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erc-c/src/option.c

198 lines
5.1 KiB
C

/*
* option.c
*
* This file contains the functions which support our CLI options; you
* are both able to parse options and retrieve information from that
* option parsing.
*/
#include <errno.h>
#include <getopt.h>
#include <string.h>
#include <unistd.h>
#include "option.h"
#include "log.h"
#include "vm_di.h"
/*
* These are the file inputs we may have to the system. What their
* contents are will vary based on emulation context, and these values
* may change through the course of the program's execution.
*/
static FILE *input1 = NULL;
static FILE *input2 = NULL;
static FILE *disasm_log = NULL;
/*
* The size of our error buffer for anything we want to record while our
* option parsing goes on.
*/
#define ERRBUF_SIZE 2048
/*
* The alluded-to error buffer.
*/
static char error_buffer[ERRBUF_SIZE] = "";
/*
* The default width and height of the window. This is "roughly"
* 640x480, but because the Apple II has a 4.375:3 aspect ratio, we had
* to bump up the width to a number that respects that ratio.
*/
static int width = 840;
static int height = 576;
/*
* These are all of the options we allow in our long-form options. It's
* a bit faster to identify them by integer symbols than to do string
* comparisons.
*/
enum options {
DISK1,
DISK2,
HELP,
DISASSEMBLE,
};
/*
* Here are the options we support for program execution.
*/
static struct option long_options[] = {
{ "disassemble", 1, NULL, DISASSEMBLE },
{ "disk1", 1, NULL, DISK1 },
{ "disk2", 1, NULL, DISK2 },
{ "help", 0, NULL, HELP },
};
/*
* This simply returns the pointer of our error buffer, with the
* qualification that the caller cannot modify the error buffer once
* they get the pointer back.
*/
const char *
option_get_error()
{
return error_buffer;
}
/*
* Directly set the error buffer with something (that has to be less
* than ERRBUF_SIZE). This function is not itself hugely useful, but
* does allow for some better testing on option_error().
*/
void
option_set_error(const char *str)
{
// Use `- 1` so that we can ensure error_buffer is NUL-terminated.
// Otherwise, strncpy will copy all of src but leave the dst
// unterminated. Not that we're _likely_ to so self-injure
// ourselves, but, ya know.
strncpy(error_buffer, str, ERRBUF_SIZE - 1);
}
/*
* Parse our command-line arguments from the given argc and argv. This
* may or may not be what the kernel passes into the main() function!
* We return 1 if we can continue beyond the option parse phase, and 0
* if something came up to cause us to exit early. But whether you
* actually exit early is left up to the caller.
*/
int
option_parse(int argc, char **argv)
{
int index;
int opt = -1;
// To begin with, let's (effectively) NUL-out the error buffer.
error_buffer[0] = '\0';
vm_di_set(VM_WIDTH, &width);
vm_di_set(VM_HEIGHT, &height);
do {
opt = getopt_long_only(argc, argv, "", long_options, &index);
switch (opt) {
case DISASSEMBLE:
if (!option_open_file(&disasm_log, optarg, "w")) {
return 0;
}
vm_di_set(VM_DISASM_LOG, disasm_log);
break;
case DISK1:
if (!option_open_file(&input1, optarg, "r+")) {
return 0;
}
vm_di_set(VM_DISK1, input1);
break;
case DISK2:
if (!option_open_file(&input2, optarg, "r+")) {
return 0;
}
vm_di_set(VM_DISK2, input2);
break;
case HELP:
option_print_help();
// The help option should terminate normal execution
return 0;
}
} while (opt != -1);
return 1;
}
/*
* Given a file path, we open a FILE stream and set our given input
* source to that stream. If we cannot do so, we will set an error
* string in the buffer. Assuming all goes well, we will return 1, and
* 0 if not.
*/
int
option_open_file(FILE **stream, const char *file, const char *opts)
{
if (!file) {
snprintf(error_buffer,
ERRBUF_SIZE,
"No file given\n");
return 0;
}
*stream = fopen(file, opts);
if (*stream == NULL) {
snprintf(error_buffer,
ERRBUF_SIZE,
"open file for %s: %s",
file, strerror(errno));
return 0;
}
return 1;
}
/*
* Print out a help message. You'll note this is not automatically
* generated; it must be manually updated as we add other options.
*/
void
option_print_help()
{
fprintf(stderr, "Usage: erc [options...]\n");
fprintf(stderr, "Options:\n");
fprintf(stderr, "\
--disassemble=FILE Write assembly notation into FILE\n\
--disk1=FILE Load FILE into disk drive 1\n\
--disk2=FILE Load FILE into disk drive 2\n\
--help Print this help message\n\
--size=WIDTHxHEIGHT Use WIDTH and HEIGHT for window size\n\
(only 700x480 and 875x600 are supported)\n");
}