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The following example program shows how a KSAM XL file can be created, accessed, and updated from an HP C/iX program. This program uses features of ANSI C. Compile with INFO=-Aa + e. This example program uses the assert macro to do quick error checking. In a production program, more comprehensive error checking and reporting would be desirable. The KSAM XL file has the following layout:
1 - 5 Employee number (primary key)
6 - 25 Name (secondary key)
26 - 34 Social Security Number
35 - 38 Department Number (secondary key)
39 - 44 Date of hire
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mpe.h>:
#pragma intrinsic FCLOSE, FFINDN, FLOCK
#pragma intrinsic FREAD, FREADBYKEY, FREMOVE
#pragma intrinsic FUNLOCK, FUPDATE, FWRITE
#pragma intrinsic HPCICOMMAND, HPFOPEN
#define FILENAME "KSAMD"
typedef char record_t[44];
static int filenum;
static void close_file(void);
static void create_file(void);
static void delete_records(void);
static void dump_file(void);
static void list_sequential(void);
static void list_sequential_primary(void);
static void list_sequential_secondary(int location);
static void lock_file(void);
static void open_file(void);
static void unlock_file(void);
static void update_records(void);
static void write_new_records(void);
static void write_record(const char *record);
main(void)
{
create_file();
open_file();
dump_file();
write_new_records();
update_records();
delete_records();
dump_file();
close_file();
return EXIT_SUCCESS;
}
static void close_file(void)
{
/* Close file */
FCLOSE(filenum, 0, 0);
assert(ccode()==CCE);
}
static void create_file(void)
{
/* Create sample KSAM XL file and load initial test data */
int status; short cmderror;
const int ksamxl=3, out=1, recsize=sizeof(record_t),
filesize=100, save=1, ascii=1;
const struct
{
short filler_1[10];
unsigned short language_id : 16;
short filler_2[4];
struct
{
unsigned short filler_1 : 10;
unsigned short chg_primary : 1;
unsigned short kslang : 1;
unsigned short ksreuse : 1;
unsigned short seq_random : 1;
unsigned short rec_numbering : 1;
unsigned short filler_2 : 1;
} flagword;
unsigned short filler_3 : 8;
unsigned short num_keys : 8;
struct
{
unsigned short key_type : 4;
unsigned short key_length : 12;
unsigned short key_location : 16;
unsigned short dflag : 1;
unsigned short filler_1 : 15;
unsigned short filler_2 : 8;
unsigned short rflag : 1;
unsigned short filler_3 : 7;
} keyparms[16];
} ksamparam = { {0}, 0, {0}, {0,0,1,0,0,0,0}, 0, 3,
{ {1, 5, 1,0,0,0,0,0},
{1,20, 6,1,0,0,0,0},
{1, 4,35,1,0,0,0,0} } };
const record_t test_data[] =
{
"11111DOE JOHN 1230067898540821201",
"03452CUSTER HERB 3218800003160821203",
"28766WORKMAN DEBBIE 0006612341520850601",
"33678MORSE EUGENE 8760098763160850715"
} ;
const int test_items = sizeof test_data / sizeof test_data[0];
int i;
/* First, purge file if it already exists */
HPCICOMMAND("PURGE " FILENAME "\r", &cmderror, , 2);
assert(!cmderror || cmderror==-383);
/* Create new KSAM XL file, output access, 44-byte
ASCII records, limit = 100, save disposition */
HPFOPEN(&filenum, &status,
2, "-" FILENAME "-",
10, &ksamxl,
11, &out,
19, &recsize,
35, &filesize,
50, &save,
53, &ascii,
54, &ksamparam);
assert(!status);
/* Write test data to file */
for (i=0; i<test_items; ++i)
write_record(test_data[i]);
printf("\n");
/* Close file */
FCLOSE(filenum, 0, 0);
assert(ccode()==CCE);
}
static void delete_records(void)
{
/* Delete records for several employees */
