* This file was part of the Independent JPEG Group's software:
* Developed 1997-2009 by Guido Vollbeding.
* libjpeg-turbo Modifications:
- * Copyright (C) 2015, D. R. Commander.
+ * Copyright (C) 2015, 2018, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*
* This file contains portable arithmetic entropy encoding routines for JPEG
- * (implementing the ISO/IEC IS 10918-1 and CCITT Recommendation ITU-T T.81).
+ * (implementing Recommendation ITU-T T.81 | ISO/IEC 10918-1).
*
* Both sequential and progressive modes are supported in this single module.
*
* Suspension is not currently supported in this module.
+ *
+ * NOTE: All referenced figures are from
+ * Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
*/
#define JPEG_INTERNALS
* in the lower bits (mask 0x7F).
*/
-#define DC_STAT_BINS 64
-#define AC_STAT_BINS 256
+#define DC_STAT_BINS 64
+#define AC_STAT_BINS 256
/* NOTE: Uncomment the following #define if you want to use the
* given formula for calculating the AC conditioning parameter Kx
#ifdef RIGHT_SHIFT_IS_UNSIGNED
#define ISHIFT_TEMPS int ishift_temp;
-#define IRIGHT_SHIFT(x,shft) \
- ((ishift_temp = (x)) < 0 ? \
- (ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
- (ishift_temp >> (shft)))
+#define IRIGHT_SHIFT(x, shft) \
+ ((ishift_temp = (x)) < 0 ? \
+ (ishift_temp >> (shft)) | ((~0) << (16 - (shft))) : \
+ (ishift_temp >> (shft)))
#else
#define ISHIFT_TEMPS
-#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
+#define IRIGHT_SHIFT(x, shft) ((x) >> (shft))
#endif
LOCAL(void)
-emit_byte (int val, j_compress_ptr cinfo)
+emit_byte(int val, j_compress_ptr cinfo)
/* Write next output byte; we do not support suspension in this module. */
{
struct jpeg_destination_mgr *dest = cinfo->dest;
- *dest->next_output_byte++ = (JOCTET) val;
+ *dest->next_output_byte++ = (JOCTET)val;
if (--dest->free_in_buffer == 0)
- if (! (*dest->empty_output_buffer) (cinfo))
+ if (!(*dest->empty_output_buffer) (cinfo))
ERREXIT(cinfo, JERR_CANT_SUSPEND);
}
*/
METHODDEF(void)
-finish_pass (j_compress_ptr cinfo)
+finish_pass(j_compress_ptr cinfo)
{
- arith_entropy_ptr e = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr e = (arith_entropy_ptr)cinfo->entropy;
JLONG temp;
/* Section D.1.8: Termination of encoding */
/* Find the e->c in the coding interval with the largest
* number of trailing zero bits */
- if ((temp = (e->a - 1 + e->c) & 0xFFFF0000L) < e->c)
+ if ((temp = (e->a - 1 + e->c) & 0xFFFF0000UL) < e->c)
e->c = temp + 0x8000L;
else
e->c = temp;
/* Send remaining bytes to output */
e->c <<= e->ct;
- if (e->c & 0xF8000000L) {
+ if (e->c & 0xF8000000UL) {
/* One final overflow has to be handled */
if (e->buffer >= 0) {
if (e->zc)
*/
LOCAL(void)
-arith_encode (j_compress_ptr cinfo, unsigned char *st, int val)
+arith_encode(j_compress_ptr cinfo, unsigned char *st, int val)
{
- register arith_entropy_ptr e = (arith_entropy_ptr) cinfo->entropy;
+ register arith_entropy_ptr e = (arith_entropy_ptr)cinfo->entropy;
register unsigned char nl, nm;
register JLONG qe, temp;
register int sv;
*/
sv = *st;
qe = jpeg_aritab[sv & 0x7F]; /* => Qe_Value */
- nl = qe & 0xFF; qe >>= 8; /* Next_Index_LPS + Switch_MPS */
- nm = qe & 0xFF; qe >>= 8; /* Next_Index_MPS */
+ nl = qe & 0xFF; qe >>= 8; /* Next_Index_LPS + Switch_MPS */
+ nm = qe & 0xFF; qe >>= 8; /* Next_Index_MPS */
/* Encode & estimation procedures per sections D.1.4 & D.1.5 */
e->a -= qe;
*/
LOCAL(void)
-emit_restart (j_compress_ptr cinfo, int restart_num)
+emit_restart(j_compress_ptr cinfo, int restart_num)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
int ci;
jpeg_component_info *compptr;
*/
METHODDEF(boolean)
-encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+encode_mcu_DC_first(j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
JBLOCKROW block;
unsigned char *st;
int blkn, ci, tbl;
/* Compute the DC value after the required point transform by Al.
* This is simply an arithmetic right shift.
