mirror of
https://libwebsockets.org/repo/libwebsockets
synced 2024-11-24 01:39:33 +00:00
517 lines
12 KiB
C
517 lines
12 KiB
C
/*
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* minilex.c
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*
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* High efficiency lexical state parser
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*
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* Copyright (C)2011-2014 Andy Green <andy@warmcat.com>
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*
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* Licensed under MIT
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*
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* Usage: gcc minihuf.c -o minihuf && ./minihuf > huftable.h
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*
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* Run it twice to test parsing on the generated table on stderr
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define LWS_ARRAY_SIZE(n) (sizeof(n) / sizeof(n[0]))
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struct huf {
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unsigned int code;
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unsigned char len;
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};
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static struct huf huf_literal[] = {
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/* 0x00 */ { 0x1ff8, 13 },
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/* 0x01 */ { 0x7fffd8, 23 },
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/* 0x02 */ { 0xfffffe2, 28 },
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/* 0x03 */ { 0xfffffe3, 28 },
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/* 0x04 */ { 0xfffffe4, 28 },
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/* 0x05 */ { 0xfffffe5, 28 },
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/* 0x06 */ { 0xfffffe6, 28 },
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/* 0x07 */ { 0xfffffe7, 28 },
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/* 0x08 */ { 0xfffffe8, 28 },
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/* 0x09 */ { 0xffffea, 24 },
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/* 0x0a */ { 0x3ffffffc, 30 },
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/* 0x0b */ { 0xfffffe9, 28 },
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/* 0x0c */ { 0xfffffea, 28 },
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/* 0x0d */ { 0x3ffffffd, 30 },
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/* 0x0e */ { 0xfffffeb, 28 },
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/* 0x0f */ { 0xfffffec, 28 },
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/* 0x10 */ { 0xfffffed, 28 },
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/* 0x11 */ { 0xfffffee, 28 },
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/* 0x12 */ { 0xfffffef, 28 },
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/* 0x13 */ { 0xffffff0, 28 },
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/* 0x14 */ { 0xffffff1, 28 },
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/* 0x15 */ { 0xffffff2, 28 },
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/* 0x16 */ { 0x3ffffffe, 30 },
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/* 0x17 */ { 0xffffff3, 28 },
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/* 0x18 */ { 0xffffff4, 28 },
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/* 0x19 */ { 0xffffff5, 28 },
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/* 0x1a */ { 0xffffff6, 28 },
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/* 0x1b */ { 0xffffff7, 28 },
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/* 0x1c */ { 0xffffff8, 28 },
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/* 0x1d */ { 0xffffff9, 28 },
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/* 0x1e */ { 0xffffffa, 28 },
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/* 0x1f */ { 0xffffffb, 28 },
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/* 0x20 */ { 0x14, 6 },
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/* 0x21 */ { 0x3f8, 10 },
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/* 0x22 */ { 0x3f9, 10 },
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/* 0x23 */ { 0xffa, 12 },
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/* 0x24 */ { 0x1ff9, 13 },
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/* 0x25 */ { 0x15, 6 },
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/* 0x26 */ { 0xf8, 8 },
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/* 0x27 */ { 0x7fa, 11 },
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/* 0x28 */ { 0x3fa, 10 },
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/* 0x29 */ { 0x3fb, 10 },
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/* 0x2a */ { 0xf9, 8 },
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/* 0x2b */ { 0x7fb, 11 },
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/* 0x2c */ { 0xfa, 8 },
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/* 0x2d */ { 0x16, 6 },
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/* 0x2e */ { 0x17, 6 },
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/* 0x2f */ { 0x18, 6 },
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/* 0x30 */ { 0x0, 5 },
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/* 0x31 */ { 0x1, 5 },
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/* 0x32 */ { 0x2, 5 },
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/* 0x33 */ { 0x19, 6 },
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/* 0x34 */ { 0x1a, 6 },
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/* 0x35 */ { 0x1b, 6 },
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/* 0x36 */ { 0x1c, 6 },
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/* 0x37 */ { 0x1d, 6 },
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/* 0x38 */ { 0x1e, 6 },
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/* 0x39 */ { 0x1f, 6 },
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/* 0x3a */ { 0x5c, 7 },
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/* 0x3b */ { 0xfb, 8 },
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/* 0x3c */ { 0x7ffc, 15 },
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/* 0x3d */ { 0x20, 6 },
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/* 0x3e */ { 0xffb, 12 },
