diff options
| -rw-r--r-- | Makefile | 3 | ||||
| -rw-r--r-- | meson.build | 5 | ||||
| -rw-r--r-- | src/lib.rs | 1 | ||||
| -rw-r--r-- | src/meson.build | 1 | ||||
| -rw-r--r-- | src/varint.rs | 92 |
5 files changed, 101 insertions, 1 deletions
@@ -1307,7 +1307,9 @@ LIB_OBJS += urlmatch.o LIB_OBJS += usage.o LIB_OBJS += userdiff.o LIB_OBJS += utf8.o +ifndef WITH_RUST LIB_OBJS += varint.o +endif LIB_OBJS += version.o LIB_OBJS += versioncmp.o LIB_OBJS += walker.o @@ -1499,6 +1501,7 @@ CLAR_TEST_OBJS += $(UNIT_TEST_DIR)/unit-test.o UNIT_TEST_OBJS += $(UNIT_TEST_DIR)/test-lib.o RUST_SOURCES += src/lib.rs +RUST_SOURCES += src/varint.rs GIT-VERSION-FILE: FORCE @OLD=$$(cat $@ 2>/dev/null || :) && \ diff --git a/meson.build b/meson.build index 234a9e9d6f..37dfa28601 100644 --- a/meson.build +++ b/meson.build @@ -522,7 +522,6 @@ libgit_sources = [ 'usage.c', 'userdiff.c', 'utf8.c', - 'varint.c', 'version.c', 'versioncmp.c', 'walker.c', @@ -1707,6 +1706,10 @@ rust_option = get_option('rust').disable_auto_if(not cargo.found()) if rust_option.allowed() subdir('src') libgit_c_args += '-DWITH_RUST' +else + libgit_sources += [ + 'varint.c', + ] endif libgit = declare_dependency( diff --git a/src/lib.rs b/src/lib.rs index e69de29bb2..9da70d8b57 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -0,0 +1 @@ +pub mod varint; diff --git a/src/meson.build b/src/meson.build index c8d874b210..25b9ad5a14 100644 --- a/src/meson.build +++ b/src/meson.build @@ -1,5 +1,6 @@ libgit_rs_sources = [ 'lib.rs', + 'varint.rs', ] # Unfortunately we must use a wrapper command to move the output file into the diff --git a/src/varint.rs b/src/varint.rs new file mode 100644 index 0000000000..6e610bdd8e --- /dev/null +++ b/src/varint.rs @@ -0,0 +1,92 @@ +#[no_mangle] +pub unsafe extern "C" fn decode_varint(bufp: *mut *const u8) -> u64 { + let mut buf = *bufp; + let mut c = *buf; + let mut val = u64::from(c & 127); + + buf = buf.add(1); + + while (c & 128) != 0 { + val = val.wrapping_add(1); + if val == 0 || val.leading_zeros() < 7 { + return 0; // overflow + } + + c = *buf; + buf = buf.add(1); + + val = (val << 7) + u64::from(c & 127); + } + + *bufp = buf; + val +} + +#[no_mangle] +pub unsafe extern "C" fn encode_varint(value: u64, buf: *mut u8) -> u8 { + let mut varint: [u8; 16] = [0; 16]; + let mut pos = varint.len() - 1; + + varint[pos] = (value & 127) as u8; + + let mut value = value >> 7; + while value != 0 { + pos -= 1; + value -= 1; + varint[pos] = 128 | (value & 127) as u8; + value >>= 7; + } + + if !buf.is_null() { + std::ptr::copy_nonoverlapping(varint.as_ptr().add(pos), buf, varint.len() - pos); + } + + (varint.len() - pos) as u8 +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn test_decode_varint() { + unsafe { + assert_eq!(decode_varint(&mut [0x00].as_slice().as_ptr()), 0); + assert_eq!(decode_varint(&mut [0x01].as_slice().as_ptr()), 1); + assert_eq!(decode_varint(&mut [0x7f].as_slice().as_ptr()), 127); + assert_eq!(decode_varint(&mut [0x80, 0x00].as_slice().as_ptr()), 128); + assert_eq!(decode_varint(&mut [0x80, 0x01].as_slice().as_ptr()), 129); + assert_eq!(decode_varint(&mut [0x80, 0x7f].as_slice().as_ptr()), 255); + + // Overflows are expected to return 0. + assert_eq!(decode_varint(&mut [0x88; 16].as_slice().as_ptr()), 0); + } + } + + #[test] + fn test_encode_varint() { + unsafe { + let mut varint: [u8; 16] = [0; 16]; + + assert_eq!(encode_varint(0, std::ptr::null_mut()), 1); + + assert_eq!(encode_varint(0, varint.as_mut_slice().as_mut_ptr()), 1); + assert_eq!(varint, [0; 16]); + + assert_eq!(encode_varint(10, varint.as_mut_slice().as_mut_ptr()), 1); + assert_eq!(varint, [10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]); + + assert_eq!(encode_varint(127, varint.as_mut_slice().as_mut_ptr()), 1); + assert_eq!(varint, [127, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]); + + assert_eq!(encode_varint(128, varint.as_mut_slice().as_mut_ptr()), 2); + assert_eq!(varint, [128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]); + + assert_eq!(encode_varint(129, varint.as_mut_slice().as_mut_ptr()), 2); + assert_eq!(varint, [128, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]); + + assert_eq!(encode_varint(255, varint.as_mut_slice().as_mut_ptr()), 2); + assert_eq!(varint, [128, 127, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]); + } + } +} |