[FEAT] Add bits and levenshtein module in lib_ccxr (#1627)

* feat: Add 2 new modules

* feat: Add `levenshtein` module & code

* feat: Add `bits` module & code

* feat: Add `extern "C"` function which are equivalent in C-RUST

* feat: Call extern ccxr_ functions in C code

* docs: Mention in Changelogs

Author: IshanGrover2004

docs/CHANGES.TXT

@@ -1,5 +1,6 @@
 0.95 (to be released)
 -----------------
+- New: Add bits and levenshtein module in lib_ccxr (#1627)
 - New:  [FEAT] Add constants module in lib_ccxr (#1624) 
 - New: Add log module in lib_ccxr (#1622)
 - New: Create `lib_ccxr` and `libccxr_exports` (#1621)

src/lib_ccx/utility.c

@@ -77,6 +77,9 @@ static uint32_t crc32_table[] = {
 
 int verify_crc32(uint8_t *buf, int len)
 {
+#ifndef DISABLE_RUST
+	return ccxr_verify_crc32(buf, len);
+#endif /* ifndef DISABLE_RUST */
 	int i = 0;
 	int32_t crc = -1;
 	for (i = 0; i < len; i++)
@@ -151,6 +154,9 @@ void timestamp_to_vtttime(uint64_t timestamp, char *buffer)
 
 int levenshtein_dist(const uint64_t *s1, const uint64_t *s2, unsigned s1len, unsigned s2len)
 {
+#ifndef DISABLE_RUST
+	return ccxr_levenshtein_dist(s1, s2, s1len, s2len);
+#endif
 	unsigned int x, y, v, lastdiag, olddiag;
 	unsigned int *column = (unsigned *)malloc((s1len + 1) * sizeof(unsigned int));
 	for (y = 1; y <= s1len; y++)
@@ -172,6 +178,9 @@ int levenshtein_dist(const uint64_t *s1, const uint64_t *s2, unsigned s1len, uns
 
 int levenshtein_dist_char(const char *s1, const char *s2, unsigned s1len, unsigned s2len)
 {
+#ifndef DISABLE_RUST
+	return ccxr_levenshtein_dist_char(s1, s2, s1len, s2len);
+#endif
 	unsigned int x, y, v, lastdiag, olddiag;
 	unsigned int *column = (unsigned *)malloc((s1len + 1) * sizeof(unsigned int));
 	for (y = 1; y <= s1len; y++)

src/lib_ccx/utility.h

@@ -26,6 +26,12 @@ struct ccx_rational
 extern int temp_debug;
 volatile extern sig_atomic_t change_filename_requested;
 
+#ifndef DISABLE_RUST
+extern int ccxr_verify_crc32(uint8_t *buf, int len);
+extern int ccxr_levenshtein_dist(const uint64_t *s1, const uint64_t *s2, unsigned s1len, unsigned s2len);
+extern int ccxr_levenshtein_dist_char(const char *s1, const char *s2, unsigned s1len, unsigned s2len);
+#endif
+
 int levenshtein_dist_char (const char *s1, const char *s2, unsigned s1len, unsigned s2len);
 void init_boundary_time (struct ccx_boundary_time *bt);
 void print_error (int mode, const char *fmt, ...);

