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musl1.1: backport CVE-2026-6042 and CVE-2026-40200.
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>From 67219f0130ec7c876ac0b299046460fad31caabf Mon Sep 17 00:00:00 2001
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From: Rich Felker <dalias@aerifal.cx>
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Date: Mon, 30 Mar 2026 16:00:50 -0400
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Subject: [PATCH] fix pathological slowness & incorrect mappings in iconv
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gb18030 decoder
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in order to implement the "UTF" aspect of gb18030 (ability to
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represent arbitrary unicode characters not present in the 2-byte
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mapping), we have to apply the index obtained from the encoded 4-byte
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sequence into the set of unmapped characters. this was done by
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scanning repeatedly over the table of mapped characters and counting
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off mapped characters below a running index by which to adjust the
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running index by on each iteration. this iterative process eventually
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leaves us with the value of the Nth unmapped character replacing the
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index, but depending on which particular character that is, the number
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of iterations needed to find it can be in the tens of thousands, and
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each iteration traverses the whole 126x190 table in the inner loop.
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this can lead to run times exceeding an entire second per character on
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moderate-speed machines.
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on top of that, the transformation logic produced wrong results for
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BMP characters above the the surrogate range, as a result of not
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correctly accounting for it being excluded, and for characters outside
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the BMP, as a result of a misunderstanding of how gb18030 encodes
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them.
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this patch replaces the unmapped character lookup with a single linear
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search of a list of unmapped ranges. there are only 206 such ranges,
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and these are permanently assigned and unchangeable as a consequence
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of the character encoding having to be stable, so a simple array of
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16-bit start/length values for each range consumes only 824 bytes, a
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very reasonable size cost here.
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this new table accounts for the previously-incorrect surrogate
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handling, and non-BMP characters are handled correctly by a single
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offset, without the need for any unmapped-range search.
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there are still a small number of mappings that are incorrect due to
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late changes made in the definition of gb18030, swapping PUA
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codepoints with proper Unicode characters. correcting these requires a
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postprocessing step that will be added later.
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---
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src/locale/gb18030utf.h | 206 ++++++++++++++++++++++++++++++++++++++++
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src/locale/iconv.c | 33 +++++--
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2 files changed, 230 insertions(+), 9 deletions(-)
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create mode 100644 src/locale/gb18030utf.h
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diff --git a/src/locale/gb18030utf.h b/src/locale/gb18030utf.h
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new file mode 100644
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index 00000000..322a2440
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--- /dev/null
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+++ b/src/locale/gb18030utf.h
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@@ -0,0 +1,206 @@
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+{ 0x80, 36 },
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+{ 0xa5, 2 },
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+{ 0xa9, 7 },
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+{ 0xb2, 5 },
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+{ 0xb8, 31 },
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+{ 0xd8, 8 },
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+{ 0xe2, 6 },
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+{ 0xeb, 1 },
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+{ 0xee, 4 },
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+{ 0xf4, 3 },
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+{ 0xf8, 1 },
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+{ 0xfb, 1 },
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+{ 0xfd, 4 },
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+{ 0x102, 17 },
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+{ 0x114, 7 },
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+{ 0x11c, 15 },
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+{ 0x12c, 24 },
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+{ 0x145, 3 },
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+{ 0x149, 4 },
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+{ 0x14e, 29 },
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+{ 0x16c, 98 },
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+{ 0x1cf, 1 },
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+{ 0x1d1, 1 },
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+{ 0x1d3, 1 },
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+{ 0x1d5, 1 },
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+{ 0x1d7, 1 },
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+{ 0x1d9, 1 },
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+{ 0x1db, 1 },
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+{ 0x1dd, 28 },
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+{ 0x1fa, 87 },
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+{ 0x252, 15 },
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+{ 0x262, 101 },
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+{ 0x2c8, 1 },
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+{ 0x2cc, 13 },
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+{ 0x2da, 183 },
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+{ 0x3a2, 1 },
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+{ 0x3aa, 7 },
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+{ 0x3c2, 1 },
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+{ 0x3ca, 55 },
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+{ 0x402, 14 },
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+{ 0x450, 1 },
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+{ 0x452, 7102 },
