Fork of Tangara with customizations
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tangara-fw/src/codecs/source_buffer.cpp

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1.9 KiB

/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include "source_buffer.hpp"
#include <sys/_stdint.h>
#include <algorithm>
#include <cstring>
#include "esp_heap_caps.h"
#include "esp_log.h"
#include "codec.hpp"
namespace codecs {
[[maybe_unused]] static constexpr char kTag[] = "dec_buf";
static constexpr size_t kBufferSize = 1024 * 16;
static constexpr size_t kReadThreshold = 1024 * 8;
SourceBuffer::SourceBuffer()
: buffer_(reinterpret_cast<std::byte*>(
heap_caps_malloc(kBufferSize, MALLOC_CAP_SPIRAM)),
kBufferSize),
bytes_in_buffer_(0),
offset_of_bytes_(0) {
assert(buffer_.data() != nullptr);
}
SourceBuffer::~SourceBuffer() {
free(buffer_.data());
}
auto SourceBuffer::Refill(IStream* src) -> bool {
if (bytes_in_buffer_ > kReadThreshold) {
return false;
}
bool eof = false;
AddBytes([&](cpp::span<std::byte> buf) -> size_t {
ssize_t bytes_read = src->Read(buf);
// Treat read errors as EOF.
eof = bytes_read <= 0;
return bytes_read;
});
return eof;
}
auto SourceBuffer::AddBytes(std::function<size_t(cpp::span<std::byte>)> writer)
-> void {
if (offset_of_bytes_ > 0) {
std::memmove(buffer_.data(), buffer_.data() + offset_of_bytes_,
bytes_in_buffer_);
offset_of_bytes_ = 0;
}
size_t added_bytes = std::invoke(writer, buffer_.subspan(bytes_in_buffer_));
assert(bytes_in_buffer_ + added_bytes <= buffer_.size_bytes());
bytes_in_buffer_ += added_bytes;
}
auto SourceBuffer::ConsumeBytes(
std::function<size_t(cpp::span<std::byte>)> reader) -> void {
size_t bytes_consumed = std::invoke(
reader, buffer_.subspan(offset_of_bytes_, bytes_in_buffer_));
assert(bytes_consumed <= bytes_in_buffer_);
bytes_in_buffer_ -= bytes_consumed;
if (bytes_in_buffer_ == 0) {
offset_of_bytes_ = 0;
} else {
offset_of_bytes_ += bytes_consumed;
}
}
} // namespace codecs