/*!
* sreadHeaderJp2k()
*
* Input: data
* size
* &w (<optional return>)
* &h (<optional return>)
* &spp (<optional return>, samples/pixel)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) The metadata is stored as follows:
* h: 4 bytes @ 48
* w: 4 bytes @ 52
* spp: 2 bytes @ 56
*/
l_int32
sreadHeaderJp2k(const l_uint8 *data,
size_t size,
l_int32 *pw,
l_int32 *ph,
l_int32 *pspp)
{
l_int32 format, val, w, h, spp;
PROCNAME("sreadHeaderJp2k");
if (pw) *pw = 0;
if (ph) *ph = 0;
if (pspp) *pspp = 0;
if (!data)
return ERROR_INT("data not defined", procName, 1);
if (size < 60)
return ERROR_INT("size < 60", procName, 1);
findFileFormatBuffer(data, &format);
if (format != IFF_JP2)
return ERROR_INT("not jp2 file", procName, 1);
val = *((l_uint32 *)data + 12);
h = convertOnLittleEnd32(val);
val = *((l_uint32 *)data + 13);
w = convertOnLittleEnd32(val);
val = *((l_uint16 *)data + 28);
spp = convertOnLittleEnd16(val);
if (w > MAX_JP2K_WIDTH || h > MAX_JP2K_HEIGHT)
return ERROR_INT("unrealistically large sizes", procName, 1);
if (pw) *pw = w;
if (ph) *ph = h;
if (pspp) *pspp = spp;
return 0;
}
/*!
* sreadHeaderPng()
*
* Input: data
* &width (<return>)
* &height (<return>)
* &bps (<return>, bits/sample)
* &spp (<return>, samples/pixel)
* &iscmap (<optional return>; input NULL to ignore)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) If there is a colormap, iscmap is returned as 1; else 0.
*/
l_int32
sreadHeaderPng(const l_uint8 *data,
l_int32 *pwidth,
l_int32 *pheight,
l_int32 *pbps,
l_int32 *pspp,
l_int32 *piscmap)
{
l_uint8 colortype, bps;
l_uint16 twobytes;
l_uint16 *pshort;
l_uint32 *pword;
PROCNAME("sreadHeaderPng");
if (!data)
return ERROR_INT("data not defined", procName, 1);
if (!pwidth || !pheight || !pbps || !pspp)
return ERROR_INT("input ptr(s) not defined", procName, 1);
*pwidth = *pheight = *pbps = *pspp = 0;
if (piscmap)
*piscmap = 0;
/* Check password */
if (data[0] != 137 || data[1] != 80 || data[2] != 78 ||
data[3] != 71 || data[4] != 13 || data[5] != 10 ||
data[6] != 26 || data[7] != 10)
return ERROR_INT("not a valid png file", procName, 1);
pword = (l_uint32 *)data;
pshort = (l_uint16 *)data;
*pwidth = convertOnLittleEnd32(pword[4]);
*pheight = convertOnLittleEnd32(pword[5]);
twobytes = convertOnLittleEnd16(pshort[12]); /* contains depth/sample */
/* and the color type */
colortype = twobytes & 0xff; /* color type */
bps = twobytes >> 8; /* bits/sample */
*pbps = bps;
if (colortype == 2) /* RGB */
*pspp = 3;
else if (colortype == 6) /* RGBA */
*pspp = 4;
else /* palette or gray */
*pspp = 1;
if (piscmap) {
if (colortype & 1) /* palette: see png.h, PNG_COLOR_TYPE_... */
*piscmap = 1;
else
*piscmap = 0;
}
return 0;
}
/*!
* readHeaderMemJp2k()
*
* Input: data
* size (at least 80)
* &w (<optional return>)
* &h (<optional return>)
* &bps (<optional return>, bits/sample)
* &spp (<optional return>, samples/pixel)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) The ISO/IEC reference for jpeg2000 is
* http://www.jpeg.org/public/15444-1annexi.pdf
* and the file format syntax begins at page 127.
* (2) The Image Header Box begins with 'ihdr' = 0x69686472 in
* big-endian order. This typically, but not always, starts
* byte 44, with the big-endian data fields beginning at byte 48:
* h: 4 bytes
* w: 4 bytes
* spp: 2 bytes
* bps: 1 byte (contains bps - 1)
*/
l_int32
readHeaderMemJp2k(const l_uint8 *data,
size_t size,
l_int32 *pw,
l_int32 *ph,
l_int32 *pbps,
l_int32 *pspp)
{
l_int32 format, val, w, h, bps, spp, loc, found, windex;
l_uint8 ihdr[4] = {0x69, 0x68, 0x64, 0x72}; /* 'ihdr' */
PROCNAME("readHeaderMemJp2k");
if (pw) *pw = 0;
if (ph) *ph = 0;
if (pbps) *pbps = 0;
if (pspp) *pspp = 0;
if (!data)
return ERROR_INT("data not defined", procName, 1);
if (size < 80)
return ERROR_INT("size < 80", procName, 1);
findFileFormatBuffer(data, &format);
if (format != IFF_JP2)
return ERROR_INT("not jp2 file", procName, 1);
/* Search for beginning of the Image Header Box: 'ihdr' */
arrayFindSequence(data, size, ihdr, 4, &loc, &found);
if (!found)
return ERROR_INT("image parameters not found", procName, 1);
if (loc != 44)
L_INFO("Beginning of ihdr is at byte %d\n", procName, loc);
windex = loc / 4 + 1;
val = *((l_uint32 *)data + windex);
h = convertOnLittleEnd32(val);
val = *((l_uint32 *)data + windex + 1);
w = convertOnLittleEnd32(val);
val = *((l_uint16 *)data + 2 * (windex + 2));
spp = convertOnLittleEnd16(val);
bps = *(data + 4 * (windex + 2) + 2) + 1;
if (w > MAX_JP2K_WIDTH || h > MAX_JP2K_HEIGHT)
return ERROR_INT("unrealistically large sizes", procName, 1);
if (pw) *pw = w;
if (ph) *ph = h;
if (pbps) *pbps = bps;
if (pspp) *pspp = spp;
return 0;
}
