1
2 /*
3 * Copyright (C) Nginx, Inc.
4 * Copyright (C) Valentin V. Bartenev
5 * Copyright (C) 2015 Vlad Krasnov
6 */
7
8
9 #include <ngx_config.h>
10 #include <ngx_core.h>
11 #include <ngx_http.h>
12
13
14 typedef struct {
15 uint32_t code;
16 uint32_t len;
17 } ngx_http_v2_huff_encode_code_t;
18
19
20 static ngx_http_v2_huff_encode_code_t ngx_http_v2_huff_encode_table[256] =
21 {
22 {0x00001ff8, 13}, {0x007fffd8, 23}, {0x0fffffe2, 28}, {0x0fffffe3, 28},
23 {0x0fffffe4, 28}, {0x0fffffe5, 28}, {0x0fffffe6, 28}, {0x0fffffe7, 28},
24 {0x0fffffe8, 28}, {0x00ffffea, 24}, {0x3ffffffc, 30}, {0x0fffffe9, 28},
25 {0x0fffffea, 28}, {0x3ffffffd, 30}, {0x0fffffeb, 28}, {0x0fffffec, 28},
26 {0x0fffffed, 28}, {0x0fffffee, 28}, {0x0fffffef, 28}, {0x0ffffff0, 28},
27 {0x0ffffff1, 28}, {0x0ffffff2, 28}, {0x3ffffffe, 30}, {0x0ffffff3, 28},
28 {0x0ffffff4, 28}, {0x0ffffff5, 28}, {0x0ffffff6, 28}, {0x0ffffff7, 28},
29 {0x0ffffff8, 28}, {0x0ffffff9, 28}, {0x0ffffffa, 28}, {0x0ffffffb, 28},
30 {0x00000014, 6}, {0x000003f8, 10}, {0x000003f9, 10}, {0x00000ffa, 12},
31 {0x00001ff9, 13}, {0x00000015, 6}, {0x000000f8, 8}, {0x000007fa, 11},
32 {0x000003fa, 10}, {0x000003fb, 10}, {0x000000f9, 8}, {0x000007fb, 11},
33 {0x000000fa, 8}, {0x00000016, 6}, {0x00000017, 6}, {0x00000018, 6},
34 {0x00000000, 5}, {0x00000001, 5}, {0x00000002, 5}, {0x00000019, 6},
35 {0x0000001a, 6}, {0x0000001b, 6}, {0x0000001c, 6}, {0x0000001d, 6},
36 {0x0000001e, 6}, {0x0000001f, 6}, {0x0000005c, 7}, {0x000000fb, 8},
37 {0x00007ffc, 15}, {0x00000020, 6}, {0x00000ffb, 12}, {0x000003fc, 10},
38 {0x00001ffa, 13}, {0x00000021, 6}, {0x0000005d, 7}, {0x0000005e, 7},
39 {0x0000005f, 7}, {0x00000060, 7}, {0x00000061, 7}, {0x00000062, 7},
40 {0x00000063, 7}, {0x00000064, 7}, {0x00000065, 7}, {0x00000066, 7},
41 {0x00000067, 7}, {0x00000068, 7}, {0x00000069, 7}, {0x0000006a, 7},
42 {0x0000006b, 7}, {0x0000006c, 7}, {0x0000006d, 7}, {0x0000006e, 7},
43 {0x0000006f, 7}, {0x00000070, 7}, {0x00000071, 7}, {0x00000072, 7},
44 {0x000000fc, 8}, {0x00000073, 7}, {0x000000fd, 8}, {0x00001ffb, 13},
45 {0x0007fff0, 19}, {0x00001ffc, 13}, {0x00003ffc, 14}, {0x00000022, 6},
46 {0x00007ffd, 15}, {0x00000003, 5}, {0x00000023, 6}, {0x00000004, 5},
47 {0x00000024, 6}, {0x00000005, 5}, {0x00000025, 6}, {0x00000026, 6},
48 {0x00000027, 6}, {0x00000006, 5}, {0x00000074, 7}, {0x00000075, 7},
49 {0x00000028, 6}, {0x00000029, 6}, {0x0000002a, 6}, {0x00000007, 5},
50 {0x0000002b, 6}, {0x00000076, 7}, {0x0000002c, 6}, {0x00000008, 5},
