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eina: Improve API docs for eina_crc.h 

Reviewers: cedric, ajwillia.ms

Reviewed By: ajwillia.ms

Subscribers: jpeg, segfaultxavi

Differential Revision: https://phab.enlightenment.org/D5468
This commit is contained in:
Bryce Harrington 2017-11-14 13:10:14 +00:00 committed by Andy Williams
parent 2f81b26367
commit 1227f914e2
1 changed files with 28 additions and 16 deletions
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44
src/lib/eina/eina_crc.h
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@ -12,31 +12,43 @@
#include "eina_magic.h"
/**
* @brief Generates a crc checksum for the given data using crc-32 algorithm.
* @brief Generates a checksum for the given data using the CRC-32 algorithm.
*
* @param key The data for which crc checksum has to be generated.
* @param len The length of the data.
* @param seed The seed used to calculate crc checksum. The value will be 0xffffffff
* for the initial data and for the remaining stream data, it will be crc value from the
* previous call to the eina_crc function.
* @param start_stream EINA_TRUE for the initial call and EINA_FALSE for the remaining stream data.
* @return 32 bit crc checksum for the given data.
* @param[in] key The data to checksum.
* @param[in] len The length of @p key in bytes.
* @param[in] seed The seed used to calculate the checksum.
* @param[in] start_stream Set as #EINA_TRUE for the initial call and
* #EINA_FALSE for the remaining stream data.
* @return A 32-bit CRC checksum for the data given in @p key.
*
* This function generates 32 bit crc checksum using crc-32 algorithm and 0xEDB88320 polynomial
* for the data which is passed to the function. Seed has to be passed which will
* be used in calculating checksum. For normal data 0xffffffff has to be passed as seed along with
* EINA_TRUE for start_stream parameter. For streaming data, initial call will be similar to normal
* data and for the rest of data, seed will be the crc returned from previous call to eina_crc
* and start_stream parameter will be EINA_FALSE
* API usage for normal data
* This function generates a checksum using the CRC-32 algorithm
* with the @c 0xEDB88320 polynomial on the data provided by @p key.
* (https://en.wikipedia.org/wiki/Cyclic_redundancy_check#CRC-32_algorithm)
*
* For streaming data eina_crc() can be called repeatedly, passing the
* returned checksum from the prior call as the @p seed to the next, and
* setting @p start_stream to #EINA_FALSE. For the initial call, set
* @p seed to @c 0xffffffff and @p start_stream to #EINA_TRUE.
*
* For normal (non-streaming) data, seed tracking is not needed, so
* @p seed should be set to @c 0xffffffff and @p start_stream to
* #EINA_TRUE.
*
* Example usage for normal data:
*
* @code
* char *tmp = "hello world";
* unsigned int crc = eina_crc(tmp, strlen(tmp), 0xffffffff, EINA_TRUE);
* @endcode
*
* API usage for streaming data
* Example usage for streaming data:
*
* @code
* char *tmp1 = "hello "
* char *tmp2 = "world"
* unsigned int crc = eina_crc(tmp1, strlen(tmp1), 0xffffffff, EINA_TRUE);
* crc = eina_crc(tmp2, strlen(tmp2), crc, EINA_FALSE);
* @endcode
*
* @since 1.15
*/