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#include "proto.h"
struct options get_options (int argc, char ** argv) {
struct options result = {.input = NULL, .output = NULL, .mode = 0, .alignment = 0, .method = COMPRESSION_METHODS};
const char * program_name = *argv;
int compressor = -1;
if (argc == 1) usage(program_name);
for (argv ++; *argv; argv ++) {
if (**argv != '-') break;
if (!1[*argv]) break;
if (!strcmp(*argv, "--")) {
argv ++;
break;
} else if (!(strcmp(*argv, "--text") && strcmp(*argv, "-t")))
result.mode = 1;
else if (!(strcmp(*argv, "--binary") && strcmp(*argv, "-b")))
result.mode = 0;
else if (!(strcmp(*argv, "--uncompress") && strcmp(*argv, "-u")))
result.mode = 2;
else if (!(strcmp(*argv, "--dump") && strcmp(*argv, "-d")))
result.mode = 3;
else if (!(strcmp(*argv, "--align") && strncmp(*argv, "-a", 2)))
result.alignment = parse_numeric_option_argument(&argv, 12);
else if (!(strcmp(*argv, "--method") && strncmp(*argv, "-m", 2)))
result.method = parse_numeric_option_argument(&argv, COMPRESSION_METHODS - 1);
else if (!(strcmp(*argv, "--compressor") && strncmp(*argv, "-c", 2)))
compressor = parse_compressor_option_argument(&argv);
else if (!(strcmp(*argv, "--optimize") && strcmp(*argv, "-o"))) {
result.method = COMPRESSION_METHODS;
compressor = -1;
} else if (!(strcmp(*argv, "--help") && strcmp(*argv, "-?")))
usage(program_name);
else if (!(strcmp(*argv, "--list") && strcmp(*argv, "-l")))
list_compressors();
else
error_exit(3, "unknown option: %s", *argv);
}
if (compressor >= 0) {
if (result.method >= COMPRESSION_METHODS) result.method = 0;
if (result.method >= compressors[compressor].methods)
error_exit(3, "method for the %s compressor must be between 0 and %u", compressors[compressor].name, compressors[compressor].methods - 1);
while (compressor > 0) result.method += compressors[-- compressor].methods;
}
if (*argv) {
if (strcmp(*argv, "-")) result.input = *argv;
if (*(++ argv)) {
if (argv[1]) error_exit(3, "too many command-line arguments");
if (strcmp(*argv, "-")) result.output = *argv;
}
}
return result;
}
unsigned parse_numeric_option_argument (char *** alp, unsigned limit) {
const char * option;
const char * value = get_argument_for_option(alp, &option);
char * error;
unsigned long result = strtoul(value, &error, 10);
if (*error) error_exit(3, "invalid argument to option %s", option);
if (result > limit) error_exit(3, "argument to option %s must be between 0 and %u", option, limit);
return result;
}
int parse_compressor_option_argument (char *** alp) {
const char * name = get_argument_for_option(alp, NULL);
if (!strcmp(name, "*")) return -1;
int result = -1;
unsigned length = strlen(name);
const struct compressor * compressor;
for (compressor = compressors; compressor -> name; compressor ++) {
if (strncmp(name, compressor -> name, length)) continue;
if (result >= 0) error_exit(3, "ambiguous compressor prefix: %s", name);
result = compressor - compressors;
}
if (result < 0) error_exit(3, "unknown compressor: %s", name);
return result;
}
const char * get_argument_for_option (char *** alp, const char ** option_name) {
// alp: argument list pointer (i.e., address of the current value of argv after indexing)
// will point at the last consumed argument on exit (since the caller will probably increment it once more)
const char * option;
const char * result;
if (1[**alp] == '-') {
option = *((*alp) ++);
result = **alp;
} else {
option_name_buffer[1] = 1[**alp];
option = option_name_buffer;
result = **alp + 2;
}
if (!(result && *result)) error_exit(3, "option %s requires an argument", option);
if (option_name) *option_name = option;
return result;
}
noreturn usage (const char * program_name) {
fprintf(stderr, "Usage: %s [<options>] [<source file> [<output>]]\n\n", program_name);
fputs("Execution mode:\n", stderr);
fputs(" -b, --binary Output the command stream as binary data (default).\n", stderr);
fputs(" -t, --text Output the command stream as text.\n", stderr);
fputs(" -u, --uncompress Process a compressed file and output the original data.\n", stderr);
fputs(" -d, --dump Process a compressed file and dump the command stream as\n", stderr);
fputs(" text (as if compressed with the --text option).\n", stderr);
fputs(" -l, --list List compressors and their method numbers.\n", stderr);
fputs(" -?, --help Print this help text and exit.\n", stderr);
fputs("Compression options:\n", stderr);
fputs(" -o, --optimize Use the best combination of compression\n", stderr);
fputs(" methods available (default).\n", stderr);
fputs(" -m<number>, --method <number> Use only one specific compression method.\n", stderr);
fprintf(stderr, " Valid method numbers are between 0 and %u.\n", COMPRESSION_METHODS - 1);
fputs(" -c<name>, --compressor <name> Use the specified compressor: the method\n", stderr);
fputs(" number will be relative to that compressor.\n", stderr);
fputs(" Any prefix of the compressor name may be\n", stderr);
fputs(" specified. Use * to indicate any compressor.\n", stderr);
fputs(" -a<number>, --align <number> Pad the compressed output with zeros until\n", stderr);
fputs(" the size has the specified number of low bits\n", stderr);
fputs(" cleared (default: 0).\n", stderr);
fputs("The source and output filenames can be given as - (or omitted) to use standard\n", stderr);
fputs("input and output. Use -- to indicate that subsequent arguments are file names.\n", stderr);
exit(3);
}
noreturn list_compressors (void) {
const struct compressor * compressor;
unsigned current, length = 10;
for (compressor = compressors; compressor -> name; compressor ++) if ((current = strlen(compressor -> name)) > length) length = current;
fprintf(stderr, "%-*s Offset Methods\n", length, "Compressor");
for (current = 0; current < length; current ++) putc('-', stderr);
fputs(" ------ -------\n", stderr);
current = 0;
for (compressor = compressors; compressor -> name; compressor ++) {
fprintf(stderr, "%-*s %6u %7u\n", length, compressor -> name, current, compressor -> methods);
current += compressor -> methods;
}
putc('\n', stderr);
fputs("Note: the offset indicates the compressor's lowest method number when the\n", stderr);
fputs("--compressor option is not given. When that option is used, every compressor's\n", stderr);
fputs("methods are numbered from zero.\n", stderr);
exit(3);
}
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