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libc/lzf: Define structures to represent LZF headers.

This commit is contained in:
Gregory Nutt 2018-03-18 12:31:50 -06:00
parent c8b567db61
commit ed59157a4b
2 changed files with 61 additions and 20 deletions
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31
include/lzf.h
View File

@ -38,8 +38,12 @@
#define LZF_VERSION 0x0105 /* 1.5, API version */
#define HLOG CONFIG_LIBC_LZF_HLOG
#define LZF_TYPE0_HDR 0
#define LZF_TYPE1_HDR 1
#define LZF_TYPE0_HDR_SIZE 5
#define LZF_TYPE1_HDR_SIZE 7
#define LZF_MAX_HDR_SIZE 7
#define LZF_MIN_HDR_SIZE 5
@ -47,6 +51,31 @@
* Public Types
****************************************************************************/
/* LZF headers */
struct lzf_header_s /* Common data header */
{
uint8_t lzf_magic[2]; /* [0]='Z', [1]='V' */
uint8_t lzf_type; /* LZF_TYPE0_HDR or LZF_TYPE1_HDR */
};
struct lzf_type0_header_s /* Uncompressed data header */
{
uint8_t lzf_magic[2]; /* [0]='Z', [1]='V' */
uint8_t lzf_type; /* LZF_TYPE0_HDR */
uint8_t lzf_len[2]; /* Data length (big-endian) */
};
struct lzf_type1_header_s /* Compressed data header */
{
uint8_t lzf_magic[2]; /* [0]='Z', [1]='V' */
uint8_t lzf_type; /* LZF_TYPE1_HDR */
uint8_t lzf_clen[2]; /* Compressed data length (big-endian) */
uint8_t lzf_ulen[2]; /* Unompressed data length (big-endian) */
};
/* LZF hash table */
#if LZF_USE_OFFSETS
# define LZF_HSLOT_BIAS ((const uint8_t *)in_data)
typedef unsigned int lzf_hslot_t;
@ -95,7 +124,7 @@ typedef lzf_hslot_t lzf_state_t[1 << HLOG];
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);
FAR struct lzf_header_s **reshdr);
/****************************************************************************
* Name: lzf_decompress

50
libc/lzf/lzf_c.c
View File

@ -126,14 +126,13 @@
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 struct lzf_header_s **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;
@ -420,30 +419,43 @@ size_t lzf_compress(FAR const void *const in_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;
FAR struct lzf_type1_header_s *header;
/* Write compressed */
header = (FAR struct lzf_type1_header_s *)
((uintptr_t)out_data - LZF_TYPE1_HDR_SIZE);
header->lzf_magic[0] = 'Z';
header->lzf_magic[1] = 'V';
header->lzf_type = LZF_TYPE1_HDR;
header->lzf_clen[0] = cs >> 8;
header->lzf_clen[1] = cs & 0xff;
header->lzf_ulen[0] = in_len >> 8;
header->lzf_ulen[1] = in_len & 0xff;
*reshdr = (FAR struct lzf_header_s *)header;
retlen = cs + LZF_TYPE1_HDR_SIZE;
}
else
{
FAR struct lzf_type0_header_s *header;
/* 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;
header = (FAR struct lzf_type0_header_s *)
((uintptr_t)in_data - LZF_TYPE0_HDR_SIZE);
header->lzf_magic[0] = 'Z';
header->lzf_magic[1] = 'V';
header->lzf_type = LZF_TYPE0_HDR;
header->lzf_len[0] = in_len >> 8;
header->lzf_len[1] = in_len & 0xff;
*reshdr = (FAR struct lzf_header_s *)header;
retlen = in_len + LZF_TYPE0_HDR_SIZE;
}
*reshdr = header;
return retlen;
}