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libaec
Commit 26488d43 authored by Mathis Rosenhauer's avatar Mathis Rosenhauer Committed by Thomas Jahns
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Remove casting of uint8_t buffer to uint16_t to avoid alignment problems.... 

Remove casting of uint8_t buffer to uint16_t to avoid alignment problems. Performance penalty negligible.
parent 3322d07e
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README
View file @ 26488d43
......@@ -2,7 +2,7 @@
libaec - Adaptive Entropy Coding library
**********************************************************************
libaec provides fast lossless compression of 1 up to 32 bit wide
Libaec provides fast lossless compression of 1 up to 32 bit wide
signed or unsigned integers (samples). The library achieves best
results for low entropy data as often encountered in space imaging
instrument data or numerical model output from weather or climate
......@@ -10,7 +10,7 @@ simulations. While floating point representations are not directly
supported, they can also be efficiently coded by grouping exponents
and mantissa.
libaec implements Golomb Rice coding as defined in the Space Data
Libaec implements Golomb Rice coding as defined in the Space Data
System Standard document 121.0-B-2 [1], [2].
......@@ -125,10 +125,13 @@ sample size storage size
17 - 32 bit 4 bytes (also for 24bit if AEC_DATA_3BYTE is not set)
If you use less bits than the storage size provides, then you have to
make sure that unused bits are not set. libaec does not check this for
make sure that unused bits are not set. Libaec does not check this for
performance reasons and will produce undefined output if unused bits
are set.
Libaec accesses next_in and next_out buffers only bytewise. There are
no alignment requirements for these buffers.
Flushing:
aec_encode can be used in a streaming fashion by chunking input and
......@@ -181,7 +184,7 @@ and output is reversed.
It is essential for decoding that parameters like bits_per_sample,
block_size, rsi, and flags are exactly the same as they were for
encoding. libaec does not store these parameters in the coded stream
encoding. Libaec does not store these parameters in the coded stream
so it is up to the calling program to keep the correct parameters
between encoding and decoding.
......
src/encode_accessors.c
View file @ 26488d43
......@@ -68,6 +68,32 @@ uint32_t get_8(struct aec_stream *strm)
return *strm->next_in++;
}
uint32_t get_lsb_16(struct aec_stream *strm)
{
uint32_t data;
data = ((uint32_t)strm->next_in[1] << 8)
| (uint32_t)strm->next_in[0];
strm->next_in += 2;
strm->total_in += 2;
strm->avail_in -= 2;
return data;
}
uint32_t get_msb_16(struct aec_stream *strm)
{
uint32_t data;
data = ((uint32_t)strm->next_in[0] << 8)
| (uint32_t)strm->next_in[1];
strm->next_in += 2;
strm->total_in += 2;
strm->avail_in -= 2;
return data;
}
uint32_t get_lsb_24(struct aec_stream *strm)
{
uint32_t data;
......@@ -96,44 +122,6 @@ uint32_t get_msb_24(struct aec_stream *strm)
return data;
}
#define GET_NATIVE_16(BO) \
uint32_t get_##BO##_16(struct aec_stream *strm) \
{ \
uint32_t data; \
\
data = *(uint16_t *)strm->next_in; \
strm->next_in += 2; \
strm->total_in += 2; \
strm->avail_in -= 2; \
return data; \
}
#define GET_NATIVE_32(BO) \
uint32_t get_##BO##_32(struct aec_stream *strm) \
{ \
uint32_t data; \
\
data = *(uint32_t *)strm->next_in; \
strm->next_in += 4; \
strm->total_in += 4; \
strm->avail_in -= 4; \
return data; \
}
#ifdef WORDS_BIGENDIAN
uint32_t get_lsb_16(struct aec_stream *strm)
{
uint32_t data;
data = ((uint32_t)strm->next_in[1] << 8)
| (uint32_t)strm->next_in[0];
strm->next_in += 2;
strm->total_in += 2;
strm->avail_in -= 2;
return data;
}
uint32_t get_lsb_32(struct aec_stream *strm)
{
uint32_t data;
......@@ -149,23 +137,6 @@ uint32_t get_lsb_32(struct aec_stream *strm)
return data;
}
GET_NATIVE_16(msb);
GET_NATIVE_32(msb);
#else /* !WORDS_BIGENDIAN */
uint32_t get_msb_16(struct aec_stream *strm)
{
uint32_t data;
data = ((uint32_t)strm->next_in[0] << 8)
| (uint32_t)strm->next_in[1];
strm->next_in += 2;
strm->total_in += 2;
strm->avail_in -= 2;
return data;
}
uint32_t get_msb_32(struct aec_stream *strm)
{
uint32_t data;
......@@ -181,11 +152,6 @@ uint32_t get_msb_32(struct aec_stream *strm)
return data;
}
GET_NATIVE_16(lsb);
GET_NATIVE_32(lsb);
#endif /* !WORDS_BIGENDIAN */
void get_rsi_8(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
......@@ -211,10 +177,76 @@ void get_rsi_8(struct aec_stream *strm)
}
}
void get_rsi_lsb_16(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
const unsigned char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 2 * rsi;
