From 9eefade7c68ce58cff47a854680f84ba110876fd Mon Sep 17 00:00:00 2001
From: Rushil Umaretiya <rushilwiz@gmail.com>
Date: Thu, 25 Apr 2024 22:56:40 -0400
Subject: [PATCH] finished parse

---
 shell.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

diff --git a/shell.c b/shell.c
index 9e1bb12..f4fe04e 100644
--- a/shell.c
+++ b/shell.c
@@ -20,7 +20,73 @@ void cleanup(command_t* p_cmd) {
     }
 }
 
-void parse(char* line, command_t* p_cmd) {}
+/**
+ * Parses line (input from user) into command_t* p_cmd.
+ *
+ * Determine the number of arguments via string parsing.
+ * Then, set p_cmd->argc to the correct value,
+ * and allocate memory for p_cmd->argv.
+ * Finally, ***copy*** the arguments from line into p_cmd->argv.
+ *
+ * When copying the arguments, do not simply assign pointers. You must
+ * use str(n)cpy (or reimplement its logic) to copy the arguments.
+ *
+ * p_cmd is NULL when this function is called (see main.c).
+ *
+ * Example 1: If line is "cd /mnt/cdrom", then the fields in p_cmd should be
+ * {argc = 2, argv = {"cd", "mnt/cdrom", NULL}}
+ *
+ * Example 2: If line is "ls -la", then the fields in p_cmd should be
+ * {argc = 2, argv = {"ls, "-la", NULL}}
+ *
+ * Example 3: If line is NULL, then the fields in p_cmd should be {argc =
+ * 0, argv = {NULL}}
+ *
+ * Example 4: If line is "   ls   -la   ", then the fields in p_cmd should be
+ * the same as in example 2. Note the additional whitespace in the input.
+ *
+ * We recommend using strtok to handle this parsing.
+ * https://systems-encyclopedia.cs.illinois.edu/articles/c-strtok/
+ *
+ * strtok's functionality is similar to that of split in Python or Java.
+ * For example, in Python, we can do
+ *
+ * >>> "cd /mnt/cdrom".split(" ")
+ * ['cd', '/mnt/cdrom']
+ *
+ * When used correctly, strtok will handle all of the above cases correctly.
+ * Alternatively, you may reimplement tokenizing logic yourself, but be sure to
+ * handle example 4 (extra whitespace) correctly.
+ *
+ * NOTE: strtok mutates the input char* (by inserting null terminators). So, to
+ * be safe, you should use strtok on a clone of the input char*. You can create
+ * a clone using strdup.
+ *
+ * @param line string input from user
+ * @param p_cmd pointer to struct that will store the parsed command
+ * @return void
+ */
+
+void parse(char* line, command_t* p_cmd) {
+    char* line_copy = strdup(line);
+    char* argc_token = strtok(line_copy, " ");
+    p_cmd->argc = 0;
+
+    while (argc_token != NULL) {
+        p_cmd->argc++;
+        argc_token = strtok(NULL, " ");
+    }
+
+    alloc_mem_for_argv(p_cmd);
+
+    line_copy = strdup(line);
+    char* argv_token = strtok(line_copy, " ");
+
+    for (int i = 0; i < p_cmd->argc; i++) {
+        strcpy(p_cmd->argv[i], argv_token);
+        argv_token = strtok(NULL, " ");
+    }
+}
 
 bool find_full_path(command_t* p_cmd) {
     // TODO: