File size: 3,384 Bytes
64f7370 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 | import Foundation
import SpeechCore
/// Loads decoded model assets (mel filters, projector weights, embedding
/// table, vocab decode table) from a verified AssetBundle.
/// Internal to the SDK; integrators only see ASRTranscriber.
package final class AssetStore {
package struct Manifest: Codable {
package struct PromptIDs: Codable {
package let user: Int
package let bos_audio: Int
package let audio: Int
package let eos_audio: Int
package let text: [Int]
package let assistant: Int
}
package struct Tokens: Codable {
package let audio_token_id: Int
package let pad_token_id: Int
package let eos_token_ids: [Int]
package let extra_block_token_ids: [Int]
}
package let prompt_ids: PromptIDs
package let tokens: Tokens
}
package let manifest: Manifest
package let hannWindow: [Float]
package let melFilters: [Float]
package let projNormW: [Float]
package let projNormB: [Float]
package let projLinW: [Float] // 512*1024 row-major [out][in]
package let projLinB: [Float]
private let embeddingData: Data // fp16, vocab*512
private let vocabBytes: Data
private let vocabOffsets: [UInt32]
package let embeddingDim = 512
package init(bundle: AssetBundle) throws {
func data(_ name: String) throws -> Data {
try Data(contentsOf: bundle.url(name), options: .mappedIfSafe)
}
func floats(_ name: String) throws -> [Float] {
try data(name).withUnsafeBytes { Array($0.bindMemory(to: Float.self)) }
}
do {
manifest = try JSONDecoder().decode(Manifest.self, from: data("asr_manifest"))
} catch let e as SpeechError {
throw e
} catch {
throw SpeechError.assetMissing("asr_manifest (decode: \(error.localizedDescription))")
}
hannWindow = try floats("hann_window")
melFilters = try floats("mel_filters")
projNormW = try floats("projector_norm_w")
projNormB = try floats("projector_norm_b")
projLinW = try floats("projector_lin_w")
projLinB = try floats("projector_lin_b")
embeddingData = try data("token_embedding")
vocabBytes = try data("vocab_bytes")
vocabOffsets = try data("vocab_offsets").withUnsafeBytes {
Array($0.bindMemory(to: UInt32.self))
}
}
/// fp16 -> fp32 embedding row lookup
package func embedding(for tokenID: Int) -> [Float] {
let rowBytes = embeddingDim * MemoryLayout<Float16>.size
let start = tokenID * rowBytes
return embeddingData.subdata(in: start..<(start + rowBytes)).withUnsafeBytes {
$0.bindMemory(to: Float16.self).map { Float($0) }
}
}
package func decode(_ tokenIDs: [Int]) -> String {
var bytes = Data()
for id in tokenIDs where id >= 0 && id + 1 < vocabOffsets.count {
let a = Int(vocabOffsets[id]), b = Int(vocabOffsets[id + 1])
bytes.append(vocabBytes.subdata(in: a..<b))
}
let raw = String(decoding: bytes, as: UTF8.self)
return raw.trimmingCharacters(in: .whitespacesAndNewlines)
.replacingOccurrences(of: #"\s+"#, with: " ", options: .regularExpression)
}
}
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