strm->total_in += 2 * rsi;
strm->avail_in -= 2 * rsi;
while (rsi) {
out[0] = (uint32_t)in[0]
| ((uint32_t)in[1] << 8);
out[1] = (uint32_t)in[2]
| ((uint32_t)in[3] << 8);
out[2] = (uint32_t)in[4]
| ((uint32_t)in[5] << 8);
out[3] = (uint32_t)in[6]
| ((uint32_t)in[7] << 8);
out[4] = (uint32_t)in[8]
| ((uint32_t)in[9] << 8);
out[5] = (uint32_t)in[10]
| ((uint32_t)in[11] << 8);
out[6] = (uint32_t)in[12]
| ((uint32_t)in[13] << 8);
out[7] = (uint32_t)in[14]
| ((uint32_t)in[15] << 8);
in += 16;
out += 8;
rsi -= 8;
}
}
void get_rsi_msb_16(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
const unsigned char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 2 * rsi;
strm->total_in += 2 * rsi;
strm->avail_in -= 2 * rsi;
while (rsi) {
out[0] = ((uint32_t)in[0] << 8)
| (uint32_t)in[1];
out[1] = ((uint32_t)in[2] << 8)
| (uint32_t)in[3];
out[2] = ((uint32_t)in[4] << 8)
| (uint32_t)in[5];
out[3] = ((uint32_t)in[6] << 8)
| (uint32_t)in[7];
out[4] = ((uint32_t)in[8] << 8)
| (uint32_t)in[9];
out[5] = ((uint32_t)in[10] << 8)
| (uint32_t)in[11];
out[6] = ((uint32_t)in[12] << 8)
| (uint32_t)in[13];
out[7] = ((uint32_t)in[14] << 8)
| (uint32_t)in[15];
in += 16;
out += 8;
rsi -= 8;
}
}
void get_rsi_lsb_24(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
unsigned const char *in = strm->next_in;
const unsigned char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 3 * rsi;
......@@ -255,7 +287,7 @@ void get_rsi_lsb_24(struct aec_stream *strm)
void get_rsi_msb_24(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
unsigned const char *in = strm->next_in;
const unsigned char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 3 * rsi;
......@@ -293,32 +325,6 @@ void get_rsi_msb_24(struct aec_stream *strm)
}
}
#define GET_RSI_NATIVE_16(BO) \
void get_rsi_##BO##_16(struct aec_stream *strm) \
{ \
uint32_t *out = strm->state->data_raw; \
uint16_t *in = (uint16_t *)strm->next_in; \
int rsi = strm->rsi * strm->block_size; \
\
strm->next_in += 2 * rsi; \
strm->total_in += 2 * rsi; \
strm->avail_in -= 2 * rsi; \
\
while (rsi) { \
out[0] = (uint32_t)in[0]; \
out[1] = (uint32_t)in[1]; \
out[2] = (uint32_t)in[2]; \
out[3] = (uint32_t)in[3]; \
out[4] = (uint32_t)in[4]; \
out[5] = (uint32_t)in[5]; \
out[6] = (uint32_t)in[6]; \
out[7] = (uint32_t)in[7]; \
in += 8; \
out += 8; \
rsi -= 8; \
} \
}
#define GET_RSI_NATIVE_32(BO) \
void get_rsi_##BO##_32(struct aec_stream *strm) \
{ \
......@@ -331,43 +337,10 @@ void get_rsi_msb_24(struct aec_stream *strm)
}
#ifdef WORDS_BIGENDIAN
void get_rsi_lsb_16(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
unsigned const char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 2 * rsi;
strm->total_in += 2 * rsi;
strm->avail_in -= 2 * rsi;
while (rsi) {
out[0] = (uint32_t)in[0]
| ((uint32_t)in[1] << 8);
out[1] = (uint32_t)in[2]
| ((uint32_t)in[3] << 8);
out[2] = (uint32_t)in[4]
| ((uint32_t)in[5] << 8);
out[3] = (uint32_t)in[6]
| ((uint32_t)in[7] << 8);
out[4] = (uint32_t)in[8]
| ((uint32_t)in[9] << 8);
out[5] = (uint32_t)in[10]
| ((uint32_t)in[11] << 8);
out[6] = (uint32_t)in[12]
| ((uint32_t)in[13] << 8);
out[7] = (uint32_t)in[14]
| ((uint32_t)in[15] << 8);
in += 16;
out += 8;
rsi -= 8;
}
}
void get_rsi_lsb_32(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
unsigned const char *in = strm->next_in;
const unsigned char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 4 * rsi;
......@@ -413,47 +386,13 @@ void get_rsi_lsb_32(struct aec_stream *strm)
}
}
GET_RSI_NATIVE_16(msb);
GET_RSI_NATIVE_32(msb);
#else /* !WORDS_BIGENDIAN */
void get_rsi_msb_16(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
unsigned const char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 2 * rsi;
strm->total_in += 2 * rsi;
strm->avail_in -= 2 * rsi;
while (rsi) {
out[0] = ((uint32_t)in[0] << 8)
| (uint32_t)in[1];
out[1] = ((uint32_t)in[2] << 8)
| (uint32_t)in[3];
out[2] = ((uint32_t)in[4] << 8)
| (uint32_t)in[5];
out[3] = ((uint32_t)in[6] << 8)
| (uint32_t)in[7];
out[4] = ((uint32_t)in[8] << 8)
| (uint32_t)in[9];
out[5] = ((uint32_t)in[10] << 8)
| (uint32_t)in[11];
out[6] = ((uint32_t)in[12] << 8)
| (uint32_t)in[13];
out[7] = ((uint32_t)in[14] << 8)
| (uint32_t)in[15];
in += 16;
out += 8;
rsi -= 8;
}
}
void get_rsi_msb_32(struct aec_stream *strm)
{
uint32_t *out = strm->state->data_raw;
unsigned const char *in = strm->next_in;
const unsigned char *in = strm->next_in;
int rsi = strm->rsi * strm->block_size;
strm->next_in += 4 * rsi;
......@@ -499,7 +438,6 @@ void get_rsi_msb_32(struct aec_stream *strm)
}
}
GET_RSI_NATIVE_16(lsb);
GET_RSI_NATIVE_32(lsb);
#endif /* !WORDS_BIGENDIAN */
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