*/
- m = IRIGHT_SHIFT((int) ((*block)[0]), cinfo->Al);
+ m = IRIGHT_SHIFT((int)((*block)[0]), cinfo->Al);
/* Sections F.1.4.1 & F.1.4.4.1: Encoding of DC coefficients */
}
arith_encode(cinfo, st, 0);
/* Section F.1.4.4.1.2: Establish dc_context conditioning category */
- if (m < (int) ((1L << cinfo->arith_dc_L[tbl]) >> 1))
+ if (m < (int)((1L << cinfo->arith_dc_L[tbl]) >> 1))
entropy->dc_context[ci] = 0; /* zero diff category */
- else if (m > (int) ((1L << cinfo->arith_dc_U[tbl]) >> 1))
+ else if (m > (int)((1L << cinfo->arith_dc_U[tbl]) >> 1))
entropy->dc_context[ci] += 8; /* large diff category */
/* Figure F.9: Encoding the magnitude bit pattern of v */
st += 14;
*/
METHODDEF(boolean)
-encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+encode_mcu_AC_first(j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
JBLOCKROW block;
unsigned char *st;
int tbl, k, ke;
break;
}
}
- arith_encode(cinfo, st + 1, 0); st += 3; k++;
+ arith_encode(cinfo, st + 1, 0); st += 3; k++;
}
st += 2;
/* Figure F.8: Encoding the magnitude category of v */
*/
METHODDEF(boolean)
-encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+encode_mcu_DC_refine(j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
unsigned char *st;
int Al, blkn;
*/
METHODDEF(boolean)
-encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+encode_mcu_AC_refine(j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
JBLOCKROW block;
unsigned char *st;
int tbl, k, ke, kex;
break;
}
}
- arith_encode(cinfo, st + 1, 0); st += 3; k++;
+ arith_encode(cinfo, st + 1, 0); st += 3; k++;
}
}
/* Encode EOB decision only if k <= cinfo->Se */
*/
METHODDEF(boolean)
-encode_mcu (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+encode_mcu(j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
jpeg_component_info *compptr;
JBLOCKROW block;
unsigned char *st;
}
arith_encode(cinfo, st, 0);
/* Section F.1.4.4.1.2: Establish dc_context conditioning category */
- if (m < (int) ((1L << cinfo->arith_dc_L[tbl]) >> 1))
+ if (m < (int)((1L << cinfo->arith_dc_L[tbl]) >> 1))
entropy->dc_context[ci] = 0; /* zero diff category */
- else if (m > (int) ((1L << cinfo->arith_dc_U[tbl]) >> 1))
+ else if (m > (int)((1L << cinfo->arith_dc_U[tbl]) >> 1))
entropy->dc_context[ci] += 8; /* large diff category */
/* Figure F.9: Encoding the magnitude bit pattern of v */
st += 14;
st = entropy->ac_stats[tbl] + 3 * (k - 1);
arith_encode(cinfo, st, 0); /* EOB decision */
while ((v = (*block)[jpeg_natural_order[k]]) == 0) {
- arith_encode(cinfo, st + 1, 0); st += 3; k++;
+ arith_encode(cinfo, st + 1, 0); st += 3; k++;
}
arith_encode(cinfo, st + 1, 1);
/* Figure F.6: Encoding nonzero value v */
*/
METHODDEF(void)
-start_pass (j_compress_ptr cinfo, boolean gather_statistics)
+start_pass(j_compress_ptr cinfo, boolean gather_statistics)
{
- arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
+ arith_entropy_ptr entropy = (arith_entropy_ptr)cinfo->entropy;
int ci, tbl;
jpeg_component_info *compptr;
if (tbl < 0 || tbl >= NUM_ARITH_TBLS)
ERREXIT1(cinfo, JERR_NO_ARITH_TABLE, tbl);
if (entropy->dc_stats[tbl] == NULL)
- entropy->dc_stats[tbl] = (unsigned char *) (*cinfo->mem->alloc_small)
- ((j_common_ptr) cinfo, JPOOL_IMAGE, DC_STAT_BINS);
+ entropy->dc_stats[tbl] = (unsigned char *)(*cinfo->mem->alloc_small)
+ ((j_common_ptr)cinfo, JPOOL_IMAGE, DC_STAT_BINS);
MEMZERO(entropy->dc_stats[tbl], DC_STAT_BINS);
/* Initialize DC predictions to 0 */
entropy->last_dc_val[ci] = 0;
if (tbl < 0 || tbl >= NUM_ARITH_TBLS)
ERREXIT1(cinfo, JERR_NO_ARITH_TABLE, tbl);
if (entropy->ac_stats[tbl] == NULL)
- entropy->ac_stats[tbl] = (unsigned char *) (*cinfo->mem->alloc_small)
- ((j_common_ptr) cinfo, JPOOL_IMAGE, AC_STAT_BINS);
+ entropy->ac_stats[tbl] = (unsigned char *)(*cinfo->mem->alloc_small)
+ ((j_common_ptr)cinfo, JPOOL_IMAGE, AC_STAT_BINS);
MEMZERO(entropy->ac_stats[tbl], AC_STAT_BINS);
#ifdef CALCULATE_SPECTRAL_CONDITIONING
if (cinfo->progressive_mode)
/* Section G.1.3.2: Set appropriate arithmetic conditioning value Kx */
- cinfo->arith_ac_K[tbl] = cinfo->Ss + ((8 + cinfo->Se - cinfo->Ss) >> 4);
+ cinfo->arith_ac_K[tbl] = cinfo->Ss +
+ ((8 + cinfo->Se - cinfo->Ss) >> 4);
#endif
}
}
*/
GLOBAL(void)
-jinit_arith_encoder (j_compress_ptr cinfo)
+jinit_arith_encoder(j_compress_ptr cinfo)
{
arith_entropy_ptr entropy;
int i;
entropy = (arith_entropy_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
sizeof(arith_entropy_encoder));
- cinfo->entropy = (struct jpeg_entropy_encoder *) entropy;
+ cinfo->entropy = (struct jpeg_entropy_encoder *)entropy;
entropy->pub.start_pass = start_pass;
entropy->pub.finish_pass = finish_pass;
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