78 lines
2.4 KiB
C++
78 lines
2.4 KiB
C++
// Copyright (c) 2016 The WebM project authors. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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#include "src/float_parser.h"
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#include <cassert>
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#include <cstdint>
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#include <cstring>
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#include <limits>
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#include "src/parser_utils.h"
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#include "webm/element.h"
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#include "webm/reader.h"
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#include "webm/status.h"
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namespace webm {
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FloatParser::FloatParser(double default_value)
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: default_value_(default_value) {}
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Status FloatParser::Init(const ElementMetadata& metadata,
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std::uint64_t max_size) {
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assert(metadata.size == kUnknownElementSize || metadata.size <= max_size);
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if (metadata.size == 0) {
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value_ = default_value_;
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} else if (metadata.size == 4 || metadata.size == 8) {
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uint64_value_ = 0;
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} else {
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return Status(Status::kInvalidElementSize);
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}
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num_bytes_remaining_ = static_cast<int>(metadata.size);
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use_32_bits_ = metadata.size == 4;
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return Status(Status::kOkCompleted);
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}
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Status FloatParser::Feed(Callback* callback, Reader* reader,
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std::uint64_t* num_bytes_read) {
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assert(callback != nullptr);
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assert(reader != nullptr);
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assert(num_bytes_read != nullptr);
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if (num_bytes_remaining_ == 0) {
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return Status(Status::kOkCompleted);
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}
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const Status status = AccumulateIntegerBytes(num_bytes_remaining_, reader,
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&uint64_value_, num_bytes_read);
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num_bytes_remaining_ -= static_cast<int>(*num_bytes_read);
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if (num_bytes_remaining_ == 0) {
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if (use_32_bits_) {
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static_assert(std::numeric_limits<float>::is_iec559,
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"Your compiler does not support 32-bit IEC 559/IEEE 754 "
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"floating point types");
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std::uint32_t uint32_value = static_cast<std::uint32_t>(uint64_value_);
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float float32_value;
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std::memcpy(&float32_value, &uint32_value, 4);
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value_ = float32_value;
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} else {
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static_assert(std::numeric_limits<double>::is_iec559,
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"Your compiler does not support 64-bit IEC 559/IEEE 754 "
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"floating point types");
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std::memcpy(&value_, &uint64_value_, 8);
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}
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}
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return status;
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}
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} // namespace webm
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