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/* 0x3f */ { 0x3fc, 10 },
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/* 0x40 */ { 0x1ffa, 13 },
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/* 0x41 */ { 0x21, 6 },
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/* 0x42 */ { 0x5d, 7 },
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/* 0x43 */ { 0x5e, 7 },
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/* 0x44 */ { 0x5f, 7 },
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/* 0x45 */ { 0x60, 7 },
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/* 0x46 */ { 0x61, 7 },
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/* 0x47 */ { 0x62, 7 },
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/* 0x48 */ { 0x63, 7 },
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/* 0x49 */ { 0x64, 7 },
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/* 0x4a */ { 0x65, 7 },
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/* 0x4b */ { 0x66, 7 },
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/* 0x4c */ { 0x67, 7 },
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/* 0x4d */ { 0x68, 7 },
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/* 0x4e */ { 0x69, 7 },
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/* 0x4f */ { 0x6a, 7 },
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/* 0x50 */ { 0x6b, 7 },
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/* 0x51 */ { 0x6c, 7 },
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/* 0x52 */ { 0x6d, 7 },
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/* 0x53 */ { 0x6e, 7 },
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/* 0x54 */ { 0x6f, 7 },
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/* 0x55 */ { 0x70, 7 },
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/* 0x56 */ { 0x71, 7 },
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/* 0x57 */ { 0x72, 7 },
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/* 0x58 */ { 0xfc, 8 },
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/* 0x59 */ { 0x73, 7 },
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/* 0x5a */ { 0xfd, 8 },
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/* 0x5b */ { 0x1ffb, 13 },
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/* 0x5c */ { 0x7fff0, 19 },
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/* 0x5d */ { 0x1ffc, 13 },
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/* 0x5e */ { 0x3ffc, 14 },
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/* 0x5f */ { 0x22, 6 },
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/* 0x60 */ { 0x7ffd, 15 },
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/* 0x61 */ { 0x3, 5 },
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/* 0x62 */ { 0x23, 6 },
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/* 0x63 */ { 0x4, 5 },
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/* 0x64 */ { 0x24, 6 },
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/* 0x65 */ { 0x5, 5 },
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/* 0x66 */ { 0x25, 6 },
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/* 0x67 */ { 0x26, 6 },
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/* 0x68 */ { 0x27, 6 },
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/* 0x69 */ { 0x6, 5 },
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/* 0x6a */ { 0x74, 7 },
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/* 0x6b */ { 0x75, 7 },
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/* 0x6c */ { 0x28, 6 },
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/* 0x6d */ { 0x29, 6 },
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/* 0x6e */ { 0x2a, 6 },
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/* 0x6f */ { 0x7, 5 },
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/* 0x70 */ { 0x2b, 6 },
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/* 0x71 */ { 0x76, 7 },
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/* 0x72 */ { 0x2c, 6 },
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/* 0x73 */ { 0x8, 5 },
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/* 0x74 */ { 0x9, 5 },
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/* 0x75 */ { 0x2d, 6 },
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/* 0x76 */ { 0x77, 7 },
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/* 0x77 */ { 0x78, 7 },
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/* 0x78 */ { 0x79, 7 },
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/* 0x79 */ { 0x7a, 7 },
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/* 0x7a */ { 0x7b, 7 },
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/* 0x7b */ { 0x7ffe, 15 },
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/* 0x7c */ { 0x7fc, 11 },
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/* 0x7d */ { 0x3ffd, 14 },
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/* 0x7e */ { 0x1ffd, 13 },
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/* 0x7f */ { 0xffffffc, 28 },
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/* 0x80 */ { 0xfffe6, 20 },
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/* 0x81 */ { 0x3fffd2, 22 },
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/* 0x82 */ { 0xfffe7, 20 },
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/* 0x83 */ { 0xfffe8, 20 },
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/* 0x84 */ { 0x3fffd3, 22 },
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/* 0x85 */ { 0x3fffd4, 22 },
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/* 0x86 */ { 0x3fffd5, 22 },
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/* 0x87 */ { 0x7fffd9, 23 },
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/* 0x88 */ { 0x3fffd6, 22 },
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/* 0x89 */ { 0x7fffda, 23 },
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/* 0x8a */ { 0x7fffdb, 23 },
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/* 0x8b */ { 0x7fffdc, 23 },
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/* 0x8c */ { 0x7fffdd, 23 },
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/* 0x8d */ { 0x7fffde, 23 },
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/* 0x8e */ { 0xffffeb, 24 },
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/* 0x8f */ { 0x7fffdf, 23 },
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/* 0x90 */ { 0xffffec, 24 },
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/* 0x91 */ { 0xffffed, 24 },
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/* 0x92 */ { 0x3fffd7, 22 },
