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/* Fixed Huffman table as per RFC1951.
*
* Lit Value Bits Codes
* --------- ---- -----
* 0 - 143 8 00110000 through 10111111
* 144 - 255 9 110010000 through 111111111
* 256 - 279 7 0000000 through 0010111
* 280 - 287 8 11000000 through 11000111
*
* The codes are encoded in reverse, the high bit of the code appears encoded
* as bit 0. The table is built by mkhuff.sh. The 16 bits are encoded this way :
* - bits 0..3 : bits
* - bits 4..12 : code
*/
static const uint16_t fixed_huff[288] = {
0x00c8, 0x08c8, 0x04c8, 0x0cc8, 0x02c8, 0x0ac8, 0x06c8, 0x0ec8, // 0
0x01c8, 0x09c8, 0x05c8, 0x0dc8, 0x03c8, 0x0bc8, 0x07c8, 0x0fc8, // 8
0x0028, 0x0828, 0x0428, 0x0c28, 0x0228, 0x0a28, 0x0628, 0x0e28, // 16
0x0128, 0x0928, 0x0528, 0x0d28, 0x0328, 0x0b28, 0x0728, 0x0f28, // 24
0x00a8, 0x08a8, 0x04a8, 0x0ca8, 0x02a8, 0x0aa8, 0x06a8, 0x0ea8, // 32
0x01a8, 0x09a8, 0x05a8, 0x0da8, 0x03a8, 0x0ba8, 0x07a8, 0x0fa8, // 40
0x0068, 0x0868, 0x0468, 0x0c68, 0x0268, 0x0a68, 0x0668, 0x0e68, // 48
0x0168, 0x0968, 0x0568, 0x0d68, 0x0368, 0x0b68, 0x0768, 0x0f68, // 56
0x00e8, 0x08e8, 0x04e8, 0x0ce8, 0x02e8, 0x0ae8, 0x06e8, 0x0ee8, // 64
0x01e8, 0x09e8, 0x05e8, 0x0de8, 0x03e8, 0x0be8, 0x07e8, 0x0fe8, // 72
0x0018, 0x0818, 0x0418, 0x0c18, 0x0218, 0x0a18, 0x0618, 0x0e18, // 80
0x0118, 0x0918, 0x0518, 0x0d18, 0x0318, 0x0b18, 0x0718, 0x0f18, // 88
0x0098, 0x0898, 0x0498, 0x0c98, 0x0298, 0x0a98, 0x0698, 0x0e98, // 96
0x0198, 0x0998, 0x0598, 0x0d98, 0x0398, 0x0b98, 0x0798, 0x0f98, // 104
0x0058, 0x0858, 0x0458, 0x0c58, 0x0258, 0x0a58, 0x0658, 0x0e58, // 112
0x0158, 0x0958, 0x0558, 0x0d58, 0x0358, 0x0b58, 0x0758, 0x0f58, // 120
0x00d8, 0x08d8, 0x04d8, 0x0cd8, 0x02d8, 0x0ad8, 0x06d8, 0x0ed8, // 128
0x01d8, 0x09d8, 0x05d8, 0x0dd8, 0x03d8, 0x0bd8, 0x07d8, 0x0fd8, // 136
0x0139, 0x1139, 0x0939, 0x1939, 0x0539, 0x1539, 0x0d39, 0x1d39, // 144
0x0339, 0x1339, 0x0b39, 0x1b39, 0x0739, 0x1739, 0x0f39, 0x1f39, // 152
0x00b9, 0x10b9, 0x08b9, 0x18b9, 0x04b9, 0x14b9, 0x0cb9, 0x1cb9, // 160
0x02b9, 0x12b9, 0x0ab9, 0x1ab9, 0x06b9, 0x16b9, 0x0eb9, 0x1eb9, // 168
0x01b9, 0x11b9, 0x09b9, 0x19b9, 0x05b9, 0x15b9, 0x0db9, 0x1db9, // 176
0x03b9, 0x13b9, 0x0bb9, 0x1bb9, 0x07b9, 0x17b9, 0x0fb9, 0x1fb9, // 184
0x0079, 0x1079, 0x0879, 0x1879, 0x0479, 0x1479, 0x0c79, 0x1c79, // 192
