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Diffstat (limited to 'man/man3/flate.3')
| -rw-r--r-- | man/man3/flate.3 | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/man/man3/flate.3 b/man/man3/flate.3 new file mode 100644 index 00000000..816875fd --- /dev/null +++ b/man/man3/flate.3 @@ -0,0 +1,207 @@ +.TH FLATE 3 +.SH NAME +deflateinit, deflate, deflatezlib, deflateblock, deflatezlibblock, inflateinit, inflate, inflatezlib, inflateblock, inflatezlibblock, flateerr, mkcrctab, blockcrc, adler32 \- deflate compression +.SH SYNOPSIS +.B #include <u.h> +.br +.B #include <libc.h> +.br +.B #include <flate.h> +.PP +.ta \w'ulongmm'u +.PP +.B +int deflateinit(void) +.PP +.B +int deflate(void *wr, int (*w)(void*,void*,int), +.br +.B + void *rr, int (*r)(void*,void*,int), +.br +.B + int level, int debug) +.PP +.B +int deflatezlib(void *wr, int (*w)(void*,void*,int), +.br +.B + void *rr, int (*r)(void*,void*,int), +.br +.B + int level, int debug) +.PP +.B +int deflateblock(uchar *dst, int dsize, +.br +.B + uchar *src, int ssize, +.br +.B + int level, int debug) +.PP +.B +int deflatezlibblock(uchar *dst, int dsize, +.br +.B + uchar *src, int ssize, +.br +.B + int level, int debug) +.PP +.B +int inflateinit(void) +.PP +.B +int inflate(void *wr, int (*w)(void*, void*, int), +.br +.B + void *getr, int (*get)(void*)) +.PP +.B +int inflatezlib(void *wr, int (*w)(void*, void*, int), +.br +.B + void *getr, int (*get)(void*)) +.PP +.B +int inflateblock(uchar *dst, int dsize, +.br +.B + uchar *src, int ssize) +.PP +.B +int inflatezlibblock(uchar *dst, int dsize, +.br +.B + uchar *src, int ssize) +.PP +.B +char *flateerr(int error) +.PP +.B +ulong *mkcrctab(ulong poly) +.PP +.B +ulong blockcrc(ulong *tab, ulong crc, void *buf, int n) +.PP +.B +ulong adler32(ulong adler, void *buf, int n) +.SH DESCRIPTION +These routines compress and decompress data using the deflate compression algorithm, +which is used for most gzip, zip, and zlib files. +.PP +.I Deflate +compresses input data retrieved by calls to +.I r +with arguments +.IR rr , +an input buffer, and a count of bytes to read. +.I R +should return the number of bytes read; +end of input is signaled by returning zero, an input error by +returning a negative number. +The compressed output is written to +.I w +with arguments +.IR wr , +the output data, and the number of bytes to write. +.I W +should return the number of bytes written; +writing fewer than the requested number of bytes is an error. +.I Level +indicates the amount of computation deflate should do while compressing the data. +Higher +.I levels +usually take more time and produce smaller outputs. +Valid values are 1 to 9, inclusive; 6 is a good compromise. +If +.I debug +is non-zero, cryptic debugging information is produced on standard error. +.PP +.I Inflate +reverses the process, converting compressed data into uncompressed output. +Input is retrieved one byte at a time by calling +.I get +with the argument +.IR getr . +End of input of signaled by returning a negative value. +The uncompressed output is written to +.IR w , +which has the same interface as for +.IR deflate . +.PP +.I +Deflateblock +and +.I inflateblock +operate on blocks of memory but are otherwise similar to +.I deflate +and +.IR inflate . +.PP +The zlib functions are similar, but operate on files with a zlib header and trailer. +.PP +.I Deflateinit +or +.I inflateinit +must be called once before any call to the corresponding routines. +.PP +If the above routines fail, +they return a negative number indicating the problem. +The possible values are +.IR FlateNoMem , +.IR FlateInputFail , +.IR FlateOutputFail , +.IR FlateCorrupted , +and +.IR FlateInternal . +.I Flateerr +converts the number into a printable message. +.I FlateOk +is defined to be zero, +the successful return value for +.IR deflateinit , +.IR deflate , +.IR deflatezlib , +.IR inflateinit , +.IR inflate , +and +.IR inflatezlib . +The block functions return the number of bytes produced when they succeed. +.PP +.I Mkcrctab +allocates +(using +.IR malloc (2)), +initializes, and returns a table for rapid computation of 32 bit CRC values using the polynomial +.IR poly . +.I Blockcrc +uses +.IR tab , +a table returned by +.IR mkcrctab , +to update +.I crc +for the +.I n +bytes of data in +.IR buf , +and returns the new value. +.I Crc +should initially be zero. +.I Blockcrc +pre-conditions and post-conditions +.I crc +by ones complementation. +.PP +.I Adler32 +updates the Adler 32-bit checksum of the +.I n +butes of data in +.IR buf. +The initial value of +.I adler +(that is, its value after seeing zero bytes) should be 1. +.SH SOURCE +.B /sys/src/libflate |