(define-constant ALL_HEX 0x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
(define-constant BASE58_CHARS "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
(define-constant STX_VER 0x16141a15)
(define-constant BTC_VER 0x00056fc4)
(define-constant LST (list))
(define-constant ERR_INVALID_ADDR (err u1))
(define-constant ERR_PLACEHOLDER (err u999))
;; Phase 1A: Add basic validation for Base58 characters
(define-constant ERR_INVALID_B58_CHAR (err u10))
(define-constant ERR_B58_TOO_LONG (err u11))
;; Check if a character is a valid Base58 character
(define-read-only (is-b58-char (c (string-ascii 1)))
(is-some (index-of? BASE58_CHARS c)))
;; Validate that a string only contains valid Base58 characters
(define-read-only (validate-b58-addr (addr (string-ascii 44)))
(let (
;; Check length
(l1 (asserts! (<= (len addr) u44) ERR_B58_TOO_LONG))
;; The address cannot be empty
(l2 (asserts! (> (len addr) u0) ERR_INVALID_B58_CHAR))
;; Check first character
(c1 (unwrap! (element-at? addr u0) ERR_INVALID_B58_CHAR))
(v1 (asserts! (is-b58-char c1) ERR_INVALID_B58_CHAR))
;; Check more characters if they exist
(c2 (if (>= (len addr) u2) (unwrap! (element-at? addr u1) ERR_INVALID_B58_CHAR) "1"))
(v2 (if (>= (len addr) u2) (asserts! (is-b58-char c2) ERR_INVALID_B58_CHAR) true))
(c3 (if (>= (len addr) u3) (unwrap! (element-at? addr u2) ERR_INVALID_B58_CHAR) "1"))
(v3 (if (>= (len addr) u3) (asserts! (is-b58-char c3) ERR_INVALID_B58_CHAR) true))
)
(ok true)))
(define-read-only (convert (addr principal))
(match (principal-destruct? addr)
;; if version byte match the network (ie. mainnet principal on mainnet, or testnet principal on testnet)
network-match-data (convert-inner network-match-data)
;; if versin byte does not match the network
network-not-match-data (convert-inner network-not-match-data)
)
)
(define-private (convert-inner (data {hash-bytes: (buff 20), name: (optional (string-ascii 40)), version:(buff 1)}))
(let (
;; exit early if contract principal
(t1 (asserts! (is-none (get name data)) ERR_INVALID_ADDR))
;; convert STX version byte to BTC version
(version (unwrap-panic (element-at? BTC_VER (unwrap-panic (index-of? STX_VER (get version data))))))
;; concat BTC version & hash160
(versioned-hash-bytes (concat version (get hash-bytes data)))
;; concat hash-bytes & 4 bytes checksum, and convert hext to uint
(to-encode (map hex-to-uint (concat
versioned-hash-bytes
;; checksum = encode versionded-hash-bytes 2x with sha256, and then extract first 4 bytes
;; we can use unwrap-panic twice, because sha256 of empty buff will alwasy return value
(unwrap-panic (as-max-len? (unwrap-panic (slice? (sha256 (sha256 versioned-hash-bytes)) u0 u4)) u4))
)))
;; "cut" leading zeros leveraging index-of? property
;; first convert list of uint's to list of booleans that tells if value was 0 or not
;; (list u0 u0 u2 u23 u0 u3 u53 u22) -> (list true true false false true false false false)
;; since index-of? always returns first index we use it to find the position of first non-zero value
;; and we default it to u0 - in case it won't find anything
;; in our example, it will return (some u2)
;; the reason why we default to u0 is that (slice? (list u0 u0 u2 u23 u0 u3 u53 u22) u0 u0) will return (some (list))
;; it guarantees that our slice? will never return (none) so we can safely use unwrap-panic here
(leading-zeros (unwrap-panic (slice? to-encode u0 (default-to u0 (index-of? (map is-zero to-encode) false)))))
)
(ok
(fold
convert-to-base58-string
;; run through "outer-loop" everything except leading zeros
;; and concatenate results with leading zeros if any
;; we use u25, because hash-bytes (aka. hash160) = 20 bytes, version = 1 byte, and checksum = 4 bytes
(concat (fold outer-loop (unwrap-panic (slice? to-encode (len leading-zeros) u25)) LST) leading-zeros)
""
)
)
)
)
