Version v0.3.21 - Fixing errors with adding entropy to file

src/entropy.c

@@ -560,6 +560,131 @@ int collect_file_entropy(unsigned char* entropy_buffer, size_t target_bytes,
     return 0; // Success
 }
 
+// Add file entropy directly to pad using streaming (for large files)
+int add_file_entropy_streaming(const char* pad_chksum, const char* file_path, size_t file_size, int display_progress) {
+    // Get pad file path
+    char pad_path[1024];
+    char state_path[1024];
+    get_pad_path(pad_chksum, pad_path, state_path);
+
+    // Check if pad exists and get size
+    struct stat pad_stat;
+    if (stat(pad_path, &pad_stat) != 0) {
+        printf("Error: Pad file not found: %s\n", pad_path);
+        return 1;
+    }
+
+    uint64_t pad_size = pad_stat.st_size;
+
+    // Open entropy file for reading
+    FILE* entropy_file = fopen(file_path, "rb");
+    if (!entropy_file) {
+        printf("Error: Cannot open entropy file '%s' for reading\n", file_path);
+        return 1;
+    }
+
+    // Open pad file for read/write
+    FILE* pad_file = fopen(pad_path, "r+b");
+    if (!pad_file) {
+        printf("Error: Cannot open pad file for modification: %s\n", pad_path);
+        fclose(entropy_file);
+        return 1;
+    }
+
+    if (display_progress) {
+        printf("Adding entropy to pad using streaming direct XOR...\n");
+        printf("Pad size: %.2f GB (%lu bytes)\n", (double)pad_size / (1024.0*1024.0*1024.0), pad_size);
+        printf("Entropy file: %.2f GB (%zu bytes)\n", (double)file_size / (1024.0*1024.0*1024.0), file_size);
+    }
+
+    // Process in chunks
+    unsigned char pad_buffer[64 * 1024];
+    unsigned char entropy_buffer[64 * 1024];
+    uint64_t offset = 0;
+    size_t entropy_offset = 0;
+    time_t start_time = time(NULL);
+
+    while (offset < pad_size) {
+        size_t chunk_size = sizeof(pad_buffer);
+        if (pad_size - offset < chunk_size) {
+            chunk_size = pad_size - offset;
+        }
+
+        // Read current pad data
+        if (fread(pad_buffer, 1, chunk_size, pad_file) != chunk_size) {
+            printf("Error: Cannot read pad data at offset %lu\n", offset);
+            fclose(entropy_file);
+            fclose(pad_file);
+            return 1;
+        }
+
+        // Read entropy data (wrap around if file smaller than pad)
+        size_t entropy_read = 0;
+        while (entropy_read < chunk_size) {
+            size_t to_read = chunk_size - entropy_read;
+            if (to_read > sizeof(entropy_buffer)) {
+                to_read = sizeof(entropy_buffer);
+            }
+
+            size_t read_bytes = fread(entropy_buffer, 1, to_read, entropy_file);
+            if (read_bytes == 0) {
+                // Reached end of entropy file, wrap around
+                fseek(entropy_file, 0, SEEK_SET);
+                entropy_offset = 0;
+                read_bytes = fread(entropy_buffer, 1, to_read, entropy_file);
+                if (read_bytes == 0) {
+                    printf("Error: Cannot read from entropy file\n");
+                    fclose(entropy_file);
+                    fclose(pad_file);
+                    return 1;
+                }
+            }
+
+            // XOR this chunk
+            for (size_t i = 0; i < read_bytes; i++) {
+                pad_buffer[entropy_read + i] ^= entropy_buffer[i];
+            }
+
+            entropy_read += read_bytes;
+            entropy_offset += read_bytes;
+        }
+
+        // Seek back and write modified data
+        if (fseek(pad_file, offset, SEEK_SET) != 0) {
+            printf("Error: Cannot seek to offset %lu\n", offset);
+            fclose(entropy_file);
+            fclose(pad_file);
+            return 1;
+        }
+
+        if (fwrite(pad_buffer, 1, chunk_size, pad_file) != chunk_size) {
+            printf("Error: Cannot write modified pad data\n");
+            fclose(entropy_file);
+            fclose(pad_file);
+            return 1;
+        }
+
+        offset += chunk_size;
+
+        // Show progress for large pads
+        if (display_progress && offset % (64 * 1024 * 1024) == 0) {
+            show_progress(offset, pad_size, start_time);
+        }
+    }
+
+    fclose(entropy_file);
+    fclose(pad_file);
+
+    if (display_progress) {
+        show_progress(pad_size, pad_size, start_time);
+        printf("\n✓ Entropy successfully added to pad using streaming direct XOR\n");
+        printf("✓ Pad integrity maintained\n");
+        printf("✓ %zu bytes of entropy distributed across entire pad\n", file_size);
+    }
+
+    return 0;
+}
+
 // Collect entropy by source type with unified interface
 int collect_entropy_by_source(entropy_source_t source, unsigned char* entropy_buffer,
                               size_t target_bytes, size_t* collected_bytes, int display_progress) {