Add basic input parsing

main.c

@@ -0,0 +1,82 @@
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "mailbox.h"
+#include "main.h"
+
+/**
+ * Parse a line of input into an input struct.
+ *
+ * @param input_line A line of input.
+ * @param res An already allocated input struct to store the result in.
+ *
+ * @return int -1 if the input is malformed, and 0 otherwise.
+ */
+static int parse_input_line(char *input_line, struct input *res) {
+	// if tmp has anything in it, then we know that extra values have been entered.
+	char tmp[2];
+	int num_matched = sscanf(input_line, " %d %d %1s", &(res->value), &(res->recipient), tmp);
+
+	return num_matched == 2 ? 0 : -1;
+}
+
+/**
+ * Convert the given input to an array of input structs.
+ *
+ * @param num_threads The number of threads that the program has been spawned with.
+ * @param res A pointer that will be allocated as an array of inputs. Must be freed by the caller.
+ *
+ * @return int the number of input lines that were read.
+ */
+static int get_input(int num_threads, struct input **res) {
+	int input_index = 0;
+	int current_buffer_size = BUFFER_SIZE;
+	char *input_buffer = malloc(current_buffer_size);
+	// Keep reaidng until we hit an EOF
+	while (true) {
+		char *read_result;
+		while((read_result = fgets(input_buffer, current_buffer_size, stdin))) {
+			int read_size = strlen(input_buffer);
+			if (input_buffer[read_size - 1] == '\n') {
+				break;
+			}
+
+			// Grow our buffer if we nede to read more input.
+			current_buffer_size *= 2;
+			input_buffer = realloc(input_buffer, current_buffer_size);
+		}
+		if (read_result == NULL) {
+			break;
+		}
+
+		struct input current_input;
+		int parse_result = parse_input_line(input_buffer, &current_input);
+		if (parse_result == -1) {
+			// On bad input, we should assume an EOF and stop.
+			break;
+		} else if (current_input.recipient >= num_threads || current_input.recipient < 0) {
+			printf("Invalid recipient id.\n");
+			continue;
+		}
+
+		*res = realloc(*res, sizeof(struct input));
+		memcpy(*res + input_index, &current_input, sizeof(struct input));
+		input_index++;
+	}
+
+	free(input_buffer);
+
+	return input_index;
+}
+
+int main(int argc, char *argv[]) {
+	struct input *inputs = NULL;
+	// TODO: Get input to get actual number of inputs. 5 is just for funzies.
+	int num_inputs = get_input(5, &inputs);
+	for (int i = 0; i < num_inputs; i++) {
+		printf("#%d recipient=%d value=%d\n", i, inputs[i].recipient, inputs[i].value);
+	}
+	free(inputs);
+}

main.h

@@ -0,0 +1,17 @@
+#ifndef MAIN_H
+#define MAIN_H
+
+// The max number of threads that can be used at once
+#define MAXTHREAD 10
+// The max size of the input buffer
+#define BUFFER_SIZE 128
+
+// input represents a pair of values inputted at the command line
+struct input {
+	// The mailbox index of the recipient.
+	int recipient;
+	// The value to send to the mailbox.
+	int value;
+};
+
+#endif