Adding libwebp: Adding clean copy of libwebp 0.4.0

This commit imports libwebp 0.4.0, including AUTHORS, COPYING, ChangeLog,
NEWS, PATENTS, README and src directories. In src, only includes header
and source files.

The patches required to build it in Qt will follow in separate
commit(s).

Task-number: QTBUG-14205
Change-Id: I747918fe2a07716f66cffb795129f7aa5e067759
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 207 insertions, 0 deletions

diff --git a/src/3rdparty/libwebp/src/utils/bit_reader.c b/src/3rdparty/libwebp/src/utils/bit_reader.c
new file mode 100644
index 0000000..bfa4d7d
--- /dev/null
+++ b/src/3rdparty/libwebp/src/utils/bit_reader.c
@@ -0,0 +1,207 @@
+// Copyright 2010 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Boolean decoder
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "./bit_reader.h"
+
+#ifndef USE_RIGHT_JUSTIFY
+#define MK(X) (((range_t)(X) << (BITS)) | (MASK))
+#else
+#define MK(X) ((range_t)(X))
+#endif
+
+//------------------------------------------------------------------------------
+// VP8BitReader
+
+void VP8InitBitReader(VP8BitReader* const br,
+                      const uint8_t* const start, const uint8_t* const end) {
+  assert(br != NULL);
+  assert(start != NULL);
+  assert(start <= end);
+  br->range_   = MK(255 - 1);
+  br->buf_     = start;
+  br->buf_end_ = end;
+  br->value_   = 0;
+  br->bits_    = -8;   // to load the very first 8bits
+  br->eof_     = 0;
+}
+
+const uint8_t kVP8Log2Range[128] = {
+     7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
+  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+  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,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  0
+};
+
+// range = (range << kVP8Log2Range[range]) + trailing 1's
+const range_t kVP8NewRange[128] = {
+  MK(127), MK(127), MK(191), MK(127), MK(159), MK(191), MK(223), MK(127),
+  MK(143), MK(159), MK(175), MK(191), MK(207), MK(223), MK(239), MK(127),
+  MK(135), MK(143), MK(151), MK(159), MK(167), MK(175), MK(183), MK(191),
+  MK(199), MK(207), MK(215), MK(223), MK(231), MK(239), MK(247), MK(127),
+  MK(131), MK(135), MK(139), MK(143), MK(147), MK(151), MK(155), MK(159),
+  MK(163), MK(167), MK(171), MK(175), MK(179), MK(183), MK(187), MK(191),
+  MK(195), MK(199), MK(203), MK(207), MK(211), MK(215), MK(219), MK(223),
+  MK(227), MK(231), MK(235), MK(239), MK(243), MK(247), MK(251), MK(127),
+  MK(129), MK(131), MK(133), MK(135), MK(137), MK(139), MK(141), MK(143),
+  MK(145), MK(147), MK(149), MK(151), MK(153), MK(155), MK(157), MK(159),
+  MK(161), MK(163), MK(165), MK(167), MK(169), MK(171), MK(173), MK(175),
+  MK(177), MK(179), MK(181), MK(183), MK(185), MK(187), MK(189), MK(191),
+  MK(193), MK(195), MK(197), MK(199), MK(201), MK(203), MK(205), MK(207),
+  MK(209), MK(211), MK(213), MK(215), MK(217), MK(219), MK(221), MK(223),
+  MK(225), MK(227), MK(229), MK(231), MK(233), MK(235), MK(237), MK(239),
+  MK(241), MK(243), MK(245), MK(247), MK(249), MK(251), MK(253), MK(127)
+};
+
+#undef MK
+
+void VP8LoadFinalBytes(VP8BitReader* const br) {
+  assert(br != NULL && br->buf_ != NULL);
+  // Only read 8bits at a time
+  if (br->buf_ < br->buf_end_) {
+#ifndef USE_RIGHT_JUSTIFY
+    br->value_ |= (bit_t)(*br->buf_++) << ((BITS) - 8 - br->bits_);
+#else
+    br->value_ = (bit_t)(*br->buf_++) | (br->value_ << 8);
+#endif
+    br->bits_ += 8;
+  } else if (!br->eof_) {
+#ifdef USE_RIGHT_JUSTIFY
+    // These are not strictly needed, but it makes the behaviour
+    // consistent for both USE_RIGHT_JUSTIFY and !USE_RIGHT_JUSTIFY.