(define-read-only (outer-loop (x uint) (out (list 44 uint)))
(let (
(new-out (fold update-out out (list x)))
(push (fold carry-push 0x0000 (list (unwrap-panic (element-at? new-out u0)))))
)
(concat
(default-to LST (slice? new-out u1 (len new-out)))
(default-to LST (slice? push u1 (len push)))
)
)
)
(define-read-only (update-out (x uint) (out (list 35 uint)))
(let (
;; first byte of out is always a carry from previous iteration
(carry (+ (unwrap-panic (element-at? out u0)) (* x u256)))
)
(unwrap-panic (as-max-len? (concat
(list (/ carry u58)) ;; new carry
(concat
(default-to LST (slice? out u1 (len out))) ;; existing list
(list (mod carry u58)) ;; new value we want to append
)
) u35))
)
)
(define-read-only (carry-push (x (buff 1)) (out (list 9 uint)))
(let (
;; first byte of out is always a carry from previous iteration
(carry (unwrap-panic (element-at? out u0)))
)
(if (> carry u0)
;; we only change out if cary is > u0
(unwrap-panic (as-max-len? (concat
(list (/ carry u58)) ;; new carry
(concat
(default-to LST (slice? out u1 (len out))) ;; existing list
(list (mod carry u58)) ;; new value we want to append
)
) u9))
;; do nothing
out
)
)
)
;; converts uint to base58 caracter and concatenate in reverse order
(define-read-only (convert-to-base58-string (x uint) (out (string-ascii 44)))
(unwrap-panic (as-max-len? (concat (unwrap-panic (element-at? BASE58_CHARS x)) out) u44))
)
(define-read-only (hex-to-uint (x (buff 1))) (unwrap-panic (index-of? ALL_HEX x)))
(define-read-only (is-zero (i uint)) (<= i u0))
;; Phase 1B-1: Add support for parsing Base58 characters to numeric values
;; Convert a Base58 character to its numeric index (0-57)
(define-read-only (b58-char-to-uint (c (string-ascii 1)))
;; Simply return the index, will panic if character is invalid
(unwrap-panic (index-of? BASE58_CHARS c)))
;; Count leading '1' characters in the address (these represent leading zeros in binary)
(define-read-only (count-leading-ones (addr (string-ascii 44)))
(let (
(len-addr (len addr))
(c1 (default-to "" (element-at? addr u0)))
(c2 (default-to "" (element-at? addr u1)))
(c3 (default-to "" (element-at? addr u2)))
(count
(+
(if (and (> len-addr u0) (is-eq c1 "1")) u1 u0)
(if (and (> len-addr u1) (is-eq c1 "1") (is-eq c2 "1")) u1 u0)
(if (and (> len-addr u2) (is-eq c1 "1") (is-eq c2 "1") (is-eq c3 "1")) u1 u0)))
)
count))
;; Phase 1B-2: Simplest possible Base58 value extraction
;; Get the decimal value of the first character in a Bitcoin address
(define-read-only (get-first-char-value (addr (string-ascii 44)))
(let (
(first-char (unwrap! (element-at? addr u0) ERR_INVALID_B58_CHAR))
)
(ok (b58-char-to-uint first-char))))
;; Phase 1B-3: Handle first non-leading-one character
;; Get the first non-leading-one character's value
(define-read-only (get-first-non-one-value (addr (string-ascii 44)))
(let (
;; Count leading '1' characters
(ones (count-leading-ones addr))
;; Get address length
(addr-len (len addr))
;; Check if there are any non-one characters
(has-non-ones (> addr-len ones))
)
(if has-non-ones
;; Get the value of the first non-one character
(let ((char (unwrap! (element-at? addr ones) ERR_INVALID_B58_CHAR)))
(ok (b58-char-to-uint char)))
;; If the address is all ones, return 0
(ok u0))))
;; Phase 1B-4: Create buffer with leading zeros
;; Create a buffer with a specified number of leading zeros
(define-read-only (create-zeroes-buffer (count uint))
(if (is-eq count u0)
(ok 0x) ;; Empty buffer
(if (is-eq count u1)
(ok 0x00)
(if (is-eq count u2)
(ok 0x0000)
(if (is-eq count u3)
(ok 0x000000)
(ok 0x00000000))))))
;; First step of decoding: handle leading ones and convert to leading zeroes
(define-read-only (get-leading-zeroes (addr (string-ascii 44)))
(let (
(ones-count (count-leading-ones addr))
)
(create-zeroes-buffer ones-count)))
;; Phase 1B-5: Extract first few significant characters from address
