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/*
* Copyright (c) 1991, 1992, 1993 Brad Eacker,
* (Music, Intuition, Software, and Computers)
* All Rights Reserved
*/
#include <stdio.h>
#include <fcntl.h>
#include "dbf.h"
#include "dbf_ndx.h"
/*
* get the ndx header for this file
*/
ndx_header_t *ndx_get_header(int fd)
{
dndx_header_t *dp;
ndx_header_t *np;
if ((dp = (dndx_header_t *)malloc(NDX_PAGE_SZ)) == NULL)
return NULL;
if ((np = (ndx_header_t *)malloc(sizeof(ndx_header_t))) == NULL) {
free(dp);
return NULL;
}
if ((lseek(fd, 0, 0) < 0) || (read(fd, dp, NDX_PAGE_SZ) < 0)) {
free(dp); free(np);
return NULL;
}
np->ndx_hpage = dp;
np->ndx_fd = fd;
np->ndx_start_pg = get_long(dp->dndx_st_pg);
np->ndx_total_pgs = get_long(dp->dndx_tot_pg);
np->ndx_key_len = get_short(dp->dndx_key_len);
np->ndx_keys_ppg = get_short(dp->dndx_keys_ppg);
np->ndx_key_type = get_short(dp->dndx_key_type);
np->ndx_key_size = get_long(dp->dndx_size_key);
np->ndx_key_name = dp->dndx_key_name;
np->ndx_unique = dp->dndx_unique;
np->ndx_fp = NULL;
return np;
}
static ndx_page_t *ndx_get_page(ndx_header_t *hp, int pageno)
{
ndx_page_t *fp;
dndx_page_t *dp;
ndx_record_t *rp;
#if PHP_DEBUG
printf("getting page %d", pageno);
#endif
if ((fp = (ndx_page_t *)malloc(sizeof(ndx_page_t))) == NULL)
return NULL;
if ((dp = (dndx_page_t *)malloc(NDX_PAGE_SZ)) == NULL) {
free(fp);
return NULL;
}
if ((rp = (ndx_record_t *)malloc(sizeof(ndx_record_t) * hp->ndx_keys_ppg)) == NULL) {
free(dp); free(fp);
return NULL;
}
fp->ndxp_page_data = dp;
if ((lseek(hp->ndx_fd, pageno * NDX_PAGE_SZ, 0) < 0) ||
(read(hp->ndx_fd, dp, NDX_PAGE_SZ) < 0)) {
free(fp); free(dp);
return NULL;
}
fp->ndxp_parent = NULL;
fp->ndxp_page_no = pageno;
fp->ndxp_num_keys = get_long(dp->dndxp_num_keys);
memset(rp, 0, sizeof(ndx_record_t) * hp->ndx_keys_ppg);
fp->ndxp_records = rp;
fp->ndxp_header_p = hp;
#if PHP_DEBUG
printf(", n_keys %ld\n", fp->ndxp_num_keys);
#endif
return fp;
}
/*
* get the first entry for this ndx
*/
static ndx_page_t *ndx_get_first_pg(ndx_header_t *hp)
{
ndx_page_t *fp;
if (hp->ndx_fp)
return hp->ndx_fp;
if ((fp = ndx_get_page(hp, hp->ndx_start_pg))) {
hp->ndx_fp = fp;
}
return fp;
}
static ndx_record_t *ndx_get_record(ndx_page_t *fp, int rec_no)
{
ndx_record_t *rp;
ndx_header_t *hp = fp->ndxp_header_p;
struct dndx_record *drp;
#if PHP_DEBUG
printf("page %ld, rec %d: ", fp->ndxp_page_no, rec_no);
#endif
if (rec_no >= fp->ndxp_num_keys)
return NULL;
rp = &(fp->ndxp_records[rec_no]);
if (!rp->ndxr_page) {
rp->ndxr_page = fp;
drp = (dndx_record_t *)((char *)&fp->ndxp_page_data->dndx_rp
+ rec_no * hp->ndx_key_size);
rp->ndxr_left = get_long(drp->dndx_left_pg);
rp->ndxr_rec = get_long(drp->dndx_dbf_rec);
rp->ndxr_key_data = &drp->dndx_key_data;
rp->ndxr_p_nrec = rec_no;
}
#if PHP_DEBUG
printf("left %ld, dbf_rec %ld, data '%s'\n", rp->ndxr_left,
rp->ndxr_rec, rp->ndxr_key_data);
#endif
return rp;
}
static ndx_record_t *ndx_scan_down(ndx_header_t *hp, ndx_page_t *fp, int recno)
{
ndx_page_t *np;
ndx_record_t *rp;
while ((rp = ndx_get_record(fp, recno)) && (rp->ndxr_rec == 0)) {
np = ndx_get_page(hp, rp->ndxr_left);
np->ndxp_parent = fp;
np->ndxp_par_rno = recno;
fp = np;
recno = 0;
}
return rp;
}
static ndx_record_t *ndx_scan_up(ndx_header_t *hp, ndx_page_t *fp, int recno)
{
ndx_record_t *rp;
if (fp == NULL)
rp = NULL;
else if (recno < fp->ndxp_num_keys) {
rp = ndx_scan_down(hp, fp, recno);
} else {
rp = ndx_scan_up(hp, fp->ndxp_parent, fp->ndxp_par_rno + 1);
}
return rp;
}
ndx_record_t *ndx_get_first_rec(ndx_header_t *hp)
{
ndx_page_t *fp;
ndx_record_t *rp = NULL;
if ((fp = ndx_get_first_pg(hp))) {
fp->ndxp_last_key = 0;
rp = ndx_scan_down(hp, fp, 0);
}
hp->ndx_cur_rec = rp;
return rp;
}
ndx_record_t *ndx_get_next_rec(ndx_header_t *hp, ndx_record_t *rp)
{
ndx_page_t *fp;
int rec_no;
fp = rp->ndxr_page;
rec_no = rp->ndxr_p_nrec + 1;
if (rec_no < fp->ndxp_num_keys) {
rp = ndx_scan_down(hp, fp, rec_no);
} else {
rp = ndx_scan_up(hp, fp->ndxp_parent, fp->ndxp_par_rno + 1);
}
return rp;
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: sw=4 ts=4 fdm=marker
* vim<600: sw=4 ts=4
*/
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