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gstreamer/gst-libs/gst/codecparsers/gstjpegparser.c
Scott D Phillips e4407d4599 Fix some MSVC warnings about const-ness 
Some miscellaneous warnings about const-ness, either casting away const
where we know it's safe or removing const where it's not correct.

https://bugzilla.gnome.org/show_bug.cgi?id=774293
2016-11-15 14:53:49 +02:00

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/* GStreamer JPEG parser
* Copyright (C) 2011-2012 Intel Corporation
* Copyright (C) 2015 Tim-Philipp Müller <tim@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
/**
* SECTION:gstjpegparser
* @short_description: Convenience library for JPEG bitstream parsing.
*
* <refsect2>
* <para>
* Provides useful functions for parsing JPEG images
* </para>
* </refsect2>
*/
#include <string.h>
#include <stdlib.h>
#include <gst/base/gstbytereader.h>
#include "gstjpegparser.h"
#ifndef GST_DISABLE_GST_DEBUG
#define GST_CAT_DEFAULT ensure_debug_category()
static GstDebugCategory *
ensure_debug_category (void)
{
static gsize cat_gonce = 0;
if (g_once_init_enter (&cat_gonce)) {
gsize cat_done;
cat_done = (gsize) _gst_debug_category_new ("codecparsers_jpeg", 0,
"GstJpegCodecParser");
g_once_init_leave (&cat_gonce, cat_done);
}
return (GstDebugCategory *) cat_gonce;
}
#else
#define ensure_debug_category() /* NOOP */
#endif /* GST_DISABLE_GST_DEBUG */
#define DEBUG_PRINT_COMMENT 0
#define READ_UINT8(reader, val) G_STMT_START { \
if (!gst_byte_reader_get_uint8 ((reader), &(val))) { \
GST_WARNING ("failed to read uint8"); \
goto failed; \
} \
} G_STMT_END
#define READ_UINT16(reader, val) G_STMT_START { \
if (!gst_byte_reader_get_uint16_be ((reader), &(val))) { \
GST_WARNING ("failed to read uint16"); \
goto failed; \
} \
} G_STMT_END
#define READ_BYTES(reader, buf, length) G_STMT_START { \
const guint8 *vals; \
if (!gst_byte_reader_get_data (reader, length, &vals)) { \
GST_WARNING ("failed to read bytes, size:%d", length); \
goto failed; \
} \
memcpy (buf, vals, length); \
} G_STMT_END
#define U_READ_UINT8(reader, val) G_STMT_START { \
(val) = gst_byte_reader_get_uint8_unchecked(reader); \
} G_STMT_END
#define U_READ_UINT16(reader, val) G_STMT_START { \
(val) = gst_byte_reader_get_uint16_be_unchecked(reader); \
} G_STMT_END
/* Table used to address an 8x8 matrix in zig-zag order */
/* *INDENT-OFF* */
static const guint8 zigzag_index[64] = {
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
};
/* *INDENT-ON* */
/* Table K.1 - Luminance quantization table */
/* *INDENT-OFF* */
static const guint8 default_luminance_quant_table[64] = {
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
};
/* *INDENT-ON* */
/* Table K.2 - Chrominance quantization table */
/* *INDENT-OFF* */
static const guint8 default_chrominance_quant_table[64] = {
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
};
/* *INDENT-ON* */
typedef struct _GstJpegHuffmanTableEntry GstJpegHuffmanTableEntry;
struct _GstJpegHuffmanTableEntry
{
