summaryrefslogtreecommitdiff
path: root/dependencies/include/libavutil/crc.h
diff options
context:
space:
mode:
Diffstat (limited to 'dependencies/include/libavutil/crc.h')
-rw-r--r--dependencies/include/libavutil/crc.h102
1 files changed, 102 insertions, 0 deletions
diff --git a/dependencies/include/libavutil/crc.h b/dependencies/include/libavutil/crc.h
new file mode 100644
index 0000000..7f59812
--- /dev/null
+++ b/dependencies/include/libavutil/crc.h
@@ -0,0 +1,102 @@
+/*
+ * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * @ingroup lavu_crc32
+ * Public header for CRC hash function implementation.
+ */
+
+#ifndef AVUTIL_CRC_H
+#define AVUTIL_CRC_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "attributes.h"
+
+/**
+ * @defgroup lavu_crc32 CRC
+ * @ingroup lavu_hash
+ * CRC (Cyclic Redundancy Check) hash function implementation.
+ *
+ * This module supports numerous CRC polynomials, in addition to the most
+ * widely used CRC-32-IEEE. See @ref AVCRCId for a list of available
+ * polynomials.
+ *
+ * @{
+ */
+
+typedef uint32_t AVCRC;
+
+typedef enum {
+ AV_CRC_8_ATM,
+ AV_CRC_16_ANSI,
+ AV_CRC_16_CCITT,
+ AV_CRC_32_IEEE,
+ AV_CRC_32_IEEE_LE, /*< reversed bitorder version of AV_CRC_32_IEEE */
+ AV_CRC_16_ANSI_LE, /*< reversed bitorder version of AV_CRC_16_ANSI */
+ AV_CRC_24_IEEE,
+ AV_CRC_8_EBU,
+ AV_CRC_MAX, /*< Not part of public API! Do not use outside libavutil. */
+}AVCRCId;
+
+/**
+ * Initialize a CRC table.
+ * @param ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
+ * @param le If 1, the lowest bit represents the coefficient for the highest
+ * exponent of the corresponding polynomial (both for poly and
+ * actual CRC).
+ * If 0, you must swap the CRC parameter and the result of av_crc
+ * if you need the standard representation (can be simplified in
+ * most cases to e.g. bswap16):
+ * av_bswap32(crc << (32-bits))
+ * @param bits number of bits for the CRC
+ * @param poly generator polynomial without the x**bits coefficient, in the
+ * representation as specified by le
+ * @param ctx_size size of ctx in bytes
+ * @return <0 on failure
+ */
+int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size);
+
+/**
+ * Get an initialized standard CRC table.
+ * @param crc_id ID of a standard CRC
+ * @return a pointer to the CRC table or NULL on failure
+ */
+const AVCRC *av_crc_get_table(AVCRCId crc_id);
+
+/**
+ * Calculate the CRC of a block.
+ * @param ctx initialized AVCRC array (see av_crc_init())
+ * @param crc CRC of previous blocks if any or initial value for CRC
+ * @param buffer buffer whose CRC to calculate
+ * @param length length of the buffer
+ * @return CRC updated with the data from the given block
+ *
+ * @see av_crc_init() "le" parameter
+ */
+uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
+ const uint8_t *buffer, size_t length) av_pure;
+
+/**
+ * @}
+ */
+
+#endif /* AVUTIL_CRC_H */