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Diffstat (limited to 'node_modules/capnp-ts/src/constants.ts')
| -rw-r--r-- | node_modules/capnp-ts/src/constants.ts | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/node_modules/capnp-ts/src/constants.ts b/node_modules/capnp-ts/src/constants.ts new file mode 100644 index 0000000..24315de --- /dev/null +++ b/node_modules/capnp-ts/src/constants.ts @@ -0,0 +1,121 @@ +/** + * @author jdiaz5513 + */ + +// Perform some bit gymnastics to determine the native endian format. + +const tmpWord = new DataView(new ArrayBuffer(8)); +new Uint16Array(tmpWord.buffer)[0] = 0x0102; + +/** Default size (in bytes) for newly allocated segments. */ + +export const DEFAULT_BUFFER_SIZE = 4096; + +export const DEFAULT_DECODE_LIMIT = 64 << 20; // 64 MiB + +/** + * Limit to how deeply nested pointers are allowed to be. The root struct of a message will start at this value, and it + * is decremented as pointers are dereferenced. + */ + +export const DEFAULT_DEPTH_LIMIT = 64; + +/** + * Limit to the number of **bytes** that can be traversed in a single message. This is necessary to prevent certain + * classes of DoS attacks where maliciously crafted data can be self-referencing in a way that wouldn't trigger the + * depth limit. + * + * For this reason, it is advised to cache pointers into variables and not constantly dereference them since the + * message's traversal limit gets decremented each time. + */ + +export const DEFAULT_TRAVERSE_LIMIT = 64 << 20; // 64 MiB + +/** + * When allocating array buffers dynamically (while packing or in certain Arena implementations) the previous buffer's + * size is multiplied by this number to determine the next buffer's size. This is chosen to keep both time spent + * reallocating and wasted memory to a minimum. + * + * Smaller numbers would save memory at the expense of CPU time. + */ + +export const GROWTH_FACTOR = 1.5; + +/** A bitmask applied to obtain the size of a list pointer. */ + +export const LIST_SIZE_MASK = 0x00000007; + +/** Maximum number of bytes to dump at once when dumping array buffers to string. */ + +export const MAX_BUFFER_DUMP_BYTES = 8192; + +/** The maximum value for a 32-bit integer. */ + +export const MAX_INT32 = 0x7fffffff; + +/** The maximum value for a 32-bit unsigned integer. */ + +export const MAX_UINT32 = 0xffffffff; + +/** The largest integer that can be precisely represented in JavaScript. */ + +export const MAX_SAFE_INTEGER = 9007199254740991; + +/** Maximum limit on the number of segments in a message stream. */ + +export const MAX_STREAM_SEGMENTS = 512; + +/** The smallest integer that can be precisely represented in JavaScript. */ + +export const MIN_SAFE_INTEGER = -9007199254740991; + +/** Minimum growth increment for a SingleSegmentArena. */ + +export const MIN_SINGLE_SEGMENT_GROWTH = 4096; + +/** + * This will be `true` if the machine running this code stores numbers natively in little-endian format. This is useful + * for some numeric type conversions when the endianness does not affect the output. Using the native endianness for + * these operations is _slightly_ faster. + */ + +export const NATIVE_LITTLE_ENDIAN = tmpWord.getUint8(0) === 0x02; + +/** + * When packing a message, this is the number of zero bytes required after a SPAN (0xff) tag is written to the packed + * message before the span is terminated. + * + * This little detail is left up to the implementation because it can be tuned for performance. Setting this to a higher + * value may help with messages that contain a ton of text/data. + * + * It is imperative to never set this below 1 or else BAD THINGS. You have been warned. + */ + +export const PACK_SPAN_THRESHOLD = 2; + +/** + * How far to travel into a nested pointer structure during a deep copy; when this limit is exhausted the copy + * operation will throw an error. + */ + +export const POINTER_COPY_LIMIT = 32; + +/** A bitmask for looking up the double-far flag on a far pointer. */ + +export const POINTER_DOUBLE_FAR_MASK = 0x00000004; + +/** A bitmask for looking up the pointer type. */ + +export const POINTER_TYPE_MASK = 0x00000003; + +/** Used for some 64-bit conversions, equal to Math.pow(2, 32). */ + +export const VAL32 = 0x100000000; + +/** The maximum value allowed for depth traversal limits. */ + +export const MAX_DEPTH = MAX_INT32; + +/** The maximum byte length for a single segment. */ + +export const MAX_SEGMENT_LENGTH = MAX_UINT32; |
