src/starboard/configuration_constants.h - cobalt - Git at Google

 // Copyright 2019 The Cobalt Authors. All Rights Reserved.
 //
 // 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.

 // Module Overview: Starboard Configuration Variables module
 //
 // Declares all configuration variables we will need to use at runtime.
 // These variables describe the current platform in detail to allow cobalt to
 // make runtime decisions based on per platform configurations.

 #ifndef STARBOARD_CONFIGURATION_CONSTANTS_H_
 #define STARBOARD_CONFIGURATION_CONSTANTS_H_

 #include "starboard/types.h"

 #if SB_API_VERSION >= 12

 // Determines the threshhold of allocation size that should be done with mmap
 // (if available), rather than allocated within the core heap.
 extern const size_t kSbDefaultMmapThreshold;

 // The current platform's maximum length of the name of a single directory
 // entry, not including the absolute path.
 extern const int32_t kSbFileMaxName;

 // The current platform's maximum number of files that can be opened at the
 // same time by one process.
 extern const uint32_t kSbFileMaxOpen;

 // The current platform's alternate file path component separator character.
 // This is like SB_FILE_SEP_CHAR, except if your platform supports an alternate
 // character, then you can place that here. For example, on windows machines,
 // the primary separator character is probably '\', but the alternate is '/'.
 extern const char kSbFileAltSepChar;

 // The string form of SB_FILE_ALT_SEP_CHAR.
 extern const char* kSbFileAltSepString;

 // The current platform's maximum length of an absolute path.
 extern const uint32_t kSbFileMaxPath;

 // The current platform's file path component separator character. This is the
 // character that appears after a directory in a file path. For example, the
 // absolute canonical path of the file "/path/to/a/file.txt" uses '/' as a path
 // component separator character.
 extern const char kSbFileSepChar;

 // The string form of SB_FILE_SEP_CHAR.
 extern const char* kSbFileSepString;

 // Allow ac3 and ec3 support
 extern const bool kSbHasAc3Audio;

 // Specifies whether this platform has webm/vp9 support.  This should be set to
 // non-zero on platforms with webm/vp9 support.
 extern const bool kSbHasMediaWebmVp9Support;

 // Whether the current platform supports thread priorities.
 extern const bool kSbHasThreadPrioritySupport;

 // Determines the alignment that allocations should have on this platform.
 extern const size_t kSbMallocAlignment;

 // The maximum number of thread local storage keys supported by this platform.
 // This comes from _POSIX_THREAD_KEYS_MAX. The value of PTHREAD_KEYS_MAX is
 // higher, but unit tests show that the implementation doesn't support nearly
 // as many keys.
 extern const uint32_t kSbMaxThreadLocalKeys;

 // The maximum length of the name for a thread, including the NULL-terminator.
 extern const int32_t kSbMaxThreadNameLength;

 // Defines the path where memory debugging logs should be written to.
 extern const char* kSbMemoryLogPath;

 // The maximum audio bitrate the platform can decode.  The following value
 // equals to 5M bytes per seconds which is more than enough for compressed
 // audio.
 extern const uint32_t kSbMediaMaxAudioBitrateInBitsPerSecond;

 // The maximum video bitrate the platform can decode.  The following value
 // equals to 8M bytes per seconds which is more than enough for compressed
 // video.
 extern const uint32_t kSbMediaMaxVideoBitrateInBitsPerSecond;

 // Specify the number of video frames to be cached during playback.  A large
 // value leads to more stable fps but also causes the app to use more memory.
 extern const uint32_t kSbMediaMaximumVideoFrames;

 // The encoded video frames are compressed in different ways, so their decoding
 // time can vary a lot.  Occasionally a single frame can take longer time to
 // decode than the average time per frame.  The player has to cache some frames
 // to account for such inconsistency.  The number of frames being cached are
 // controlled by SB_MEDIA_MAXIMUM_VIDEO_PREROLL_FRAMES and
 // SB_MEDIA_MAXIMUM_VIDEO_FRAMES.
 //
 // Specify the number of video frames to be cached before the playback starts.
 // Note that setting this value too large may increase the playback start delay.
 extern const uint32_t kSbMediaMaximumVideoPrerollFrames;

 // Specifies how video frame buffers must be aligned on this platform.
 extern const uint32_t kSbMediaVideoFrameAlignment;