0x0279, 0x1279, 0x0a79, 0x1a79, 0x0679, 0x1679, 0x0e79, 0x1e79, // 200
0x0179, 0x1179, 0x0979, 0x1979, 0x0579, 0x1579, 0x0d79, 0x1d79, // 208
0x0379, 0x1379, 0x0b79, 0x1b79, 0x0779, 0x1779, 0x0f79, 0x1f79, // 216
0x00f9, 0x10f9, 0x08f9, 0x18f9, 0x04f9, 0x14f9, 0x0cf9, 0x1cf9, // 224
0x02f9, 0x12f9, 0x0af9, 0x1af9, 0x06f9, 0x16f9, 0x0ef9, 0x1ef9, // 232
0x01f9, 0x11f9, 0x09f9, 0x19f9, 0x05f9, 0x15f9, 0x0df9, 0x1df9, // 240
0x03f9, 0x13f9, 0x0bf9, 0x1bf9, 0x07f9, 0x17f9, 0x0ff9, 0x1ff9, // 248
0x0007, 0x0407, 0x0207, 0x0607, 0x0107, 0x0507, 0x0307, 0x0707, // 256
0x0087, 0x0487, 0x0287, 0x0687, 0x0187, 0x0587, 0x0387, 0x0787, // 264
0x0047, 0x0447, 0x0247, 0x0647, 0x0147, 0x0547, 0x0347, 0x0747, // 272
0x0038, 0x0838, 0x0438, 0x0c38, 0x0238, 0x0a38, 0x0638, 0x0e38 // 280
};
/* length from 3 to 258 converted to bit strings for use with fixed huffman
* coding. It was built by tools/dump_len.c. The format is the following :
* - bits 0..15 = code
* - bits 16..19 = #bits
*/
static const uint32_t len_fh[259] = {
0x000000, 0x000000, 0x000000, 0x070040, /* 0-3 */
0x070020, 0x070060, 0x070010, 0x070050, /* 4-7 */
0x070030, 0x070070, 0x070008, 0x080048, /* 8-11 */
0x0800c8, 0x080028, 0x0800a8, 0x080068, /* 12-15 */
0x0800e8, 0x080018, 0x080098, 0x090058, /* 16-19 */
0x0900d8, 0x090158, 0x0901d8, 0x090038, /* 20-23 */
0x0900b8, 0x090138, 0x0901b8, 0x090078, /* 24-27 */
0x0900f8, 0x090178, 0x0901f8, 0x090004, /* 28-31 */
0x090084, 0x090104, 0x090184, 0x0a0044, /* 32-35 */
0x0a00c4, 0x0a0144, 0x0a01c4, 0x0a0244, /* 36-39 */
0x0a02c4, 0x0a0344, 0x0a03c4, 0x0a0024, /* 40-43 */
0x0a00a4, 0x0a0124, 0x0a01a4, 0x0a0224, /* 44-47 */
0x0a02a4, 0x0a0324, 0x0a03a4, 0x0a0064, /* 48-51 */
0x0a00e4, 0x0a0164, 0x0a01e4, 0x0a0264, /* 52-55 */
0x0a02e4, 0x0a0364, 0x0a03e4, 0x0a0014, /* 56-59 */
0x0a0094, 0x0a0114, 0x0a0194, 0x0a0214, /* 60-63 */
0x0a0294, 0x0a0314, 0x0a0394, 0x0b0054, /* 64-67 */
0x0b00d4, 0x0b0154, 0x0b01d4, 0x0b0254, /* 68-71 */
0x0b02d4, 0x0b0354, 0x0b03d4, 0x0b0454, /* 72-75 */
0x0b04d4, 0x0b0554, 0x0b05d4, 0x0b0654, /* 76-79 */
0x0b06d4, 0x0b0754, 0x0b07d4, 0x0b0034, /* 80-83 */
0x0b00b4, 0x0b0134, 0x0b01b4, 0x0b0234, /* 84-87 */
0x0b02b4, 0x0b0334, 0x0b03b4, 0x0b0434, /* 88-91 */
0x0b04b4, 0x0b0534, 0x0b05b4, 0x0b0634, /* 92-95 */
0x0b06b4, 0x0b0734, 0x0b07b4, 0x0b0074, /* 96-99 */
