Crypto and Hashing
[Common utility functions]




unsigned long av_adler32_update (unsigned long adler, const uint8_t *buf, unsigned int len) av_pure
 Calculate the Adler32 checksum of a buffer.
uint32_t av_get_random_seed (void)
 Get a seed to use in conjunction with random functions.

Function Documentation

unsigned long av_adler32_update ( unsigned long  adler,
const uint8_t *  buf,
unsigned int  len 

Calculate the Adler32 checksum of a buffer.

Passing the return value to a subsequent av_adler32_update() call allows the checksum of multiple buffers to be calculated as though they were concatenated.

adler initial checksum value
buf pointer to input buffer
len size of input buffer
updated checksum

Definition at line 33 of file adler32.c.

Referenced by crc_write_packet(), end_frame(), filter_samples(), and framecrc_write_packet().

uint32_t av_get_random_seed ( void   ) 

Get a seed to use in conjunction with random functions.

This function tries to provide a good seed at a best effort bases. Its possible to call this function multiple times if more bits are needed. It can be quite slow, which is why it should only be used as seed for a faster PRNG. The quality of the seed depends on the platform.

Definition at line 73 of file random_seed.c.

Referenced by av_parse_color(), config_input(), init(), main(), make_digest_auth(), mkv_write_attachments(), mkv_write_header(), mxf_gen_umid(), ogg_write_header(), rtp_write_header(), and sap_write_header().

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