diff options
| author | sanine <sanine.not@pm.me> | 2022-08-24 00:02:17 -0500 |
|---|---|---|
| committer | sanine <sanine.not@pm.me> | 2022-08-24 00:02:17 -0500 |
| commit | 2cb3c3df4099297b0a0554bb482e2de04fe86b5c (patch) | |
| tree | 7796b4064c16460d9d603707b5256027649aa8b6 /libs/cargs/src | |
| parent | 709e1b6e1ce86f8da4fc136747fcefbc6c6057bd (diff) | |
add command-line arguments
Diffstat (limited to 'libs/cargs/src')
| -rw-r--r-- | libs/cargs/src/cargs.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/libs/cargs/src/cargs.c b/libs/cargs/src/cargs.c new file mode 100644 index 0000000..2d7d945 --- /dev/null +++ b/libs/cargs/src/cargs.c @@ -0,0 +1,437 @@ +#include <assert.h>
+#include <cargs.h>
+#include <memory.h>
+#include <stdio.h>
+#include <string.h>
+
+#define CAG_OPTION_PRINT_DISTANCE 4
+#define CAG_OPTION_PRINT_MIN_INDENTION 20
+
+static void cag_option_print_value(const cag_option *option,
+ size_t *accessor_length, FILE *destination)
+{
+ if (option->value_name != NULL) {
+ *accessor_length += fprintf(destination, "=%s", option->value_name);
+ }
+}
+
+static void cag_option_print_letters(const cag_option *option, bool *first,
+ size_t *accessor_length, FILE *destination)
+{
+ const char *access_letter;
+ access_letter = option->access_letters;
+ if (access_letter != NULL) {
+ while (*access_letter) {
+ if (*first) {
+ *accessor_length += fprintf(destination, "-%c", *access_letter);
+ *first = false;
+ } else {
+ *accessor_length += fprintf(destination, ", -%c", *access_letter);
+ }
+ ++access_letter;
+ }
+ }
+}
+
+static void cag_option_print_name(const cag_option *option, bool *first,
+ size_t *accessor_length, FILE *destination)
+{
+ if (option->access_name != NULL) {
+ if (*first) {
+ *accessor_length += fprintf(destination, "--%s", option->access_name);
+ } else {
+ *accessor_length += fprintf(destination, ", --%s", option->access_name);
+ }
+ }
+}
+
+static size_t cag_option_get_print_indention(const cag_option *options,
+ size_t option_count)
+{
+ size_t option_index, indention, result;
+ const cag_option *option;
+
+ result = CAG_OPTION_PRINT_MIN_INDENTION;
+
+ for (option_index = 0; option_index < option_count; ++option_index) {
+ indention = CAG_OPTION_PRINT_DISTANCE;
+ option = &options[option_index];
+ if (option->access_letters != NULL && *option->access_letters) {
+ indention += strlen(option->access_letters) * 4 - 2;
+ if (option->access_name != NULL) {
+ indention += strlen(option->access_name) + 4;
+ }
+ } else if (option->access_name != NULL) {
+ indention += strlen(option->access_name) + 2;
+ }
+
+ if (option->value_name != NULL) {
+ indention += strlen(option->value_name) + 1;
+ }
+
+ if (indention > result) {
+ result = indention;
+ }
+ }
+
+ return result;
+}
+
+void cag_option_print(const cag_option *options, size_t option_count,
+ FILE *destination)
+{
+ size_t option_index, indention, i, accessor_length;
+ const cag_option *option;
+ bool first;
+
+ indention = cag_option_get_print_indention(options, option_count);
+
+ for (option_index = 0; option_index < option_count; ++option_index) {
+ option = &options[option_index];
+ accessor_length = 0;
+ first = true;
+
+ fputs(" ", destination);
+
+ cag_option_print_letters(option, &first, &accessor_length, destination);
+ cag_option_print_name(option, &first, &accessor_length, destination);
+ cag_option_print_value(option, &accessor_length, destination);
+
+ for (i = accessor_length; i < indention; ++i) {
+ fputs(" ", destination);
+ }
+
+ fputs(" ", destination);
+ fputs(option->description, destination);
+
+ fprintf(destination, "\n");
+ }
+}
+
+void cag_option_prepare(cag_option_context *context, const cag_option *options,
+ size_t option_count, int argc, char **argv)
+{
+ // This just initialized the values to the beginning of all the arguments.
+ context->options = options;
+ context->option_count = option_count;
+ context->argc = argc;
+ context->argv = argv;
+ context->index = 1;
+ context->inner_index = 0;
+ context->forced_end = false;
+}
+
+static const cag_option *cag_option_find_by_name(cag_option_context *context,
+ char *name, size_t name_size)
+{
+ const cag_option *option;
+ size_t i;
+
+ // We loop over all the available options and stop as soon as we have found
+ // one. We don't use any hash map table, since there won't be that many
+ // arguments anyway.