0x0b00f4, 0x0b0174, 0x0b01f4, 0x0b0274, /* 100-103 */
0x0b02f4, 0x0b0374, 0x0b03f4, 0x0b0474, /* 104-107 */
0x0b04f4, 0x0b0574, 0x0b05f4, 0x0b0674, /* 108-111 */
0x0b06f4, 0x0b0774, 0x0b07f4, 0x0c0003, /* 112-115 */
0x0c0103, 0x0c0203, 0x0c0303, 0x0c0403, /* 116-119 */
0x0c0503, 0x0c0603, 0x0c0703, 0x0c0803, /* 120-123 */
0x0c0903, 0x0c0a03, 0x0c0b03, 0x0c0c03, /* 124-127 */
0x0c0d03, 0x0c0e03, 0x0c0f03, 0x0d0083, /* 128-131 */
0x0d0183, 0x0d0283, 0x0d0383, 0x0d0483, /* 132-135 */
0x0d0583, 0x0d0683, 0x0d0783, 0x0d0883, /* 136-139 */
0x0d0983, 0x0d0a83, 0x0d0b83, 0x0d0c83, /* 140-143 */
0x0d0d83, 0x0d0e83, 0x0d0f83, 0x0d1083, /* 144-147 */
0x0d1183, 0x0d1283, 0x0d1383, 0x0d1483, /* 148-151 */
0x0d1583, 0x0d1683, 0x0d1783, 0x0d1883, /* 152-155 */
0x0d1983, 0x0d1a83, 0x0d1b83, 0x0d1c83, /* 156-159 */
0x0d1d83, 0x0d1e83, 0x0d1f83, 0x0d0043, /* 160-163 */
0x0d0143, 0x0d0243, 0x0d0343, 0x0d0443, /* 164-167 */
0x0d0543, 0x0d0643, 0x0d0743, 0x0d0843, /* 168-171 */
0x0d0943, 0x0d0a43, 0x0d0b43, 0x0d0c43, /* 172-175 */
0x0d0d43, 0x0d0e43, 0x0d0f43, 0x0d1043, /* 176-179 */
0x0d1143, 0x0d1243, 0x0d1343, 0x0d1443, /* 180-183 */
0x0d1543, 0x0d1643, 0x0d1743, 0x0d1843, /* 184-187 */
0x0d1943, 0x0d1a43, 0x0d1b43, 0x0d1c43, /* 188-191 */
0x0d1d43, 0x0d1e43, 0x0d1f43, 0x0d00c3, /* 192-195 */
0x0d01c3, 0x0d02c3, 0x0d03c3, 0x0d04c3, /* 196-199 */
0x0d05c3, 0x0d06c3, 0x0d07c3, 0x0d08c3, /* 200-203 */
0x0d09c3, 0x0d0ac3, 0x0d0bc3, 0x0d0cc3, /* 204-207 */
0x0d0dc3, 0x0d0ec3, 0x0d0fc3, 0x0d10c3, /* 208-211 */
0x0d11c3, 0x0d12c3, 0x0d13c3, 0x0d14c3, /* 212-215 */
0x0d15c3, 0x0d16c3, 0x0d17c3, 0x0d18c3, /* 216-219 */
0x0d19c3, 0x0d1ac3, 0x0d1bc3, 0x0d1cc3, /* 220-223 */
0x0d1dc3, 0x0d1ec3, 0x0d1fc3, 0x0d0023, /* 224-227 */
0x0d0123, 0x0d0223, 0x0d0323, 0x0d0423, /* 228-231 */
0x0d0523, 0x0d0623, 0x0d0723, 0x0d0823, /* 232-235 */
0x0d0923, 0x0d0a23, 0x0d0b23, 0x0d0c23, /* 236-239 */
0x0d0d23, 0x0d0e23, 0x0d0f23, 0x0d1023, /* 240-243 */
0x0d1123, 0x0d1223, 0x0d1323, 0x0d1423, /* 244-247 */
0x0d1523, 0x0d1623, 0x0d1723, 0x0d1823, /* 248-251 */
0x0d1923, 0x0d1a23, 0x0d1b23, 0x0d1c23, /* 252-255 */
0x0d1d23, 0x0d1e23, 0x0800a3 /* 256-258 */
};
#if !defined(__ARM_FEATURE_CRC32)
static uint32_t crc32_fast[4][256];
#endif
static uint32_t fh_dist_table[32768];
#if !defined(__ARM_FEATURE_CRC32)
/* Make the table for a fast CRC.
