Huge savedata driver refactor

bdk/libs/nx_savedata/allocation_table_iterator.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2019-2020 shchmue
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ISC License
+
+hactool Copyright (c) 2018, SciresM
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "allocation_table_iterator.h"
+
+#include <gfx_utils.h>
+
+bool save_allocation_table_iterator_begin(allocation_table_iterator_ctx_t *ctx, allocation_table_ctx_t *table, uint32_t initial_block) {
+    ctx->fat = table;
+    ctx->physical_block = initial_block;
+    ctx->virtual_block = 0;
+
+    allocation_table_entry_t entry;
+    ctx->current_segment_size = save_allocation_table_read_entry_with_length(ctx->fat, initial_block, &entry);
+    if (ctx->current_segment_size == 0) {
+        EPRINTF("Invalid entry detected in allocation table!");
+        return false;
+    }
+    ctx->next_block = entry.next;
+    ctx->prev_block = entry.prev;
+
+    if (ctx->prev_block != 0xFFFFFFFF) {
+        EPRINTFARGS("Attempted to start FAT iteration from\n invalid block %x!", initial_block);
+        return false;
+    }
+    return true;
+}
+
+bool save_allocation_table_iterator_move_next(allocation_table_iterator_ctx_t *ctx) {
+    if (ctx->next_block == 0xFFFFFFFF)
+        return false;
+
+    ctx->virtual_block += ctx->current_segment_size;
+    ctx->physical_block = ctx->next_block;
+
+    allocation_table_entry_t entry;
+    ctx->current_segment_size = save_allocation_table_read_entry_with_length(ctx->fat, ctx->next_block, &entry);
+    if (ctx->current_segment_size == 0) {
+        EPRINTF("Invalid entry detected in allocation table!");
+        return false;
+    }
+    ctx->next_block = entry.next;
+    ctx->prev_block = entry.prev;
+
+    return true;
+}
+
+bool save_allocation_table_iterator_move_prev(allocation_table_iterator_ctx_t *ctx) {
+    if (ctx->prev_block == 0xFFFFFFFF)
+        return false;
+
+    ctx->physical_block = ctx->prev_block;
+
+    allocation_table_entry_t entry;
+    ctx->current_segment_size = save_allocation_table_read_entry_with_length(ctx->fat, ctx->prev_block, &entry);
+    if (ctx->current_segment_size == 0) {
+        EPRINTF("Invalid entry detected in allocation table!");
+        return false;
+    }
+    ctx->next_block = entry.next;
+    ctx->prev_block = entry.prev;
+
+    ctx->virtual_block -= ctx->current_segment_size;
+
+    return true;
+}
+
+bool save_allocation_table_iterator_seek(allocation_table_iterator_ctx_t *ctx, uint32_t block) {
+    for ( ; ; ) {
+        if (block < ctx->virtual_block) {
+            if (!save_allocation_table_iterator_move_prev(ctx))
+                return false;
+        } else if (block >= ctx->virtual_block + ctx->current_segment_size) {
+            if (!save_allocation_table_iterator_move_next(ctx))
+                return false;
+        } else {
+            return true;
+        }
+    }
+}