Merge ef5529a0bd into 146936c3a1

ZIP 302: Revert "Final changes to remove undecided parts of the draft"
This reverts commit de694d4509.
2024-03-15 08:31:05 +10:00 · 2022-10-07 07:22:36 +13:00
2 changed files with 45 additions and 2 deletions
--- a/zip-0302.html
+++ b/zip-0302.html
@ -3,6 +3,7 @@
 <head>
    <title>ZIP 302: Standardized Memo Field Format</title>
    <meta charset="utf-8" />
+    <script src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js?config=TeX-AMS-MML_HTMLorMML"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" href="css/style.css"></head>
 <body>
    <section>
@ -37,10 +38,38 @@ Pull-Request: &lt;<a href="https://github.com/zcash/zips/pull/105">https://githu
                        <li>decode it as a UTF-8 string (if decoding fails then report an error).</li>
                    </ul>
                </li>
+                <li>
+                    <dl>
+                        <dt>If the first byte has a value of 0xF5, then the reader MUST:</dt>
+                        <dd>
+                            <ul>
+                                <li>Interpret the next few bytes (1 to 9 of them) as a 64-bit unsigned variable-length integer <a id="footnote-reference-3" class="footnote_reference" href="#bitcoin-compactsize">3</a>, and use it as an arbitrary application-defined "type" field.</li>
+                                <li>Interpret the next 1 or 2 bytes as a CompactSize value constrained to the range 0..510, and use the resulting value as the length of the remaining data.</li>
+                                <li>If 1 + the number bytes used for the type field + the number of bytes used for the length field + the length &gt; 512 then report an error.</li>
+                                <li>Inspect the padding after the end of the indicated length, and if it contains anything other than bytes of value 0x00 then report an error.</li>
+                                <li>
+                                    <dl>
+                                        <dt>Return to the caller a 3-tuple of the following data:</dt>
+                                        <dd>
+                                            <ul>
+                                                <li>the type — an integer in
+                                                    <span class="math">\([0...2^{64})\)</span>
+                                                </li>
+                                                <li>the length — an integer in
+                                                    <span class="math">\([0...510)\)</span>
+                                                </li>
+                                                <li>a byte string of that length that contains the payload</li>
+                                            </ul>
+                                        </dd>
+                                    </dl>
+                                </li>
+                            </ul>
+                        </dd>
+                    </dl>
+                </li>
                <li>If the first byte has a value of 0xF6, and the remaining 511 bytes are 0x00, then the user supplied no memo, and the encrypted memo field is to be treated as empty.</li>
                <li>If the memo matches any of these patterns, then this memo is from the future, because these ranges are reserved for future updates to this specification:
                    <ul>
-                        <li>The first byte has a value of 0xF5.</li>
                        <li>The first byte has a value of 0xF6, and the remaining 511 bytes are not all 0x00.</li>
                        <li>The first byte has a value between 0xF7 and 0xFE inclusive.</li>
                    </ul>
--- a/zip-0302.rst
+++ b/zip-0302.rst
@ -45,13 +45,27 @@ contents of a memo. It does not define consensus requirements.
     + strip any trailing zero bytes
     + decode it as a UTF-8 string (if decoding fails then report an error).

+ If the first byte has a value of 0xF5, then the reader MUST:
+     + Interpret the next few bytes (1 to 9 of them) as a 64-bit unsigned variable-length
+       integer [#Bitcoin-CompactSize]_, and use it as an arbitrary application-defined
+       "type" field.
+     + Interpret the next 1 or 2 bytes as a CompactSize value constrained to the range 0..510, and use
+       the resulting value as the length of the remaining data.
+     + If 1 + the number bytes used for the type field + the number of bytes used for the
+       length field + the length > 512 then report an error.
+     + Inspect the padding after the end of the indicated length, and if it
+       contains anything other than bytes of value 0x00 then report an error.
+     + Return to the caller a 3-tuple of the following data:
+           + the type — an integer in :math:`[0...2^{64})`
+           + the length — an integer in :math:`[0...510)`
+           + a byte string of that length that contains the payload
+
 + If the first byte has a value of 0xF6, and the remaining 511 bytes are 0x00, then the user
  supplied no memo, and the encrypted memo field is to be treated as empty.

 + If the memo matches any of these patterns, then this memo is from the future, because
  these ranges are reserved for future updates to this specification:

-     + The first byte has a value of 0xF5.
     + The first byte has a value of 0xF6, and the remaining 511 bytes are not all 0x00.
     + The first byte has a value between 0xF7 and 0xFE inclusive.
Author	SHA1	Message	Date
str4d	0fd8a9e08f	Merge `ef5529a0bd` into `146936c3a1`	2024-03-15 08:31:05 +10:00
Jack Grigg	ef5529a0bd	ZIP 302: Revert "Final changes to remove undecided parts of the draft" This reverts commit `de694d4509`.	2022-10-07 07:22:36 +13:00