const char delete_data[][5] = {"33678", "03452"};
const int delete_items =
sizeof delete_data / sizeof delete_data[0];
int i;
record_t buffer;
for (i=0; i<delete_items; ++i)
{
printf("Deleting employee %.5s: ", delete_data[i]);
lock_file();
FREADBYKEY(filenum, buffer, - sizeof buffer,
delete_data[i], 0);
assert(ccode()==CCE);
printf("%.20s\n", buffer+5);
FREMOVE(filenum);
assert(ccode()==CCE);
unlock_file();
}
printf("\n");
}
static void dump_file(void)
{
/* List the file several different ways */
list_sequential_primary();
list_sequential_secondary(6);
list_sequential_secondary(35);
}
static void list_sequential(void)
{
/* List the file, looping on FREAD until end-of-data */
int save_ccode;
record_t buffer;
for (;;)
{
FREAD(filenum, buffer, - sizeof buffer);
if ((save_ccode=ccode()) == CCG)
break;
assert(save_ccode==CCE);
printf(" %.5s %.20s %.3s-%.2s-%.4s "
"%.4s %.2s/%.2s/%.2s\n",
buffer, buffer+5, buffer+25, buffer+28, buffer+30,
buffer+34, buffer+40, buffer+42, buffer+38);
}
printf("\n");
}
static void list_sequential_primary(void)
{
/* List file in sequence on primary key */
printf("In sequence by primary key:\n");
lock_file();
/* Following call to FFINDN not necessary if this
is the first access since the file was opened */
FFINDN(filenum, -1, 0);
assert(ccode()==CCE);
list_sequential();
unlock_file();
}
static void list_sequential_secondary(const int location)
{
/* List file in sequence on specified secondary key */
printf("In sequence by secondary key in location %d:\n",
location);
lock_file();
FFINDN(filenum, -1, location);
assert(ccode()==CCE);
list_sequential();
unlock_file();
}
static void lock_file(void)
{
/* Lock the file unconditionally */
FLOCK(filenum, 1);
assert(ccode()==CCE);
}
static void open_file(void)
{
/* Open file for shared update access with locking */
int status;
const int old=1, update=5, lock=1, shr=3;
HPFOPEN(&filenum, &status,
2, "-" FILENAME "-",
3, &old,
11, &update,
12, &lock,
13, &shr);
assert(!status);
}
static void unlock_file(void)
{
/* Unlock the file */
FUNLOCK(filenum);
assert(ccode()==CCE);
}
static void update_records(void)
{
/* Update department code for several employees */
const struct {char empno[5]; char new_dept[4];} update_data[] =
{{"28766", "9901"}, {"11111", "9905"}};
const int update_items =
sizeof update_data / sizeof update_data[0];
int i;
record_t buffer;
for (i=0; i<update_items; ++i)
{
printf("Updating employee %.5s to department %.4s: ",
update_data[i].empno, update_data[i].new_dept);
lock_file();
FREADBYKEY(filenum, buffer, - sizeof buffer,
update_data[i].empno, 0);
assert(ccode()==CCE);
printf("%.20s\n", buffer+5);
memcpy(buffer+34, update_data[i].new_dept, 4);
FUPDATE(filenum, buffer, - sizeof buffer);
assert(ccode()==CCE);
unlock_file();
}
printf("\n");
}
static void write_new_records(void)
{
/* Add some entries to the file */
const record_t test_data[] =
{
"77777NEWMAN GEORGE 7770066661520871012",
"55555GOODMAN BRIAN 5553300008540880815",
"66666MANLEY SHAUNA 0003526143360890930"
} ;
const int test_items = sizeof test_data / sizeof test_data[0];
int i;
for (i=0; i<test_items; ++i)
{
lock_file();
write_record(test_data[i]);
unlock_file();
}
printf("\n");
}
static void write_record(const char * const record)
{
/* Write one record to the file */
printf("Writing record for %.5s, %.20s\n", record, record+5);
FWRITE(filenum, record, - sizeof(record_t), 0);
assert(ccode()==CCE);
}
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