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|
// SPDX-License-Identifier: GPL-2.0-only
/*
* V4L2 JPEG header parser helpers.
*
* Copyright (C) 2019 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
*
* For reference, see JPEG ITU-T.81 (ISO/IEC 10918-1) [1]
*
* [1] https://www.w3.org/Graphics/JPEG/itu-t81.pdf
*/
#include <asm/unaligned.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <media/v4l2-jpeg.h>
MODULE_DESCRIPTION("V4L2 JPEG header parser helpers");
MODULE_AUTHOR("Philipp Zabel <kernel@pengutronix.de>");
MODULE_LICENSE("GPL");
/* Table B.1 - Marker code assignments */
#define SOF0 0xffc0 /* start of frame */
#define SOF1 0xffc1
#define SOF2 0xffc2
#define SOF3 0xffc3
#define SOF5 0xffc5
#define SOF7 0xffc7
#define JPG 0xffc8 /* extensions */
#define SOF9 0xffc9
#define SOF11 0xffcb
#define SOF13 0xffcd
#define SOF15 0xffcf
#define DHT 0xffc4 /* huffman table */
#define DAC 0xffcc /* arithmetic coding conditioning */
#define RST0 0xffd0 /* restart */
#define RST7 0xffd7
#define SOI 0xffd8 /* start of image */
#define EOI 0xffd9 /* end of image */
#define SOS 0xffda /* start of stream */
#define DQT 0xffdb /* quantization table */
#define DNL 0xffdc /* number of lines */
#define DRI 0xffdd /* restart interval */
#define DHP 0xffde /* hierarchical progression */
#define EXP 0xffdf /* expand reference */
#define APP0 0xffe0 /* application data */
#define APP14 0xffee /* application data for colour encoding */
#define APP15 0xffef
#define JPG0 0xfff0 /* extensions */
#define JPG13 0xfffd
#define COM 0xfffe /* comment */
#define TEM 0xff01 /* temporary */
/* Luma and chroma qp tables to achieve 50% compression quality
* This is as per example in Annex K.1 of ITU-T.81
*/
const u8 v4l2_jpeg_ref_table_luma_qt[V4L2_JPEG_PIXELS_IN_BLOCK] = {
16, 11, 10, 16, 24, 40, 51, 61,
12, 12, 14, 19, 26, 58, 60, 55,
14, 13, 16, 24, 40, 57, 69, 56,
14, 17, 22, 29, 51, 87, 80, 62,
18, 22, 37, 56, 68, 109, 103, 77,
24, 35, 55, 64, 81, 104, 113, 92,
49, 64, 78, 87, 103, 121, 120, 101,
72, 92, 95, 98, 112, 100, 103, 99
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_ref_table_luma_qt);
const u8 v4l2_jpeg_ref_table_chroma_qt[V4L2_JPEG_PIXELS_IN_BLOCK] = {
17, 18, 24, 47, 99, 99, 99, 99,
18, 21, 26, 66, 99, 99, 99, 99,
24, 26, 56, 99, 99, 99, 99, 99,
47, 66, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_ref_table_chroma_qt);
/* Zigzag scan pattern indexes */
const u8 v4l2_jpeg_zigzag_scan_index[V4L2_JPEG_PIXELS_IN_BLOCK] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_zigzag_scan_index);
/*
* Contains the data that needs to be sent in the marker segment of an
* interchange format JPEG stream or an abbreviated format table specification
* data stream. Specifies the huffman table used for encoding the luminance DC
* coefficient differences. The table represents Table K.3 of ITU-T.81
*/
const u8 v4l2_jpeg_ref_table_luma_dc_ht[V4L2_JPEG_REF_HT_DC_LEN] = {
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
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_ref_table_luma_dc_ht);
/*
* Contains the data that needs to be sent in the marker segment of an
* interchange format JPEG stream or an abbreviated format table specification
* data stream. Specifies the huffman table used for encoding the luminance AC
* coefficients. The table represents Table K.5 of ITU-T.81
*/
const u8 v4l2_jpeg_ref_table_luma_ac_ht[V4L2_JPEG_REF_HT_AC_LEN] = {
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
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_ref_table_luma_ac_ht);
/*
* Contains the data that needs to be sent in the marker segment of an interchange format JPEG
* stream or an abbreviated format table specification data stream.
