util_accid

Summary. Convert a base58-check encoded r-address string into a 20-byte AccountID. Inverse of util_raddr.

Signature.

int64_t util_accid(
    uint32_t write_ptr,   // where to write the 20-byte AccountID
    uint32_t write_len,   // must be >= 20
    uint32_t read_ptr,    // r-address string
    uint32_t read_len);   // string length (<= 49)

Parameters.

Name	Meaning
write_ptr, write_len	Output buffer for the AccountID. write_len must be at least 20; exactly 20 bytes are written.
read_ptr, read_len	The r-address string. read_len must be at most 49. The string does not need to be NUL-terminated in memory (the API copies read_len bytes and NUL-terminates internally).

Return value. On success, the number of bytes written (write_len is passed through; 20 bytes of AccountID are written). Errors:

Code	Value	Cause
OUT_OF_BOUNDS	-1	write or read region out of bounds.
TOO_SMALL	-4	write_len < 20.
TOO_BIG	-3	read_len > 49.
INVALID_ARGUMENT	-7	The string is not a valid AccountID r-address (base58/checksum failure).

Common failure patterns.

• Feeding an X-address or a currency/family-seed base58 string → INVALID_ARGUMENT (only TokenType::AccountID decodes).
• A trailing NUL counted in read_len can shift decoding; pass the exact character count, not sizeof(buffer).

Caveats. Only classic r-addresses are accepted. There is no validation that the resulting account exists on-ledger — this is a pure string decode.

Minimal example.

uint8_t accid[20];
int64_t r = util_accid(SBUF(accid), SBUF("rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh"));
if (r < 0)
    rollback(SBUF("bad r-address"), r);

Practical example. Decode an r-address supplied as a hook parameter, then use it to look up a trustline keylet:

uint8_t raddr[64];
int64_t rlen = otxn_param(SBUF(raddr), SBUF("DST"));
if (rlen > 0)
{
    uint8_t dst[20];
    if (util_accid(SBUF(dst), raddr, rlen) == 20)
    {
        // dst now usable with util_keylet(..., KEYLET_LINE, ...)
    }
}

Related APIs. util_raddr, otxn_param, util_keylet.