+ for (i = 0; i < context->option_count; ++i) {
+ option = &context->options[i];
+
+ // The option might not have an item name, we can just skip those.
+ if (option->access_name == NULL) {
+ continue;
+ }
+
+ // Try to compare the name of the access name. We can use the name_size or
+ // this comparison, since we are guaranteed to have null-terminated access
+ // names.
+ if (strncmp(option->access_name, name, name_size) == 0) {
+ return option;
+ }
+ }
+
+ return NULL;
+}
+
+static const cag_option *cag_option_find_by_letter(cag_option_context *context,
+ char letter)
+{
+ const cag_option *option;
+ size_t i;
+
+ // We loop over all the available options and stop as soon as we have found
+ // one. We don't use any look up table, since there won't be that many
+ // arguments anyway.
+ for (i = 0; i < context->option_count; ++i) {
+ option = &context->options[i];
+
+ // If this option doesn't have any access letters we will skip them.
+ if (option->access_letters == NULL) {
+ continue;
+ }
+
+ // Verify whether this option has the access letter in it's access letter
+ // string. If it does, then this is our option.
+ if (strchr(option->access_letters, letter) != NULL) {
+ return option;
+ }
+ }
+
+ return NULL;
+}
+
+static void cag_option_parse_value(cag_option_context *context,
+ const cag_option *option, char **c)
+{
+ // And now let's check whether this option is supposed to have a value, which
+ // is the case if there is a value name set. The value can be either submitted
+ // with a '=' sign or a space, which means we would have to jump over to the
+ // next argv index. This is somewhat ugly, but we do it to behave the same as
+ // the other option parsers.
+ if (option->value_name != NULL) {
+ if (**c == '=') {
+ context->value = ++(*c);
+ } else {
+ // If the next index is larger or equal to the argument count, then the
+ // parameter for this option is missing. The user will know about this,
+ // since the value pointer of the context will be NULL because we don't
+ // set it here in that case.
+ if (context->argc > context->index + 1) {
+ // We consider this argv to be the value, no matter what the contents
+ // are.
+ ++context->index;
+ *c = context->argv[context->index];
+ context->value = *c;
+ }
+ }
+
+ // Move c to the end of the value, to not confuse the caller about our
+ // position.
+ while (**c) {
+ ++(*c);
+ }
+ }
+}
+
+static void cag_option_parse_access_name(cag_option_context *context, char **c)
+{
+ const cag_option *option;
+ char *n;
+
+ // Now we need to extract the access name, which is any symbol up to a '=' or
+ // a '\0'.
+ n = *c;
+ while (**c && **c != '=') {
+ ++*c;
+ }
+
+ // Now this will obviously always be true, but we are paranoid. Sometimes. It
+ // doesn't hurt to check.
+ assert(*c >= n);
+
+ // Figure out which option this name belongs to. This might return NULL if the
+ // name is not registered, which means the user supplied an unknown option. In
+ // that case we return true to indicate that we finished with this option. We
+ // have to skip the value parsing since we don't know whether the user thinks
+ // this option has one or not. Since we don't set any identifier specifically,
+ // it will remain '?' within the context.
+ option = cag_option_find_by_name(context, n, (size_t)(*c - n));
+ if (option == NULL) {
+ // Since this option is invalid, we will move on to the next index. There is
+ // nothing we can do about this.
+ ++context->index;
+ return;
+ }
+
+ // We found an option and now we can specify the identifier within the
+ // context.
+ context->identifier = option->identifier;
+
+ // And now we try to parse the value. This function will also check whether
+ // this option is actually supposed to have a value.
+ cag_option_parse_value(context, option, c);
+
+ // And finally we move on to the next index.
+ ++context->index;
+}
+
+static void cag_option_parse_access_letter(cag_option_context *context,
+ char **c)
+{
+ const cag_option *option;
+ char *n = *c;
+ char *v;
+
+ // Figure out which option this letter belongs to. This might return NULL if
+ // the letter is not registered, which means the user supplied an unknown
+ // option. In that case we return true to indicate that we finished with this
+ // option. We have to skip the value parsing since we don't know whether the
+ // user thinks this option has one or not. Since we don't set any identifier
+ // specifically, it will remain '?' within the context.
+ option = cag_option_find_by_letter(context, n[context->inner_index]);
+ if (option == NULL) {
+ ++context->index;
+ context->inner_index = 0;
+ return;
+ }
+
+ // We found an option and now we can specify the identifier within the
+ // context.
+ context->identifier = option->identifier;
+
+ // And now we try to parse the value. This function will also check whether
+ // this option is actually supposed to have a value.
