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package org.jf.dexlib2.util;
import org.jf.dexlib2.iface.instruction.Instruction;
import org.jf.util.ExceptionWithContext;
import javax.annotation.Nonnull;
import java.util.Arrays;
import java.util.List;
public class InstructionOffsetMap {
@Nonnull private final int[] instructionCodeOffsets;
public InstructionOffsetMap(@Nonnull List<? extends Instruction> instructions) {
this.instructionCodeOffsets = new int[instructions.size()];
int codeOffset = 0;
for (int i=0; i<instructions.size(); i++) {
instructionCodeOffsets[i] = codeOffset;
codeOffset += instructions.get(i).getCodeUnits();
}
}
public int getInstructionIndexAtCodeOffset(int codeOffset) {
return getInstructionIndexAtCodeOffset(codeOffset, true);
}
public int getInstructionIndexAtCodeOffset(int codeOffset, boolean exact) {
int index = Arrays.binarySearch(instructionCodeOffsets, codeOffset);
if (index < 0) {
if (exact) {
throw new InvalidInstructionOffset(codeOffset);
} else {
// This calculation would be incorrect if index was -1 (i.e. insertion point of 0). Luckily, we can
// ignore this case, because codeOffset will always be non-negative, and the code offset of the first
// instruction will always be 0.
return (~index) - 1;
}
}
return index;
}
public int getInstructionCodeOffset(int index) {
if (index < 0 || index >= instructionCodeOffsets.length) {
throw new InvalidInstructionIndex(index);
}
return instructionCodeOffsets[index];
}
public static class InvalidInstructionOffset extends ExceptionWithContext {
private final int instructionOffset;
public InvalidInstructionOffset(int instructionOffset) {
super("No instruction at offset %d", instructionOffset);
this.instructionOffset = instructionOffset;
}
public int getInstructionOffset() {
return instructionOffset;
}
}
public static class InvalidInstructionIndex extends ExceptionWithContext {
private final int instructionIndex;
public InvalidInstructionIndex(int instructionIndex) {
super("Instruction index out of bounds: %d", instructionIndex);
this.instructionIndex = instructionIndex;
}
public int getInstructionIndex() {
return instructionIndex;
}
}
}