public static int stbi__zexpand(StbiZbuf *z, sbyte *zout, int n)
{
sbyte *q;
var cur = 0;
var limit = 0;
var old_limit = 0;
z->zout = zout;
if (z->z_expandable == 0)
{
return(stbi__err("output buffer limit"));
}
cur = (int)(z->zout - z->zout_start);
limit = old_limit = (int)(z->zout_end - z->zout_start);
while (cur + n > limit)
{
limit *= 2;
}
q = (sbyte *)CRuntime.Realloc(z->zout_start, (ulong)limit);
if (q == null)
{
return(stbi__err("outofmem"));
}
z->zout_start = q;
z->zout = q + cur;
z->zout_end = q + limit;
return(1);
}
public static int stbi__parse_png_file(StbiPng z, int scan, int reqComp)
{
var palette = stackalloc byte[1024];
var pal_img_n = (byte)0;
var has_trans = (byte)0;
var tc = stackalloc byte[3];
tc[0] = 0;
var tc16 = stackalloc ushort[3];
var ioff = (uint)0;
var idata_limit = (uint)0;
uint i = 0;
var pal_len = (uint)0;
var first = 1;
var k = 0;
var interlace = 0;
var color = 0;
var is_iphone = 0;
var s = z.S;
z.Expanded = null;
z.Idata = null;
z.Out = null;
if (stbi__check_png_header(s) == 0)
{
return(0);
}
if (scan == STBI_SCAN_TYPE)
{
return(1);
}
for (; ;)
{
var c = stbi__get_chunk_header(s);
switch (c.type)
{
case ((uint)'C' << 24) + ((uint)'g' << 16) + ((uint)'B' << 8) + 'I':
is_iphone = 1;
stbi__skip(s, (int)c.length);
break;
case ((uint)'I' << 24) + ((uint)'H' << 16) + ((uint)'D' << 8) + 'R':
{
var comp = 0;
var filter = 0;
if (first == 0)
{
return(stbi__err("multiple IHDR"));
}
first = 0;
if (c.length != 13)
{
return(stbi__err("bad IHDR len"));
}
s.ImgX = stbi__get32be(s);
if (s.ImgX > 1 << 24)
{
return(stbi__err("too large"));
}
s.ImgY = stbi__get32be(s);
if (s.ImgY > 1 << 24)
{
return(stbi__err("too large"));
}
z.Depth = stbi__get8(s);
if (z.Depth != 1 && z.Depth != 2 && z.Depth != 4 && z.Depth != 8 && z.Depth != 16)
{
return(stbi__err("1/2/4/8/16-bit only"));
}
color = stbi__get8(s);
if (color > 6)
{
return(stbi__err("bad ctype"));
}
if (color == 3 && z.Depth == 16)
{
return(stbi__err("bad ctype"));
}
if (color == 3)
{
pal_img_n = 3;
}
else if ((color & 1) != 0)
{
return(stbi__err("bad ctype"));
}
comp = stbi__get8(s);
if (comp != 0)
{
return(stbi__err("bad comp method"));
}
filter = stbi__get8(s);
if (filter != 0)
{
return(stbi__err("bad filter method"));
}
interlace = stbi__get8(s);
if (interlace > 1)
{
return(stbi__err("bad interlace method"));
}
if (s.ImgX == 0 || s.ImgY == 0)
{
return(stbi__err("0-pixel image"));
}
if (pal_img_n == 0)
{
s.ImgN = ((color & 2) != 0 ? 3 : 1) + ((color & 4) != 0 ? 1 : 0);
if ((1 << 30) / s.ImgX / s.ImgN < s.ImgY)
{
return(stbi__err("too large"));
}
if (scan == STBI_SCAN_HEADER)
{
return(1);
}
}
else
{
s.ImgN = 1;
if ((1 << 30) / s.ImgX / 4 < s.ImgY)
{
return(stbi__err("too large"));
}
}
break;
}
case ((uint)'P' << 24) + ((uint)'L' << 16) + ((uint)'T' << 8) + 'E':
{
if (first != 0)
{
return(stbi__err("first not IHDR"));
}
if (c.length > 256 * 3)
{
return(stbi__err("invalid PLTE"));
}
pal_len = c.length / 3;
if (pal_len * 3 != c.length)
{
return(stbi__err("invalid PLTE"));
}
for (i = (uint)0; i < pal_len; ++i)
{
palette[i * 4 + 0] = stbi__get8(s);
palette[i * 4 + 1] = stbi__get8(s);
palette[i * 4 + 2] = stbi__get8(s);
palette[i * 4 + 3] = 255;
}
break;
}
case ((uint)'t' << 24) + ((uint)'R' << 16) + ((uint)'N' << 8) + 'S':