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/* 0x93 */ { 0x7fffe0, 23 },
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/* 0x94 */ { 0xffffee, 24 },
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/* 0x95 */ { 0x7fffe1, 23 },
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/* 0x96 */ { 0x7fffe2, 23 },
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/* 0x97 */ { 0x7fffe3, 23 },
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/* 0x98 */ { 0x7fffe4, 23 },
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/* 0x99 */ { 0x1fffdc, 21 },
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/* 0x9a */ { 0x3fffd8, 22 },
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/* 0x9b */ { 0x7fffe5, 23 },
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/* 0x9c */ { 0x3fffd9, 22 },
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/* 0x9d */ { 0x7fffe6, 23 },
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/* 0x9e */ { 0x7fffe7, 23 },
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/* 0x9f */ { 0xffffef, 24 },
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/* 0xa0 */ { 0x3fffda, 22 },
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/* 0xa1 */ { 0x1fffdd, 21 },
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/* 0xa2 */ { 0xfffe9, 20 },
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/* 0xa3 */ { 0x3fffdb, 22 },
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/* 0xa4 */ { 0x3fffdc, 22 },
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/* 0xa5 */ { 0x7fffe8, 23 },
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/* 0xa6 */ { 0x7fffe9, 23 },
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/* 0xa7 */ { 0x1fffde, 21 },
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/* 0xa8 */ { 0x7fffea, 23 },
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/* 0xa9 */ { 0x3fffdd, 22 },
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/* 0xaa */ { 0x3fffde, 22 },
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/* 0xab */ { 0xfffff0, 24 },
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/* 0xac */ { 0x1fffdf, 21 },
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/* 0xad */ { 0x3fffdf, 22 },
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/* 0xae */ { 0x7fffeb, 23 },
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/* 0xaf */ { 0x7fffec, 23 },
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/* 0xb0 */ { 0x1fffe0, 21 },
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/* 0xb1 */ { 0x1fffe1, 21 },
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/* 0xb2 */ { 0x3fffe0, 22 },
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/* 0xb3 */ { 0x1fffe2, 21 },
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/* 0xb4 */ { 0x7fffed, 23 },
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/* 0xb5 */ { 0x3fffe1, 22 },
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/* 0xb6 */ { 0x7fffee, 23 },
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/* 0xb7 */ { 0x7fffef, 23 },
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/* 0xb8 */ { 0xfffea, 20 },
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/* 0xb9 */ { 0x3fffe2, 22 },
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/* 0xba */ { 0x3fffe3, 22 },
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/* 0xbb */ { 0x3fffe4, 22 },
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/* 0xbc */ { 0x7ffff0, 23 },
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/* 0xbd */ { 0x3fffe5, 22 },
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/* 0xbe */ { 0x3fffe6, 22 },
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/* 0xbf */ { 0x7ffff1, 23 },
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/* 0xc0 */ { 0x3ffffe0, 26 },
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/* 0xc1 */ { 0x3ffffe1, 26 },
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/* 0xc2 */ { 0xfffeb, 20 },
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/* 0xc3 */ { 0x7fff1, 19 },
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/* 0xc4 */ { 0x3fffe7, 22 },
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/* 0xc5 */ { 0x7ffff2, 23 },
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/* 0xc6 */ { 0x3fffe8, 22 },
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/* 0xc7 */ { 0x1ffffec, 25 },
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/* 0xc8 */ { 0x3ffffe2, 26 },
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/* 0xc9 */ { 0x3ffffe3, 26 },
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/* 0xca */ { 0x3ffffe4, 26 },
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/* 0xcb */ { 0x7ffffde, 27 },
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/* 0xcc */ { 0x7ffffdf, 27 },
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/* 0xcd */ { 0x3ffffe5, 26 },
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/* 0xce */ { 0xfffff1, 24 },
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/* 0xcf */ { 0x1ffffed, 25 },
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/* 0xd0 */ { 0x7fff2, 19 },
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/* 0xd1 */ { 0x1fffe3, 21 },
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/* 0xd2 */ { 0x3ffffe6, 26 },
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/* 0xd3 */ { 0x7ffffe0, 27 },
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/* 0xd4 */ { 0x7ffffe1, 27 },
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/* 0xd5 */ { 0x3ffffe7, 26 },
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/* 0xd6 */ { 0x7ffffe2, 27 },
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/* 0xd7 */ { 0xfffff2, 24 },
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/* 0xd8 */ { 0x1fffe4, 21 },
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/* 0xd9 */ { 0x1fffe5, 21 },
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/* 0xda */ { 0x3ffffe8, 26 },
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/* 0xdb */ { 0x3ffffe9, 26 },
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/* 0xdc */ { 0xffffffd, 28 },
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/* 0xdd */ { 0x7ffffe3, 27 },
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/* 0xde */ { 0x7ffffe4, 27 },
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/* 0xdf */ { 0x7ffffe5, 27 },
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/* 0xe0 */ { 0xfffec, 20 },
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/* 0xe1 */ { 0xfffff3, 24 },
