mirror of
https://github.com/webmproject/libwebp.git
synced 2025-02-13 07:22:52 +01:00
f67b5939ad
just flushing the pile: - get rid of Put4 in dsp.c - move LD4 enum value - move more fields and code under the ONLY_KEYFRAME_CODE compile flag - update test_ref.ppm reference (now with FANCY_UPSCALER) - simplify VP8GetSignedValue() - use HE and VE naming for prediction mode instead of H and V - some missing c89 fixes - code style nits all test vectors still passing
79 lines
2.5 KiB
C
79 lines
2.5 KiB
C
// Copyright 2010 Google Inc.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Boolean decoder
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include "bits.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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//-----------------------------------------------------------------------------
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// VP8BitReader
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int VP8Init(VP8BitReader* const br, const uint8_t* buf, uint32_t size) {
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if (!br || !buf || size < 2) {
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return 0;
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}
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br->buf_ = buf + 2;
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br->buf_end_ = buf + size;
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br->left_ = -8;
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br->value_ = (buf[0] << 8) | buf[1];
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br->range_ = 255 - 1;
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return 1;
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}
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const uint8_t kVP8Log2Range[128] = {
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7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
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3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
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2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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0
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};
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// range = ((range + 1) << kVP8Log2Range[range]) - 1
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const uint8_t kVP8NewRange[128] = {
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127, 127, 191, 127, 159, 191, 223, 127, 143, 159, 175, 191, 207, 223, 239,
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127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239,
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247, 127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179,
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183, 187, 191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239,
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243, 247, 251, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149,
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151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179,
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181, 183, 185, 187, 189, 191, 193, 195, 197, 199, 201, 203, 205, 207, 209,
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211, 213, 215, 217, 219, 221, 223, 225, 227, 229, 231, 233, 235, 237, 239,
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241, 243, 245, 247, 249, 251, 253, 127
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};
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//-----------------------------------------------------------------------------
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// Higher-level calls
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uint32_t VP8GetValue(VP8BitReader* const br, int bits) {
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uint32_t v = 0;
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while (bits-- > 0) {
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v |= VP8GetBit(br, 0x80) << bits;
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}
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return v;
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}
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int32_t VP8GetSignedValue(VP8BitReader* const br, int bits) {
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const int value = VP8GetValue(br, bits);
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return VP8Get(br) ? -value : value;
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}
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//-----------------------------------------------------------------------------
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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