auto import from //depot/cupcake/@135843

1 files changed, 141 insertions, 0 deletions

diff --git a/libdex/DexDataMap.c b/libdex/DexDataMap.c
new file mode 100644
index 000000000..a9d429e18
--- /dev/null
+++ b/libdex/DexDataMap.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Verification-time map of data section items
+ */
+
+#include "DexDataMap.h"
+#include <safe_iop.h>
+#include <stdlib.h>
+
+/*
+ * Allocate and initialize a DexDataMap. Returns NULL on failure.
+ */
+DexDataMap* dexDataMapAlloc(u4 maxCount) {
+    /*
+     * Allocate a single chunk for the DexDataMap per se as well as the
+     * two arrays.
+     */
+    size_t size = 0;
+    DexDataMap* map = NULL;
+
+    /*
+     * Avoiding pulling in safe_iop for safe_iopf.
+     */
+    if (!safe_mul(&size, maxCount, sizeof(u4) + sizeof(u2)) ||
+        !safe_add(&size, size, sizeof(DexDataMap))) {
+      return NULL;
+    }
+
+    map = malloc(size);
+
+    if (map == NULL) {
+        return NULL;
+    }
+
+    map->count = 0;
+    map->max = maxCount;
+    map->offsets = (u4*) (map + 1);
+    map->types = (u2*) (map->offsets + maxCount);
+
+    return map;
+}
+
+/*
+ * Free a DexDataMap.
+ */
+void dexDataMapFree(DexDataMap* map) {
+    /*
+     * Since everything got allocated together, everything can be freed
+     * in one fell swoop. Also, free(NULL) is a nop (per spec), so we
+     * don't have to worry about an explicit test for that.
+     */
+    free(map);
+}
+
+/*
+ * Add a new element to the map. The offset must be greater than the
+ * all previously added offsets.
+ */
+void dexDataMapAdd(DexDataMap* map, u4 offset, u2 type) {
+    assert(map != NULL);
+    assert(map->count < map->max);
+
+    if ((map->count != 0) &&
+            (map->offsets[map->count - 1] >= offset)) {
+        LOGE("Out-of-order data map offset: 0x%x then 0x%x\n",
+                map->offsets[map->count - 1], offset);
+        return;
+    }
+
+    map->offsets[map->count] = offset;
+    map->types[map->count] = type;
+    map->count++;
+}
+
+/*
+ * Get the type associated with the given offset. This returns -1 if
+ * there is no entry for the given offset.
+ */
+int dexDataMapGet(DexDataMap* map, u4 offset) {
+    assert(map != NULL);
+
+    // Note: Signed type is important for max and min.
+    int min = 0;
+    int max = map->count - 1;
+    u4* offsets = map->offsets;
+
+    while (max >= min) {
+        int guessIdx = (min + max) >> 1;
+        u4 guess = offsets[guessIdx];
+
+        if (offset < guess) {
+            max = guessIdx - 1;
+        } else if (offset > guess) {
+            min = guessIdx + 1;
+        } else {
+            // We have a winner!
+            return map->types[guessIdx];
+        }
+    }
+
+    // No match.
+    return -1;
+}
+
+/*
+ * Verify that there is an entry in the map, mapping the given offset to
+ * the given type. This will return true if such an entry exists and
+ * return false as well as log an error if not.
+ */
+bool dexDataMapVerify(DexDataMap* map, u4 offset, u2 type) {
+    int found = dexDataMapGet(map, offset);
+
+    if (found == type) {
+        return true;
+    }
+
+    if (found < 0) {
+        LOGE("No data map entry found @ 0x%x; expected %x\n",
+                offset, type);
+    } else {
+        LOGE("Unexpected data map entry @ 0x%x: expected %x, found %x\n",
+                offset, type, found);
+    }
+
+    return false;
+}