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Unified Diff: third_party/brotli/enc/context.h

Issue 2537133002: Update brotli to v1.0.0-snapshot. (Closed)
Patch Set: Rebase Created 4 years ago
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Index: third_party/brotli/enc/context.h
diff --git a/third_party/brotli/enc/context.h b/third_party/brotli/enc/context.h
index 00c065bccd68f2835b882f1c59171d8816c5d601..9cde400b3816a69ad852487585606a199fb3ccd9 100644
--- a/third_party/brotli/enc/context.h
+++ b/third_party/brotli/enc/context.h
@@ -4,91 +4,95 @@
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
-// Functions to map previous bytes into a context id.
+/* Functions to map previous bytes into a context id. */
#ifndef BROTLI_ENC_CONTEXT_H_
#define BROTLI_ENC_CONTEXT_H_
-#include "./types.h"
-
-namespace brotli {
-
-// Second-order context lookup table for UTF8 byte streams.
-//
-// If p1 and p2 are the previous two bytes, we calculate the context as
-//
-// context = kUTF8ContextLookup[p1] | kUTF8ContextLookup[p2 + 256].
-//
-// If the previous two bytes are ASCII characters (i.e. < 128), this will be
-// equivalent to
-//
-// context = 4 * context1(p1) + context2(p2),
-//
-// where context1 is based on the previous byte in the following way:
-//
-// 0 : non-ASCII control
-// 1 : \t, \n, \r
-// 2 : space
-// 3 : other punctuation
-// 4 : " '
-// 5 : %
-// 6 : ( < [ {
-// 7 : ) > ] }
-// 8 : , ; :
-// 9 : .
-// 10 : =
-// 11 : number
-// 12 : upper-case vowel
-// 13 : upper-case consonant
-// 14 : lower-case vowel
-// 15 : lower-case consonant
-//
-// and context2 is based on the second last byte:
-//
-// 0 : control, space
-// 1 : punctuation
-// 2 : upper-case letter, number
-// 3 : lower-case letter
-//
-// If the last byte is ASCII, and the second last byte is not (in a valid UTF8
-// stream it will be a continuation byte, value between 128 and 191), the
-// context is the same as if the second last byte was an ASCII control or space.
-//
-// If the last byte is a UTF8 lead byte (value >= 192), then the next byte will
-// be a continuation byte and the context id is 2 or 3 depending on the LSB of
-// the last byte and to a lesser extent on the second last byte if it is ASCII.
-//
-// If the last byte is a UTF8 continuation byte, the second last byte can be:
-// - continuation byte: the next byte is probably ASCII or lead byte (assuming
-// 4-byte UTF8 characters are rare) and the context id is 0 or 1.
-// - lead byte (192 - 207): next byte is ASCII or lead byte, context is 0 or 1
-// - lead byte (208 - 255): next byte is continuation byte, context is 2 or 3
-//
-// The possible value combinations of the previous two bytes, the range of
-// context ids and the type of the next byte is summarized in the table below:
-//
-// |--------\-----------------------------------------------------------------|
-// | \ Last byte |
-// | Second \---------------------------------------------------------------|
-// | last byte \ ASCII | cont. byte | lead byte |
-// | \ (0-127) | (128-191) | (192-) |
-// |=============|===================|=====================|==================|
-// | ASCII | next: ASCII/lead | not valid | next: cont. |
-// | (0-127) | context: 4 - 63 | | context: 2 - 3 |
-// |-------------|-------------------|---------------------|------------------|
-// | cont. byte | next: ASCII/lead | next: ASCII/lead | next: cont. |
-// | (128-191) | context: 4 - 63 | context: 0 - 1 | context: 2 - 3 |
-// |-------------|-------------------|---------------------|------------------|
-// | lead byte | not valid | next: ASCII/lead | not valid |
-// | (192-207) | | context: 0 - 1 | |
-// |-------------|-------------------|---------------------|------------------|
-// | lead byte | not valid | next: cont. | not valid |
-// | (208-) | | context: 2 - 3 | |
-// |-------------|-------------------|---------------------|------------------|
+#include <brotli/port.h>
+#include <brotli/types.h>
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+/* Second-order context lookup table for UTF8 byte streams.
+
+ If p1 and p2 are the previous two bytes, we calculate the context as
+
+ context = kUTF8ContextLookup[p1] | kUTF8ContextLookup[p2 + 256].
+
+ If the previous two bytes are ASCII characters (i.e. < 128), this will be
+ equivalent to
+
+ context = 4 * context1(p1) + context2(p2),
+
+ where context1 is based on the previous byte in the following way:
+
+ 0 : non-ASCII control
+ 1 : \t, \n, \r
+ 2 : space
+ 3 : other punctuation
+ 4 : " '
+ 5 : %
+ 6 : ( < [ {
+ 7 : ) > ] }
+ 8 : , ; :
+ 9 : .
+ 10 : =
+ 11 : number
+ 12 : upper-case vowel
+ 13 : upper-case consonant
+ 14 : lower-case vowel
+ 15 : lower-case consonant
+
+ and context2 is based on the second last byte:
+
+ 0 : control, space
+ 1 : punctuation
+ 2 : upper-case letter, number
+ 3 : lower-case letter
+
+ If the last byte is ASCII, and the second last byte is not (in a valid UTF8
+ stream it will be a continuation byte, value between 128 and 191), the
+ context is the same as if the second last byte was an ASCII control or space.
