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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | 10x 10x 10x 4x 6x 6x 19x 19x 9x 10x 19x 6x 13x 8x 9x 2x | /**
* Helper utilities for generating bit range access code.
* Extracted from CodeGenerator to improve testability.
*/
import NarrowingCastHelper from "./NarrowingCastHelper.js";
/**
* Options for generating float bit read expressions.
*/
interface IFloatBitReadOptions {
shadowName: string;
varName: string;
start: string;
mask: string;
shadowIsCurrent: boolean;
}
/**
* Options for generating integer bit read expressions.
*/
interface IIntegerBitReadOptions {
varName: string;
start: string;
mask: string;
sourceType?: string; // Optional: source variable type for cast detection
targetType?: string; // Optional: target variable type for cast
}
/**
* Helper class for bit range access code generation.
*/
class BitRangeHelper {
/**
* Build the bit read expression for floats.
* Uses memcpy pattern to safely reinterpret float bits.
*/
static buildFloatBitReadExpr(options: IFloatBitReadOptions): string {
const { shadowName, varName, start, mask, shadowIsCurrent } = options;
const shiftedRead =
start === "0"
? `(${shadowName} & ${mask})`
: `((${shadowName} >> ${start}) & ${mask})`;
if (shadowIsCurrent) {
return shiftedRead;
}
// Need memcpy to update shadow
const memcpyPrefix = `memcpy(&${shadowName}, &${varName}, sizeof(${varName}))`;
return `(${memcpyPrefix}, ${shiftedRead})`;
}
/**
* Generate integer bit range read: ((value >> start) & mask)
* Optimizes away the shift when start is 0.
*
* When sourceType and targetType are provided, wraps the expression
* with MISRA 10.3 compliant cast if needed.
*/
static buildIntegerBitReadExpr(options: IIntegerBitReadOptions): string {
const { varName, start, mask, sourceType, targetType } = options;
let expr: string;
if (start === "0") {
expr = `((${varName}) & ${mask})`;
} else {
expr = `((${varName} >> ${start}) & ${mask})`;
}
// If target type provided, wrap with MISRA cast if needed
if (sourceType && targetType) {
return NarrowingCastHelper.wrap(expr, sourceType, targetType);
}
return expr;
}
/**
* Generate the shadow variable name for float bit access.
*/
static getShadowVarName(rawName: string): string {
return `__bits_${rawName}`;
}
/**
* Get the shadow type for a float type.
*/
static getShadowType(baseType: string): string {
return baseType === "f64" ? "uint64_t" : "uint32_t";
}
/**
* Generate a shadow variable declaration.
*/
static buildShadowDeclaration(
shadowName: string,
shadowType: string,
): string {
return `${shadowType} ${shadowName};`;
}
}
export default BitRangeHelper;
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