From f981262907a207963e9f90553772c182810d2349 Mon Sep 17 00:00:00 2001
From: Guamss <guams@duck.com>
Date: Sun, 10 May 2026 15:07:25 +0200
Subject: [PATCH] add: grep

---
 src/const.h |  1 +
 src/disk.c  | 69 +++++++++++++++++++++++++++++++++++++++++++++++++----
 src/disk.h  |  1 +
 src/exec.c  |  5 ++--
 4 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/src/const.h b/src/const.h
index 832f163..5a1b771 100644
--- a/src/const.h
+++ b/src/const.h
@@ -10,6 +10,7 @@
 #define TYPE_DIRECTORY 3
 #define TYPE_SYMBOLIC_LINK 4
 
+#define COLOR_RED "\e[0;31m"
 #define COLOR_BLUE "\x1b[34m"
 #define COLOR_GREEN "\x1b[32m"
 #define ESCAPE_COLOR "\x1b[0m"
diff --git a/src/disk.c b/src/disk.c
index f8613e1..a1f8b5e 100644
--- a/src/disk.c
+++ b/src/disk.c
@@ -525,11 +525,10 @@ char *read_in_file(disk *d, int file_index) {
 int do_cat(disk *disk, char *path_to_file) {
 
   if (path_to_file == NULL) {
-    char buffer[4096];
-    ssize_t bytes_read;
+    char buffer[1024];
 
-    while ((bytes_read = read(STDIN_FILENO, buffer, sizeof(buffer))) > 0) {
-      write(STDOUT_FILENO, buffer, bytes_read);
+    while (fgets(buffer, 1024, stdin)) {
+      dprintf(STDOUT_FILENO, "%s", buffer);
     }
   }
 
@@ -557,6 +556,68 @@ int do_cat(disk *disk, char *path_to_file) {
   return 1;
 }
 
+int *find_all_occ_of_pattern(char *pattern, char *txt) {
+  int nbr_occ = 0;
+  int *idx_occs = NULL;
+  int pat_len = strlen(pattern);
+  int txt_len = strlen(txt);
+  if (pat_len == 0)
+    return NULL;
+  for (int i = 0; i <= txt_len - pat_len; i++) {
+    if (strncmp(&txt[i], pattern, pat_len) == 0) {
+      nbr_occ++;
+      idx_occs = realloc(idx_occs, (nbr_occ + 1) * sizeof(int));
+      if (idx_occs == NULL)
+        exit(EXIT_FAILURE);
+      idx_occs[nbr_occ - 1] = i;
+      idx_occs[nbr_occ] = -1;
+    }
+  }
+  return idx_occs;
+}
+
+int do_grep(char *pattern) {
+    char buffer[1024];
+    if (pattern == NULL) {
+        dprintf(STDERR_FILENO, "grep: pattern missing\n");
+        return -1;
+    }
+    ssize_t n;
+    while ((n = read(STDIN_FILENO, buffer, sizeof(buffer) - 1)) > 0) {
+        buffer[n] = '\0';
+
+        int *occs = find_all_occ_of_pattern(pattern, buffer);
+        
+        if (occs == NULL || occs[0] == -1) {
+            continue; 
+        }
+
+        int nbr_occ = 0;
+        for (nbr_occ = 0; occs[nbr_occ] != -1; nbr_occ++);
+        
+        int new_size = n + (nbr_occ * (strlen(COLOR_RED) + strlen(ESCAPE_COLOR)));
+        char *colored_line = malloc(new_size + 1);
+        
+        int last_pos = 0;
+        colored_line[0] = '\0';
+
+        for (int i = 0; occs[i] != -1; i++) {
+            int pos = occs[i];
+            strncat(colored_line, buffer + last_pos, pos - last_pos);
+            strcat(colored_line, COLOR_RED);
+            strncat(colored_line, buffer + pos, strlen(pattern));
+            strcat(colored_line, ESCAPE_COLOR);
+            
+            last_pos = pos + strlen(pattern);
+        }
+        strcat(colored_line, buffer + last_pos);
+        write(STDOUT_FILENO, colored_line, strlen(colored_line));
+        free(occs);
+        free(colored_line);
+    }
+    return 1;
+}
+
 /**
  * @brief Créer un fichier "disk" de taille MAX_BYTES_PER_BLOC * MAX_BLOCS,
  * renvoi ce disque
diff --git a/src/disk.h b/src/disk.h
index 4a75888..6792d9f 100644
--- a/src/disk.h
+++ b/src/disk.h
@@ -21,5 +21,6 @@ int do_df(disk *d);
 int do_rm(disk *disk, char *filepath);
 int do_rmdir(disk *disk, char *filepath);
 int do_cat(disk *disk, char* path_to_file);
+int do_grep(char* arg);
 int find_dir_inode_by_name(char *name, int dir_index, disk *d);
 void persist_on_disk(disk* d);
\ No newline at end of file
diff --git a/src/exec.c b/src/exec.c
index 1b65edf..307ee71 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -6,9 +6,6 @@
 #include <string.h>
 #include <unistd.h>
 
-const char *cmd_list[] = {"ls",  "touch", "df", "rm", "rmdir",
-                          "cat", "echo",  "cd", 0};
-
 int do_cd(disk *d, char *path) {
   char full_path[1024] = {0};
 
@@ -106,6 +103,8 @@ int exec_cmd_job(disk *d, char **args) {
     persist_on_disk(d);
   } else if (strcmp("cat", args[0]) == 0) {
     do_cat(d, args[1]);
+  } else if(strcmp("grep", args[0]) == 0) {
+    do_grep(args[1]);
   } else {
     dprintf(STDERR_FILENO, "%s: command does not exist\n", args[0]);
     return 0;