src/rust/lib_ccxr/src/util/bits.rs

@@ -0,0 +1,224 @@
+//! This module provides various bit-level operations, including parity calculation,
+//! bit reversal, and hamming code decoding.
+//!
+//! - [`get_parity`]: Calculate the parity of an 8-bit value.
+//! - [`get_reverse_byte`]: Reverse the bits in an 8-bit value.
+//! - [`decode_hamming_8_4`]: Decode a Hamming(8,4) encoded byte.
+//! - [`decode_hamming_24_18`]: Decode a Hamming(24,18) encoded value.
+//!
+//! # Conversion Guide
+//!
+//! | From                                       | To                             |
+//! |--------------------------------------------|--------------------------------|
+//! | `PARITY_8`                                 | [`get_parity`]                 |
+//! | `REVERSE_8`                                | [`get_reverse_byte`]           |
+//! | `UNHAM_8_4` const or `unham_8_4` funcn     | [`decode_hamming_8_4`]         |
+//! | `unham_24_18`                              | [`decode_hamming_24_18`]       |
+//! | `crc32_table`                              | [`get_crc32_byte`]             |
+//! | `verify_crc32`                             | [`verify_crc32`]               |
+
+/// Equivalent to `PARITY_8[256]` const in `hamming.h` C code.
+/// Instead use [`get_parity`] function to get parity bit based on your input.
+const PARITY_TABLE: [bool; 256] = [
+    false, true, true, false, true, false, false, true, true, false, false, true, false, true,
+    true, false, true, false, false, true, false, true, true, false, false, true, true, false,
+    true, false, false, true, true, false, false, true, false, true, true, false, false, true,
+    true, false, true, false, false, true, false, true, true, false, true, false, false, true,
+    true, false, false, true, false, true, true, false, true, false, false, true, false, true,
+    true, false, false, true, true, false, true, false, false, true, false, true, true, false,
+    true, false, false, true, true, false, false, true, false, true, true, false, false, true,
+    true, false, true, false, false, true, true, false, false, true, false, true, true, false,
+    true, false, false, true, false, true, true, false, false, true, true, false, true, false,
+    false, true, true, false, false, true, false, true, true, false, false, true, true, false,
+    true, false, false, true, false, true, true, false, true, false, false, true, true, false,
+    false, true, false, true, true, false, false, true, true, false, true, false, false, true,
+    true, false, false, true, false, true, true, false, true, false, false, true, false, true,
+    true, false, false, true, true, false, true, false, false, true, false, true, true, false,
+    true, false, false, true, true, false, false, true, false, true, true, false, true, false,
+    false, true, false, true, true, false, false, true, true, false, true, false, false, true,
+    true, false, false, true, false, true, true, false, false, true, true, false, true, false,
+    false, true, false, true, true, false, true, false, false, true, true, false, false, true,
+    false, true, true, false,
+];
+
+/// Equivalent to `REVERSE_8[256]` const in `hamming.h` C code
+/// Instead use [`get_reverse_byte`] function to get any reversed bit based on your input.
+const BIT_REVERSE_TABLE: [u8; 256] = [
+    0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
+    0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
+    0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
+    0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
+    0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
+    0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
+    0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
+    0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
+    0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
+    0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
+    0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
+    0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
+    0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
+    0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
+    0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
+    0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
+];
+
+/// Equivalent to `UNHAM_8_4[256]` const in `hamming.h` C code
+/// Instead use [`decode_hamming_8_4`] function to get decoded hamming code.
+const HAMMING_8_4_DECODER_TABLE: [u8; 256] = [
+    0x01, 0xff, 0x01, 0x01, 0xff, 0x00, 0x01, 0xff, 0xff, 0x02, 0x01, 0xff, 0x0a, 0xff, 0xff, 0x07,
+    0xff, 0x00, 0x01, 0xff, 0x00, 0x00, 0xff, 0x00, 0x06, 0xff, 0xff, 0x0b, 0xff, 0x00, 0x03, 0xff,
+    0xff, 0x0c, 0x01, 0xff, 0x04, 0xff, 0xff, 0x07, 0x06, 0xff, 0xff, 0x07, 0xff, 0x07, 0x07, 0x07,
+    0x06, 0xff, 0xff, 0x05, 0xff, 0x00, 0x0d, 0xff, 0x06, 0x06, 0x06, 0xff, 0x06, 0xff, 0xff, 0x07,
+    0xff, 0x02, 0x01, 0xff, 0x04, 0xff, 0xff, 0x09, 0x02, 0x02, 0xff, 0x02, 0xff, 0x02, 0x03, 0xff,
+    0x08, 0xff, 0xff, 0x05, 0xff, 0x00, 0x03, 0xff, 0xff, 0x02, 0x03, 0xff, 0x03, 0xff, 0x03, 0x03,
+    0x04, 0xff, 0xff, 0x05, 0x04, 0x04, 0x04, 0xff, 0xff, 0x02, 0x0f, 0xff, 0x04, 0xff, 0xff, 0x07,
+    0xff, 0x05, 0x05, 0x05, 0x04, 0xff, 0xff, 0x05, 0x06, 0xff, 0xff, 0x05, 0xff, 0x0e, 0x03, 0xff,
+    0xff, 0x0c, 0x01, 0xff, 0x0a, 0xff, 0xff, 0x09, 0x0a, 0xff, 0xff, 0x0b, 0x0a, 0x0a, 0x0a, 0xff,
