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Add counters for number of bytes/bits read in streams since the beginning of time

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This commit is contained in:
codedread 2018-01-26 00:02:16 -08:00
parent 295413af0b
commit 8c630c170c
2 changed files with 28 additions and 6 deletions
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23
io/bitstream.js
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@ -38,11 +38,19 @@ bitjs.io.BitStream = class {
this.bytePtr = 0; // tracks which byte we are on this.bytePtr = 0; // tracks which byte we are on
this.bitPtr = 0; // tracks which bit we are on (can have values 0 through 7) this.bitPtr = 0; // tracks which bit we are on (can have values 0 through 7)
this.peekBits = rtl ? this.peekBits_rtl : this.peekBits_ltr; this.peekBits = rtl ? this.peekBits_rtl : this.peekBits_ltr;
// An ever-increasing number.
this.bitsRead_ = 0;
} }
/**
* Returns how many bites have been read in the stream since the beginning of time.
*/
getNumBitsRead() {
return this.bitsRead_;
}
/** /**
* Returns how many bytes are currently in the stream left to be read. * Returns how many bits are currently in the stream left to be read.
*/ */
getNumBitsLeft() { getNumBitsLeft() {
const bitsLeftInByte = 8 - this.bitPtr; const bitsLeftInByte = 8 - this.bitPtr;
@ -58,6 +66,7 @@ bitjs.io.BitStream = class {
*/ */
movePointer_(n) { movePointer_(n) {
this.bitPtr += n; this.bitPtr += n;
this.bitsRead_ += n;
while (this.bitPtr >= 8) { while (this.bitPtr >= 8) {
this.bitPtr -= 8; this.bitPtr -= 8;
this.bytePtr++; this.bytePtr++;
@ -88,8 +97,8 @@ bitjs.io.BitStream = class {
} }
if (num > this.getNumBitsLeft()) { if (num > this.getNumBitsLeft()) {
throw 'Error! Overflowed the bit stream! n=' + n + ', bytePtr=' + bytePtr + throw 'Error! Overflowed the bit stream! n=' + n + ', bytePtr=' + this.bytePtr +
', bytes.length=' + bytes.length + ', bitPtr=' + bitPtr; ', bytes.length=' + this.bytes.length + ', bitPtr=' + this.bitPtr;
} }
const movePointers = opt_movePointers || false; const movePointers = opt_movePointers || false;
@ -153,8 +162,8 @@ bitjs.io.BitStream = class {
} }
if (num > this.getNumBitsLeft()) { if (num > this.getNumBitsLeft()) {
throw 'Error! Overflowed the bit stream! n=' + n + ', bytePtr=' + bytePtr + throw 'Error! Overflowed the bit stream! n=' + n + ', bytePtr=' + this.bytePtr +
', bytes.length=' + bytes.length + ', bitPtr=' + bitPtr; ', bytes.length=' + this.bytes.length + ', bitPtr=' + this.bitPtr;
} }
const movePointers = opt_movePointers || false; const movePointers = opt_movePointers || false;
@ -227,7 +236,7 @@ bitjs.io.BitStream = class {
peekBytes(n, opt_movePointers) { peekBytes(n, opt_movePointers) {
const num = parseInt(n, 10); const num = parseInt(n, 10);
if (n !== num || num < 0) { if (n !== num || num < 0) {
throw 'Error! Called peekBytes() with a non-positive integer'; throw 'Error! Called peekBytes() with a non-positive integer: ' + n;
} else if (num === 0) { } else if (num === 0) {
return new Uint8Array(); return new Uint8Array();
} }
@ -260,6 +269,7 @@ bitjs.io.BitStream = class {
if (movePointers) { if (movePointers) {
this.bytePtr += num; this.bytePtr += num;
this.bitsRead_ += (num * 8);
} }
return result; return result;
@ -296,6 +306,7 @@ bitjs.io.BitStream = class {
clone.bytePtr = this.bytePtr; clone.bytePtr = this.bytePtr;
clone.bitPtr = this.bitPtr; clone.bitPtr = this.bitPtr;
clone.peekBits = this.peekBits; clone.peekBits = this.peekBits;
clone.bitsRead_ = this.bitsRead_;
return clone; return clone;
} }
} }

11
io/bytestream.js
View file

@ -35,6 +35,15 @@ bitjs.io.ByteStream = class {
this.bytes = new Uint8Array(ab, offset, length); this.bytes = new Uint8Array(ab, offset, length);
this.ptr = 0; this.ptr = 0;
this.pages_ = []; this.pages_ = [];
// An ever-increasing number.
this.bytesRead_ = 0;
}
/**
* Returns how many bytes have been read in the stream since the beginning of time.
*/
getNumBytesRead() {
return this.bytesRead_;
} }
/** /**
@ -54,6 +63,7 @@ bitjs.io.ByteStream = class {
*/ */
movePointer_(n) { movePointer_(n) {
this.ptr += n; this.ptr += n;
this.bytesRead_ += n;
while (this.ptr >= this.bytes.length && this.pages_.length > 0) { while (this.ptr >= this.bytes.length && this.pages_.length > 0) {
this.ptr -= this.bytes.length; this.ptr -= this.bytes.length;
this.bytes = this.pages_.shift(); this.bytes = this.pages_.shift();
@ -262,6 +272,7 @@ bitjs.io.ByteStream = class {
clone.bytes = this.bytes; clone.bytes = this.bytes;
clone.ptr = this.ptr; clone.ptr = this.ptr;
clone.pages_ = this.pages_.slice(); clone.pages_ = this.pages_.slice();
clone.bytesRead_ = this.bytesRead_;
return clone; return clone;
} }
} }