guint8 value; /* category */
guint8 length; /* code length in bits */
};
/* Table K.3 - Table for luminance DC coefficient differences */
static const GstJpegHuffmanTableEntry default_luminance_dc_table[] = {
{0x00, 2}, {0x01, 3}, {0x02, 3}, {0x03, 3}, {0x04, 3}, {0x05, 3},
{0x06, 4}, {0x07, 5}, {0x08, 6}, {0x09, 7}, {0x0a, 8}, {0x0b, 9}
};
/* Table K.4 - Table for chrominance DC coefficient differences */
static const GstJpegHuffmanTableEntry default_chrominance_dc_table[] = {
{0x00, 2}, {0x01, 2}, {0x02, 2}, {0x03, 3}, {0x04, 4}, {0x05, 5},
{0x06, 6}, {0x07, 7}, {0x08, 8}, {0x09, 9}, {0x0a, 10}, {0x0b, 11}
};
/* Table K.5 - Table for luminance AC coefficients */
/* *INDENT-OFF* */
static const GstJpegHuffmanTableEntry default_luminance_ac_table[] = {
{0x00, 4}, {0x01, 2}, {0x02, 2}, {0x03, 3}, {0x04, 4}, {0x05, 5},
{0x06, 7}, {0x07, 8}, {0x08, 10}, {0x09, 16}, {0x0a, 16}, {0x11, 4},
{0x12, 5}, {0x13, 7}, {0x14, 9}, {0x15, 11}, {0x16, 16}, {0x17, 16},
{0x18, 16}, {0x19, 16}, {0x1a, 16}, {0x21, 5}, {0x22, 8}, {0x23, 10},
{0x24, 12}, {0x25, 16}, {0x26, 16}, {0x27, 16}, {0x28, 16}, {0x29, 16},
{0x2a, 16}, {0x31, 6}, {0x32, 9}, {0x33, 12}, {0x34, 16}, {0x35, 16},
{0x36, 16}, {0x37, 16}, {0x38, 16}, {0x39, 16}, {0x3a, 16}, {0x41, 6},
{0x42, 10}, {0x43, 16}, {0x44, 16}, {0x45, 16}, {0x46, 16}, {0x47, 16},
{0x48, 16}, {0x49, 16}, {0x4a, 16}, {0x51, 7}, {0x52, 11}, {0x53, 16},
{0x54, 16}, {0x55, 16}, {0x56, 16}, {0x57, 16}, {0x58, 16}, {0x59, 16},
{0x5a, 16}, {0x61, 7}, {0x62, 12}, {0x63, 16}, {0x64, 16}, {0x65, 16},
{0x66, 16}, {0x67, 16}, {0x68, 16}, {0x69, 16}, {0x6a, 16}, {0x71, 8},
{0x72, 12}, {0x73, 16}, {0x74, 16}, {0x75, 16}, {0x76, 16}, {0x77, 16},
{0x78, 16}, {0x79, 16}, {0x7a, 16}, {0x81, 9}, {0x82, 15}, {0x83, 16},
{0x84, 16}, {0x85, 16}, {0x86, 16}, {0x87, 16}, {0x88, 16}, {0x89, 16},
{0x8a, 16}, {0x91, 9}, {0x92, 16}, {0x93, 16}, {0x94, 16}, {0x95, 16},
{0x96, 16}, {0x97, 16}, {0x98, 16}, {0x99, 16}, {0x9a, 16}, {0xa1, 9},
{0xa2, 16}, {0xa3, 16}, {0xa4, 16}, {0xa5, 16}, {0xa6, 16}, {0xa7, 16},
{0xa8, 16}, {0xa9, 16}, {0xaa, 16}, {0xb1, 10}, {0xb2, 16}, {0xb3, 16},
{0xb4, 16}, {0xb5, 16}, {0xb6, 16}, {0xb7, 16}, {0xb8, 16}, {0xb9, 16},
{0xba, 16}, {0xc1, 10}, {0xc2, 16}, {0xc3, 16}, {0xc4, 16}, {0xc5, 16},
{0xc6, 16}, {0xc7, 16}, {0xc8, 16}, {0xc9, 16}, {0xca, 16}, {0xd1, 11},
{0xd2, 16}, {0xd3, 16}, {0xd4, 16}, {0xd5, 16}, {0xd6, 16}, {0xd7, 16},
{0xd8, 16}, {0xd9, 16}, {0xda, 16}, {0xe1, 16}, {0xe2, 16}, {0xe3, 16},
{0xe4, 16}, {0xe5, 16}, {0xe6, 16}, {0xe7, 16}, {0xe8, 16}, {0xe9, 16},
{0xea, 16}, {0xf0, 11}, {0xf1, 16}, {0xf2, 16}, {0xf3, 16}, {0xf4, 16},
{0xf5, 16}, {0xf6, 16}, {0xf7, 16}, {0xf8, 16}, {0xf9, 16}, {0xfa, 16}
};
/* *INDENT-ON* */
/* Table K.6 - Table for chrominance AC coefficients */
/* *INDENT-OFF* */
static const GstJpegHuffmanTableEntry default_chrominance_ac_table[] = {
{0x00, 2}, {0x01, 2}, {0x02, 3}, {0x03, 4}, {0x04, 5}, {0x05, 5},
{0x06, 6}, {0x07, 7}, {0x08, 9}, {0x09, 10}, {0x0a, 12}, {0x11, 4},