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/* 0xe2 */ { 0xfffed, 20 },
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/* 0xe3 */ { 0x1fffe6, 21 },
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/* 0xe4 */ { 0x3fffe9, 22 },
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/* 0xe5 */ { 0x1fffe7, 21 },
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/* 0xe6 */ { 0x1fffe8, 21 },
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/* 0xe7 */ { 0x7ffff3, 23 },
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/* 0xe8 */ { 0x3fffea, 22 },
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/* 0xe9 */ { 0x3fffeb, 22 },
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/* 0xea */ { 0x1ffffee, 25 },
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/* 0xeb */ { 0x1ffffef, 25 },
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/* 0xec */ { 0xfffff4, 24 },
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/* 0xed */ { 0xfffff5, 24 },
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/* 0xee */ { 0x3ffffea, 26 },
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/* 0xef */ { 0x7ffff4, 23 },
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/* 0xf0 */ { 0x3ffffeb, 26 },
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/* 0xf1 */ { 0x7ffffe6, 27 },
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/* 0xf2 */ { 0x3ffffec, 26 },
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/* 0xf3 */ { 0x3ffffed, 26 },
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/* 0xf4 */ { 0x7ffffe7, 27 },
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/* 0xf5 */ { 0x7ffffe8, 27 },
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/* 0xf6 */ { 0x7ffffe9, 27 },
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/* 0xf7 */ { 0x7ffffea, 27 },
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/* 0xf8 */ { 0x7ffffeb, 27 },
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/* 0xf9 */ { 0xffffffe, 28 },
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/* 0xfa */ { 0x7ffffec, 27 },
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/* 0xfb */ { 0x7ffffed, 27 },
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/* 0xfc */ { 0x7ffffee, 27 },
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/* 0xfd */ { 0x7ffffef, 27 },
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/* 0xfe */ { 0x7fffff0, 27 },
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/* 0xff */ { 0x3ffffee, 26 },
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/* 0x100 */ { 0x3fffffff, 30 },
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};
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int code_bit(int idx, int bit)
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{
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if (bit < huf_literal[idx].len)
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return !!(huf_literal[idx].code & (1 << (huf_literal[idx].len - 1 - bit)));
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return -1;
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}
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#include "huftable.h"
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#define PARALLEL 2
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struct state {
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int terminal;
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int state[PARALLEL];
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int bytepos;
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int real_pos;
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};
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struct state state[2000];
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unsigned char terms[2000];
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int next = 1;
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int lextable_decode(int pos, char c)
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{
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int q = pos + !!c;
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if (lextable_terms[q >> 3] & (1 << (q & 7))) /* terminal */
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return lextable[q] | 0x8000;
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return pos + (lextable[q] << 1);
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}
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int main(void)
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{
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int n = 0;
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int m = 0;
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int prev;
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char c;
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int walk;
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int saw;
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int y;
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int j;
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int pos = 0;
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int biggest = 0;
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int fails = 0;
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m = 0;
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while (m < LWS_ARRAY_SIZE(state)) {
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for (j = 0; j < PARALLEL; j++) {
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state[m].state[j] = 0xffff;
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state[m].terminal = 0;
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}
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m++;
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}
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while (n < LWS_ARRAY_SIZE(huf_literal)) {
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m = 0;
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walk = 0;
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prev = 0;
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while (m < huf_literal[n].len) {
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saw = 0;
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if (state[walk].state[code_bit(n, m)] != 0xffff) {
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/* exists -- go forward */
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walk = state[walk].state[code_bit(n, m)];
