diff options
Diffstat (limited to 'src/util')
| -rw-r--r-- | src/util/PeakBuffer.cxx | 143 | ||||
| -rw-r--r-- | src/util/PeakBuffer.hxx | 66 |
2 files changed, 209 insertions, 0 deletions
diff --git a/src/util/PeakBuffer.cxx b/src/util/PeakBuffer.cxx new file mode 100644 index 000000000..a3659b8f4 --- /dev/null +++ b/src/util/PeakBuffer.cxx @@ -0,0 +1,143 @@ +/* + * Copyright (C) 2003-2013 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that 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, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "PeakBuffer.hxx" +#include "HugeAllocator.hxx" +#include "fifo_buffer.h" + +#include <algorithm> + +#include <assert.h> +#include <stdint.h> +#include <string.h> + +PeakBuffer::~PeakBuffer() +{ + if (normal_buffer != nullptr) + fifo_buffer_free(normal_buffer); + + if (peak_buffer != nullptr) + HugeFree(peak_buffer, peak_size); +} + +bool +PeakBuffer::IsEmpty() const +{ + return (normal_buffer == nullptr || + fifo_buffer_is_empty(normal_buffer)) && + (peak_buffer == nullptr || + fifo_buffer_is_empty(peak_buffer)); +} + +const void * +PeakBuffer::Read(size_t *length_r) const +{ + if (normal_buffer != nullptr) { + const void *p = fifo_buffer_read(normal_buffer, length_r); + if (p != nullptr) + return p; + } + + if (peak_buffer != nullptr) { + const void *p = fifo_buffer_read(peak_buffer, length_r); + if (p != nullptr) + return p; + } + + return nullptr; +} + +void +PeakBuffer::Consume(size_t length) +{ + if (normal_buffer != nullptr && !fifo_buffer_is_empty(normal_buffer)) { + fifo_buffer_consume(normal_buffer, length); + return; + } + + if (peak_buffer != nullptr && !fifo_buffer_is_empty(peak_buffer)) { + fifo_buffer_consume(peak_buffer, length); + if (fifo_buffer_is_empty(peak_buffer)) { + HugeFree(peak_buffer, peak_size); + peak_buffer = nullptr; + } + + return; + } +} + +static size_t +AppendTo(fifo_buffer *buffer, const void *data, size_t length) +{ + assert(data != nullptr); + assert(length > 0); + + size_t total = 0; + + do { + size_t max_length; + void *p = fifo_buffer_write(buffer, &max_length); + if (p == nullptr) + break; + + const size_t nbytes = std::min(length, max_length); + memcpy(p, data, nbytes); + fifo_buffer_append(buffer, nbytes); + + data = (const uint8_t *)data + nbytes; + length -= nbytes; + total += nbytes; + } while (length > 0); + + return total; +} + +bool +PeakBuffer::Append(const void *data, size_t length) +{ + if (length == 0) + return true; + + if (peak_buffer != nullptr && !fifo_buffer_is_empty(peak_buffer)) { + size_t nbytes = AppendTo(peak_buffer, data, length); + return nbytes == length; + } + + if (normal_buffer == nullptr) + normal_buffer = fifo_buffer_new(normal_size); + + size_t nbytes = AppendTo(normal_buffer, data, length); + if (nbytes > 0) { + data = (const uint8_t *)data + nbytes; + length -= nbytes; + if (length == 0) + return true; + } + + if (peak_buffer == nullptr && peak_size > 0) { + peak_buffer = (fifo_buffer *)HugeAllocate(peak_size); + if (peak_buffer == nullptr) + return false; + + fifo_buffer_init(peak_buffer, peak_size); + } + + nbytes = AppendTo(peak_buffer, data, length); + return nbytes == length; +} diff --git a/src/util/PeakBuffer.hxx b/src/util/PeakBuffer.hxx new file mode 100644 index 000000000..0fbba8d77 --- /dev/null +++ b/src/util/PeakBuffer.hxx @@ -0,0 +1,66 @@ +/* + * Copyright (C) 2003-2013 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that 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, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef MPD_PEAK_BUFFER_HXX +#define MPD_PEAK_BUFFER_HXX + +#include "gcc.h" + +#include <stddef.h> + +struct fifo_buffer; + +/** + * A FIFO-like buffer that will allocate more memory on demand to + * allow large peaks. This second buffer will be given back to the + * kernel when it has been consumed. + */ +class PeakBuffer { + size_t normal_size, peak_size; + + fifo_buffer *normal_buffer, *peak_buffer; + +public: + PeakBuffer(size_t _normal_size, size_t _peak_size) + :normal_size(_normal_size), peak_size(_peak_size), + normal_buffer(nullptr), peak_buffer(nullptr) {} + + PeakBuffer(PeakBuffer &&other) + :normal_size(other.normal_size), peak_size(other.peak_size), + normal_buffer(other.normal_buffer), + peak_buffer(other.peak_buffer) { + other.normal_buffer = nullptr; + other.peak_buffer = nullptr; + } + + ~PeakBuffer(); + + PeakBuffer(const PeakBuffer &) = delete; + PeakBuffer &operator=(const PeakBuffer &) = delete; + + gcc_pure + bool IsEmpty() const; + + const void *Read(size_t *length_r) const; + void Consume(size_t length); + + bool Append(const void *data, size_t length); +}; + +#endif |