TransactionDecoderTrait
Bitcoin transaction decoder trait providing methods to decode raw Bitcoin transaction data.
This trait implements the complete Bitcoin transaction format decoder, supporting both legacy and SegWit transaction formats according to BIP 141. It handles variable-length encoding (compact size), little-endian integer decoding, and proper transaction structure parsing.
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait
pub trait TransactionDecoderTrait
Trait functions
new
Creates a new Bitcoin transaction decoder from raw transaction data.
Arguments
data- Raw Bitcoin transaction data as a ByteArray
Returns
BTCDecoder- Initialized decoder context with offset set to 0
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::new
fn new(data: ByteArray) -> BTCDecoderdecode_transaction
Decodes a complete Bitcoin transaction from the current decoder context.
Parses the entire transaction structure including version, inputs, outputs, witness data (if SegWit), and locktime. Automatically detects SegWit transactions by checking for the marker (0x00) and flag (0x01) bytes.
Arguments
self- Mutable reference to the decoder context
Returns
BitcoinTransaction- Complete decoded transaction structure
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::decode_transaction
fn decode_transaction(ref self: BTCDecoder) -> BitcoinTransactiondecode_input
Decodes a single Bitcoin transaction input from the current position.
Parses input structure: previous TXID (32 bytes), previous output index, script signature with compact size length prefix, and sequence number.
Arguments
self- Mutable reference to the decoder context
Returns
TransactionInput- Decoded input with all fields populated
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::decode_input
fn decode_input(ref self: BTCDecoder) -> TransactionInputdecode_output
Decodes a single Bitcoin transaction output from the current position.
Parses output structure: value (8 bytes, little-endian) and script public key with compact size length prefix.
Arguments
self- Mutable reference to the decoder context
Returns
TransactionOutput- Decoded output with value and script
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::decode_output
fn decode_output(ref self: BTCDecoder) -> TransactionOutputdecode_witness
Decodes SegWit witness data for a single input.
Parses witness stack structure: witness item count (compact size) followed by each witness item with its length prefix and data.
Arguments
self- Mutable reference to the decoder context
Returns
TransactionWitness- Decoded witness data with all stack items
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::decode_witness
fn decode_witness(ref self: BTCDecoder) -> TransactionWitnessread_compact_size
Reads a Bitcoin compact size integer (variable-length encoding).
Implements Bitcoin’s compact size encoding:
- < 0xfd: 1 byte value
- 0xfd: 3 bytes (1 + 2 little-endian)
- 0xfe: 5 bytes (1 + 4 little-endian)
- 0xff: 9 bytes (1 + 8 little-endian)
Arguments
self- Mutable reference to the decoder context
Returns
u64- The decoded integer value
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::read_compact_size
fn read_compact_size(ref self: BTCDecoder) -> u64read_u8
Reads a single byte from the current position.
Arguments
self- Mutable reference to the decoder context
Returns
u8- The byte value at the current position
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::read_u8
fn read_u8(ref self: BTCDecoder) -> u8read_u32_le
Reads 4 bytes as a little-endian unsigned 32-bit integer.
####### Arguments
self- Mutable reference to the decoder context
####### Returns
u32- The decoded little-endian u32 value
Panics
Panics with ‘Not enough bytes for u32’ if fewer than 4 bytes remain.
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::read_u32_le
fn read_u32_le(ref self: BTCDecoder) -> u32read_u64_le
Reads 8 bytes as a little-endian unsigned 64-bit integer.
####### Arguments
self- Mutable reference to the decoder context
####### Returns
u64- The decoded little-endian u64 value
Panics
Panics with ‘Not enough bytes for u64’ if fewer than 8 bytes remain.
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::read_u64_le
fn read_u64_le(ref self: BTCDecoder) -> u64remaining
Checks if there are sufficient bytes remaining to read from the specified offset.
####### Arguments
self- Reference to the decoder contextoffset- The offset position to check fromcount- Number of bytes needed
####### Returns
bool- True if sufficient bytes remain, false otherwise
Fully qualified path: alexandria_btc::decoder::TransactionDecoderTrait::remaining
fn remaining(self: @BTCDecoder, offset: u32, count: u32) -> bool