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goto again;
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}
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/* something we didn't see before */
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state[walk].state[code_bit(n, m)] = next;
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walk = next++;
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again:
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m++;
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}
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state[walk].terminal = n++;
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state[walk].state[0] = 0; /* terminal marker */
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}
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walk = 0;
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for (n = 0; n < next; n++) {
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state[n].bytepos = walk;
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walk += (2 * 2);
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}
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/* compute everyone's position first */
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pos = 0;
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walk = 0;
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for (n = 0; n < next; n++) {
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state[n].real_pos = pos;
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if (state[n].state[0]) /* nonterminal */
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pos += 2;
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walk ++;
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}
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fprintf(stdout, "static unsigned char lextable[] = {\n");
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#define TERMINAL_MASK 0x8000
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walk = 0;
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pos = 0;
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for (n = 0; n < next; n++) {
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for (m = 0; m < 2; m++) {
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saw = state[n].state[m];
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if (saw == 0) { // c is a terminal then
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m = 2;
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continue;
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}
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if (!m)
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fprintf(stdout, "/* pos %04x: %3d */ ",
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state[n].real_pos, n);
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else
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fprintf(stdout, " ");
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if (saw == 0xffff) {
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fprintf(stdout,
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" 0xff, 0xff, /* 0 = fail */\n ");
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pos ++; /* fail */
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fails++;
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continue;
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}
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if (state[saw].state[0] == 0) { /* points to terminal */
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fprintf(stdout, " /* terminal %d */ 0x%02X,\n",
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state[saw].terminal,
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state[saw].terminal & 0xff);
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terms[(state[n].real_pos + m) >> 3] |=
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1 << ((state[n].real_pos + m) & 7);
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pos++;
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walk++;
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continue;
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}
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j = (state[saw].real_pos - q) >> 1;
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if (j > biggest)
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biggest = j;
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if (j > 0xffff) {
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fprintf(stderr,
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"Jump > 64K bytes ahead (%d to %d)\n",
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state[n].real_pos, state[saw].real_pos);
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return 1;
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}
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fprintf(stdout, " /* %d */ 0x%02X "
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"/* (to 0x%04X state %3d) */,\n",
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m,
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j & 0xff,
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|
state[saw].real_pos, saw);
|
|
pos++;
|
|
|
|
walk++;
|
|
}
|
|
}
|
|
|
|
fprintf(stdout, "/* total size %d bytes, biggest jump %d/256, fails=%d */\n};\n"
|
|
"\n static unsigned char lextable_terms[] = {\n",
|
|
pos, biggest, fails);
|
|
|
|
for (n = 0; n < (walk + 7) / 8; n++) {
|
|
if (!(n & 7))
|
|
fprintf(stdout, "\n\t");
|
|
fprintf(stdout, "0x%02x, ", terms[n]);
|
|
}
|
|
fprintf(stdout, "\n};\n");
|
|
|
|
/*
|
|
* Try to parse every legal input string
|
|
*/
|
|
|
|
for (n = 0; n < LWS_ARRAY_SIZE(huf_literal); n++) {
|
|
walk = 0;
|
|
m = 0;
|
|
y = -1;
|
|
|
|
fprintf(stderr, " trying %d\n", n);
|
|
|
|
while (m < huf_literal[n].len) {
|
|
prev = walk;
|
|
walk = lextable_decode(walk, code_bit(n, m));
|
|
|
|
if (walk == 0xffff) {
|
|
fprintf(stderr, "failed\n");
|
|
return 3;
|
|
}
|
|
|
|
if (walk & 0x8000) {
|
|
y = walk & 0x7fff;
|
|
if (y == 0 && m == 29) {
|
|
y |= 0x100;
|
|
fprintf(stdout,
|
|
"\n/* state that points to "
|
|
"0x100 for disambiguation with "
|
|
"0x0 */\n"
|
|
"#define HUFTABLE_0x100_PREV "
|
|
"%d\n", prev);
|
|
}
|
|
break;
|
|
}
|
|
m++;
|
|
}
|
|
|
|
if (y != n) {
|
|
fprintf(stderr, "decode failed %d got %d (0x%x)\n", n, y, y);
|
|
return 4;
|
|
}
|
|
}
|
|
|
|
fprintf(stderr, "All decode OK\n");
|
|
|
|
return 0;
|
|
}
|