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linux-next/drivers/media/usb/gspca/jpeg.h
Mauro Carvalho Chehab 32654fba2f [media] gpsca: remove the risk of a division by zero 
As reported by Coverity, there's a potential risk of a division
by zero on some calls to jpeg_set_qual(), if quality is zero.

As quality can't be 0 or lower than that, adds an extra clause
to cover this special case.

Coverity reports: CID#11922280, CID#11922293, CID#11922295

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-04-08 11:01:12 -03:00

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5.9 KiB
C
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#ifndef JPEG_H
#define JPEG_H 1
/*
* Insert a JPEG header at start of frame
*
* This module is used by the gspca subdrivers.
* A special case is done for Conexant webcams.
*
* Copyright (C) Jean-Francois Moine (http://moinejf.free.fr)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*
* generation options
* CONEX_CAM Conexant if present
*/
/* JPEG header */
static const u8 jpeg_head[] = {
0xff, 0xd8, /* jpeg */
/* quantization table quality 50% */
0xff, 0xdb, 0x00, 0x84, /* DQT */
0,
#define JPEG_QT0_OFFSET 7
0x10, 0x0b, 0x0c, 0x0e, 0x0c, 0x0a, 0x10, 0x0e,
0x0d, 0x0e, 0x12, 0x11, 0x10, 0x13, 0x18, 0x28,
0x1a, 0x18, 0x16, 0x16, 0x18, 0x31, 0x23, 0x25,
0x1d, 0x28, 0x3a, 0x33, 0x3d, 0x3c, 0x39, 0x33,
0x38, 0x37, 0x40, 0x48, 0x5c, 0x4e, 0x40, 0x44,
0x57, 0x45, 0x37, 0x38, 0x50, 0x6d, 0x51, 0x57,
0x5f, 0x62, 0x67, 0x68, 0x67, 0x3e, 0x4d, 0x71,
0x79, 0x70, 0x64, 0x78, 0x5c, 0x65, 0x67, 0x63,
1,
#define JPEG_QT1_OFFSET 72
0x11, 0x12, 0x12, 0x18, 0x15, 0x18, 0x2f, 0x1a,
0x1a, 0x2f, 0x63, 0x42, 0x38, 0x42, 0x63, 0x63,
0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
/* huffman table */
0xff, 0xc4, 0x01, 0xa2,
0x00, 0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0a, 0x0b, 0x01, 0x00, 0x03,
0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x0a, 0x0b, 0x10, 0x00, 0x02, 0x01, 0x03, 0x03,
0x02, 0x04, 0x03, 0x05, 0x05, 0x04, 0x04, 0x00,
0x00, 0x01, 0x7d, 0x01, 0x02, 0x03, 0x00, 0x04,
0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13,
0x51, 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81,
0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1, 0xc1, 0x15,
0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82,
0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25,
0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36,
0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46,
0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56,
0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66,
0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76,
0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86,
0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95,
0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4,
0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3,
0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2,
0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca,
0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9,
0xda, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5,
0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0x11, 0x00, 0x02,
0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07, 0x05,
0x04, 0x04, 0x00, 0x01, 0x02, 0x77, 0x00, 0x01,
0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06,
0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22,
0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1,
0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62,
0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25,
0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27, 0x28,
0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a,
0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3,
0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf2,
0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa,
#ifdef CONEX_CAM
/* the Conexant frames start with SOF0 */
#define JPEG_HDR_SZ 556
#else
0xff, 0xc0, 0x00, 0x11, /* SOF0 (start of frame 0 */
0x08, /* data precision */
#define JPEG_HEIGHT_OFFSET 561
0x01, 0xe0, /* height */
0x02, 0x80, /* width */
0x03, /* component number */
0x01,
0x21, /* samples Y */
0x00, /* quant Y */
0x02, 0x11, 0x01, /* samples CbCr - quant CbCr */
0x03, 0x11, 0x01,
0xff, 0xda, 0x00, 0x0c, /* SOS (start of scan) */
0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00
#define JPEG_HDR_SZ 589
#endif
};
/* define the JPEG header */
static void jpeg_define(u8 *jpeg_hdr,
int height,
int width,
int samplesY)
{
memcpy(jpeg_hdr, jpeg_head, sizeof jpeg_head);
#ifndef CONEX_CAM
jpeg_hdr[JPEG_HEIGHT_OFFSET + 0] = height >> 8;
jpeg_hdr[JPEG_HEIGHT_OFFSET + 1] = height;
jpeg_hdr[JPEG_HEIGHT_OFFSET + 2] = width >> 8;
jpeg_hdr[JPEG_HEIGHT_OFFSET + 3] = width;
jpeg_hdr[JPEG_HEIGHT_OFFSET + 6] = samplesY;
#endif
}
/* set the JPEG quality */
static void jpeg_set_qual(u8 *jpeg_hdr,
int quality)
{
int i, sc;
if (quality <= 0)
sc = 5000;
else if (quality < 50)
sc = 5000 / quality;
else
sc = 200 - quality * 2;
for (i = 0; i < 64; i++) {
jpeg_hdr[JPEG_QT0_OFFSET + i] =
(jpeg_head[JPEG_QT0_OFFSET + i] * sc + 50) / 100;
jpeg_hdr[JPEG_QT1_OFFSET + i] =
(jpeg_head[JPEG_QT1_OFFSET + i] * sc + 50) / 100;
}
}
#endif
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