 // The memory page size, which controls the size of chunks on memory that
 // allocators deal with, and the alignment of those chunks. This doesn't have to
 // be the hardware-defined physical page size, but it should be a multiple of
 // it.
 extern const size_t kSbMemoryPageSize;

 // Specifies the network receive buffer size in bytes, set via
 // SbSocketSetReceiveBufferSize().
 //
 // Setting this to 0 indicates that SbSocketSetReceiveBufferSize() should
 // not be called. Use this for OSs (such as Linux) where receive buffer
 // auto-tuning is better.
 //
 // On some platforms, this may affect max TCP window size which may
 // dramatically affect throughput in the presence of latency.
 //
 // If your platform does not have a good TCP auto-tuning mechanism,
 // a setting of (128 * 1024) here is recommended.
 extern const uint32_t kSbNetworkReceiveBufferSize;

 // Defines the maximum number of simultaneous threads for this platform. Some
 // platforms require sharing thread handles with other kinds of system handles,
 // like mutexes, so we want to keep this manageable.
 extern const uint32_t kSbMaxThreads;

 // Specifies the preferred byte order of color channels in a pixel. Refer to
 // starboard/configuration.h for the possible values. EGL/GLES platforms should
 // generally prefer a byte order of RGBA, regardless of endianness.
 extern const int kSbPreferredRgbaByteOrder;

 // The current platform's search path component separator character. When
 // specifying an ordered list of absolute paths of directories to search for a
 // given reason, this is the character that appears between entries. For
 // example, the search path of "/etc/search/first:/etc/search/second" uses ':'
 // as a search path component separator character.
 #ifdef __cplusplus
 extern "C" {
 #endif
 extern const char kSbPathSepChar;
 #ifdef __cplusplus
 }  // extern "C"
 #endif

 // The string form of SB_PATH_SEP_CHAR.
 extern const char* kSbPathSepString;

 // The maximum number of users that can be signed in at the same time.
 extern const uint32_t kSbUserMaxSignedIn;

 #endif  // SB_API_VERSION >= 12

 #endif  // STARBOARD_CONFIGURATION_CONSTANTS_H_
	// Copyright 2019 The Cobalt Authors. All Rights Reserved.
	//
	// 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.

	// Module Overview: Starboard Configuration Variables module
	//
	// Declares all configuration variables we will need to use at runtime.
	// These variables describe the current platform in detail to allow cobalt to
	// make runtime decisions based on per platform configurations.

	#ifndef STARBOARD_CONFIGURATION_CONSTANTS_H_
	#define STARBOARD_CONFIGURATION_CONSTANTS_H_

	#include "starboard/types.h"

	#if SB_API_VERSION >= 12

	// Determines the threshhold of allocation size that should be done with mmap
	// (if available), rather than allocated within the core heap.
	extern const size_t kSbDefaultMmapThreshold;

	// The current platform's maximum length of the name of a single directory
	// entry, not including the absolute path.
	extern const int32_t kSbFileMaxName;

	// The current platform's maximum number of files that can be opened at the
	// same time by one process.
	extern const uint32_t kSbFileMaxOpen;

	// The current platform's alternate file path component separator character.
	// This is like SB_FILE_SEP_CHAR, except if your platform supports an alternate
	// character, then you can place that here. For example, on windows machines,
	// the primary separator character is probably '\', but the alternate is '/'.
	extern const char kSbFileAltSepChar;

	// The string form of SB_FILE_ALT_SEP_CHAR.
	extern const char* kSbFileAltSepString;

	// The current platform's maximum length of an absolute path.
	extern const uint32_t kSbFileMaxPath;

	// The current platform's file path component separator character. This is the
	// character that appears after a directory in a file path. For example, the
	// absolute canonical path of the file "/path/to/a/file.txt" uses '/' as a path
	// component separator character.
	extern const char kSbFileSepChar;

	// The string form of SB_FILE_SEP_CHAR.
	extern const char* kSbFileSepString;

	// Allow ac3 and ec3 support
	extern const bool kSbHasAc3Audio;

	// Specifies whether this platform has webm/vp9 support. This should be set to
	// non-zero on platforms with webm/vp9 support.
	extern const bool kSbHasMediaWebmVp9Support;