;; Get first few characters after leading ones and convert to their Base58 values
(define-read-only (get-first-few-chars (addr (string-ascii 44)))
(let (
;; Find where to start (after any leading ones)
(start-idx (count-leading-ones addr))
;; Get the address length
(addr-len (len addr))
;; Determine how many characters to process (up to 3 non-one chars)
(chars-to-process (if (< (- addr-len start-idx) u3)
(- addr-len start-idx)
u3))
;; Get the first character value if available
(val1 (if (>= chars-to-process u1)
(b58-char-to-uint (unwrap! (element-at? addr (+ start-idx u0)) ERR_INVALID_B58_CHAR))
u0))
;; Get the second character value if available
(val2 (if (>= chars-to-process u2)
(b58-char-to-uint (unwrap! (element-at? addr (+ start-idx u1)) ERR_INVALID_B58_CHAR))
u0))
;; Get the third character value if available
(val3 (if (>= chars-to-process u3)
(b58-char-to-uint (unwrap! (element-at? addr (+ start-idx u2)) ERR_INVALID_B58_CHAR))
u0))
)
;; Return a tuple with the parsed values
(ok {
processed-count: chars-to-process,
val1: val1,
val2: val2,
val3: val3
})))
;; Phase 2A-1: Start implementing the full Base58 decoder
;; Initialize an array of zeros for result buffer
(define-read-only (make-zero-buffer (length uint))
(list u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0 u0))
;; Helper function to multiply a byte by 58 and handle carry
(define-read-only (mul-byte-by-58 (byte uint) (state {carry: uint, result: (list 25 uint), index: uint}))
(let (
;; Multiply current byte by 58 and add carry from previous
(product (+ (* byte u58) (get carry state)))
;; Store the remainder (byte value after applying carry)
(remainder (mod product u256))
;; Calculate new carry for next byte
(new-carry (/ product u256))
;; Current index we're processing
(current-index (get index state))
;; Update result list with new byte value
(new-result (unwrap-panic (replace-at? (get result state) current-index remainder)))
)
;; Return updated state
{
carry: new-carry,
result: new-result,
index: (+ current-index u1)
}
)
)
;; Process a single base58 digit during decoding
(define-read-only (process-b58-digit (digit uint) (accumulator (list 25 uint)))
(let (
;; Initial state with zero carry, original accumulator, and starting at index 0
(initial-state {carry: u0, result: accumulator, index: u0})
;; Apply mul-byte-by-58 to each byte in the accumulator (from left to right)
(final-state (fold mul-byte-by-58 accumulator initial-state))
)
;; Return the result from the final state
(get result final-state)))
;; Phase 2B: Extract and map version byte
;; Define a constant for BTC to STX version mapping
(define-constant BTC_TO_STX_VER 0x16141a15) ;; Same bytes as STX_VER but interpreted in reverse
;; Extract version byte (first byte) from decoded data and map to STX version
(define-read-only (map-btc-to-stx-version (decoded-bytes (list 25 uint)))
(let (
;; Get the first byte (version) from decoded data
(btc-version (unwrap! (element-at? decoded-bytes u0) ERR_INVALID_ADDR))
;; Convert version to buffer for lookup
(btc-ver-buff (if (is-eq btc-version u0)
0x00
(if (is-eq btc-version u5)
0x05
(if (is-eq btc-version u111) ;; 0x6f (testnet P2PKH)
0x6f
0xc4)))) ;; 0xc4 (testnet P2SH)
;; Map BTC version to STX version
(index (unwrap! (index-of? BTC_VER btc-ver-buff) ERR_INVALID_ADDR))
(stx-version (unwrap-panic (element-at? STX_VER index)))
)
(ok stx-version)))
;; Phase 2C: Extract hash160 payload from decoded data
;; Define error code for hash160 extraction
(define-constant ERR_INVALID_HASH160 (err u12))
;; Fix extract-hash160 to handle errors consistently
(define-read-only (extract-hash160 (decoded-bytes (list 25 uint)))
(let (
;; Make sure we have at least 21 bytes
(has-enough-bytes (>= (len decoded-bytes) u21))
)
(if has-enough-bytes
;; Get bytes 1-21 (skip version byte at index 0)
(ok (unwrap-panic (as-max-len?
