greenplumn compress_io 源码
greenplumn compress_io 代码
文件路径：/src/bin/pg_dump/compress_io.h
/*-------------------------------------------------------------------------
*
* compress_io.h
* Interface to compress_io.c routines
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/bin/pg_dump/compress_io.h
*
*-------------------------------------------------------------------------
*/
#ifndef __COMPRESS_IO__
#define __COMPRESS_IO__
#include "pg_backup_archiver.h"
/* Initial buffer sizes used in zlib compression. */
#define ZLIB_OUT_SIZE 4096
#define ZLIB_IN_SIZE 4096
typedef enum
{
COMPR_ALG_NONE,
COMPR_ALG_LIBZ
} CompressionAlgorithm;
/* Prototype for callback function to WriteDataToArchive() */
typedef void (*WriteFunc) (ArchiveHandle *AH, const char *buf, size_t len);
/*
* Prototype for callback function to ReadDataFromArchive()
*
* ReadDataFromArchive will call the read function repeatedly, until it
* returns 0 to signal EOF. ReadDataFromArchive passes a buffer to read the
* data into in *buf, of length *buflen. If that's not big enough for the
* callback function, it can free() it and malloc() a new one, returning the
* new buffer and its size in *buf and *buflen.
*
* Returns the number of bytes read into *buf, or 0 on EOF.
*/
typedef size_t (*ReadFunc) (ArchiveHandle *AH, char **buf, size_t *buflen);
/* struct definition appears in compress_io.c */
typedef struct CompressorState CompressorState;
extern CompressorState *AllocateCompressor(int compression, WriteFunc writeF);
extern void ReadDataFromArchive(ArchiveHandle *AH, int compression,
ReadFunc readF);
extern void WriteDataToArchive(ArchiveHandle *AH, CompressorState *cs,
const void *data, size_t dLen);
extern void EndCompressor(ArchiveHandle *AH, CompressorState *cs);
typedef struct cfp cfp;
extern cfp *cfopen(const char *path, const char *mode, int compression);
extern cfp *cfopen_read(const char *path, const char *mode);
extern cfp *cfopen_write(const char *path, const char *mode, int compression);
extern int cfread(void *ptr, int size, cfp *fp);
extern int cfwrite(const void *ptr, int size, cfp *fp);
extern int cfgetc(cfp *fp);
extern char *cfgets(cfp *fp, char *buf, int len);
extern int cfclose(cfp *fp);
extern int cfeof(cfp *fp);
extern const char *get_cfp_error(cfp *fp);
#endif
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