view contrib/python-zstandard/zstd/deprecated/zbuff_compress.c @ 39857:8dab7c8a93eb

upgrade: report size of backing files, not internal storage size

upgrade.py is the only consumer of filelog.index, which I'd like
to eliminate from the file storage interface.

This commit changes the upgrade code to report the storage size
of files by looking at the size of the files backing its storage
instead of looking at the index.

I'm not convinced the approach in this patch will live very long
because it is relying on low-level attributes like "opener" and
"files," which may behave very differently on non-revlog storage.
But the data is only used for reporting purposes and it does get
us one step closer to eliminating "index."

A side-effect of this change is we now report the size of the revlog
index data - not just the revision data. I think this is more
accurate.

Differential Revision: https://phab.mercurial-scm.org/D4717

/*
 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */



/* *************************************
*  Dependencies
***************************************/
#define ZBUFF_STATIC_LINKING_ONLY
#include "zbuff.h"


/*-***********************************************************
*  Streaming compression
*
*  A ZBUFF_CCtx object is required to track streaming operation.
*  Use ZBUFF_createCCtx() and ZBUFF_freeCCtx() to create/release resources.
*  Use ZBUFF_compressInit() to start a new compression operation.
*  ZBUFF_CCtx objects can be reused multiple times.
*
*  Use ZBUFF_compressContinue() repetitively to consume your input.
*  *srcSizePtr and *dstCapacityPtr can be any size.
*  The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
*  Note that it may not consume the entire input, in which case it's up to the caller to call again the function with remaining input.
*  The content of dst will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters or change dst .
*  @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency)
*            or an error code, which can be tested using ZBUFF_isError().
*
*  ZBUFF_compressFlush() can be used to instruct ZBUFF to compress and output whatever remains within its buffer.
*  Note that it will not output more than *dstCapacityPtr.
*  Therefore, some content might still be left into its internal buffer if dst buffer is too small.
*  @return : nb of bytes still present into internal buffer (0 if it's empty)
*            or an error code, which can be tested using ZBUFF_isError().
*
*  ZBUFF_compressEnd() instructs to finish a frame.
*  It will perform a flush and write frame epilogue.
*  Similar to ZBUFF_compressFlush(), it may not be able to output the entire internal buffer content if *dstCapacityPtr is too small.
*  @return : nb of bytes still present into internal buffer (0 if it's empty)
*            or an error code, which can be tested using ZBUFF_isError().
*
*  Hint : recommended buffer sizes (not compulsory)
*  input : ZSTD_BLOCKSIZE_MAX (128 KB), internal unit size, it improves latency to use this value.
*  output : ZSTD_compressBound(ZSTD_BLOCKSIZE_MAX) + ZSTD_blockHeaderSize + ZBUFF_endFrameSize : ensures it's always possible to write/flush/end a full block at best speed.
* ***********************************************************/

ZBUFF_CCtx* ZBUFF_createCCtx(void)
{
    return ZSTD_createCStream();
}

ZBUFF_CCtx* ZBUFF_createCCtx_advanced(ZSTD_customMem customMem)
{
    return ZSTD_createCStream_advanced(customMem);
}

size_t ZBUFF_freeCCtx(ZBUFF_CCtx* zbc)
{
    return ZSTD_freeCStream(zbc);
}


/* ======   Initialization   ====== */

size_t ZBUFF_compressInit_advanced(ZBUFF_CCtx* zbc,
                                   const void* dict, size_t dictSize,
                                   ZSTD_parameters params, unsigned long long pledgedSrcSize)
{
    if (pledgedSrcSize==0) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;  /* preserve "0 == unknown" behavior */
    return ZSTD_initCStream_advanced(zbc, dict, dictSize, params, pledgedSrcSize);
}


size_t ZBUFF_compressInitDictionary(ZBUFF_CCtx* zbc, const void* dict, size_t dictSize, int compressionLevel)
{
    return ZSTD_initCStream_usingDict(zbc, dict, dictSize, compressionLevel);
}

size_t ZBUFF_compressInit(ZBUFF_CCtx* zbc, int compressionLevel)
{
    return ZSTD_initCStream(zbc, compressionLevel);
}

/* ======   Compression   ====== */


size_t ZBUFF_compressContinue(ZBUFF_CCtx* zbc,
                              void* dst, size_t* dstCapacityPtr,
                        const void* src, size_t* srcSizePtr)
{
    size_t result;
    ZSTD_outBuffer outBuff;
    ZSTD_inBuffer inBuff;
    outBuff.dst = dst;
    outBuff.pos = 0;
    outBuff.size = *dstCapacityPtr;
    inBuff.src = src;
    inBuff.pos = 0;
    inBuff.size = *srcSizePtr;
    result = ZSTD_compressStream(zbc, &outBuff, &inBuff);
    *dstCapacityPtr = outBuff.pos;
    *srcSizePtr = inBuff.pos;
    return result;
}



/* ======   Finalize   ====== */

size_t ZBUFF_compressFlush(ZBUFF_CCtx* zbc, void* dst, size_t* dstCapacityPtr)
{
    size_t result;
    ZSTD_outBuffer outBuff;
    outBuff.dst = dst;
    outBuff.pos = 0;
    outBuff.size = *dstCapacityPtr;
    result = ZSTD_flushStream(zbc, &outBuff);
    *dstCapacityPtr = outBuff.pos;
    return result;
}


size_t ZBUFF_compressEnd(ZBUFF_CCtx* zbc, void* dst, size_t* dstCapacityPtr)
{
    size_t result;
    ZSTD_outBuffer outBuff;
    outBuff.dst = dst;
    outBuff.pos = 0;
    outBuff.size = *dstCapacityPtr;
    result = ZSTD_endStream(zbc, &outBuff);
    *dstCapacityPtr = outBuff.pos;
    return result;
}



/* *************************************
*  Tool functions
***************************************/
size_t ZBUFF_recommendedCInSize(void)  { return ZSTD_CStreamInSize(); }
size_t ZBUFF_recommendedCOutSize(void) { return ZSTD_CStreamOutSize(); }