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refactor: Removes dead code paths from number serialization #399

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Merged
merged 1 commit into from
Sep 28, 2020
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refactor: Removes dead code paths from number serialization #399

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4 changes: 2 additions & 2 deletions src/constants.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,9 @@ export const BSON_INT64_MIN = -Math.pow(2, 63);

// JS MAX PRECISE VALUES
// Any integer up to 2^53 can be precisely represented by a double.
export const JS_INT_MAX = Number.MAX_SAFE_INTEGER + 1;
export const JS_INT_MAX = Math.pow(2, 53);
// Any integer down to -2^53 can be precisely represented by a double.
export const JS_INT_MIN = Number.MIN_SAFE_INTEGER - 1;
export const JS_INT_MIN = -Math.pow(2, 53);

/** Number BSON Type */
export const BSON_DATA_NUMBER = 1;
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77 changes: 18 additions & 59 deletions src/parser/serializer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -80,68 +80,27 @@ function serializeNumber(
isArray?: boolean
) {
// We have an integer value
// TODO(NODE-2769): Issue serializing large integers as doubles
// TODO(NODE-2529): Add support for big int
if (
Math.floor(value) === value &&
value >= constants.JS_INT_MIN &&
value <= constants.JS_INT_MAX
Number.isInteger(value) &&
value >= constants.BSON_INT32_MIN &&
value <= constants.BSON_INT32_MAX
) {
// If the value fits in 32 bits encode as int, if it fits in a double
// encode it as a double, otherwise long
if (value >= constants.BSON_INT32_MIN && value <= constants.BSON_INT32_MAX) {
// Set int type 32 bits or less
buffer[index++] = constants.BSON_DATA_INT;
// Number of written bytes
const numberOfWrittenBytes = !isArray
? buffer.write(key, index, undefined, 'utf8')
: buffer.write(key, index, undefined, 'ascii');
// Encode the name
index = index + numberOfWrittenBytes;
buffer[index++] = 0;
// Write the int value
buffer[index++] = value & 0xff;
buffer[index++] = (value >> 8) & 0xff;
buffer[index++] = (value >> 16) & 0xff;
buffer[index++] = (value >> 24) & 0xff;
} else if (value >= constants.JS_INT_MIN && value <= constants.JS_INT_MAX) {
// Encode as double
buffer[index++] = constants.BSON_DATA_NUMBER;
// Number of written bytes
const numberOfWrittenBytes = !isArray
? buffer.write(key, index, undefined, 'utf8')
: buffer.write(key, index, undefined, 'ascii');
// Encode the name
index = index + numberOfWrittenBytes;
buffer[index++] = 0;
// Write float
writeIEEE754(buffer, value, index, 'little', 52, 8);
// Adjust index
index = index + 8;
} else {
// Set long type
buffer[index++] = constants.BSON_DATA_LONG;
// Number of written bytes
const numberOfWrittenBytes = !isArray
? buffer.write(key, index, undefined, 'utf8')
: buffer.write(key, index, undefined, 'ascii');
// Encode the name
index = index + numberOfWrittenBytes;
buffer[index++] = 0;
const longVal = Long.fromNumber(value);
const lowBits = longVal.getLowBits();
const highBits = longVal.getHighBits();
// Encode low bits
buffer[index++] = lowBits & 0xff;
buffer[index++] = (lowBits >> 8) & 0xff;
buffer[index++] = (lowBits >> 16) & 0xff;
buffer[index++] = (lowBits >> 24) & 0xff;
// Encode high bits
buffer[index++] = highBits & 0xff;
buffer[index++] = (highBits >> 8) & 0xff;
buffer[index++] = (highBits >> 16) & 0xff;
buffer[index++] = (highBits >> 24) & 0xff;
}
// If the value fits in 32 bits encode as int32
// Set int type 32 bits or less
buffer[index++] = constants.BSON_DATA_INT;
// Number of written bytes
const numberOfWrittenBytes = !isArray
? buffer.write(key, index, undefined, 'utf8')
: buffer.write(key, index, undefined, 'ascii');
// Encode the name
index = index + numberOfWrittenBytes;
buffer[index++] = 0;
// Write the int value
buffer[index++] = value & 0xff;
buffer[index++] = (value >> 8) & 0xff;
buffer[index++] = (value >> 16) & 0xff;
buffer[index++] = (value >> 24) & 0xff;
} else {
// Encode as double
buffer[index++] = constants.BSON_DATA_NUMBER;
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