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-rw-r--r--media/libyuv/source/mjpeg_validate.cc71
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diff --git a/media/libyuv/source/mjpeg_validate.cc b/media/libyuv/source/mjpeg_validate.cc
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+/*
+ * Copyright 2012 The LibYuv Project Authors. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "libyuv/mjpeg_decoder.h"
+
+#include <string.h> // For memchr.
+
+#ifdef __cplusplus
+namespace libyuv {
+extern "C" {
+#endif
+
+// Helper function to scan for EOI marker (0xff 0xd9).
+static LIBYUV_BOOL ScanEOI(const uint8* sample, size_t sample_size) {
+ if (sample_size >= 2) {
+ const uint8* end = sample + sample_size - 1;
+ const uint8* it = sample;
+ while (it < end) {
+ // TODO(fbarchard): scan for 0xd9 instead.
+ it = static_cast<const uint8 *>(memchr(it, 0xff, end - it));
+ if (it == NULL) {
+ break;
+ }
+ if (it[1] == 0xd9) {
+ return LIBYUV_TRUE; // Success: Valid jpeg.
+ }
+ ++it; // Skip over current 0xff.
+ }
+ }
+ // ERROR: Invalid jpeg end code not found. Size sample_size
+ return LIBYUV_FALSE;
+}
+
+// Helper function to validate the jpeg appears intact.
+LIBYUV_BOOL ValidateJpeg(const uint8* sample, size_t sample_size) {
+ // Maximum size that ValidateJpeg will consider valid.
+ const size_t kMaxJpegSize = 0x7fffffffull;
+ const size_t kBackSearchSize = 1024;
+ if (sample_size < 64 || sample_size > kMaxJpegSize || !sample) {
+ // ERROR: Invalid jpeg size: sample_size
+ return LIBYUV_FALSE;
+ }
+ if (sample[0] != 0xff || sample[1] != 0xd8) { // SOI marker
+ // ERROR: Invalid jpeg initial start code
+ return LIBYUV_FALSE;
+ }
+
+ // Look for the End Of Image (EOI) marker near the end of the buffer.
+ if (sample_size > kBackSearchSize) {
+ if (ScanEOI(sample + sample_size - kBackSearchSize, kBackSearchSize)) {
+ return LIBYUV_TRUE; // Success: Valid jpeg.
+ }
+ // Reduce search size for forward search.
+ sample_size = sample_size - kBackSearchSize + 1;
+ }
+ // Step over SOI marker and scan for EOI.
+ return ScanEOI(sample + 2, sample_size - 2);
+}
+
+#ifdef __cplusplus
+} // extern "C"
+} // namespace libyuv
+#endif
+