* Specifies the huffman table used for encoding the chrominance DC coefficient differences.
* The table represents Table K.4 of ITU-T.81
*/
const u8 v4l2_jpeg_ref_table_chroma_dc_ht[V4L2_JPEG_REF_HT_DC_LEN] = {
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
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_ref_table_chroma_dc_ht);
/*
* Contains the data that needs to be sent in the marker segment of an
* interchange format JPEG stream or an abbreviated format table specification
* data stream. Specifies the huffman table used for encoding the chrominance
* AC coefficients. The table represents Table K.6 of ITU-T.81
*/
const u8 v4l2_jpeg_ref_table_chroma_ac_ht[V4L2_JPEG_REF_HT_AC_LEN] = {
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
};
EXPORT_SYMBOL_GPL(v4l2_jpeg_ref_table_chroma_ac_ht);
/**
* struct jpeg_stream - JPEG byte stream
* @curr: current position in stream
* @end: end position, after last byte
*/
struct jpeg_stream {
u8 *curr;
u8 *end;
};
/* returns a value that fits into u8, or negative error */
static int jpeg_get_byte(struct jpeg_stream *stream)
{
if (stream->curr >= stream->end)
return -EINVAL;
return *stream->curr++;
}
/* returns a value that fits into u16, or negative error */
static int jpeg_get_word_be(struct jpeg_stream *stream)
{
u16 word;
if (stream->curr + sizeof(__be16) > stream->end)
return -EINVAL;
word = get_unaligned_be16(stream->curr);
stream->curr += sizeof(__be16);
return word;
}
static int jpeg_skip(struct jpeg_stream *stream, size_t len)
{
if (stream->curr + len > stream->end)
return -EINVAL;
stream->curr += len;
return 0;
}
static int jpeg_next_marker(struct jpeg_stream *stream)
{
int byte;
u16 marker = 0;
while ((byte = jpeg_get_byte(stream)) >= 0) {
marker = (marker << 8) | byte;
/* skip stuffing bytes and REServed markers */
if (marker == TEM || (marker > 0xffbf && marker < 0xffff))
return marker;
}
return byte;
}
/* this does not advance the current position in the stream */
static int jpeg_reference_segment(struct jpeg_stream *stream,
struct v4l2_jpeg_reference *segment)
{
u16 len;
if (stream->curr + sizeof(__be16) > stream->end)
return -EINVAL;
len = get_unaligned_be16(stream->curr);
if (stream->curr + len > stream->end)
return -EINVAL;
segment->start = stream->curr;
segment->length = len;
return 0;
}
static int v4l2_jpeg_decode_subsampling(u8 nf, u8 h_v)
{
if (nf == 1)
return V4L2_JPEG_CHROMA_SUBSAMPLING_GRAY;
/* no chroma subsampling for 4-component images */
if (nf == 4 && h_v != 0x11)
return -EINVAL;
switch (h_v) {
case 0x11:
return V4L2_JPEG_CHROMA_SUBSAMPLING_444;
case 0x21:
return V4L2_JPEG_CHROMA_SUBSAMPLING_422;
case 0x22:
return V4L2_JPEG_CHROMA_SUBSAMPLING_420;
case 0x41:
return V4L2_JPEG_CHROMA_SUBSAMPLING_411;
default:
return -EINVAL;
}
}
static int jpeg_parse_frame_header(struct jpeg_stream *stream, u16 sof_marker,
struct v4l2_jpeg_frame_header *frame_header)
{
int len = jpeg_get_word_be(stream);
if (len < 0)
return len;
/* Lf = 8 + 3 * Nf, Nf >= 1 */
if (len < 8 + 3)
return -EINVAL;
if (frame_header) {
/* Table B.2 - Frame header parameter sizes and values */
int p, y, x, nf;
int i;
p = jpeg_get_byte(stream);
if (p < 0)
return p;
/*
* Baseline DCT only supports 8-bit precision.
* Extended sequential DCT also supports 12-bit precision.
*/
if (p != 8 && (p != 12 || sof_marker != SOF1))
return -EINVAL;
y = jpeg_get_word_be(stream);
if (y < 0)
return y;
if (y == 0)
return -EINVAL;
x = jpeg_get_word_be(stream);
if (x < 0)
return x;
if (x == 0)
return -EINVAL;
nf = jpeg_get_byte(stream);
if (nf < 0)
return nf;
/*
* The spec allows 1 <= Nf <= 255, but we only support up to 4
* components.
