kukemuna-cs50/problems/2024/x/recover@20240313T073054.151925695Z

recover.c

@@ -0,0 +1,66 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define BLOCKSIZE 512
+#define NAMESIZE 8
+
+int main(int argc, char *argv[])
+{
+    if (argc != 2)
+    {
+        printf("Usage: ./recover FILE\n");
+        return 1;
+    }
+
+    FILE *card = fopen(argv[1], "r");
+    if (card == NULL)
+    {
+        printf("Could not open file.\n");
+        return 1;
+    }
+
+    uint8_t buffer[BLOCKSIZE];
+    int count = 0, first = 1;
+    char *filename = malloc(NAMESIZE);
+    FILE *jpg = NULL;
+
+    while (fread(buffer, 1, BLOCKSIZE, card) == BLOCKSIZE)
+    {
+        // JPG header found
+        if (buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff &&
+            (buffer[3] & 0xf0) == 0xe0)
+        {
+            if (first == 1)
+            {
+                sprintf(filename, "%03i.jpg", count);
+                jpg = fopen(filename, "w");
+                if (jpg == NULL)
+                {
+                    printf("Could not open file.\n");
+                    return 1;
+                }
+                first = 0;
+            }
+            else
+            {
+                fclose(jpg);
+                sprintf(filename, "%03i.jpg", count);
+                jpg = fopen(filename, "w");
+                if (jpg == NULL)
+                {
+                    printf("Could not open file.\n");
+                    return 1;
+                }
+            }
+            count++;
+        }
+        if (first == 0) // Ignore data before first JPG header
+        {
+            fwrite(buffer, 1, BLOCKSIZE, jpg);
+        }
+    }
+    fclose(jpg);
+    fclose(card);
+    free(filename);
+}