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55 changes: 55 additions & 0 deletions
55
src/main/kotlin/app/revanced/patches/all/misc/hex/HexPatch.kt
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|---|---|---|
| @@ -0,0 +1,55 @@ | ||
| package app.revanced.patches.all.misc.hex | ||
|
|
||
| import app.revanced.patcher.patch.PatchException | ||
| import app.revanced.patcher.patch.annotation.Patch | ||
| import app.revanced.patcher.patch.options.PatchOption.PatchExtensions.registerNewPatchOption | ||
| import app.revanced.patches.shared.misc.hex.BaseHexPatch | ||
| import app.revanced.util.Utils.trimIndentMultiline | ||
| import app.revanced.patcher.patch.Patch as PatchClass | ||
|
|
||
| @Patch( | ||
| name = "Hex", | ||
| description = "Replaces a hexadecimal patterns of bytes of files in an APK.", | ||
| use = false, | ||
| ) | ||
| @Suppress("unused") | ||
| class HexPatch : BaseHexPatch() { | ||
| // TODO: Instead of stringArrayOption, use a custom option type to work around | ||
| // https://github.com/ReVanced/revanced-library/issues/48. | ||
| // Replace the custom option type with a stringArrayOption once the issue is resolved. | ||
| private val replacementsOption by registerNewPatchOption<PatchClass<*>, List<String>>( | ||
| key = "replacements", | ||
| title = "replacements", | ||
| description = """ | ||
| Hexadecimal patterns to search for and replace with another in a target file. | ||
| A pattern is a sequence of case insensitive strings, each representing hexadecimal bytes, separated by spaces. | ||
| An example pattern is 'aa 01 02 FF'. | ||
| Every pattern must be followed by a pipe ('|'), the replacement pattern, | ||
| another pipe ('|'), and the path to the file to make the changes in relative to the APK root. | ||
| The replacement pattern must have the same length as the original pattern. | ||
| Full example of a valid input: | ||
| 'aa 01 02 FF|00 00 00 00|path/to/file' | ||
| """.trimIndentMultiline(), | ||
| required = true, | ||
| valueType = "StringArray", | ||
| ) | ||
|
|
||
| override val replacements | ||
| get() = replacementsOption!!.map { from -> | ||
| val (pattern, replacementPattern, targetFilePath) = try { | ||
| from.split("|", limit = 3) | ||
| } catch (e: Exception) { | ||
| throw PatchException( | ||
| "Invalid input: $from.\n" + | ||
| "Every pattern must be followed by a pipe ('|'), " + | ||
| "the replacement pattern, another pipe ('|'), " + | ||
| "and the path to the file to make the changes in relative to the APK root. ", | ||
| ) | ||
| } | ||
|
|
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| Replacement(pattern, replacementPattern, targetFilePath) | ||
| } | ||
| } |
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src/main/kotlin/app/revanced/patches/shared/misc/hex/BaseHexPatch.kt
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| package app.revanced.patches.shared.misc.hex | ||
|
|
||
| import app.revanced.patcher.data.ResourceContext | ||
| import app.revanced.patcher.patch.PatchException | ||
| import app.revanced.patcher.patch.RawResourcePatch | ||
| import kotlin.math.max | ||
|
|
||
| abstract class BaseHexPatch : RawResourcePatch() { | ||
| internal abstract val replacements: List<Replacement> | ||
|
|
||
| override fun execute(context: ResourceContext) { | ||
| replacements.groupBy { it.targetFilePath }.forEach { (targetFilePath, replacements) -> | ||
| val targetFile = try { | ||
| context[targetFilePath, true] | ||
| } catch (e: Exception) { | ||
| throw PatchException("Could not find target file: $targetFilePath") | ||
| } | ||
|
|
||
| // TODO: Use a file channel to read and write the file instead of reading the whole file into memory, | ||
| // in order to reduce memory usage. | ||
| val targetFileBytes = targetFile.readBytes() | ||
|
|
||
| replacements.forEach { replacement -> | ||
| replacement.replacePattern(targetFileBytes) | ||
| } | ||
|
|
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| targetFile.writeBytes(targetFileBytes) | ||
| } | ||
| } | ||
|
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| /** | ||
| * Represents a pattern to search for and its replacement pattern. | ||
| * | ||
| * @property pattern The pattern to search for. | ||
| * @property replacementPattern The pattern to replace the [pattern] with. | ||
| * @property targetFilePath The path to the file to make the changes in relative to the APK root. | ||
| */ | ||
| class Replacement( | ||
| private val pattern: String, | ||
| replacementPattern: String, | ||
| internal val targetFilePath: String, | ||
| ) { | ||
| private val patternBytes = pattern.toByteArrayPattern() | ||
| private val replacementPattern = replacementPattern.toByteArrayPattern() | ||
|
|
||
| init { | ||
| if (this.patternBytes.size != this.replacementPattern.size) { | ||
| throw PatchException("Pattern and replacement pattern must have the same length: $pattern") | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * Replaces the [patternBytes] with the [replacementPattern] in the [targetFileBytes]. | ||
| * | ||
| * @param targetFileBytes The bytes of the file to make the changes in. | ||
| */ | ||
| fun replacePattern(targetFileBytes: ByteArray) { | ||
| val startIndex = indexOfPatternIn(targetFileBytes) | ||
|
|
||
| if (startIndex == -1) { | ||
| throw PatchException("Pattern not found in target file: $pattern") | ||
| } | ||
|
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| replacementPattern.copyInto(targetFileBytes, startIndex) | ||
| } | ||
|
|
||
| // TODO: Allow searching in a file channel instead of a byte array to reduce memory usage. | ||
| /** | ||
| * Returns the index of the first occurrence of [patternBytes] in the haystack | ||
| * using the Boyer-Moore algorithm. | ||
| * | ||
| * @param haystack The array to search in. | ||
| * | ||
| * @return The index of the first occurrence of the [patternBytes] in the haystack or -1 | ||
| * if the [patternBytes] is not found. | ||
| */ | ||
| private fun indexOfPatternIn(haystack: ByteArray): Int { | ||
| val needle = patternBytes | ||
|
|
||
| val haystackLength = haystack.size - 1 | ||
| val needleLength = needle.size - 1 | ||
| val right = IntArray(256) { -1 } | ||
|
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| for (i in 0 until needleLength) right[needle[i].toInt().and(0xFF)] = i | ||
|
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| var skip: Int | ||
| for (i in 0..haystackLength - needleLength) { | ||
| skip = 0 | ||
|
|
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| for (j in needleLength - 1 downTo 0) | ||
| if (needle[j] != haystack[i + j]) { | ||
| skip = max(1, j - right[haystack[i + j].toInt().and(0xFF)]) | ||
|
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| break | ||
| } | ||
|
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| if (skip == 0) return i | ||
| } | ||
| return -1 | ||
| } | ||
|
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| companion object { | ||
| /** | ||
| * Convert a string representing a pattern of hexadecimal bytes to a byte array. | ||
| * | ||
| * @return The byte array representing the pattern. | ||
| * @throws PatchException If the pattern is invalid. | ||
| */ | ||
| private fun String.toByteArrayPattern() = try { | ||
| split(" ").map { it.toInt(16).toByte() }.toByteArray() | ||
| } catch (e: NumberFormatException) { | ||
| throw PatchException( | ||
| "Could not parse pattern: $this. A pattern is a sequence of case insensitive strings " + | ||
| "representing hexadecimal bytes separated by spaces", | ||
| e, | ||
| ) | ||
| } | ||
| } | ||
| } | ||
| } |