39 lines
1.3 KiB
Rust
39 lines
1.3 KiB
Rust
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pub fn encode_float(f: f32) -> (i32, i32) {
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let bits = f.to_bits();
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let mantissa = (bits & 0x007FFFFF) as i32;
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let exponent = ((bits >> 23) & 0xFF) as i32;
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let sign = if f < 0.0 { 1 } else { 0 }; // Determine sign as 1 for negative, 0 for positive
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(mantissa | (sign << 23), exponent) // Include the sign bit in the mantissa
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}
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pub fn decode_float(mantissa: i32, exponent: i32) -> f32 {
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let sign_bit = ((mantissa >> 23) & 1) as u32; // Extract the sign bit
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let mantissa_bits = (mantissa & 0x007FFFFF) as u32;
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let exponent_bits = (exponent as u32 & 0xFF) << 23;
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let bits = (sign_bit << 31) | exponent_bits | mantissa_bits; // Reconstruct all bits including sign
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f32::from_bits(bits)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[rustfmt::skip]
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#[test]
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fn test_encode_decode() {
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let original_floats = [
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0.0, 1.0, -1.0, 123.456, -123.456, 1e-10, -1e10, f32::MAX, f32::MIN,
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];
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for &original in &original_floats {
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let (mantissa, exponent) = encode_float(original);
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let decoded = decode_float(mantissa, exponent);
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assert!(
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(decoded - original).abs() < 1e-6,
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"Mismatch: original {} vs decoded {}",
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original,
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decoded
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);
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}
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}
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}
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