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Build: separating optional PNG filter natives from compression code
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@Oldes
Oldes committed Oct 4, 2021
1 parent 924854c commit cbad7a7
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Showing 3 changed files with 260 additions and 226 deletions.
7 changes: 6 additions & 1 deletion make/rebol3.nest
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Original file line number Diff line number Diff line change
Expand Up @@ -444,6 +444,11 @@ include-lzma-compression: [
core-files: %core/u-lzma.c
]

include-png-filter-native: [
config: INCLUDE_PNG_FILTER
core-files: %core/u-png-filter.c
]

include-view: [
; currently only on Windows!
host-files: :host-files-view
Expand Down Expand Up @@ -500,7 +505,7 @@ include-codec-ico: [
]
include-codec-json: [mezz-lib-files: %mezz/codec-json.reb ]
include-codec-xml: [mezz-lib-files: %mezz/codec-xml.reb ]
include-codec-pdf: [mezz-lib-files: %mezz/codec-pdf.reb config: INCLUDE_PNG_FILTER] ; pdf may use special png pre-compression
include-codec-pdf: [mezz-lib-files: %mezz/codec-pdf.reb :include-png-filter-native] ; pdf may use special png pre-compression
include-codec-swf: [mezz-lib-files: %mezz/codec-swf.reb ]
include-codec-wav: [mezz-lib-files: %mezz/codec-wav.reb ]
include-codec-unixtime: [mezz-lib-files: %mezz/codec-unixtime.reb ]
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225 changes: 0 additions & 225 deletions src/core/u-compress.c
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Original file line number Diff line number Diff line change
Expand Up @@ -343,228 +343,3 @@ static const ISzAlloc g_Alloc = { SzAlloc, SzFree };

#endif //INCLUDE_LZMA


#ifdef INCLUDE_PNG_FILTER
#ifdef INCLUDE_PNG_CODEC
int paeth_predictor(int a, int b, int c);
#else
#define int_abs(a) (((a)<0)?(-(a)):(a))
static int paeth_predictor(int a, int b, int c) {
int p, pa, pb, pc;

p = a + b - c;
pa = int_abs(p - a);
pb = int_abs(p - b);
pc = int_abs(p - c);
if ((pa <= pb) && (pa <= pc))
return a;
else if (pb <= pc)
return b;
return c;
}
#endif

enum PNG_Filter_Types {
PNG_FILTER_SUB = 1,
PNG_FILTER_UP,
PNG_FILTER_AVERAGE,
PNG_FILTER_PAETH
};

static REBYTE get_png_filter_type(REBVAL* val) {
if (IS_WORD(val)) {
switch (VAL_WORD_SYM(val)) {
case SYM_SUB: return PNG_FILTER_SUB;
case SYM_UP: return PNG_FILTER_UP;
case SYM_AVERAGE: return PNG_FILTER_AVERAGE;
case SYM_PAETH: return PNG_FILTER_PAETH;
}
}
else if (IS_INTEGER(val)) {
return MIN(PNG_FILTER_PAETH, MAX(0, VAL_INT32(val)));
}
Trap1(RE_INVALID_ARG, val);
return 0; // to make xcode happy
}

// See: https://www.rfc-editor.org/rfc/rfc2083.html#page-31
// https://en.wikipedia.org/wiki/Portable_Network_Graphics#Filtering
/***********************************************************************
**
*/ REBNATIVE(filter)
/*
// filter: native [
// "PNG delta filter"
// data [binary!] "Input"
// width [number!] "Scanline width"
// type [integer! word!] "1..4 or one of: [sub up average paeth]"
// /skip bpp [integer!] "Bytes per pixel"
// ]
***********************************************************************/
{
REBVAL *val_data = D_ARG(1);
REBVAL *val_width = D_ARG(2);
REBVAL *val_type = D_ARG(3);
REBOOL ref_skip = D_REF(4);
REBVAL *val_bpp = D_ARG(5);

REBSER *ser;
REBYTE *bin = VAL_BIN_DATA(val_data);
REBYTE *scan, *prev, *temp, *out;
REBCNT r, c, rows, bytes;
REBINT width = AS_INT32(val_width);
REBYTE filter = get_png_filter_type(val_type);
REBCNT bpp = ref_skip ? VAL_INT32(val_bpp) : 1;

bytes = VAL_LEN(val_data);

if (width <= 1 || width > bytes)
Trap1(RE_INVALID_ARG, val_width);
if (bpp < 1 || bpp > width)
Trap1(RE_INVALID_ARG, val_bpp);

rows = bytes / width;
ser = Make_Binary(bytes);
out = BIN_DATA(ser);