+    br->value_ <<= 8;
+    br->bits_ += 8;
+#endif
+    br->eof_ = 1;
+  }
+}
+
+//------------------------------------------------------------------------------
+// Higher-level calls
+
+uint32_t VP8GetValue(VP8BitReader* const br, int bits) {
+  uint32_t v = 0;
+  while (bits-- > 0) {
+    v |= VP8GetBit(br, 0x80) << bits;
+  }
+  return v;
+}
+
+int32_t VP8GetSignedValue(VP8BitReader* const br, int bits) {
+  const int value = VP8GetValue(br, bits);
+  return VP8Get(br) ? -value : value;
+}
+
+//------------------------------------------------------------------------------
+// VP8LBitReader
+
+#define MAX_NUM_BIT_READ 25
+
+#define LBITS 64      // Number of bits prefetched.
+#define WBITS 32      // Minimum number of bytes needed after VP8LFillBitWindow.
+#define LOG8_WBITS 4  // Number of bytes needed to store WBITS bits.
+
+static const uint32_t kBitMask[MAX_NUM_BIT_READ] = {
+  0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767,
+  65535, 131071, 262143, 524287, 1048575, 2097151, 4194303, 8388607, 16777215
+};
+
+void VP8LInitBitReader(VP8LBitReader* const br,
+                       const uint8_t* const start,
+                       size_t length) {
+  size_t i;
+  assert(br != NULL);
+  assert(start != NULL);
+  assert(length < 0xfffffff8u);   // can't happen with a RIFF chunk.
+
+  br->buf_ = start;
+  br->len_ = length;
+  br->val_ = 0;
+  br->pos_ = 0;
+  br->bit_pos_ = 0;
+  br->eos_ = 0;
+  br->error_ = 0;
+  for (i = 0; i < sizeof(br->val_) && i < br->len_; ++i) {
+    br->val_ |= ((vp8l_val_t)br->buf_[br->pos_]) << (8 * i);
+    ++br->pos_;
+  }
+}
+
+void VP8LBitReaderSetBuffer(VP8LBitReader* const br,
+                            const uint8_t* const buf, size_t len) {
+  assert(br != NULL);
+  assert(buf != NULL);
+  assert(len < 0xfffffff8u);   // can't happen with a RIFF chunk.
+  br->eos_ = (br->pos_ >= len);
+  br->buf_ = buf;
+  br->len_ = len;
+}
+
+// If not at EOS, reload up to LBITS byte-by-byte
+static void ShiftBytes(VP8LBitReader* const br) {
+  while (br->bit_pos_ >= 8 && br->pos_ < br->len_) {
+    br->val_ >>= 8;
+    br->val_ |= ((vp8l_val_t)br->buf_[br->pos_]) << (LBITS - 8);
+    ++br->pos_;
+    br->bit_pos_ -= 8;
+  }
+}
+
+void VP8LFillBitWindow(VP8LBitReader* const br) {
+  if (br->bit_pos_ >= WBITS) {
+#if (defined(__x86_64__) || defined(_M_X64))
+    if (br->pos_ + sizeof(br->val_) < br->len_) {
+      br->val_ >>= WBITS;
+      br->bit_pos_ -= WBITS;
+      // The expression below needs a little-endian arch to work correctly.
+      // This gives a large speedup for decoding speed.
+      br->val_ |= *(const vp8l_val_t*)(br->buf_ + br->pos_) << (LBITS - WBITS);
+      br->pos_ += LOG8_WBITS;
+      return;
+    }
+#endif
+    ShiftBytes(br);       // Slow path.
+    if (br->pos_ == br->len_ && br->bit_pos_ >= LBITS) {
+      br->eos_ = 1;
+    }
+  }
+}
+
+uint32_t VP8LReadBits(VP8LBitReader* const br, int n_bits) {
+  assert(n_bits >= 0);
+  // Flag an error if end_of_stream or n_bits is more than allowed limit.
+  if (!br->eos_ && n_bits < MAX_NUM_BIT_READ) {
+    const uint32_t val =
+        (uint32_t)(br->val_ >> br->bit_pos_) & kBitMask[n_bits];
+    const int new_bits = br->bit_pos_ + n_bits;
+    br->bit_pos_ = new_bits;
+    // If this read is going to cross the read buffer, set the eos flag.
+    if (br->pos_ == br->len_) {
+      if (new_bits >= LBITS) {
+        br->eos_ = 1;
+      }
+    }
+    ShiftBytes(br);
+    return val;
+  } else {
+    br->error_ = 1;
+    return 0;
+  }
+}
+
+//------------------------------------------------------------------------------
+