+
+ If the last byte is a UTF8 lead byte (value >= 192), then the next byte will
+ be a continuation byte and the context id is 2 or 3 depending on the LSB of
+ the last byte and to a lesser extent on the second last byte if it is ASCII.
+
+ If the last byte is a UTF8 continuation byte, the second last byte can be:
+ - continuation byte: the next byte is probably ASCII or lead byte (assuming
+ 4-byte UTF8 characters are rare) and the context id is 0 or 1.
+ - lead byte (192 - 207): next byte is ASCII or lead byte, context is 0 or 1
+ - lead byte (208 - 255): next byte is continuation byte, context is 2 or 3
+
+ The possible value combinations of the previous two bytes, the range of
+ context ids and the type of the next byte is summarized in the table below:
+
+ |--------\-----------------------------------------------------------------|
+ | \ Last byte |
+ | Second \---------------------------------------------------------------|
+ | last byte \ ASCII | cont. byte | lead byte |
+ | \ (0-127) | (128-191) | (192-) |
+ |=============|===================|=====================|==================|
+ | ASCII | next: ASCII/lead | not valid | next: cont. |
+ | (0-127) | context: 4 - 63 | | context: 2 - 3 |
+ |-------------|-------------------|---------------------|------------------|
+ | cont. byte | next: ASCII/lead | next: ASCII/lead | next: cont. |
+ | (128-191) | context: 4 - 63 | context: 0 - 1 | context: 2 - 3 |
+ |-------------|-------------------|---------------------|------------------|
+ | lead byte | not valid | next: ASCII/lead | not valid |
+ | (192-207) | | context: 0 - 1 | |
+ |-------------|-------------------|---------------------|------------------|
+ | lead byte | not valid | next: cont. | not valid |
+ | (208-) | | context: 2 - 3 | |
+ |-------------|-------------------|---------------------|------------------|
+*/
static const uint8_t kUTF8ContextLookup[512] = {
- // Last byte.
- //
- // ASCII range.
+ /* Last byte. */
+ /* */
+ /* ASCII range. */
0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 0, 4, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
8, 12, 16, 12, 12, 20, 12, 16, 24, 28, 12, 12, 32, 12, 36, 12,
@@ -97,19 +101,19 @@ static const uint8_t kUTF8ContextLookup[512] = {
52, 52, 52, 52, 52, 48, 52, 52, 52, 52, 52, 24, 12, 28, 12, 12,
12, 56, 60, 60, 60, 56, 60, 60, 60, 56, 60, 60, 60, 60, 60, 56,
60, 60, 60, 60, 60, 56, 60, 60, 60, 60, 60, 24, 12, 28, 12, 0,
- // UTF8 continuation byte range.
+ /* UTF8 continuation byte range. */
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
- // UTF8 lead byte range.
+ /* UTF8 lead byte range. */
2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,
2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,
2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,
2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,
- // Second last byte.
- //
- // ASCII range.
+ /* Second last byte. */
+ /* */
+ /* ASCII range. */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
@@ -118,19 +122,19 @@ static const uint8_t kUTF8ContextLookup[512] = {
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1,
1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 0,
- // UTF8 continuation byte range.
+ /* UTF8 continuation byte range. */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
- // UTF8 lead byte range.
+ /* UTF8 lead byte range. */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
};
-// Context lookup table for small signed integers.
+/* Context lookup table for small signed integers. */
static const uint8_t kSigned3BitContextLookup[] = {
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
@@ -150,29 +154,31 @@ static const uint8_t kSigned3BitContextLookup[] = {
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7,
};
-enum ContextType {
+typedef enum ContextType {
CONTEXT_LSB6 = 0,
CONTEXT_MSB6 = 1,
CONTEXT_UTF8 = 2,
CONTEXT_SIGNED = 3
-};
+} ContextType;
-static inline uint8_t Context(uint8_t p1, uint8_t p2, ContextType mode) {
+static BROTLI_INLINE uint8_t Context(uint8_t p1, uint8_t p2, ContextType mode) {
switch (mode) {
case CONTEXT_LSB6:
return p1 & 0x3f;
case CONTEXT_MSB6:
- return static_cast<uint8_t>(p1 >> 2);
+ return (uint8_t)(p1 >> 2);
case CONTEXT_UTF8:
return kUTF8ContextLookup[p1] | kUTF8ContextLookup[p2 + 256];
case CONTEXT_SIGNED:
- return static_cast<uint8_t>((kSigned3BitContextLookup[p1] << 3) +
- kSigned3BitContextLookup[p2]);
+ return (uint8_t)((kSigned3BitContextLookup[p1] << 3) +
+ kSigned3BitContextLookup[p2]);
default:
return 0;
}
}
-} // namespace brotli
+#if defined(__cplusplus) || defined(c_plusplus)
+} /* extern "C" */
+#endif
-#endif // BROTLI_ENC_CONTEXT_H_
+#endif /* BROTLI_ENC_CONTEXT_H_ */
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