compress()

Compress header cache data. More...

Collaboration diagram for compress():

Functions
static void *	compr_lz4_compress (ComprHandle *handle, const char *data, size_t dlen, size_t *clen)
	Compress header cache data - Implements ComprOps::compress() -.
static void *	compr_zlib_compress (ComprHandle *handle, const char *data, size_t dlen, size_t *clen)
	Compress header cache data - Implements ComprOps::compress() -.
static void *	compr_zstd_compress (ComprHandle *handle, const char *data, size_t dlen, size_t *clen)
	Compress header cache data - Implements ComprOps::compress() -.

Detailed Description

Compress header cache data.

Parameters

[in]	handle	Compression handle
[in]	data	Data to be compressed
[in]	dlen	Length of the uncompressed data
[out]	clen	Length of returned compressed data

Return values

ptr	Success, pointer to compressed data
NULL	Otherwise

Note

This function returns a pointer to data, which will be freed by the close() function.

Function Documentation

compr_lz4_compress()

void * compr_lz4_compress ( ComprHandle * handle, const char * data, size_t dlen, size_t * clen )

static

Compress header cache data - Implements ComprOps::compress() -.

Definition at line 101 of file lz4.c.

{
  if (!handle || (dlen > INT_MAX))
    return NULL;
 
  // Decloak an opaque pointer
  struct Lz4ComprData *cdata = handle;
 
  int datalen = dlen;
  int len = LZ4_compressBound(dlen);
  if (len > (INT_MAX - 4))
    return NULL; // LCOV_EXCL_LINE
  mutt_mem_realloc(&cdata->buf, len + 4);
  char *cbuf = cdata->buf;
 
  len = LZ4_compress_fast(data, cbuf + 4, datalen, len, cdata->level);
  if (len == 0)
    return NULL; // LCOV_EXCL_LINE
  *clen = len + 4;
 
  /* save ulen to first 4 bytes */
  unsigned char *cs = cdata->buf;
  cs[0] = dlen & 0xff;
  dlen >>= 8;
  cs[1] = dlen & 0xff;
  dlen >>= 8;
  cs[2] = dlen & 0xff;
  dlen >>= 8;
  cs[3] = dlen & 0xff;
 
  return cdata->buf;
}

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compr_zlib_compress()

void * compr_zlib_compress ( ComprHandle * handle, const char * data, size_t dlen, size_t * clen )

static

Compress header cache data - Implements ComprOps::compress() -.

Definition at line 102 of file zlib.c.

{
  if (!handle || (dlen > UINT32_MAX))
    return NULL;
 
  // Decloak an opaque pointer
  struct ZlibComprData *cdata = handle;
 
  uLong len = compressBound(dlen);
  mutt_mem_realloc(&cdata->buf, len + 4);
  Bytef *cbuf = (unsigned char *) cdata->buf + 4;
  const void *ubuf = data;
  int rc = compress2(cbuf, &len, ubuf, dlen, cdata->level);
  if (rc != Z_OK)
    return NULL; // LCOV_EXCL_LINE
  *clen = len + 4;
 
  /* save ulen to first 4 bytes */
  unsigned char *cs = cdata->buf;
  cs[0] = dlen & 0xff;
  dlen >>= 8;
  cs[1] = dlen & 0xff;
  dlen >>= 8;
  cs[2] = dlen & 0xff;
  dlen >>= 8;
  cs[3] = dlen & 0xff;
 
  return cdata->buf;
}

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compr_zstd_compress()

void * compr_zstd_compress ( ComprHandle * handle, const char * data, size_t dlen, size_t * clen )

static

Compress header cache data - Implements ComprOps::compress() -.

Definition at line 115 of file zstd.c.

{
  if (!handle)
    return NULL;
 
  // Decloak an opaque pointer
  struct ZstdComprData *cdata = handle;
 
  size_t len = ZSTD_compressBound(dlen);
  mutt_mem_realloc(&cdata->buf, len);
 
  size_t rc = ZSTD_compressCCtx(cdata->cctx, cdata->buf, len, data, dlen, cdata->level);
  if (ZSTD_isError(rc))
    return NULL; // LCOV_EXCL_LINE
 
  *clen = rc;
 
  return cdata->buf;
}

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