flatbuffers

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import { Builder } from './builder.js'
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import { BitWidth } from './bit-width.js'
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import { paddingSize, uwidth, fromByteWidth } from './bit-width-util.js'
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import { ValueType } from './value-type.js'
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import { isInline, packedType } from './value-type-util.js'
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export class StackValue {
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  constructor(private builder: Builder, public type: ValueType, public width: number, public value: number | boolean | null = null, public offset: number = 0) {
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  }
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  elementWidth(size: number, index: number): BitWidth {
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    if (isInline(this.type)) return this.width;
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    for (let i = 0; i < 4; i++) {
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      const width = 1 << i;
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      const offsetLoc = size + paddingSize(size, width) + index * width;
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      const offset = offsetLoc - this.offset;
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      const bitWidth = uwidth(offset);
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      if (1 << bitWidth === width) {
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        return bitWidth;
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      }
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    }
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    throw `Element is unknown. Size: ${size} at index: ${index}. This might be a bug. Please create an issue https://github.com/google/flatbuffers/issues/new`;
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  }
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  writeToBuffer(byteWidth: number): void {
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    const newOffset = this.builder.computeOffset(byteWidth);
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    if (this.type === ValueType.FLOAT) {
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      if (this.width === BitWidth.WIDTH32) {
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        this.builder.view.setFloat32(this.builder.offset, this.value as number, true);
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      } else {
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        this.builder.view.setFloat64(this.builder.offset, this.value as number, true);
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      }
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    } else if (this.type === ValueType.INT) {
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      const bitWidth = fromByteWidth(byteWidth);
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      this.builder.pushInt(this.value as number, bitWidth);
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    } else if (this.type === ValueType.UINT) {
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      const bitWidth = fromByteWidth(byteWidth);
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      this.builder.pushUInt(this.value as number, bitWidth);
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    } else if (this.type === ValueType.NULL) {
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      this.builder.pushInt(0, this.width);
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    } else if (this.type === ValueType.BOOL) {
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      this.builder.pushInt(this.value ? 1 : 0, this.width);
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    } else {
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      throw `Unexpected type: ${this.type}. This might be a bug. Please create an issue https://github.com/google/flatbuffers/issues/new`
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    }
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    this.offset = newOffset;
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  }
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  storedWidth(width = BitWidth.WIDTH8): BitWidth {
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    return isInline(this.type) ? Math.max(width, this.width) : this.width;
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  }
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  storedPackedType(width = BitWidth.WIDTH8): ValueType {
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    return packedType(this.type, this.storedWidth(width));
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  }
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  isOffset(): boolean {
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    return !isInline(this.type)
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  }
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}