/*!
* readHeaderWebP()
*
* Input: filename
* &w (<return> width)
* &h (<return> height)
* &spp (<return> spp (3 or 4))
* Return: 0 if OK, 1 on error
*/
l_int32
readHeaderWebP(const char *filename,
l_int32 *pw,
l_int32 *ph,
l_int32 *pspp)
{
l_uint8 data[100]; /* expect size info within the first 50 bytes or so */
l_int32 nbytes, bytesread;
size_t filesize;
FILE *fp;
PROCNAME("readHeaderWebP");
if (!pw || !ph || !pspp)
return ERROR_INT("input ptr(s) not defined", procName, 1);
*pw = *ph = *pspp = 0;
if (!filename)
return ERROR_INT("filename not defined", procName, 1);
/* Read no more than 100 bytes from the file */
if ((filesize = nbytesInFile(filename)) == 0)
return ERROR_INT("no file size found", procName, 1);
if (filesize < 100)
L_WARNING("very small webp file\n", procName);
nbytes = L_MIN(filesize, 100);
if ((fp = fopenReadStream(filename)) == NULL)
return ERROR_INT("image file not found", procName, 1);
bytesread = fread((char *)data, 1, nbytes, fp);
fclose(fp);
if (bytesread != nbytes)
return ERROR_INT("failed to read requested data", procName, 1);
return readHeaderMemWebP(data, nbytes, pw, ph, pspp);
}
/*!
* pixReadHeaderMem()
*
* Input: data (const; encoded)
* datasize (size of data)
* &format (<optional returns> image format)
* &w, &h (<optional returns> width and height)
* &bps <optional return> bits/sample
* &spp <optional return> samples/pixel (1, 3 or 4)
* &iscmap (<optional return> 1 if cmap exists; 0 otherwise)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This reads the actual headers for jpeg, png, tiff, jp2k and pnm.
* For bmp and gif, we cheat and read all the data into a pix,
* from which we extract the "header" information.
* (2) The amount of data required depends on the format. For
* png, it requires less than 30 bytes, but for jpeg it can
* require most of the compressed file. In practice, the data
* is typically the entire compressed file in memory.
* (3) findFileFormatBuffer() requires up to 8 bytes to decide on
* the format, which we require.
*/
l_int32
pixReadHeaderMem(const l_uint8 *data,
size_t size,
l_int32 *pformat,
l_int32 *pw,
l_int32 *ph,
l_int32 *pbps,
l_int32 *pspp,
l_int32 *piscmap)
{
l_int32 format, ret, w, h, d, bps, spp, iscmap;
l_int32 type; /* not used */
PIX *pix;
PROCNAME("pixReadHeaderMem");
if (pw) *pw = 0;
if (ph) *ph = 0;
if (pbps) *pbps = 0;
if (pspp) *pspp = 0;
if (piscmap) *piscmap = 0;
if (pformat) *pformat = 0;
iscmap = 0; /* init to false */
if (!data)
return ERROR_INT("data not defined", procName, 1);
if (size < 8)
return ERROR_INT("size < 8", procName, 1);
findFileFormatBuffer(data, &format);
switch (format)
{
case IFF_BMP: /* cheating: read the pix */
if ((pix = pixReadMemBmp(data, size)) == NULL)
return ERROR_INT( "bmp: pix not read", procName, 1);
pixGetDimensions(pix, &w, &h, &d);
pixDestroy(&pix);
bps = (d == 32) ? 8 : d;
spp = (d == 32) ? 3 : 1;
break;
case IFF_JFIF_JPEG:
ret = readHeaderMemJpeg(data, size, &w, &h, &spp, NULL, NULL);
bps = 8;
if (ret)
return ERROR_INT( "jpeg: no header info returned", procName, 1);
break;
case IFF_PNG:
ret = readHeaderMemPng(data, size, &w, &h, &bps, &spp, &iscmap);
if (ret)
return ERROR_INT( "png: no header info returned", procName, 1);
break;
case IFF_TIFF:
case IFF_TIFF_PACKBITS:
case IFF_TIFF_RLE:
case IFF_TIFF_G3:
case IFF_TIFF_G4:
case IFF_TIFF_LZW:
case IFF_TIFF_ZIP:
/* Reading page 0 by default; possibly redefine format */
ret = readHeaderMemTiff(data, size, 0, &w, &h, &bps, &spp,
NULL, &iscmap, &format);
if (ret)
return ERROR_INT( "tiff: no header info returned", procName, 1);
break;
case IFF_PNM:
ret = readHeaderMemPnm(data, size, &w, &h, &d, &type, &bps, &spp);
if (ret)
return ERROR_INT( "pnm: no header info returned", procName, 1);
break;
case IFF_GIF: /* cheating: read the pix */
if ((pix = pixReadMemGif(data, size)) == NULL)
return ERROR_INT( "gif: pix not read", procName, 1);
pixGetDimensions(pix, &w, &h, &d);
pixDestroy(&pix);
iscmap = 1; /* always colormapped; max 256 colors */
spp = 1;
bps = d;
break;
case IFF_JP2:
ret = readHeaderMemJp2k(data, size, &w, &h, &bps, &spp);
break;
case IFF_WEBP:
bps = 8;
ret = readHeaderMemWebP(data, size, &w, &h, &spp);
break;
case IFF_SPIX:
ret = sreadHeaderSpix((l_uint32 *)data, &w, &h, &bps,
&spp, &iscmap);
if (ret)
return ERROR_INT( "pnm: no header info returned", procName, 1);
break;
case IFF_UNKNOWN:
return ERROR_INT("unknown format; no data returned", procName, 1);
break;
}
if (pw) *pw = w;
if (ph) *ph = h;
if (pbps) *pbps = bps;
if (pspp) *pspp = spp;
if (piscmap) *piscmap = iscmap;
if (pformat) *pformat = format;
return 0;
}