+    0x08, 0xff, 0xff, 0x0b, 0xff, 0x00, 0x0d, 0xff, 0xff, 0x0b, 0x0b, 0x0b, 0x0a, 0xff, 0xff, 0x0b,
+    0x0c, 0x0c, 0xff, 0x0c, 0xff, 0x0c, 0x0d, 0xff, 0xff, 0x0c, 0x0f, 0xff, 0x0a, 0xff, 0xff, 0x07,
+    0xff, 0x0c, 0x0d, 0xff, 0x0d, 0xff, 0x0d, 0x0d, 0x06, 0xff, 0xff, 0x0b, 0xff, 0x0e, 0x0d, 0xff,
+    0x08, 0xff, 0xff, 0x09, 0xff, 0x09, 0x09, 0x09, 0xff, 0x02, 0x0f, 0xff, 0x0a, 0xff, 0xff, 0x09,
+    0x08, 0x08, 0x08, 0xff, 0x08, 0xff, 0xff, 0x09, 0x08, 0xff, 0xff, 0x0b, 0xff, 0x0e, 0x03, 0xff,
+    0xff, 0x0c, 0x0f, 0xff, 0x04, 0xff, 0xff, 0x09, 0x0f, 0xff, 0x0f, 0x0f, 0xff, 0x0e, 0x0f, 0xff,
+    0x08, 0xff, 0xff, 0x05, 0xff, 0x0e, 0x0d, 0xff, 0xff, 0x0e, 0x0f, 0xff, 0x0e, 0x0e, 0xff, 0x0e,
+];
+
+/// Equivalent to `crc32_table[256]` const in `utility.c` C code
+/// Instead use [`get_crc32_byte`] function to get CRC32 bit.
+const CRC32_TABLE: [u32; 256] = [
+    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
+    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
+    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
+    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
+    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
+    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
+    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
+    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
+    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
+    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
+    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
+    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
+    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
+    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
+    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
+    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
+    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
+    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
+    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
+    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
+    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
+    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
+    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
+    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
+    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
+    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
+];
+
+/// Returns the parity of the given 8-bit unsigned integer.
+///
+/// # Exmaples
+/// ```rust
+/// # use lib_ccxr::util::bits::*;
+/// assert_eq!(get_parity(0), false);
+/// assert_eq!(get_parity(1), true);
+/// ```
+pub fn get_parity(value: u8) -> bool {
+    PARITY_TABLE[value as usize]
+}
+
+/// Returns a byte with its bits flipped from given 8-bit unsigned integer.
+///
+/// # Exmaples
+/// ```rust
+/// # use lib_ccxr::util::bits::*;
+/// assert_eq!(get_reverse_byte(0), 0x00);
+/// assert_eq!(get_reverse_byte(1), 0x80);
+/// ```
+pub fn get_reverse_byte(value: u8) -> u8 {
+    BIT_REVERSE_TABLE[value as usize]
+}
+
+/// Returns an Option of the decoded byte given a \[8,4\] hamming code byte.
+/// (ETS 300 706, chapter 8.2)
+///
+/// # Exmaples
+/// ```rust
+/// # use lib_ccxr::util::bits::*;
+/// assert_eq!(decode_hamming_8_4(0x00), Some(0x01));
+/// assert_eq!(decode_hamming_8_4(0x01), None);
+/// ```
+pub fn decode_hamming_8_4(value: u8) -> Option<u8> {
+    let decoded = HAMMING_8_4_DECODER_TABLE[value as usize];
+    if decoded == 0xff {
+        None
+    } else {
+        Some(decoded & 0x0f)
+    }
+}
+
+/// Returns an Option of the decoded byte given a \[24,18\] hamming code byte.
+/// (ETS 300 706, chapter 8.3)
+///
+/// # Exmaples
+/// ```rust
+/// # use lib_ccxr::util::bits::*;
+/// assert_eq!(decode_hamming_24_18(0x00000000), Some(0x00000000));
+/// assert_eq!(decode_hamming_24_18(0x00000001), None);
+/// ```
+pub fn decode_hamming_24_18(mut value: u32) -> Option<u32> {
+    let mut test: u8 = 0;
+
+    // Tests A-F correspond to bits 0-6 respectively in 'test'.
+    for i in 0..23 {
+        test ^= (((value >> i) & 0x01) as u8) * (i + 33);
+    }
+
+    // Only parity bit is tested for bit 24
+    test ^= (((value >> 23) & 0x01) as u8) * 32u8;
+
+    if (test & 0x1f) != 0x1f {
+        // Not all tests A-E correct
+        if (test & 0x20) == 0x20 {
+            // F correct: Double error
+            return None;
+        }
+        // Test F incorrect: Single error
+        value ^= 1 << (30 - test);
+    }
+
+    Some(
+        (value & 0x000004) >> 2
+            | (value & 0x000070) >> 3
+            | (value & 0x007f00) >> 4
+            | (value & 0x7f0000) >> 5,
+    )
+}
+
+/// Returns a crc 32-bit from given 8-bit unsigned integer.
+///
+/// # Exmaples
+/// ```rust
+/// # use lib_ccxr::util::bits::*;
+/// assert_eq!(get_crc32_byte(0), 0x00000000);
+/// assert_eq!(get_crc32_byte(1), 0x04c11db7);
+/// ```
+pub fn get_crc32_byte(value: u8) -> u32 {
+    CRC32_TABLE[value as usize]
+}
+
+/// Verifies the CRC32-bit value
+/// Rust equivalent for `verify_crc32` function in C. Uses Rust-native types as input and output.
+pub fn verify_crc32(buf: &[u8]) -> bool {
+    let mut crc: i32 = -1;
+    for &byte in buf {
+        let expr = ((crc >> 24) ^ (byte & 0xff) as i32) & 0xff;
+        crc = (crc << 8) ^ get_crc32_byte(expr as u8) as i32;
+    }
+    crc == 0
+}

