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libc/lzf: Refactor so that the user is no longer required to generate the LZF header

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This commit is contained in:
Boris Astardzhiev 2018-03-16 09:54:55 -06:00 committed by Gregory Nutt
parent 90c6d71503
commit 6cd607c298
2 changed files with 56 additions and 11 deletions
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12
include/lzf.h
View File

@ -38,6 +38,11 @@
#define LZF_VERSION 0x0105 /* 1.5, API version */
#define HLOG CONFIG_LIBC_LZF_HLOG
#define LZF_TYPE0_HDR_SIZE 5
#define LZF_TYPE1_HDR_SIZE 7
#define LZF_MAX_HDR_SIZE 7
#define LZF_MIN_HDR_SIZE 5
/****************************************************************************
* Public Types
****************************************************************************/
@ -87,9 +92,10 @@ typedef lzf_hslot_t lzf_state_t[1 << HLOG];
*
****************************************************************************/
unsigned int lzf_compress(FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len, lzf_state_t htab);
size_t lzf_compress(FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len, lzf_state_t htab,
FAR uint8_t **reshdr);
/****************************************************************************
* Name: lzf_decompress

55
libc/lzf/lzf_c.c
View File

@ -123,15 +123,19 @@
*
****************************************************************************/
unsigned int lzf_compress(FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len, lzf_state_t htab)
size_t lzf_compress(FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len, lzf_state_t htab,
uint8_t **reshdr)
{
FAR const uint8_t *ip = (const uint8_t *)in_data;
FAR uint8_t *op = (uint8_t *)out_data;
FAR const uint8_t *in_end = ip + in_len;
FAR uint8_t *out_end = op + out_len;
FAR const uint8_t *ref;
FAR uint8_t *header;
ssize_t cs;
ssize_t retlen;
/* off requires a type wide enough to hold a general pointer difference.
* ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
@ -151,7 +155,8 @@ unsigned int lzf_compress(FAR const void *const in_data,
if (!in_len || !out_len)
{
return 0;
cs = 0;
goto genhdr;
}
#if INIT_HTAB
@ -198,7 +203,8 @@ unsigned int lzf_compress(FAR const void *const in_data,
if (op - !lit + 3 + 1 >= out_end)
{
return 0;
cs = 0;
goto genhdr;
}
}
@ -370,7 +376,10 @@ unsigned int lzf_compress(FAR const void *const in_data,
/* One more literal byte we must copy */
if (expect_false (op >= out_end))
return 0;
{
cs = 0;
goto genhdr;
}
lit++;
*op++ = *ip++;
@ -387,7 +396,8 @@ unsigned int lzf_compress(FAR const void *const in_data,
if (op + 3 > out_end)
{
return 0;
cs = 0;
goto genhdr;
}
while (ip < in_end)
@ -405,7 +415,36 @@ unsigned int lzf_compress(FAR const void *const in_data,
op [- lit - 1] = lit - 1; /* End run */
op -= !lit; /* Undo run if length is zero */
return op - (uint8_t *)out_data;
cs = op - (uint8_t *)out_data;
genhdr:
if (cs)
{
header = (uint8_t *)out_data - LZF_TYPE1_HDR_SIZE;
header[0] = 'Z';
header[1] = 'V';
header[2] = 1;
header[3] = cs >> 8;
header[4] = cs & 0xff;
header[5] = in_len >> 8;
header[6] = in_len & 0xff;
retlen = cs + LZF_TYPE1_HDR_SIZE;
}
else
{
/* Write uncompressed */
header = (uint8_t *)in_data - LZF_TYPE0_HDR_SIZE;
header[0] = 'Z';
header[1] = 'V';
header[2] = 0;
header[3] = in_len >> 8;
header[4] = in_len & 0xff;
retlen = in_len + LZF_TYPE0_HDR_SIZE;
}
*reshdr = header;
return retlen;
}
#endif /* CONFIG_LIBC_LZF */