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#include "src/tint/fuzzers/tint_ast_fuzzer/probability_context.h"

#include <cassert>

namespace tint::fuzzers::ast_fuzzer {
namespace {

const std::pair<uint32_t, uint32_t> kChanceOfChangingBinaryOperators = {30, 90};
const std::pair<uint32_t, uint32_t> kChanceOfChangingUnaryOperators = {30, 70};
const std::pair<uint32_t, uint32_t> kChanceOfDeletingStatements = {30, 70};
const std::pair<uint32_t, uint32_t> kChanceOfReplacingIdentifiers = {30, 70};
const std::pair<uint32_t, uint32_t> kChanceOfWrappingUnaryOperators = {30, 70};

}  // namespace

ProbabilityContext::ProbabilityContext(RandomGenerator* generator)
    : generator_(generator),
      chance_of_changing_binary_operators_(RandomFromRange(kChanceOfChangingBinaryOperators)),
      chance_of_changing_unary_operators_(RandomFromRange(kChanceOfChangingUnaryOperators)),
      chance_of_deleting_statements_(RandomFromRange(kChanceOfDeletingStatements)),
      chance_of_replacing_identifiers_(RandomFromRange(kChanceOfReplacingIdentifiers)),
      chance_of_wrapping_unary_operators_(RandomFromRange(kChanceOfWrappingUnaryOperators)) {
    assert(generator != nullptr && "generator must not be nullptr");
}

uint32_t ProbabilityContext::RandomFromRange(std::pair<uint32_t, uint32_t> range) {
    assert(range.first <= range.second && "Range must be non-decreasing");
    return generator_->GetUInt32(range.first,
                                 range.second + 1);  // + 1 need since range is inclusive.
}

}  // namespace tint::fuzzers::ast_fuzzer