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#include <stdio.h>
#include <errno.h>
#include <string.h>
#include "xex.h"
int xex_errno;
static int xex_sys_errno;
int xex_verbose = 0;
static char *errors[] = {
"OK", /* XERR_NONE 0 */
"Failed system call", /* XERR_SYSCALL 1 */
"End address < start address", /* XERR_REVERSED 2 */
"Truncated segment", /* XERR_TRUNCATED 3 */
"No data", /* XERR_NULLDATA 4 */
"Unknown/Invalid XEX error code", /* XERR_MAXERR 5 */
};
int xex_new_seg(xex_segment *seg, unsigned char *data) {
int offset = 0;
if(data[0] == 0xff && data[1] == 0xff) {
offset = 2;
seg->has_ff_header = 1;
} else {
seg->has_ff_header = 0;
}
seg->start_addr = data[offset] + (data[offset + 1] << 8);
offset += 2;
seg->end_addr = data[offset] + (data[offset + 1] << 8);
offset += 2;
seg->object = &data[offset];
seg->len = seg->end_addr - seg->start_addr + 1;
return xex_check_seg(seg);
}
int xex_init_seg(xex_segment *seg, unsigned char *object, unsigned short addr) {
object[0] = XEX_LSB(addr);
object[1] = XEX_MSB(addr);
seg->start_addr = XEX_INITAD;
seg->end_addr = XEX_INITAD + 1;
seg->object = object;
seg->len = 2;
seg->has_ff_header = 0;
if(xex_verbose) {
fprintf(stderr, "xex_init_seg(): created init segment @ %04X:\n", addr);
xex_print_seg_info(seg);
}
return 1;
}
int xex_run_seg(xex_segment *seg, unsigned char *object, unsigned short addr) {
object[0] = XEX_LSB(addr);
object[1] = XEX_MSB(addr);
seg->start_addr = XEX_RUNAD;
seg->end_addr = XEX_RUNAD + 1;
seg->object = object;
seg->len = 2;
seg->has_ff_header = 0;
if(xex_verbose) {
fprintf(stderr, "xex_run(): created run segment @ %04X:\n", addr);
xex_print_seg_info(seg);
}
return 1;
}
static int read_char(FILE *file) {
int c;
c = getc(file);
if(c == EOF) {
if(ferror(file)) {
xex_sys_errno = errno;
xex_errno = XERR_SYSCALL;
} else {
xex_errno = XERR_TRUNCATED;
}
}
return c;
}
int xex_fread_seg_header(xex_segment *seg, FILE *file) {
int c, d;
unsigned short addr;
xex_errno = XERR_NONE;
seg->has_ff_header = 0;
seg->object = NULL;
c = read_char(file);
if(c == EOF) {
if(feof(file))
xex_errno = XERR_NONE;
return 0;
}
d = read_char(file);
if(d == EOF) return 0;
addr = XEX_ADDR(c, d);
if(addr == 0x0984) {
fprintf(stderr, "xex_fread_seg_header(): warning: this might be a DOS 1.0 file (not supported)\n");
}
if(addr == 0xffff) {
seg->has_ff_header = 1;
c = read_char(file);
if(c == EOF) return 0;
d = read_char(file);
if(d == EOF) return 0;
addr = XEX_ADDR(c, d);
}
if(addr == 0xffff) {
xex_errno = XERR_REVERSED;
return 0;
}
seg->start_addr = addr;
c = read_char(file);
if(c == EOF) return 0;
d = read_char(file);
if(d == EOF) return 0;
addr = XEX_ADDR(c, d);
seg->end_addr = addr;
seg->len = seg->end_addr - seg->start_addr + 1;
if(seg->end_addr < seg->start_addr) {
xex_errno = XERR_REVERSED;
return 0;
}
if(xex_verbose) {
fprintf(stderr, "xex_fread_seg_header(): read header:\n");
xex_print_seg_info(seg);
}
return 1;
}
int xex_fread_seg_data(xex_segment *seg, FILE *file) {
int res;
xex_errno = XERR_NONE;
res = fread(seg->object, 1, seg->len, file);
xex_sys_errno = errno;
if(xex_verbose) {