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+{ 0x2011, 2 },
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+{ 0x2017, 1 },
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+{ 0x201a, 2 },
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+{ 0x201e, 7 },
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+{ 0x2027, 9 },
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+{ 0x2031, 1 },
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+{ 0x2034, 1 },
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+{ 0x2036, 5 },
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+{ 0x203c, 112 },
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+{ 0x20ad, 86 },
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+{ 0x2104, 1 },
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+{ 0x2106, 3 },
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+{ 0x210a, 12 },
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+{ 0x2117, 10 },
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+{ 0x2122, 62 },
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+{ 0x216c, 4 },
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+{ 0x217a, 22 },
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+{ 0x2194, 2 },
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+{ 0x219a, 110 },
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+{ 0x2209, 6 },
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+{ 0x2210, 1 },
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+{ 0x2212, 3 },
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+{ 0x2216, 4 },
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+{ 0x221b, 2 },
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+{ 0x2221, 2 },
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+{ 0x2224, 1 },
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+{ 0x2226, 1 },
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+{ 0x222c, 2 },
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+{ 0x222f, 5 },
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+{ 0x2238, 5 },
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+{ 0x223e, 10 },
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+{ 0x2249, 3 },
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+{ 0x224d, 5 },
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+{ 0x2253, 13 },
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+{ 0x2262, 2 },
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+{ 0x2268, 6 },
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+{ 0x2270, 37 },
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+{ 0x2296, 3 },
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+{ 0x229a, 11 },
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+{ 0x22a6, 25 },
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+{ 0x22c0, 82 },
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+{ 0x2313, 333 },
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+{ 0x246a, 10 },
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+{ 0x249c, 100 },
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+{ 0x254c, 4 },
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+{ 0x2574, 13 },
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+{ 0x2590, 3 },
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+{ 0x2596, 10 },
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+{ 0x25a2, 16 },
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+{ 0x25b4, 8 },
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+{ 0x25be, 8 },
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+{ 0x25c8, 3 },
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+{ 0x25cc, 2 },
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+{ 0x25d0, 18 },
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+{ 0x25e6, 31 },
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+{ 0x2607, 2 },
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+{ 0x260a, 54 },
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+{ 0x2641, 1 },
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+{ 0x2643, 2110 },
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+{ 0x2e82, 2 },
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+{ 0x2e85, 3 },
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+{ 0x2e89, 2 },
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+{ 0x2e8d, 10 },
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+{ 0x2e98, 15 },
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+{ 0x2ea8, 2 },
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+{ 0x2eab, 3 },
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+{ 0x2eaf, 4 },
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+{ 0x2eb4, 2 },
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+{ 0x2eb8, 3 },
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+{ 0x2ebc, 14 },
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+{ 0x2ecb, 293 },
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+{ 0x2ffc, 4 },
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+{ 0x3004, 1 },
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+{ 0x3018, 5 },
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+{ 0x301f, 2 },
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+{ 0x302a, 20 },
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+{ 0x303f, 2 },
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+{ 0x3094, 7 },
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+{ 0x309f, 2 },
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+{ 0x30f7, 5 },
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+{ 0x30ff, 6 },
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+{ 0x312a, 246 },
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+{ 0x322a, 7 },
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+{ 0x3232, 113 },
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+{ 0x32a4, 234 },
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+{ 0x3390, 12 },
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+{ 0x339f, 2 },
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+{ 0x33a2, 34 },
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+{ 0x33c5, 9 },
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+{ 0x33cf, 2 },
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+{ 0x33d3, 2 },
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+{ 0x33d6, 113 },
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+{ 0x3448, 43 },
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+{ 0x3474, 298 },
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+{ 0x359f, 111 },
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+{ 0x360f, 11 },
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+{ 0x361b, 765 },
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+{ 0x3919, 85 },
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+{ 0x396f, 96 },
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+{ 0x39d1, 14 },
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+{ 0x39e0, 147 },
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+{ 0x3a74, 218 },
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+{ 0x3b4f, 287 },
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+{ 0x3c6f, 113 },
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+{ 0x3ce1, 885 },
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+{ 0x4057, 264 },
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+{ 0x4160, 471 },
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+{ 0x4338, 116 },
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+{ 0x43ad, 4 },
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+{ 0x43b2, 43 },
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+{ 0x43de, 248 },
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+{ 0x44d7, 373 },
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+{ 0x464d, 20 },
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+{ 0x4662, 193 },