temp = malloc(width);
if (!temp) {
Trap0(RE_NO_MEMORY);
return R_NONE;
}
memset(temp, 0, width);

prev = temp;
for (r = 0; r < rows; r++) {
scan = bin + (r * width);
out = BIN_SKIP(ser, r * width);

switch (filter) {
case PNG_FILTER_SUB:
for (c = 0; c < bpp; c++)
out[c] = scan[c];
for (c = bpp; c < width; c++)
out[c] = scan[c] - scan[c - bpp];
break;
case PNG_FILTER_UP:
for (c = 0; c < width; c++)
out[c] = scan[c] - prev[c];
break;
case PNG_FILTER_AVERAGE:
for (c = 0; c < bpp; c++)
out[c] = scan[c] - (prev[c] >> 1);
for (c = bpp; c < width; c++)
out[c] = scan[c] - ((scan[c - bpp] + prev[c]) >> 1) & 0xFF;
break;
case PNG_FILTER_PAETH:
for (c = 0; c < bpp; c++)
out[c] = scan[c] - prev[c];
for (c = bpp; c < width; c++)
out[c] = scan[c] - paeth_predictor(scan[c - bpp], prev[c], prev[c - bpp]);
break;
}
prev = scan;
}
free(temp);
SET_BINARY(D_RET, ser);
VAL_TAIL(D_RET) = bytes;
return R_RET;
}

/***********************************************************************
**
*/ REBNATIVE(unfilter)
/*
// unfilter: native [
// "Reversed PNG delta filter"
// data [binary!] "Input"
// width [number!] "Scanline width (not counting the type byte)"
// /as "Filter type. If not used, type is decoded from first byte on each line."
// type [integer! word!] "1..4 or one of: [sub up average paeth]"
// /skip
// bpp [integer!] "Bytes per pixel"
// ]
***********************************************************************/
{
REBVAL *val_data = D_ARG(1);
REBVAL *val_width = D_ARG(2);
REBOOL ref_as = D_REF(3);
REBVAL *val_type = D_ARG(4);
REBOOL ref_skip = D_REF(5);
REBVAL *val_bpp = D_ARG(6);

REBSER *ser;
REBYTE *bin = VAL_BIN_DATA(val_data);
REBINT width = AS_INT32(val_width);
REBCNT r, c, rows;
REBYTE *scan, *prev, *temp, *out;
REBYTE filter = 0;
REBCNT bytes = VAL_LEN(val_data);
REBCNT bpp = ref_skip ? VAL_INT32(val_bpp) : 1;

if (!ref_as) width++;
if (width <= 1 || width > bytes)
Trap1(RE_INVALID_ARG, val_width);
if (bpp < 1 || bpp > width)
Trap1(RE_INVALID_ARG, val_bpp);

rows = ceil(bytes / width);
ser = Make_Binary(bytes);
out = BIN_DATA(ser);

if (ref_as)
filter = get_png_filter_type(val_type);

temp = malloc(width);
if (!temp) {
Trap0(RE_NO_MEMORY);
return R_NONE;
}
memset(temp, 0, width);

if (!ref_as) width--;

prev = temp;
for (r = 0; r < rows; r++) {
if (ref_as) {
scan = bin + r * width;
out = BIN_SKIP(ser, r * width);
} else {
scan = bin + r * (width + 1);
out = BIN_SKIP(ser, r * (width));
filter = scan[0];
scan++;
}

switch (filter) {
case PNG_FILTER_SUB:
for (c = 0; c < bpp; c++)
out[c] = scan[c];
for (c = bpp; c < width; c++)
out[c] = scan[c] + out[c - bpp];
break;
case PNG_FILTER_UP:
for (c = 0; c < width; c++)
out[c] = scan[c] + prev[c];
break;
case PNG_FILTER_AVERAGE:
for (c = 0; c < bpp; c++)
out[c] = scan[c] + (prev[c] >> 1) & 0xFF;
for (c = bpp; c < width; c++)
out[c] = scan[c] + ((out[c - bpp] + prev[c]) >> 1) & 0xFF;
break;
case PNG_FILTER_PAETH:
for (c = 0; c < bpp; c++)
out[c] = scan[c] + prev[c];
for (c = bpp; c < width; c++)
out[c] = scan[c] + paeth_predictor(out[c - bpp], prev[c], prev[c - bpp]);
break;
}
prev = out;
}
free(temp);
SET_BINARY(D_RET, ser);
VAL_TAIL(D_RET) = ref_as ? bytes : bytes - rows;
return R_RET;
}
#endif //INCLUDE_PNG_FILTER
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