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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
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diff --git a/media/ffvpx/libavutil/adler32.c b/media/ffvpx/libavutil/adler32.c
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+/*
+ * Compute the Adler-32 checksum of a data stream.
+ * This is a modified version based on adler32.c from the zlib library.
+ *
+ * Copyright (C) 1995 Mark Adler
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+/**
+ * @file
+ * Computes the Adler-32 checksum of a data stream
+ *
+ * This is a modified version based on adler32.c from the zlib library.
+ * @author Mark Adler
+ * @ingroup lavu_adler32
+ */
+
+#include "config.h"
+#include "adler32.h"
+#include "common.h"
+#include "intreadwrite.h"
+
+#define BASE 65521L /* largest prime smaller than 65536 */
+
+#define DO1(buf) { s1 += *buf++; s2 += s1; }
+#define DO4(buf) DO1(buf); DO1(buf); DO1(buf); DO1(buf);
+#define DO16(buf) DO4(buf); DO4(buf); DO4(buf); DO4(buf);
+
+unsigned long av_adler32_update(unsigned long adler, const uint8_t * buf,
+ unsigned int len)
+{
+ unsigned long s1 = adler & 0xffff;
+ unsigned long s2 = adler >> 16;
+
+ while (len > 0) {
+#if HAVE_FAST_64BIT && HAVE_FAST_UNALIGNED && !CONFIG_SMALL
+ unsigned len2 = FFMIN((len-1) & ~7, 23*8);
+ if (len2) {
+ uint64_t a1= 0;
+ uint64_t a2= 0;
+ uint64_t b1= 0;
+ uint64_t b2= 0;
+ len -= len2;
+ s2 += s1*len2;
+ while (len2 >= 8) {
+ uint64_t v = AV_RN64(buf);
+ a2 += a1;
+ b2 += b1;
+ a1 += v &0x00FF00FF00FF00FF;
+ b1 += (v>>8)&0x00FF00FF00FF00FF;
+ len2 -= 8;
+ buf+=8;
+ }
+
+ //We combine the 8 interleaved adler32 checksums without overflows
+ //Decreasing the number of iterations would allow below code to be
+ //simplified but would likely be slower due to the fewer iterations
+ //of the inner loop
+ s1 += ((a1+b1)*0x1000100010001)>>48;
+ s2 += ((((a2&0xFFFF0000FFFF)+(b2&0xFFFF0000FFFF)+((a2>>16)&0xFFFF0000FFFF)+((b2>>16)&0xFFFF0000FFFF))*0x800000008)>>32)
+#if HAVE_BIGENDIAN
+ + 2*((b1*0x1000200030004)>>48)
+ + ((a1*0x1000100010001)>>48)
+ + 2*((a1*0x0000100020003)>>48);
+#else
+ + 2*((a1*0x4000300020001)>>48)
+ + ((b1*0x1000100010001)>>48)
+ + 2*((b1*0x3000200010000)>>48);
+#endif
+ }
+#else
+ while (len > 4 && s2 < (1U << 31)) {
+ DO4(buf);
+ len -= 4;
+ }
+#endif
+ DO1(buf); len--;
+ s1 %= BASE;
+ s2 %= BASE;
+ }
+ return (s2 << 16) | s1;
+}