*/
if (nf < 1 || nf > V4L2_JPEG_MAX_COMPONENTS)
return -EINVAL;
if (len != 8 + 3 * nf)
return -EINVAL;
frame_header->precision = p;
frame_header->height = y;
frame_header->width = x;
frame_header->num_components = nf;
for (i = 0; i < nf; i++) {
struct v4l2_jpeg_frame_component_spec *component;
int c, h_v, tq;
c = jpeg_get_byte(stream);
if (c < 0)
return c;
h_v = jpeg_get_byte(stream);
if (h_v < 0)
return h_v;
if (i == 0) {
int subs;
subs = v4l2_jpeg_decode_subsampling(nf, h_v);
if (subs < 0)
return subs;
frame_header->subsampling = subs;
} else if (h_v != 0x11) {
/* all chroma sampling factors must be 1 */
return -EINVAL;
}
tq = jpeg_get_byte(stream);
if (tq < 0)
return tq;
component = &frame_header->component[i];
component->component_identifier = c;
component->horizontal_sampling_factor =
(h_v >> 4) & 0xf;
component->vertical_sampling_factor = h_v & 0xf;
component->quantization_table_selector = tq;
}
} else {
return jpeg_skip(stream, len - 2);
}
return 0;
}
static int jpeg_parse_scan_header(struct jpeg_stream *stream,
struct v4l2_jpeg_scan_header *scan_header)
{
size_t skip;
int len = jpeg_get_word_be(stream);
if (len < 0)
return len;
/* Ls = 8 + 3 * Ns, Ns >= 1 */
if (len < 6 + 2)
return -EINVAL;
if (scan_header) {
int ns;
int i;
ns = jpeg_get_byte(stream);
if (ns < 0)
return ns;
if (ns < 1 || ns > 4 || len != 6 + 2 * ns)
return -EINVAL;
scan_header->num_components = ns;
for (i = 0; i < ns; i++) {
struct v4l2_jpeg_scan_component_spec *component;
int cs, td_ta;
cs = jpeg_get_byte(stream);
if (cs < 0)
return cs;
td_ta = jpeg_get_byte(stream);
if (td_ta < 0)
return td_ta;
component = &scan_header->component[i];
component->component_selector = cs;
component->dc_entropy_coding_table_selector =
(td_ta >> 4) & 0xf;
component->ac_entropy_coding_table_selector =
td_ta & 0xf;
}
skip = 3; /* skip Ss, Se, Ah, and Al */
} else {
skip = len - 2;
}
return jpeg_skip(stream, skip);
}
/* B.2.4.1 Quantization table-specification syntax */
static int jpeg_parse_quantization_tables(struct jpeg_stream *stream,
u8 precision,
struct v4l2_jpeg_reference *tables)
{
int len = jpeg_get_word_be(stream);
if (len < 0)
return len;
/* Lq = 2 + n * 65 (for baseline DCT), n >= 1 */
if (len < 2 + 65)
return -EINVAL;
len -= 2;
while (len >= 65) {
u8 pq, tq, *qk;
int ret;
int pq_tq = jpeg_get_byte(stream);
if (pq_tq < 0)
return pq_tq;
/* quantization table element precision */
pq = (pq_tq >> 4) & 0xf;
/*
* Only 8-bit Qk values for 8-bit sample precision. Extended
* sequential DCT with 12-bit sample precision also supports
* 16-bit Qk values.
