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allow negative jumps

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This commit is contained in:
Pascal Zittlau
2025-12-03 10:33:42 +01:00
parent b46bfc8dd7
commit 96b192f4af
1 changed files with 27 additions and 26 deletions
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53
src/PatchLocationIterator.zig
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@@ -95,22 +95,14 @@ pub fn init(patch_bytes: [patch_size]PatchByte, addr: u64) PatchLocationIterator
pub fn next(self: *PatchLocationIterator) ?Range {
defer self.first = false;
// If the first byte is predetermined and the offset would always be negative we don't need to
// iterate.
const last_byte = self.patch_bytes[patch_size - 1];
if (last_byte == .used and last_byte.used & 0x80 != 0) {
log.info(
"next: Search aborted, pattern has predetermined negative offset (last_byte=0x{x})",
.{last_byte.used},
);
return null;
}
// If all bytes are free we can just return the maximum range.
if (self.trailing_free_count == patch_size) {
if (self.first) {
const range = Range{ .start = self.offset, .end = self.offset + std.math.maxInt(i32) };
log.debug("next: All bytes free, returning full positive range: {f}", .{range});
const range = Range{
.start = self.offset + std.math.minInt(i32),
.end = self.offset + std.math.maxInt(i32),
};
log.debug("next: All bytes free, returning full range: {f}", .{range});
return range;
} else {
log.info("next: All bytes free, iteration finished.", .{});
@@ -137,8 +129,7 @@ pub fn next(self: *PatchLocationIterator) ?Range {
defer assert(self.start[i] == self.end[i]);
if (overflow == 1) {
const max: u8 = if (i < patch_size - 1) std.math.maxInt(u8) else std.math.maxInt(i8);
if (self.start[i] == max) {
if (self.start[i] == std.math.maxInt(u8)) {
self.start[i] = 0;
self.end[i] = 0;
} else {
@@ -187,7 +178,7 @@ test "free bytes" {
var it = PatchLocationIterator.init(pattern, 0);
try testing.expectEqual(
Range{ .start = 0x00000000, .end = 0x7fffffff },
Range{ .start = std.math.minInt(i32), .end = std.math.maxInt(i32) },
it.next().?,
);
try testing.expectEqual(null, it.next());
@@ -201,9 +192,10 @@ test "predetermined negative" {
.{ .used = 0xe9 },
};
var it = PatchLocationIterator.init(pattern, 0);
try testing.expectEqual(null, it.next());
it = PatchLocationIterator.init(pattern, 0x12345678);
try testing.expectEqual(null, it.next());
try testing.expectEqual(Range{
.start = @as(i32, @bitCast(@as(u32, 0xe9000000))),
.end = @as(i32, @bitCast(@as(u32, 0xe9ffffff))),
}, it.next());
}
test "trailing free bytes" {
@@ -296,10 +288,13 @@ test "inner and leading free bytes" {
count += 1;
}
try testing.expectEqual(
Range{ .start = 0x7fe8ffe9, .end = 0x7fe8ffe9 },
Range{
.start = @as(i32, @bitCast(@as(u32, 0xffe8ffe9))),
.end = @as(i32, @bitCast(@as(u32, 0xffe8ffe9))),
},
r_last,
);
try testing.expectEqual(256 * 128, count);
try testing.expectEqual(256 * 256, count);
}
test "only inner" {
@@ -378,10 +373,13 @@ test "trailing and leading offset" {
count += 1;
}
try testing.expectEqual(
Range{ .start = offset + 0x7fe8e900, .end = offset + 0x7fe8e9ff },
Range{
.start = offset + @as(i32, @bitCast(@as(u32, 0xffe8e900))),
.end = offset + @as(i32, @bitCast(@as(u32, 0xffe8e9ff))),
},
r_last,
);
try testing.expectEqual(128, count);
try testing.expectEqual(256, count);
}
test "trailing free bytes large offset" {
@@ -408,7 +406,7 @@ test "trailing and leading large offset" {
.{ .used = 0xe8 },
.{ .free = {} },
};
const offset = 0x12345678;
const offset = 0x123456789a;
var it = PatchLocationIterator.init(pattern, offset);
try testing.expectEqual(
@@ -428,8 +426,11 @@ test "trailing and leading large offset" {
count += 1;
}
try testing.expectEqual(
Range{ .start = offset + 0x7fe8e900, .end = offset + 0x7fe8e9ff },
Range{
.start = offset + @as(i64, @intCast(@as(i32, @bitCast(@as(u32, 0xffe8e900))))),
.end = offset + @as(i64, @intCast(@as(i32, @bitCast(@as(u32, 0xffe8e9ff))))),
},
r_last,
);
try testing.expectEqual(128, count);
try testing.expectEqual(256, count);
}