feat: multi-tariff decimal scaling engine with overflow protection (#3) - #87
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elizabetheonoja-art merged 1 commit intoJun 25, 2026
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…tility-Protocol#3) Hardens src/utils/math.ts for 7-decimal Soroban fixed-point conversions: input range validation, explicit truncation instead of silent rounding, and i128 overflow guards. - validateScale(value): rejects >7 decimal places, exponential notation that isn't a safe integer, and integer parts beyond 10^12 (the round-to-zero bug for rates like 0.00000001 is now surfaced) - toContractUnits: explicitly truncates excess precision (ROUND_DOWN), supports a strict mode that rejects invalid scale, and throws OverflowError past i128; guards invalid numeric input - fromContractUnits: pure 7-decimal descaling - addSafe/subtractSafe/multiplySafe/divideSafe: throw OverflowError on i128 overflow and on divide-by-zero - adds I128_MAX/I128_MIN/MAX_INTEGER_PART constants and OverflowError/ ScaleValidationError; preserves the existing helper surface - tests cover zero, negative, max i128, very small values, exponential forms, truncation, overflow and round-trips (placed under tests/unit since vitest only collects tests/**, not src/__tests__)
elizabetheonoja-art
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Jun 25, 2026
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Multi-Tariff Decimal Scaling Engine Using Big-Number Arithmetic (#3)
Closes #3
Changes (
src/utils/math.ts)validateScale(value): { valid, reason? }— regex + BigNumber checks:10^12.Surfaces
0.00000001as invalid rather than rounding it to zero.toContractUnits(value, { strict? })— explicitly truncates excess precision (ROUND_DOWN, no silent round-up), throwsOverflowErrorpast i128, and guards invalid numeric input.strict: truerejects values that failvalidateScale.fromContractUnits(value)— pure 7-decimal descaling.addSafe/subtractSafe/multiplySafe/divideSafe— throwOverflowErroron i128 overflow and on divide-by-zero.I128_MAX,I128_MIN,MAX_INTEGER_PART,OverflowError,ScaleValidationError(plus existingSCALE/SCALE_FACTOR). The original helper surface (add/subtract/compare/formatDisplay/…) is preserved.