*/
if (pq != 0 && (pq != 1 || precision != 12))
return -EINVAL;
/* quantization table destination identifier */
tq = pq_tq & 0xf;
if (tq > 3)
return -EINVAL;
/* quantization table element */
qk = stream->curr;
ret = jpeg_skip(stream, pq ? 128 : 64);
if (ret < 0)
return -EINVAL;
if (tables) {
tables[tq].start = qk;
tables[tq].length = pq ? 128 : 64;
}
len -= pq ? 129 : 65;
}
return 0;
}
/* B.2.4.2 Huffman table-specification syntax */
static int jpeg_parse_huffman_tables(struct jpeg_stream *stream,
struct v4l2_jpeg_reference *tables)
{
int mt;
int len = jpeg_get_word_be(stream);
if (len < 0)
return len;
/* Table B.5 - Huffman table specification parameter sizes and values */
if (len < 2 + 17)
return -EINVAL;
for (len -= 2; len >= 17; len -= 17 + mt) {
u8 tc, th, *table;
int tc_th = jpeg_get_byte(stream);
int i, ret;
if (tc_th < 0)
return tc_th;
/* table class - 0 = DC, 1 = AC */
tc = (tc_th >> 4) & 0xf;
if (tc > 1)
return -EINVAL;
/* huffman table destination identifier */
th = tc_th & 0xf;
/* only two Huffman tables for baseline DCT */
if (th > 1)
return -EINVAL;
/* BITS - number of Huffman codes with length i */
table = stream->curr;
mt = 0;
for (i = 0; i < 16; i++) {
int li;
li = jpeg_get_byte(stream);
if (li < 0)
return li;
mt += li;
}
/* HUFFVAL - values associated with each Huffman code */
ret = jpeg_skip(stream, mt);
if (ret < 0)
return ret;
if (tables) {
tables[(tc << 1) | th].start = table;
tables[(tc << 1) | th].length = stream->curr - table;
}
}
return jpeg_skip(stream, len - 2);
}
/* B.2.4.4 Restart interval definition syntax */
static int jpeg_parse_restart_interval(struct jpeg_stream *stream,
u16 *restart_interval)
{
int len = jpeg_get_word_be(stream);
int ri;
if (len < 0)
return len;
if (len != 4)
return -EINVAL;
ri = jpeg_get_word_be(stream);
if (ri < 0)
return ri;
*restart_interval = ri;
return 0;
}
static int jpeg_skip_segment(struct jpeg_stream *stream)
{
int len = jpeg_get_word_be(stream);
if (len < 0)
return len;
if (len < 2)
return -EINVAL;
return jpeg_skip(stream, len - 2);
}
/* Rec. ITU-T T.872 (06/2012) 6.5.3 */
static int jpeg_parse_app14_data(struct jpeg_stream *stream,
enum v4l2_jpeg_app14_tf *tf)
{
int ret;
int lp;
int skip;
lp = jpeg_get_word_be(stream);
if (lp < 0)
return lp;
/* Check for "Adobe\0" in Ap1..6 */
if (stream->curr + 6 > stream->end ||
strncmp(stream->curr, "Adobe\0", 6))
return jpeg_skip(stream, lp - 2);
/* get to Ap12 */
ret = jpeg_skip(stream, 11);
if (ret < 0)
return ret;
ret = jpeg_get_byte(stream);
if (ret < 0)
return ret;
*tf = ret;
/* skip the rest of the segment, this ensures at least it is complete */
skip = lp - 2 - 11 - 1;
return jpeg_skip(stream, skip);
}
/**
* v4l2_jpeg_parse_header - locate marker segments and optionally parse headers
* @buf: address of the JPEG buffer, should start with a SOI marker
* @len: length of the JPEG buffer
* @out: returns marker segment positions and optionally parsed headers
*
* The out->scan_header pointer must be initialized to NULL or point to a valid
* v4l2_jpeg_scan_header structure. The out->huffman_tables and
* out->quantization_tables pointers must be initialized to NULL or point to a
* valid array of 4 v4l2_jpeg_reference structures each.
*
* Returns 0 or negative error if parsing failed.