+ v = &n[++context->inner_index];
+ cag_option_parse_value(context, option, &v);
+
+ // Check whether we reached the end of this option argument.
+ if (*v == '\0') {
+ ++context->index;
+ context->inner_index = 0;
+ }
+}
+
+static void cag_option_shift(cag_option_context *context, int start, int option,
+ int end)
+{
+ char *tmp;
+ int a_index, shift_index, shift_count, left_index, right_index;
+
+ shift_count = option - start;
+
+ // There is no shift is required if the start and the option have the same
+ // index.
+ if (shift_count == 0) {
+ return;
+ }
+
+ // Lets loop through the option strings first, which we will move towards the
+ // beginning.
+ for (a_index = option; a_index < end; ++a_index) {
+ // First remember the current option value, because we will have to save
+ // that later at the beginning.
+ tmp = context->argv[a_index];
+
+ // Let's loop over all option values and shift them one towards the end.
+ // This will override the option value we just stored temporarily.
+ for (shift_index = 0; shift_index < shift_count; ++shift_index) {
+ left_index = a_index - shift_index;
+ right_index = a_index - shift_index - 1;
+ context->argv[left_index] = context->argv[right_index];
+ }
+
+ // Now restore the saved option value at the beginning.
+ context->argv[a_index - shift_count] = tmp;
+ }
+
+ // The new index will be before all non-option values, in such a way that they
+ // all will be moved again in the next fetch call.
+ context->index = end - shift_count;
+}
+
+static bool cag_option_is_argument_string(const char *c)
+{
+ return *c == '-' && *(c + 1) != '\0';
+}
+
+static int cag_option_find_next(cag_option_context *context)
+{
+ int next_index, next_option_index;
+ char *c;
+
+ // Prepare to search the next option at the next index.
+ next_index = context->index;
+ next_option_index = next_index;
+
+ // Grab a pointer to the string and verify that it is not the end. If it is
+ // the end, we have to return false to indicate that we finished.
+ c = context->argv[next_option_index];
+ if (context->forced_end || c == NULL) {
+ return -1;
+ }
+
+ // Check whether it is a '-'. We need to find the next option - and an option
+ // always starts with a '-'. If there is a string "-\0", we don't consider it
+ // as an option neither.
+ while (!cag_option_is_argument_string(c)) {
+ c = context->argv[++next_option_index];
+ if (c == NULL) {
+ // We reached the end and did not find any argument anymore. Let's tell
+ // our caller that we reached the end.
+ return -1;
+ }
+ }
+
+ // Indicate that we found an option which can be processed. The index of the
+ // next option will be returned.
+ return next_option_index;
+}
+
+bool cag_option_fetch(cag_option_context *context)
+{
+ char *c;
+ int old_index, new_index;
+
+ // Reset our identifier to a question mark, which indicates an "unknown"
+ // option. The value is set to NULL, to make sure we are not carrying the
+ // parameter from the previous option to this one.
+ context->identifier = '?';
+ context->value = NULL;
+
+ // Check whether there are any options left to parse and remember the old
+ // index as well as the new index. In the end we will move the option junk to
+ // the beginning, so that non option arguments can be read.
+ old_index = context->index;
+ new_index = cag_option_find_next(context);
+ if (new_index >= 0) {
+ context->index = new_index;
+ } else {
+ return false;
+ }
+
+ // Grab a pointer to the beginning of the option. At this point, the next
+ // character must be a '-', since if it was not the prepare function would
+ // have returned false. We will skip that symbol and proceed.
+ c = context->argv[context->index];
+ assert(*c == '-');
+ ++c;
+
+ // Check whether this is a long option, starting with a double "--".
+ if (*c == '-') {
+ ++c;
+
+ // This might be a double "--" which indicates the end of options. If this
+ // is the case, we will not move to the next index. That ensures that
+ // another call to the fetch function will not skip the "--".
+ if (*c == '\0') {
+ context->forced_end = true;
+ } else {
+ // We parse now the access name. All information about it will be written
+ // to the context.
+ cag_option_parse_access_name(context, &c);
+ }
+ } else {
+ // This is no long option, so we can just parse an access letter.
+ cag_option_parse_access_letter(context, &c);
+ }
+
+ // Move the items so that the options come first followed by non-option
+ // arguments.
+ cag_option_shift(context, old_index, new_index, context->index);
+
+ return context->forced_end == false;
+}
+
+char cag_option_get(const cag_option_context *context)
+{
+ // We just return the identifier here.
+ return context->identifier;
+}
+
+const char *cag_option_get_value(const cag_option_context *context)
+{
+ // We just return the internal value pointer of the context.
+ return context->value;
+}
+
+int cag_option_get_index(const cag_option_context *context)
+{
+ // Either we point to a value item,
+ return context->index;
+}
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