memory pointer is allowed to be NULL.
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*/
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if (F_ISSET(dbt, DB_DBT_MALLOC)) {
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dbt->data = db_malloc == NULL ?
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(void *)__db_malloc(len) :
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(void *)db_malloc(len + 1);
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if (dbt->data == NULL)
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return (ENOMEM);
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} else if (F_ISSET(dbt, DB_DBT_USERMEM)) {
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if (len != 0 && (dbt->data == NULL || dbt->ulen < len))
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return (ENOMEM);
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} else if (memp == NULL || memsize == NULL) {
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return (EINVAL);
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} else {
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if (len != 0 && (*memsize == 0 || *memsize < len)) {
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*memp = *memp == NULL ?
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(void *)__db_malloc(len) :
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(void *)__db_realloc(*memp, len);
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if (*memp == NULL) {
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*memsize = 0;
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return (ENOMEM);
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}
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*memsize = len;
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}
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dbt->data = *memp;
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}
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if (len != 0)
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memcpy(dbt->data, data, len);
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return (0);
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}
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