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erc-c/src/option.c
2018-01-07 16:07:29 -06:00

291 lines
6.9 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"
/*
* 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;
/*
* 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 = 700;
static int height = 480;
static int flags = 0;
/*
* 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,
SIZE,
FLASH,
DISASSEMBLE,
};
/*
* Here are the options we support for program execution.
*/
static struct option long_options[] = {
{ "disassemble", 0, NULL, DISASSEMBLE },
{ "disk1", 1, NULL, DISK1 },
{ "disk2", 1, NULL, DISK2 },
{ "flash", 0, NULL, FLASH },
{ "help", 0, NULL, HELP },
{ "size", 1, NULL, SIZE },
};
/*
* 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';
do {
int input_source = 0;
opt = getopt_long_only(argc, argv, "", long_options, &index);
switch (opt) {
case DISASSEMBLE:
flags |= OPTION_DISASSEMBLE;
break;
case DISK1:
input_source = 1;
break;
case DISK2:
input_source = 2;
break;
case FLASH:
flags |= OPTION_FLASH;
break;
case HELP:
option_print_help();
// The help option should terminate normal execution
return 0;
case SIZE:
if (option_set_size(optarg) != OK) {
return 0;
}
break;
}
// We seem to have a request to load a file, so let's do so.
if (input_source) {
if (!option_read_file(input_source, optarg)) {
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_read_file(int source, const char *file)
{
FILE *stream;
if (!file) {
snprintf(error_buffer,
ERRBUF_SIZE,
"No file given for --disk%d\n",
source);
return 0;
}
stream = fopen(file, "r+");
if (stream == NULL) {
snprintf(error_buffer,
ERRBUF_SIZE,
"--disk%d: %s",
source,
strerror(errno));
return 0;
}
option_set_input(source, stream);
return 1;
}
/*
* Return the FILE stream for a given input, or NULL if none can be
* found. NULL may also be returned if the input has not previously been
* assigned.
*/
FILE *
option_get_input(int source)
{
switch (source) {
case 1: return input1;
case 2: return input2;
}
return NULL;
}
/*
* Set the given input source to a given FILE stream. If the input
* source is invalid, then nothing is done.
*/
void
option_set_input(int source, FILE *stream)
{
switch (source) {
case 1: input1 = stream;
case 2: input2 = stream;
}
}
/*
* 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 Print assembly notation from CPU memory\n\
--disk1=FILE Load FILE into disk drive 1\n\
--disk2=FILE Load FILE into disk drive 2\n\
--flash Flash CPU memory with contents of drive 1\n\
--help Print this help message\n\
--size=WIDTHxHEIGHT Use WIDTH and HEIGHT for window size\n\
(only 700x480 and 875x600 are supported)\n");
}
/*
* Set the size of our window in visible width and height. The size
* string is expected to be in the form of WIDTHxHEIGHT, where WIDTH
* and HEIGHT are integers representing the window width and height
* respectively. Arbitrary values for width and height are not
* necessarily allowed; generally, we can only support values which
* respect the aspect ratio used by the machine we are emulating.
*/
int
option_set_size(const char *size)
{
if (strcmp(size, "700x480") == 0) {
return OK;
} else if (strcmp(size, "875x600") == 0) {
width = 875;
height = 600;
return OK;
}
snprintf(error_buffer, ERRBUF_SIZE, "Ignoring bad window size: %s", size);
return ERR_BADOPT;
}
/*
* Return the window width we've been configured to use.
*/
int
option_get_width()
{
return width;
}
/*
* Return the window height we want.
*/
int
option_get_height()
{
return height;
}
/*
* Return true if the given option flag is set.
*/
bool
option_flag(int flag)
{
return flags & flag;
}