47 lines
1.5 KiB
TypeScript
47 lines
1.5 KiB
TypeScript
// ── Little-endian read helpers ─────────────────────────────────────
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export function readU8(buf: Uint8Array, off: number): number {
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return buf[off];
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}
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export function readU16(buf: Uint8Array, off: number): number {
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return buf[off] | (buf[off + 1] << 8);
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}
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export function readU32(buf: Uint8Array, off: number): number {
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return (buf[off] | (buf[off + 1] << 8) | (buf[off + 2] << 16) | (buf[off + 3] << 24)) >>> 0;
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}
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export function readI8(buf: Uint8Array, off: number): number {
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const v = buf[off];
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return v > 127 ? v - 256 : v;
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}
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export function readI16(buf: Uint8Array, off: number): number {
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const v = readU16(buf, off);
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return v > 32767 ? v - 65536 : v;
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}
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export function readI32(buf: Uint8Array, off: number): number {
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return buf[off] | (buf[off + 1] << 8) | (buf[off + 2] << 16) | (buf[off + 3] << 24);
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}
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export function readU64(buf: Uint8Array, off: number): bigint {
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const lo = BigInt(readU32(buf, off));
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const hi = BigInt(readU32(buf, off + 4));
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return (hi << 32n) | lo;
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}
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export function readI64(buf: Uint8Array, off: number): bigint {
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const v = readU64(buf, off);
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return v > 0x7FFFFFFFFFFFFFFFn ? v - 0x10000000000000000n : v;
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}
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/** Read null-terminated ASCII string of max `maxLen` bytes */
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export function readNullTermString(buf: Uint8Array, off: number, maxLen: number): string {
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let end = off;
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while (end < off + maxLen && buf[end] !== 0) end++;
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const decoder = new TextDecoder('ascii');
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return decoder.decode(buf.subarray(off, end));
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}
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