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+{ 0x4724, 5 },
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+{ 0x472a, 82 },
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+{ 0x477d, 16 },
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+{ 0x478e, 441 },
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+{ 0x4948, 50 },
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+{ 0x497b, 2 },
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+{ 0x497e, 4 },
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+{ 0x4984, 1 },
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+{ 0x4987, 20 },
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+{ 0x499c, 3 },
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+{ 0x49a0, 22 },
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+{ 0x49b8, 703 },
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+{ 0x4c78, 39 },
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+{ 0x4ca4, 111 },
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+{ 0x4d1a, 148 },
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+{ 0x4daf, 81 },
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+{ 0x9fa6, 14426 },
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+{ 0xe76c, 1 },
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+{ 0xe7c8, 1 },
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+{ 0xe7e7, 13 },
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+{ 0xe815, 1 },
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+{ 0xe819, 5 },
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+{ 0xe81f, 7 },
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+{ 0xe827, 4 },
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+{ 0xe82d, 4 },
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+{ 0xe833, 8 },
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+{ 0xe83c, 7 },
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+{ 0xe844, 16 },
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+{ 0xe856, 14 },
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+{ 0xe865, 4295 },
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+{ 0xf92d, 76 },
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+{ 0xf97a, 27 },
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+{ 0xf996, 81 },
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+{ 0xf9e8, 9 },
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+{ 0xf9f2, 26 },
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+{ 0xfa10, 1 },
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+{ 0xfa12, 1 },
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+{ 0xfa15, 3 },
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+{ 0xfa19, 6 },
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+{ 0xfa22, 1 },
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+{ 0xfa25, 2 },
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+{ 0xfa2a, 1030 },
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+{ 0xfe32, 1 },
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+{ 0xfe45, 4 },
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+{ 0xfe53, 1 },
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+{ 0xfe58, 1 },
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+{ 0xfe67, 1 },
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+{ 0xfe6c, 149 },
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+{ 0xff5f, 129 },
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+{ 0xffe6, 26 },
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diff --git a/src/locale/iconv.c b/src/locale/iconv.c
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index 52178950..4151411d 100644
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--- a/src/locale/iconv.c
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+++ b/src/locale/iconv.c
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@@ -74,6 +74,10 @@ static const unsigned short gb18030[126][190] = {
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#include "gb18030.h"
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};
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+static const unsigned short gb18030utf[][2] = {
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+#include "gb18030utf.h"
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+};
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+
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static const unsigned short big5[89][157] = {
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#include "big5.h"
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};
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@@ -224,6 +228,8 @@ static unsigned uni_to_jis(unsigned c)
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}
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}
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+#define countof(a) (sizeof (a) / sizeof *(a))
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+
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size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restrict out, size_t *restrict outb)
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{
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size_t x=0;
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@@ -430,15 +436,24 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
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d = *((unsigned char *)*in + 3);
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if (d-'0'>9) goto ilseq;
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c += d-'0';
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- c += 128;
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- for (d=0; d<=c; ) {
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- k = 0;
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- for (int i=0; i<126; i++)
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- for (int j=0; j<190; j++)
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- if (gb18030[i][j]-d <= c-d)
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- k++;
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- d = c+1;
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- c += k;
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+ /* Starting at 90 30 81 30 (189000), mapping is
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+ * linear without gaps, to U+10000 and up. */
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+ if (c >= 189000) {
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+ c -= 189000;
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+ c += 0x10000;
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+ if (c >= 0x110000) goto ilseq;
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+ break;
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+ }
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+ /* Otherwise we must process an index into set
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+ * of characters unmapped by 2-byte table. */
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+ for (int i=0; ; i++) {
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+ if (i==countof(gb18030utf))
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+ goto ilseq;
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+ if (c<gb18030utf[i][1]) {
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+ c += gb18030utf[i][0];
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+ break;
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+ }
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+ c -= gb18030utf[i][1];
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}
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break;
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}
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--
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2.21.0
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