* Not thread-safe, must be called exactly once.
*/
static inline void __slz_make_crc_table(void)
{
uint32_t c;
int n, k;
for (n = 0; n < 256; n++) {
c = (uint32_t) n ^ 255;
for (k = 0; k < 8; k++) {
if (c & 1) {
c = 0xedb88320 ^ (c >> 1);
} else {
c = c >> 1;
}
}
crc32_fast[0][n] = c ^ 0xff000000;
}
/* Note: here we *do not* have to invert the bits corresponding to the
* byte position, because [0] already has the 8 highest bits inverted,
* and these bits are shifted by 8 at the end of the operation, which
* results in having the next 8 bits shifted in turn. That's why we
* have the xor in the index used just after a computation.
*/
for (n = 0; n < 256; n++) {
crc32_fast[1][n] = 0xff000000 ^ crc32_fast[0][(0xff000000 ^ crc32_fast[0][n] ^ 0xff) & 0xff] ^ (crc32_fast[0][n] >> 8);
crc32_fast[2][n] = 0xff000000 ^ crc32_fast[0][(0x00ff0000 ^ crc32_fast[1][n] ^ 0xff) & 0xff] ^ (crc32_fast[1][n] >> 8);
crc32_fast[3][n] = 0xff000000 ^ crc32_fast[0][(0x0000ff00 ^ crc32_fast[2][n] ^ 0xff) & 0xff] ^ (crc32_fast[2][n] >> 8);
}
}
#endif
/* Returns code for lengths 1 to 32768. The bit size for the next value can be
* found this way :
*
* bits = code >> 1;
* if (bits)
* bits--;
*
*/
static inline uint32_t dist_to_code(uint32_t l)
{
uint32_t code;
code = 0;
switch (l) {
case 24577 ... 32768: code++; /* fall through */
case 16385 ... 24576: code++; /* fall through */
case 12289 ... 16384: code++; /* fall through */
case 8193 ... 12288: code++; /* fall through */
case 6145 ... 8192: code++; /* fall through */
case 4097 ... 6144: code++; /* fall through */
case 3073 ... 4096: code++; /* fall through */
case 2049 ... 3072: code++; /* fall through */
case 1537 ... 2048: code++; /* fall through */
case 1025 ... 1536: code++; /* fall through */
case 769 ... 1024: code++; /* fall through */
case 513 ... 768: code++; /* fall through */
case 385 ... 512: code++; /* fall through */
case 257 ... 384: code++; /* fall through */
case 193 ... 256: code++; /* fall through */
case 129 ... 192: code++; /* fall through */
case 97 ... 128: code++; /* fall through */
case 65 ... 96: code++; /* fall through */
case 49 ... 64: code++; /* fall through */
case 33 ... 48: code++; /* fall through */
case 25 ... 32: code++; /* fall through */
case 17 ... 24: code++; /* fall through */
case 13 ... 16: code++; /* fall through */
case 9 ... 12: code++; /* fall through */
case 7 ... 8: code++; /* fall through */
case 5 ... 6: code++; /* fall through */
case 4 : code++; /* fall through */
case 3 : code++; /* fall through */
case 2 : code++; /* fall through */
}
return code;
}
/* not thread-safe, must be called exactly once */
static inline void __slz_prepare_dist_table()
{
uint32_t dist;
uint32_t code;
uint32_t bits;
for (dist = 0; dist < sizeof(fh_dist_table) / sizeof(*fh_dist_table); dist++) {
code = dist_to_code(dist + 1);
bits = code >> 1;
if (bits)
bits--;
/* Distance codes are stored on 5 bits reversed. The RFC
* doesn't state that they are reversed, but it's the only
* way it works.
*/
code = ((code & 0x01) << 4) | ((code & 0x02) << 2) |
(code & 0x04) |
((code & 0x08) >> 2) | ((code & 0x10) >> 4);
code += (dist & ((1 << bits) - 1)) << 5;
fh_dist_table[dist] = (code << 5) + bits + 5;
}
}
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