51 {0x00000009, 5}, {0x0000002d, 6}, {0x00000077, 7}, {0x00000078, 7},
52 {0x00000079, 7}, {0x0000007a, 7}, {0x0000007b, 7}, {0x00007ffe, 15},
53 {0x000007fc, 11}, {0x00003ffd, 14}, {0x00001ffd, 13}, {0x0ffffffc, 28},
54 {0x000fffe6, 20}, {0x003fffd2, 22}, {0x000fffe7, 20}, {0x000fffe8, 20},
55 {0x003fffd3, 22}, {0x003fffd4, 22}, {0x003fffd5, 22}, {0x007fffd9, 23},
56 {0x003fffd6, 22}, {0x007fffda, 23}, {0x007fffdb, 23}, {0x007fffdc, 23},
57 {0x007fffdd, 23}, {0x007fffde, 23}, {0x00ffffeb, 24}, {0x007fffdf, 23},
58 {0x00ffffec, 24}, {0x00ffffed, 24}, {0x003fffd7, 22}, {0x007fffe0, 23},
59 {0x00ffffee, 24}, {0x007fffe1, 23}, {0x007fffe2, 23}, {0x007fffe3, 23},
60 {0x007fffe4, 23}, {0x001fffdc, 21}, {0x003fffd8, 22}, {0x007fffe5, 23},
61 {0x003fffd9, 22}, {0x007fffe6, 23}, {0x007fffe7, 23}, {0x00ffffef, 24},
62 {0x003fffda, 22}, {0x001fffdd, 21}, {0x000fffe9, 20}, {0x003fffdb, 22},
63 {0x003fffdc, 22}, {0x007fffe8, 23}, {0x007fffe9, 23}, {0x001fffde, 21},
64 {0x007fffea, 23}, {0x003fffdd, 22}, {0x003fffde, 22}, {0x00fffff0, 24},
65 {0x001fffdf, 21}, {0x003fffdf, 22}, {0x007fffeb, 23}, {0x007fffec, 23},
66 {0x001fffe0, 21}, {0x001fffe1, 21}, {0x003fffe0, 22}, {0x001fffe2, 21},
67 {0x007fffed, 23}, {0x003fffe1, 22}, {0x007fffee, 23}, {0x007fffef, 23},
68 {0x000fffea, 20}, {0x003fffe2, 22}, {0x003fffe3, 22}, {0x003fffe4, 22},
69 {0x007ffff0, 23}, {0x003fffe5, 22}, {0x003fffe6, 22}, {0x007ffff1, 23},
70 {0x03ffffe0, 26}, {0x03ffffe1, 26}, {0x000fffeb, 20}, {0x0007fff1, 19},
71 {0x003fffe7, 22}, {0x007ffff2, 23}, {0x003fffe8, 22}, {0x01ffffec, 25},
72 {0x03ffffe2, 26}, {0x03ffffe3, 26}, {0x03ffffe4, 26}, {0x07ffffde, 27},
73 {0x07ffffdf, 27}, {0x03ffffe5, 26}, {0x00fffff1, 24}, {0x01ffffed, 25},
74 {0x0007fff2, 19}, {0x001fffe3, 21}, {0x03ffffe6, 26}, {0x07ffffe0, 27},
75 {0x07ffffe1, 27}, {0x03ffffe7, 26}, {0x07ffffe2, 27}, {0x00fffff2, 24},
76 {0x001fffe4, 21}, {0x001fffe5, 21}, {0x03ffffe8, 26}, {0x03ffffe9, 26},
77 {0x0ffffffd, 28}, {0x07ffffe3, 27}, {0x07ffffe4, 27}, {0x07ffffe5, 27},
78 {0x000fffec, 20}, {0x00fffff3, 24}, {0x000fffed, 20}, {0x001fffe6, 21},
79 {0x003fffe9, 22}, {0x001fffe7, 21}, {0x001fffe8, 21}, {0x007ffff3, 23},
80 {0x003fffea, 22}, {0x003fffeb, 22}, {0x01ffffee, 25}, {0x01ffffef, 25},
81 {0x00fffff4, 24}, {0x00fffff5, 24}, {0x03ffffea, 26}, {0x007ffff4, 23},
82 {0x03ffffeb, 26}, {0x07ffffe6, 27}, {0x03ffffec, 26}, {0x03ffffed, 26},
83 {0x07ffffe7, 27}, {0x07ffffe8, 27}, {0x07ffffe9, 27}, {0x07ffffea, 27},