	// Whether the current platform supports thread priorities.
	extern const bool kSbHasThreadPrioritySupport;

	// Determines the alignment that allocations should have on this platform.
	extern const size_t kSbMallocAlignment;

	// The maximum number of thread local storage keys supported by this platform.
	// This comes from _POSIX_THREAD_KEYS_MAX. The value of PTHREAD_KEYS_MAX is
	// higher, but unit tests show that the implementation doesn't support nearly
	// as many keys.
	extern const uint32_t kSbMaxThreadLocalKeys;

	// The maximum length of the name for a thread, including the NULL-terminator.
	extern const int32_t kSbMaxThreadNameLength;

	// Defines the path where memory debugging logs should be written to.
	extern const char* kSbMemoryLogPath;

	// The maximum audio bitrate the platform can decode. The following value
	// equals to 5M bytes per seconds which is more than enough for compressed
	// audio.
	extern const uint32_t kSbMediaMaxAudioBitrateInBitsPerSecond;

	// The maximum video bitrate the platform can decode. The following value
	// equals to 8M bytes per seconds which is more than enough for compressed
	// video.
	extern const uint32_t kSbMediaMaxVideoBitrateInBitsPerSecond;

	// Specify the number of video frames to be cached during playback. A large
	// value leads to more stable fps but also causes the app to use more memory.
	extern const uint32_t kSbMediaMaximumVideoFrames;

	// The encoded video frames are compressed in different ways, so their decoding
	// time can vary a lot. Occasionally a single frame can take longer time to
	// decode than the average time per frame. The player has to cache some frames
	// to account for such inconsistency. The number of frames being cached are
	// controlled by SB_MEDIA_MAXIMUM_VIDEO_PREROLL_FRAMES and
	// SB_MEDIA_MAXIMUM_VIDEO_FRAMES.
	//
	// Specify the number of video frames to be cached before the playback starts.
	// Note that setting this value too large may increase the playback start delay.
	extern const uint32_t kSbMediaMaximumVideoPrerollFrames;

	// Specifies how video frame buffers must be aligned on this platform.
	extern const uint32_t kSbMediaVideoFrameAlignment;

	// The memory page size, which controls the size of chunks on memory that
	// allocators deal with, and the alignment of those chunks. This doesn't have to
	// be the hardware-defined physical page size, but it should be a multiple of
	// it.
	extern const size_t kSbMemoryPageSize;

	// Specifies the network receive buffer size in bytes, set via
	// SbSocketSetReceiveBufferSize().
	//
	// Setting this to 0 indicates that SbSocketSetReceiveBufferSize() should
	// not be called. Use this for OSs (such as Linux) where receive buffer
	// auto-tuning is better.
	//
	// On some platforms, this may affect max TCP window size which may
	// dramatically affect throughput in the presence of latency.
	//
	// If your platform does not have a good TCP auto-tuning mechanism,
	// a setting of (128 * 1024) here is recommended.
	extern const uint32_t kSbNetworkReceiveBufferSize;

	// Defines the maximum number of simultaneous threads for this platform. Some
	// platforms require sharing thread handles with other kinds of system handles,
	// like mutexes, so we want to keep this manageable.
	extern const uint32_t kSbMaxThreads;

	// Specifies the preferred byte order of color channels in a pixel. Refer to
	// starboard/configuration.h for the possible values. EGL/GLES platforms should
	// generally prefer a byte order of RGBA, regardless of endianness.
	extern const int kSbPreferredRgbaByteOrder;

	// The current platform's search path component separator character. When
	// specifying an ordered list of absolute paths of directories to search for a
	// given reason, this is the character that appears between entries. For
	// example, the search path of "/etc/search/first:/etc/search/second" uses ':'
	// as a search path component separator character.
	#ifdef __cplusplus
	extern "C" {
	#endif
	extern const char kSbPathSepChar;
	#ifdef __cplusplus
	} // extern "C"
	#endif

	// The string form of SB_PATH_SEP_CHAR.
	extern const char* kSbPathSepString;

	// The maximum number of users that can be signed in at the same time.
	extern const uint32_t kSbUserMaxSignedIn;

	#endif // SB_API_VERSION >= 12

	#endif // STARBOARD_CONFIGURATION_CONSTANTS_H_