*/
int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out)
{
struct jpeg_stream stream;
int marker;
int ret = 0;
stream.curr = buf;
stream.end = stream.curr + len;
out->num_dht = 0;
out->num_dqt = 0;
/* the first bytes must be SOI, B.2.1 High-level syntax */
if (jpeg_get_word_be(&stream) != SOI)
return -EINVAL;
/* init value to signal if this marker is not present */
out->app14_tf = V4L2_JPEG_APP14_TF_UNKNOWN;
/* loop through marker segments */
while ((marker = jpeg_next_marker(&stream)) >= 0) {
switch (marker) {
/* baseline DCT, extended sequential DCT */
case SOF0 ... SOF1:
ret = jpeg_reference_segment(&stream, &out->sof);
if (ret < 0)
return ret;
ret = jpeg_parse_frame_header(&stream, marker,
&out->frame);
break;
/* progressive, lossless */
case SOF2 ... SOF3:
/* differential coding */
case SOF5 ... SOF7:
/* arithmetic coding */
case SOF9 ... SOF11:
case SOF13 ... SOF15:
case DAC:
case TEM:
return -EINVAL;
case DHT:
ret = jpeg_reference_segment(&stream,
&out->dht[out->num_dht++ % 4]);
if (ret < 0)
return ret;
if (!out->huffman_tables) {
ret = jpeg_skip_segment(&stream);
break;
}
ret = jpeg_parse_huffman_tables(&stream,
out->huffman_tables);
break;
case DQT:
ret = jpeg_reference_segment(&stream,
&out->dqt[out->num_dqt++ % 4]);
if (ret < 0)
return ret;
if (!out->quantization_tables) {
ret = jpeg_skip_segment(&stream);
break;
}
ret = jpeg_parse_quantization_tables(&stream,
out->frame.precision,
out->quantization_tables);
break;
case DRI:
ret = jpeg_parse_restart_interval(&stream,
&out->restart_interval);
break;
case APP14:
ret = jpeg_parse_app14_data(&stream,
&out->app14_tf);
break;
case SOS:
ret = jpeg_reference_segment(&stream, &out->sos);
if (ret < 0)
return ret;
ret = jpeg_parse_scan_header(&stream, out->scan);
/*
* stop parsing, the scan header marks the beginning of
* the entropy coded segment
*/
out->ecs_offset = stream.curr - (u8 *)buf;
return ret;
/* markers without parameters */
case RST0 ... RST7: /* restart */
case SOI: /* start of image */
case EOI: /* end of image */
break;
/* skip unknown or unsupported marker segments */
default:
ret = jpeg_skip_segment(&stream);
break;
}
if (ret < 0)
return ret;
}
return marker;
}
EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_header);
/**
* v4l2_jpeg_parse_frame_header - parse frame header
* @buf: address of the frame header, after the SOF0 marker
* @len: length of the frame header
* @frame_header: returns the parsed frame header
*
* Returns 0 or negative error if parsing failed.
*/
int v4l2_jpeg_parse_frame_header(void *buf, size_t len,
struct v4l2_jpeg_frame_header *frame_header)
{
struct jpeg_stream stream;
stream.curr = buf;
stream.end = stream.curr + len;
return jpeg_parse_frame_header(&stream, SOF0, frame_header);
}
EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_frame_header);
/**
* v4l2_jpeg_parse_scan_header - parse scan header
* @buf: address of the scan header, after the SOS marker
* @len: length of the scan header
* @scan_header: returns the parsed scan header
*
* Returns 0 or negative error if parsing failed.
*/
int v4l2_jpeg_parse_scan_header(void *buf, size_t len,
struct v4l2_jpeg_scan_header *scan_header)
{
struct jpeg_stream stream;
stream.curr = buf;
stream.end = stream.curr + len;
return jpeg_parse_scan_header(&stream, scan_header);
}
EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_scan_header);
/**
* v4l2_jpeg_parse_quantization_tables - parse quantization tables segment
* @buf: address of the quantization table segment, after the DQT marker
* @len: length of the quantization table segment
* @precision: sample precision (P) in bits per component
* @q_tables: returns four references into the buffer for the
* four possible quantization table destinations
*
* Returns 0 or negative error if parsing failed.
*/
int v4l2_jpeg_parse_quantization_tables(void *buf, size_t len, u8 precision,
struct v4l2_jpeg_reference *q_tables)
{
struct jpeg_stream stream;
stream.curr = buf;
stream.end = stream.curr + len;
return jpeg_parse_quantization_tables(&stream, precision, q_tables);
}
EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_quantization_tables);
/**
* v4l2_jpeg_parse_huffman_tables - parse huffman tables segment
* @buf: address of the Huffman table segment, after the DHT marker
* @len: length of the Huffman table segment
* @huffman_tables: returns four references into the buffer for the
* four possible Huffman table destinations, in
* the order DC0, DC1, AC0, AC1
*
* Returns 0 or negative error if parsing failed.
*/
int v4l2_jpeg_parse_huffman_tables(void *buf, size_t len,
struct v4l2_jpeg_reference *huffman_tables)
{
struct jpeg_stream stream;
stream.curr = buf;
stream.end = stream.curr + len;
return jpeg_parse_huffman_tables(&stream, huffman_tables);
}
EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_huffman_tables);
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