84 {0x07ffffeb, 27}, {0x0ffffffe, 28}, {0x07ffffec, 27}, {0x07ffffed, 27},
85 {0x07ffffee, 27}, {0x07ffffef, 27}, {0x07fffff0, 27}, {0x03ffffee, 26}
86 };
87
88
89 /* same as above, but embeds lowercase transformation */
90 static ngx_http_v2_huff_encode_code_t ngx_http_v2_huff_encode_table_lc[256] =
91 {
92 {0x00001ff8, 13}, {0x007fffd8, 23}, {0x0fffffe2, 28}, {0x0fffffe3, 28},
93 {0x0fffffe4, 28}, {0x0fffffe5, 28}, {0x0fffffe6, 28}, {0x0fffffe7, 28},
94 {0x0fffffe8, 28}, {0x00ffffea, 24}, {0x3ffffffc, 30}, {0x0fffffe9, 28},
95 {0x0fffffea, 28}, {0x3ffffffd, 30}, {0x0fffffeb, 28}, {0x0fffffec, 28},
96 {0x0fffffed, 28}, {0x0fffffee, 28}, {0x0fffffef, 28}, {0x0ffffff0, 28},
97 {0x0ffffff1, 28}, {0x0ffffff2, 28}, {0x3ffffffe, 30}, {0x0ffffff3, 28},
98 {0x0ffffff4, 28}, {0x0ffffff5, 28}, {0x0ffffff6, 28}, {0x0ffffff7, 28},
99 {0x0ffffff8, 28}, {0x0ffffff9, 28}, {0x0ffffffa, 28}, {0x0ffffffb, 28},
100 {0x00000014, 6}, {0x000003f8, 10}, {0x000003f9, 10}, {0x00000ffa, 12},
101 {0x00001ff9, 13}, {0x00000015, 6}, {0x000000f8, 8}, {0x000007fa, 11},
102 {0x000003fa, 10}, {0x000003fb, 10}, {0x000000f9, 8}, {0x000007fb, 11},
103 {0x000000fa, 8}, {0x00000016, 6}, {0x00000017, 6}, {0x00000018, 6},
104 {0x00000000, 5}, {0x00000001, 5}, {0x00000002, 5}, {0x00000019, 6},
105 {0x0000001a, 6}, {0x0000001b, 6}, {0x0000001c, 6}, {0x0000001d, 6},
106 {0x0000001e, 6}, {0x0000001f, 6}, {0x0000005c, 7}, {0x000000fb, 8},
107 {0x00007ffc, 15}, {0x00000020, 6}, {0x00000ffb, 12}, {0x000003fc, 10},
108 {0x00001ffa, 13}, {0x00000003, 5}, {0x00000023, 6}, {0x00000004, 5},
109 {0x00000024, 6}, {0x00000005, 5}, {0x00000025, 6}, {0x00000026, 6},
110 {0x00000027, 6}, {0x00000006, 5}, {0x00000074, 7}, {0x00000075, 7},
111 {0x00000028, 6}, {0x00000029, 6}, {0x0000002a, 6}, {0x00000007, 5},
112 {0x0000002b, 6}, {0x00000076, 7}, {0x0000002c, 6}, {0x00000008, 5},
113 {0x00000009, 5}, {0x0000002d, 6}, {0x00000077, 7}, {0x00000078, 7},
114 {0x00000079, 7}, {0x0000007a, 7}, {0x0000007b, 7}, {0x00001ffb, 13},
115 {0x0007fff0, 19}, {0x00001ffc, 13}, {0x00003ffc, 14}, {0x00000022, 6},
116 {0x00007ffd, 15}, {0x00000003, 5}, {0x00000023, 6}, {0x00000004, 5},
117 {0x00000024, 6}, {0x00000005, 5}, {0x00000025, 6}, {0x00000026, 6},
118 {0x00000027, 6}, {0x00000006, 5}, {0x00000074, 7}, {0x00000075, 7},
119 {0x00000028, 6}, {0x00000029, 6}, {0x0000002a, 6}, {0x00000007, 5},
120 {0x0000002b, 6}, {0x00000076, 7}, {0x0000002c, 6}, {0x00000008, 5},