src/rust/lib_ccxr/src/util/levenshtein.rs

@@ -0,0 +1,39 @@
+//! Provides function for calculating levenshtein distance.
+
+use std::cmp::min;
+
+/// Calculates the levenshtein distance between two slices.
+///
+/// # Examples
+/// ```rust
+/// # use lib_ccxr::util::levenshtein::*;
+/// assert_eq!(levenshtein(&[1,2,3,4,5], &[1,3,2,4,5,6]), 3);
+/// ```
+pub fn levenshtein<T: Copy + PartialEq>(a: &[T], b: &[T]) -> usize {
+    let mut column: Vec<usize> = (0..).take(a.len() + 1).collect();
+
+    for x in 1..=b.len() {
+        column[0] = x;
+        let mut lastdiag = x - 1;
+        for y in 1..=a.len() {
+            let olddiag = column[y];
+            column[y] = min(
+                min(column[y] + 1, column[y - 1] + 1),
+                lastdiag + (if a[y - 1] == b[x - 1] { 0 } else { 1 }),
+            );
+            lastdiag = olddiag;
+        }
+    }
+
+    column[a.len()]
+}
+
+/// Rust equivalent for `levenshtein_dist` function in C. Uses Rust-native types as input and output.
+pub fn levenshtein_dist(s1: &[u64], s2: &[u64]) -> usize {
+    levenshtein(s1, s2)
+}
+
+/// Rust equivalent for `levenshtein_dist_char` function in C. Uses Rust-native types as input and output.
+pub fn levenshtein_dist_char<T: Copy + PartialEq>(s1: &[T], s2: &[T]) -> usize {
+    levenshtein(s1, s2)
+}