{
if (first != 0)
{
return(stbi__err("first not IHDR"));
}
if (z.Idata != null)
{
return(stbi__err("tRNS after IDAT"));
}
if (pal_img_n != 0)
{
if (scan == STBI_SCAN_HEADER)
{
s.ImgN = 4;
return(1);
}
if (pal_len == 0)
{
return(stbi__err("tRNS before PLTE"));
}
if (c.length > pal_len)
{
return(stbi__err("bad tRNS len"));
}
pal_img_n = 4;
for (i = (uint)0; i < c.length; ++i)
{
palette[i * 4 + 3] = stbi__get8(s);
}
}
else
{
if ((s.ImgN & 1) == 0)
{
return(stbi__err("tRNS with alpha"));
}
if (c.length != (uint)s.ImgN * 2)
{
return(stbi__err("bad tRNS len"));
}
has_trans = 1;
if (z.Depth == 16)
{
for (k = 0; k < s.ImgN; ++k)
{
tc16[k] = (ushort)stbi__get16be(s);
}
}
else
{
for (k = 0; k < s.ImgN; ++k)
{
tc[k] = (byte)((byte)(stbi__get16be(s) & 255) * StbiDepthScaleTable[z.Depth]);
}
}
}
break;
}
case ((uint)'I' << 24) + ((uint)'D' << 16) + ((uint)'A' << 8) + 'T':
{
if (first != 0)
{
return(stbi__err("first not IHDR"));
}
if (pal_img_n != 0 && pal_len == 0)
{
return(stbi__err("no PLTE"));
}
if (scan == STBI_SCAN_HEADER)
{
s.ImgN = pal_img_n;
return(1);
}
if ((int)(ioff + c.length) < (int)ioff)
{
return(0);
}
if (ioff + c.length > idata_limit)
{
var idata_limit_old = idata_limit;
byte *p;
if (idata_limit == 0)
{
idata_limit = c.length > 4096 ? c.length : 4096;
}
while (ioff + c.length > idata_limit)
{
idata_limit *= 2;
}
p = (byte *)CRuntime.Realloc(z.Idata, (ulong)idata_limit);
if (p == null)
{
return(stbi__err("outofmem"));
}
z.Idata = p;
}
if (stbi__getn(s, z.Idata + ioff, (int)c.length) == 0)
{
return(stbi__err("outofdata"));
}
ioff += c.length;
break;
}
case ((uint)'I' << 24) + ((uint)'E' << 16) + ((uint)'N' << 8) + 'D':
{
uint raw_len = 0;
uint bpl = 0;
if (first != 0)
{
return(stbi__err("first not IHDR"));
}
if (scan != STBI_SCAN_LOAD)
{
return(1);
}
if (z.Idata == null)
{
return(stbi__err("no IDAT"));
}
bpl = (uint)((s.ImgX * z.Depth + 7) / 8);
raw_len = (uint)(bpl * s.ImgY * s.ImgN + s.ImgY);
z.Expanded = (byte *)stbi_zlib_decode_malloc_guesssize_headerflag((sbyte *)z.Idata, (int)ioff,
(int)raw_len, (int *)&raw_len, is_iphone != 0 ? 0 : 1);
if (z.Expanded == null)
{
return(0);
}
CRuntime.Free(z.Idata);
z.Idata = null;
if (reqComp == s.ImgN + 1 && reqComp != 3 && pal_img_n == 0 || has_trans != 0)
{
s.ImgOutN = s.ImgN + 1;
}
else
{
s.ImgOutN = s.ImgN;
}
if (stbi__create_png_image(z, z.Expanded, raw_len, s.ImgOutN, z.Depth, color, interlace) == 0)
{
return(0);
}
if (has_trans != 0)
{
if (z.Depth == 16)
{
if (stbi__compute_transparency16(z, tc16, s.ImgOutN) == 0)
{
return(0);
}
}
else
{
if (stbi__compute_transparency(z, tc, s.ImgOutN) == 0)
{
return(0);
}
}
}
if (is_iphone != 0 && StbiDeIphoneFlag != 0 && s.ImgOutN > 2)
{
stbi__de_iphone(z);
}
if (pal_img_n != 0)
{
s.ImgN = pal_img_n;
s.ImgOutN = pal_img_n;
if (reqComp >= 3)
{
s.ImgOutN = reqComp;
}
if (stbi__expand_png_palette(z, palette, (int)pal_len, s.ImgOutN) == 0)
{
return(0);
}
}
else if (has_trans != 0)
{
++s.ImgN;
}
CRuntime.Free(z.Expanded);
z.Expanded = null;
return(1);
}
default:
if (first != 0)
{
return(stbi__err("first not IHDR"));
}
if ((c.type & (1 << 29)) == 0)
{
var invalid_chunk = c.type + " PNG chunk not known";
return(stbi__err(invalid_chunk));
}
stbi__skip(s, (int)c.length);
break;
}
stbi__get32be(s);
}
}