121 {0x00000009, 5}, {0x0000002d, 6}, {0x00000077, 7}, {0x00000078, 7},
122 {0x00000079, 7}, {0x0000007a, 7}, {0x0000007b, 7}, {0x00007ffe, 15},
123 {0x000007fc, 11}, {0x00003ffd, 14}, {0x00001ffd, 13}, {0x0ffffffc, 28},
124 {0x000fffe6, 20}, {0x003fffd2, 22}, {0x000fffe7, 20}, {0x000fffe8, 20},
125 {0x003fffd3, 22}, {0x003fffd4, 22}, {0x003fffd5, 22}, {0x007fffd9, 23},
126 {0x003fffd6, 22}, {0x007fffda, 23}, {0x007fffdb, 23}, {0x007fffdc, 23},
127 {0x007fffdd, 23}, {0x007fffde, 23}, {0x00ffffeb, 24}, {0x007fffdf, 23},
128 {0x00ffffec, 24}, {0x00ffffed, 24}, {0x003fffd7, 22}, {0x007fffe0, 23},
129 {0x00ffffee, 24}, {0x007fffe1, 23}, {0x007fffe2, 23}, {0x007fffe3, 23},
130 {0x007fffe4, 23}, {0x001fffdc, 21}, {0x003fffd8, 22}, {0x007fffe5, 23},
131 {0x003fffd9, 22}, {0x007fffe6, 23}, {0x007fffe7, 23}, {0x00ffffef, 24},
132 {0x003fffda, 22}, {0x001fffdd, 21}, {0x000fffe9, 20}, {0x003fffdb, 22},
133 {0x003fffdc, 22}, {0x007fffe8, 23}, {0x007fffe9, 23}, {0x001fffde, 21},
134 {0x007fffea, 23}, {0x003fffdd, 22}, {0x003fffde, 22}, {0x00fffff0, 24},
135 {0x001fffdf, 21}, {0x003fffdf, 22}, {0x007fffeb, 23}, {0x007fffec, 23},
136 {0x001fffe0, 21}, {0x001fffe1, 21}, {0x003fffe0, 22}, {0x001fffe2, 21},
137 {0x007fffed, 23}, {0x003fffe1, 22}, {0x007fffee, 23}, {0x007fffef, 23},
138 {0x000fffea, 20}, {0x003fffe2, 22}, {0x003fffe3, 22}, {0x003fffe4, 22},
139 {0x007ffff0, 23}, {0x003fffe5, 22}, {0x003fffe6, 22}, {0x007ffff1, 23},
140 {0x03ffffe0, 26}, {0x03ffffe1, 26}, {0x000fffeb, 20}, {0x0007fff1, 19},
141 {0x003fffe7, 22}, {0x007ffff2, 23}, {0x003fffe8, 22}, {0x01ffffec, 25},
142 {0x03ffffe2, 26}, {0x03ffffe3, 26}, {0x03ffffe4, 26}, {0x07ffffde, 27},
143 {0x07ffffdf, 27}, {0x03ffffe5, 26}, {0x00fffff1, 24}, {0x01ffffed, 25},
144 {0x0007fff2, 19}, {0x001fffe3, 21}, {0x03ffffe6, 26}, {0x07ffffe0, 27},
145 {0x07ffffe1, 27}, {0x03ffffe7, 26}, {0x07ffffe2, 27}, {0x00fffff2, 24},
146 {0x001fffe4, 21}, {0x001fffe5, 21}, {0x03ffffe8, 26}, {0x03ffffe9, 26},
147 {0x0ffffffd, 28}, {0x07ffffe3, 27}, {0x07ffffe4, 27}, {0x07ffffe5, 27},
148 {0x000fffec, 20}, {0x00fffff3, 24}, {0x000fffed, 20}, {0x001fffe6, 21},
149 {0x003fffe9, 22}, {0x001fffe7, 21}, {0x001fffe8, 21}, {0x007ffff3, 23},
150 {0x003fffea, 22}, {0x003fffeb, 22}, {0x01ffffee, 25}, {0x01ffffef, 25},
151 {0x00fffff4, 24}, {0x00fffff5, 24}, {0x03ffffea, 26}, {0x007ffff4, 23},
152 {0x03ffffeb, 26}, {0x07ffffe6, 27}, {0x03ffffec, 26}, {0x03ffffed, 26},