fprintf(stderr, "xex_fread_seg_data(): read data, len==%d, res==%d:\n", seg->len, res);
xex_print_seg_info(seg);
}
if(res == seg->len) {
return 1;
}
if(res < 0 || ferror(file)) {
xex_errno = XERR_SYSCALL;
} else {
/* EOF or short read */
xex_errno = XERR_TRUNCATED;
seg->len = res;
}
return xex_check_seg(seg);
}
int xex_fread_seg(xex_segment *seg, FILE *file) {
unsigned char *tmp = seg->object;
int res;
xex_errno = XERR_NONE;
if(tmp == NULL) {
if(xex_verbose)
fprintf(stderr, "xex_fread_seg(): seg->object == NULL\n");
xex_errno = XERR_NULLDATA;
return 0;
}
res = xex_fread_seg_header(seg, file);
seg->object = tmp;
if(!res)
return 0;
if(!xex_fread_seg_data(seg, file))
return 0;
return 1;
}
int xex_fwrite_seg(xex_segment *seg, FILE *file) {
int res;
xex_errno = XERR_NONE;
if(xex_verbose) {
fprintf(stderr, "xex_fwrite_seg(): about to write:\n");
xex_print_seg_info(seg);
}
if(!xex_check_seg(seg))
return 0;
if(seg->has_ff_header) {
putc(0xff, file);
putc(0xff, file);
}
putc(XEX_LSB(seg->start_addr), file);
putc(XEX_MSB(seg->start_addr), file);
putc(XEX_LSB(seg->end_addr), file);
putc(XEX_MSB(seg->end_addr), file);
res = fwrite(seg->object, 1, seg->len, file);
if(res == seg->len)
return 1;
if(ferror(file)) {
xex_errno = XERR_SYSCALL;
xex_sys_errno = errno;
} else {
xex_errno = XERR_TRUNCATED;
}
return 0;
}
int xex_get_object(xex_segment *seg, unsigned char *data) {
int offset = 0;
if(!xex_check_seg(seg))
return 0;
if(seg->has_ff_header) {
data[0] = data[1] = 0xff;
offset = 2;
}
data[offset] = XEX_LSB(seg->start_addr);
data[offset + 1] = XEX_MSB(seg->start_addr);
offset += 2;
data[offset] = XEX_LSB(seg->end_addr);
data[offset + 1] = XEX_MSB(seg->end_addr);
offset += 2;
memcpy(&data[offset], seg->object, seg->len);
return 1;
}
int xex_check_seg(xex_segment *seg) {
int ret = 1;
xex_errno = XERR_NONE;
if(seg->end_addr < seg->start_addr) {
xex_errno = XERR_REVERSED;
ret = 0;
}
if(seg->len != (seg->end_addr - seg->start_addr) + 1) {
xex_errno = XERR_TRUNCATED;
ret = 0;
}
if(seg->object == NULL) {
xex_errno = XERR_NULLDATA;
ret = 0;
}
if(xex_verbose && !ret && xex_errno != XERR_NULLDATA)
fprintf(stderr, "xex_check_seg() FAILED: %s\n", xex_strerror(xex_errno));
return ret;
}
static int xex_get_addr_from(xex_segment *seg, int location) {
int i;
if(seg->start_addr > location) return -1;
if(seg->end_addr <= location) return -1;
i = location - seg->start_addr;
return XEX_ADDR(seg->object[i], seg->object[i + 1]);
}
int xex_get_run_addr(xex_segment *seg) {
return xex_get_addr_from(seg, XEX_RUNAD);
}
int xex_get_init_addr(xex_segment *seg) {
return xex_get_addr_from(seg, XEX_INITAD);
}
char *xex_strerror(int err) {
if(err < 0 || err >= XERR_MAXERR)
err = XERR_MAXERR;
if(err == XERR_SYSCALL)
return strerror(xex_sys_errno);
else
return errors[err];
}
void xex_perror(char *msg) {
fprintf(stderr, "%s: %s\n", msg, xex_strerror(xex_errno));
}
void xex_print_seg_info(xex_segment *seg) {
xex_check_seg(seg);
fprintf(stderr,
"has_ff_header==%d start==%04X end==%04X "
"len==%04X status==%s\n",
seg->has_ff_header, seg->start_addr, seg->end_addr,
seg->len, xex_strerror(xex_errno));
}
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