(unwrap-panic (slice? decoded-bytes u1 u21))
u20)))
;; Return specific error if not enough bytes
ERR_INVALID_HASH160)))
;; Phase 2D: Create Stacks principal from version and hash160
;; Define error code for principal construction
(define-constant ERR_PRINCIPAL_CONSTRUCTION (err u13))
;; Phase 2E: Implement more realistic hash160 conversion
;; Convert integers to a buffer byte (helper for hash160 conversion)
(define-read-only (int-to-byte (n uint))
(if (is-eq n u0) 0x00
(if (< n u16)
(unwrap-panic (element-at? ALL_HEX n))
(if (< n u32)
(unwrap-panic (element-at? ALL_HEX n))
(unwrap-panic (element-at? ALL_HEX n))))))
;; Create a simple hash160 buffer from the first few integers
(define-read-only (create-hash160-buff (hash160-ints (list 20 uint)))
(let (
;; Get first 4 bytes from hash160 list for a start
(byte1 (default-to u0 (element-at? hash160-ints u0)))
(byte2 (default-to u0 (element-at? hash160-ints u1)))
(byte3 (default-to u0 (element-at? hash160-ints u2)))
(byte4 (default-to u0 (element-at? hash160-ints u3)))
;; Convert to buffer bytes
(b1 (int-to-byte byte1))
(b2 (int-to-byte byte2))
(b3 (int-to-byte byte3))
(b4 (int-to-byte byte4))
;; Combine into a buffer (just 4 bytes for now)
(partial-buff (concat (concat (concat b1 b2) b3) b4))
;; Pad to full 20 bytes
(full-buff (concat partial-buff 0x0000000000000000000000000000000000))
)
;; Return the buffer trimmed to exactly 20 bytes
(unwrap-panic (as-max-len? full-buff u20))))
;; Update create-stx-principal to use our hash160 buffer conversion
(define-read-only (create-stx-principal (version (buff 1)) (hash160-uint (list 20 uint)))
(let (
;; Convert integers to a buffer
(hash160-buff (create-hash160-buff hash160-uint))
;; Create principal
(principal (principal-construct? version hash160-buff))
)
(match principal
success (ok success)
failure ERR_PRINCIPAL_CONSTRUCTION)))
;; Update main function to actually return the constructed principal
(define-read-only (btc->stx-addr (btc-addr (string-ascii 44)))
(begin
;; Validate the address
(try! (validate-b58-addr btc-addr))
;; Process characters and get decoded bytes (just first few for now)
(let (
(char-data (unwrap! (get-first-few-chars btc-addr) ERR_PLACEHOLDER))
(digit1 (get val1 char-data))
(bytes (process-b58-digit digit1 (make-zero-buffer u25)))
;; Map BTC version to STX version
(stx-version (try! (map-btc-to-stx-version bytes)))
;; Extract hash160 payload
(hash160 (try! (extract-hash160 bytes)))
;; Create Stacks principal
(principal (try! (create-stx-principal stx-version hash160)))
)
;; Return the principal instead of placeholder error
(ok principal))))