153 {0x07ffffe7, 27}, {0x07ffffe8, 27}, {0x07ffffe9, 27}, {0x07ffffea, 27},
154 {0x07ffffeb, 27}, {0x0ffffffe, 28}, {0x07ffffec, 27}, {0x07ffffed, 27},
155 {0x07ffffee, 27}, {0x07ffffef, 27}, {0x07fffff0, 27}, {0x03ffffee, 26}
156 };
157
158
159 #if (NGX_PTR_SIZE == 8)
160
161 #if (NGX_HAVE_LITTLE_ENDIAN)
162
163 #if (NGX_HAVE_GCC_BSWAP64)
164 #define ngx_http_v2_huff_encode_buf(dst, buf) \
165 (*(uint64_t *) (dst) = __builtin_bswap64(buf))
166 #else
167 #define ngx_http_v2_huff_encode_buf(dst, buf) \
168 ((dst)[0] = (u_char) ((buf) >> 56), \
169 (dst)[1] = (u_char) ((buf) >> 48), \
170 (dst)[2] = (u_char) ((buf) >> 40), \
171 (dst)[3] = (u_char) ((buf) >> 32), \
172 (dst)[4] = (u_char) ((buf) >> 24), \
173 (dst)[5] = (u_char) ((buf) >> 16), \
174 (dst)[6] = (u_char) ((buf) >> 8), \
175 (dst)[7] = (u_char) (buf))
176 #endif
177
178 #else /* !NGX_HAVE_LITTLE_ENDIAN */
179 #define ngx_http_v2_huff_encode_buf(dst, buf) \
180 (*(uint64_t *) (dst) = (buf))
181 #endif
182
183 #else /* NGX_PTR_SIZE == 4 */
184
185 #define ngx_http_v2_huff_encode_buf(dst, buf) \
186 (*(uint32_t *) (dst) = htonl(buf))
187
188 #endif
189
190
191 size_t
ngx_http_v2_huff_encode(u_char * src,size_t len,u_char * dst,ngx_uint_t lower)192 ngx_http_v2_huff_encode(u_char *src, size_t len, u_char *dst, ngx_uint_t lower)
193 {
194 u_char *end;
195 size_t hlen;
196 ngx_uint_t buf, pending, code;
197 ngx_http_v2_huff_encode_code_t *table, *next;
198
199 table = lower ? ngx_http_v2_huff_encode_table_lc
200 : ngx_http_v2_huff_encode_table;
201 hlen = 0;
202 buf = 0;
203 pending = 0;
204
205 end = src + len;
206
207 while (src != end) {
208 next = &table[*src++];
209
210 code = next->code;
211 pending += next->len;
212
213 /* accumulate bits */
214 if (pending < sizeof(buf) * 8) {
215 buf |= code << (sizeof(buf) * 8 - pending);
216 continue;
217 }
218
219 if (hlen + sizeof(buf) >= len) {
220 return 0;
221 }
222
223 pending -= sizeof(buf) * 8;
224
225 buf |= code >> pending;
226
227 ngx_http_v2_huff_encode_buf(&dst[hlen], buf);
228
229 hlen += sizeof(buf);
230
231 buf = pending ? code << (sizeof(buf) * 8 - pending) : 0;
232 }
233
234 if (pending == 0) {
235 return hlen;
236 }
237
238 buf |= (ngx_uint_t) -1 >> pending;
239
240 pending = ngx_align(pending, 8);
241
242 if (hlen + pending / 8 >= len) {
243 return 0;
244 }
245
246 buf >>= sizeof(buf) * 8 - pending;
247
248 do {
249 pending -= 8;
250 dst[hlen++] = (u_char) (buf >> pending);
251 } while (pending);
252
253 return hlen;
254 }
255