src/rust/lib_ccxr/src/util/mod.rs

@@ -1,3 +1,5 @@
 //! Provides basic utilities used throughout the program.
 
+pub mod bits;
+pub mod levenshtein;
 pub mod log;

src/rust/src/libccxr_exports/mod.rs

@@ -1,9 +1,12 @@
 //! Provides C-FFI functions that are direct equivalent of functions available in C.
 
 use crate::ccx_s_options;
-use core::panic;
 use lib_ccxr::util::log::*;
+use lib_ccxr::util::{bits::*, levenshtein::*};
+
+use core::panic;
 use std::convert::TryInto;
+use std::os::raw::{c_char, c_int, c_uint};
 
 /// Initializes the logger at the rust side.
 ///
@@ -48,3 +51,62 @@ pub unsafe extern "C" fn ccxr_init_basic_logger(ccx_options: *const ccx_s_option
     ))
     .expect("Failed to initialize and setup the logger");
 }
+
+/// Rust equivalent for `verify_crc32` function in C. Uses C-native types as input and output.
+///
+/// # Safety
+///
+/// `buf` should not be a NULL pointer and the length of buffer pointed by `buf` should be equal to
+/// or less than `len`.
+#[no_mangle]
+pub unsafe extern "C" fn ccxr_verify_crc32(buf: *const u8, len: c_int) -> c_int {
+    let buf = std::slice::from_raw_parts(buf, len as usize);
+    if verify_crc32(buf) {
+        1
+    } else {
+        0
+    }
+}
+
+/// Rust equivalent for `levenshtein_dist` function in C. Uses C-native types as input and output.
+///
+/// # Safety
+///
+/// `s1` and `s2` must valid slices of data with lengths of `s1len` and `s2len` respectively.
+#[no_mangle]
+pub unsafe extern "C" fn ccxr_levenshtein_dist(
+    s1: *const u64,
+    s2: *const u64,
+    s1len: c_uint,
+    s2len: c_uint,
+) -> c_int {
+    let s1 = std::slice::from_raw_parts(s1, s1len.try_into().unwrap());
+    let s2 = std::slice::from_raw_parts(s2, s2len.try_into().unwrap());
+
+    let ans = levenshtein_dist(s1, s2);
+
+    ans.try_into()
+        .expect("Failed to convert the levenshtein distance to C int")
+}
+
+/// Rust equivalent for `levenshtein_dist_char` function in C. Uses C-native types as input and output.
+///
+/// # Safety
+///
+/// `s1` and `s2` must valid slices of data and therefore not be null. They must have lengths
+/// of `s1len` and `s2len` respectively.
+#[no_mangle]
+pub unsafe extern "C" fn ccxr_levenshtein_dist_char(
+    s1: *const c_char,
+    s2: *const c_char,
+    s1len: c_uint,
+    s2len: c_uint,
+) -> c_int {
+    let s1 = std::slice::from_raw_parts(s1, s1len.try_into().unwrap());
+    let s2 = std::slice::from_raw_parts(s2, s2len.try_into().unwrap());
+
+    let ans = levenshtein_dist_char(s1, s2);
+
+    ans.try_into()
+        .expect("Failed to convert the levenshtein distance to C int")
+}