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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
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parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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-rw-r--r--netwerk/protocol/http/make_incoming_tables.py194
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diff --git a/netwerk/protocol/http/make_incoming_tables.py b/netwerk/protocol/http/make_incoming_tables.py
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+# This script exists to auto-generate Http2HuffmanIncoming.h from the table
+# contained in the HPACK spec. It's pretty simple to run:
+# python make_incoming_tables.py < http2_huffman_table.txt > Http2HuffmanIncoming.h
+# where huff_incoming.txt is copy/pasted text from the latest version of the
+# HPACK spec, with all non-relevant lines removed (the most recent version
+# of huff_incoming.txt also lives in this directory as an example).
+import sys
+
+def char_cmp(x, y):
+ rv = cmp(x['nbits'], y['nbits'])
+ if not rv:
+ rv = cmp(x['bpat'], y['bpat'])
+ if not rv:
+ rv = cmp(x['ascii'], y['ascii'])
+ return rv
+
+characters = []
+
+for line in sys.stdin:
+ line = line.rstrip()
+ obracket = line.rfind('[')
+ nbits = int(line[obracket + 1:-1])
+
+ oparen = line.find(' (')
+ ascii = int(line[oparen + 2:oparen + 5].strip())
+
+ bar = line.find('|', oparen)
+ space = line.find(' ', bar)
+ bpat = line[bar + 1:space].strip().rstrip('|')
+
+ characters.append({'ascii': ascii, 'nbits': nbits, 'bpat': bpat})
+
+characters.sort(cmp=char_cmp)
+raw_entries = []
+for c in characters:
+ raw_entries.append((c['ascii'], c['bpat']))
+
+class DefaultList(list):
+ def __init__(self, default=None):
+ self.__default = default
+
+ def __ensure_size(self, sz):
+ while sz > len(self):
+ self.append(self.__default)
+
+ def __getitem__(self, idx):
+ self.__ensure_size(idx + 1)
+ rv = super(DefaultList, self).__getitem__(idx)
+ return rv
+
+ def __setitem__(self, idx, val):
+ self.__ensure_size(idx + 1)
+ super(DefaultList, self).__setitem__(idx, val)
+
+def expand_to_8bit(bstr):
+ while len(bstr) < 8:
+ bstr += '0'
+ return int(bstr, 2)
+
+table = DefaultList()
+for r in raw_entries:
+ ascii, bpat = r
+ ascii = int(ascii)
+ bstrs = bpat.split('|')
+ curr_table = table
+ while len(bstrs) > 1:
+ idx = expand_to_8bit(bstrs[0])
+ if curr_table[idx] is None:
+ curr_table[idx] = DefaultList()
+ curr_table = curr_table[idx]
+ bstrs.pop(0)
+
+ idx = expand_to_8bit(bstrs[0])
+ curr_table[idx] = {'prefix_len': len(bstrs[0]),
+ 'mask': int(bstrs[0], 2),
+ 'value': ascii}
+
+
+def output_table(table, name_suffix=''):
+ max_prefix_len = 0
+ for i, t in enumerate(table):
+ if isinstance(t, dict):
+ if t['prefix_len'] > max_prefix_len:
+ max_prefix_len = t['prefix_len']
+ elif t is not None:
+ output_table(t, '%s_%s' % (name_suffix, i))
+
+ tablename = 'HuffmanIncoming%s' % (name_suffix if name_suffix else 'Root',)
+ entriestable = tablename.replace('HuffmanIncoming', 'HuffmanIncomingEntries')
+ nexttable = tablename.replace('HuffmanIncoming', 'HuffmanIncomingNextTables')
+ sys.stdout.write('static const HuffmanIncomingEntry %s[] = {\n' %
+ (entriestable,))
+ prefix_len = 0
+ value = 0
+ i = 0
+ while i < 256:
+ t = table[i]
+ if isinstance(t, dict):
+ value = t['value']
+ prefix_len = t['prefix_len']
+ elif t is not None:
+ break
+
+ sys.stdout.write(' { %s, %s }' %
+ (value, prefix_len))
+ sys.stdout.write(',\n')
+ i += 1
+
+ indexOfFirstNextTable = i
+ if i < 256:
+ sys.stdout.write('};\n')
+ sys.stdout.write('\n')
+ sys.stdout.write('static const HuffmanIncomingTable* %s[] = {\n' %
+ (nexttable,))
+ while i < 256:
+ subtable = '%s_%s' % (name_suffix, i)
+ ptr = '&HuffmanIncoming%s' % (subtable,)
+ sys.stdout.write(' %s' %
+ (ptr))
+ sys.stdout.write(',\n')
+ i += 1
+ else:
+ nexttable = 'nullptr'
+
+ sys.stdout.write('};\n')
+ sys.stdout.write('\n')
+ sys.stdout.write('static const HuffmanIncomingTable %s = {\n' % (tablename,))
+ sys.stdout.write(' %s,\n' % (entriestable,))
+ sys.stdout.write(' %s,\n' % (nexttable,))
+ sys.stdout.write(' %s,\n' % (indexOfFirstNextTable,))
+ sys.stdout.write(' %s\n' % (max_prefix_len,))
+ sys.stdout.write('};\n')
+ sys.stdout.write('\n')
+
+sys.stdout.write('''/*
+ * THIS FILE IS AUTO-GENERATED. DO NOT EDIT!
+ */
+#ifndef mozilla__net__Http2HuffmanIncoming_h
+#define mozilla__net__Http2HuffmanIncoming_h
+
+namespace mozilla {
+namespace net {
+
+struct HuffmanIncomingTable;
+
+struct HuffmanIncomingEntry {
+ const uint16_t mValue:9; // 9 bits so it can hold 0..256
+ const uint16_t mPrefixLen:7; // only holds 1..8
+};
+
+// The data members are public only so they can be statically constructed. All
+// accesses should be done through the functions.
+struct HuffmanIncomingTable {
+ // The normal entries, for indices in the range 0..(mNumEntries-1).
+ const HuffmanIncomingEntry* const mEntries;
+
+ // The next tables, for indices in the range mNumEntries..255. Must be
+ // |nullptr| if mIndexOfFirstNextTable is 256.
+ const HuffmanIncomingTable** const mNextTables;
+
+ // The index of the first next table (equal to the number of entries in
+ // mEntries). This cannot be a uint8_t because it can have the value 256,
+ // in which case there are no next tables and mNextTables must be |nullptr|.
+ const uint16_t mIndexOfFirstNextTable;
+
+ const uint8_t mPrefixLen;
+
+ bool IndexHasANextTable(uint8_t aIndex) const
+ {
+ return aIndex >= mIndexOfFirstNextTable;
+ }
+
+ const HuffmanIncomingEntry* Entry(uint8_t aIndex) const
+ {
+ MOZ_ASSERT(aIndex < mIndexOfFirstNextTable);
+ return &mEntries[aIndex];
+ }
+
+ const HuffmanIncomingTable* NextTable(uint8_t aIndex) const
+ {
+ MOZ_ASSERT(aIndex >= mIndexOfFirstNextTable);
+ return mNextTables[aIndex - mIndexOfFirstNextTable];
+ }
+};
+
+''')
+
+output_table(table)
+
+sys.stdout.write('''} // namespace net
+} // namespace mozilla
+
+#endif // mozilla__net__Http2HuffmanIncoming_h
+''')