{0x12, 6}, {0x13, 8}, {0x14, 9}, {0x15, 11}, {0x16, 12}, {0x17, 16},
{0x18, 16}, {0x19, 16}, {0x1a, 16}, {0x21, 5}, {0x22, 8}, {0x23, 10},
{0x24, 12}, {0x25, 15}, {0x26, 16}, {0x27, 16}, {0x28, 16}, {0x29, 16},
{0x2a, 16}, {0x31, 5}, {0x32, 8}, {0x33, 10}, {0x34, 12}, {0x35, 16},
{0x36, 16}, {0x37, 16}, {0x38, 16}, {0x39, 16}, {0x3a, 16}, {0x41, 6},
{0x42, 9}, {0x43, 16}, {0x44, 16}, {0x45, 16}, {0x46, 16}, {0x47, 16},
{0x48, 16}, {0x49, 16}, {0x4a, 16}, {0x51, 6}, {0x52, 10}, {0x53, 16},
{0x54, 16}, {0x55, 16}, {0x56, 16}, {0x57, 16}, {0x58, 16}, {0x59, 16},
{0x5a, 16}, {0x61, 7}, {0x62, 11}, {0x63, 16}, {0x64, 16}, {0x65, 16},
{0x66, 16}, {0x67, 16}, {0x68, 16}, {0x69, 16}, {0x6a, 16}, {0x71, 7},
{0x72, 11}, {0x73, 16}, {0x74, 16}, {0x75, 16}, {0x76, 16}, {0x77, 16},
{0x78, 16}, {0x79, 16}, {0x7a, 16}, {0x81, 8}, {0x82, 16}, {0x83, 16},
{0x84, 16}, {0x85, 16}, {0x86, 16}, {0x87, 16}, {0x88, 16}, {0x89, 16},
{0x8a, 16}, {0x91, 9}, {0x92, 16}, {0x93, 16}, {0x94, 16}, {0x95, 16},
{0x96, 16}, {0x97, 16}, {0x98, 16}, {0x99, 16}, {0x9a, 16}, {0xa1, 9},
{0xa2, 16}, {0xa3, 16}, {0xa4, 16}, {0xa5, 16}, {0xa6, 16}, {0xa7, 16},
{0xa8, 16}, {0xa9, 16}, {0xaa, 16}, {0xb1, 9}, {0xb2, 16}, {0xb3, 16},
{0xb4, 16}, {0xb5, 16}, {0xb6, 16}, {0xb7, 16}, {0xb8, 16}, {0xb9, 16},
{0xba, 16}, {0xc1, 9}, {0xc2, 16}, {0xc3, 16}, {0xc4, 16}, {0xc5, 16},
{0xc6, 16}, {0xc7, 16}, {0xc8, 16}, {0xc9, 16}, {0xca, 16}, {0xd1, 11},
{0xd2, 16}, {0xd3, 16}, {0xd4, 16}, {0xd5, 16}, {0xd6, 16}, {0xd7, 16},
{0xd8, 16}, {0xd9, 16}, {0xda, 16}, {0xe1, 14}, {0xe2, 16}, {0xe3, 16},
{0xe4, 16}, {0xe5, 16}, {0xe6, 16}, {0xe7, 16}, {0xe8, 16}, {0xe9, 16},
{0xea, 16}, {0xf0, 10}, {0xf1, 15}, {0xf2, 16}, {0xf3, 16}, {0xf4, 16},
{0xf5, 16}, {0xf6, 16}, {0xf7, 16}, {0xf8, 16}, {0xf9, 16}, {0xfa, 16}
};
/* *INDENT-ON* */
static gint gst_jpeg_scan_for_marker_code (const guint8 * data, gsize size,
guint offset);
static inline gboolean
jpeg_parse_to_next_marker (GstByteReader * br, GstJpegMarker * marker)
{
gint ofs;
ofs = gst_jpeg_scan_for_marker_code (br->data, br->size, br->byte);
if (ofs < 0)
return FALSE;
if (marker)
*marker = (GstJpegMarker) br->data[ofs + 1];
gst_byte_reader_skip_unchecked (br, ofs - br->byte);
return TRUE;
}
/* gst_jpeg_scan_for_marker_code:
* @data: The data to parse
* @size: The size of @data
* @offset: The offset from which to start parsing
*
* Scans the JPEG bitstream contained in @data for the next marker
* code. If found, the function returns an offset to the marker code,
* including the 0xff prefix code but excluding any extra fill bytes.
*
* Returns: offset to the marker code if found, or -1 if not found.
*/
static gint
gst_jpeg_scan_for_marker_code (const guint8 * data, gsize size, guint offset)
{
guint i;
i = offset + 1;
while (i < size) {
const guint8 v = data[i];
if (v < 0xc0)
i += 2;
else if (v < 0xff && data[i - 1] == 0xff)
return i - 1;
else
i++;
}
return -1;
}
/**
* gst_jpeg_segment_parse_frame_header:
* @segment: the JPEG segment
* @frame_hdr: (out): The #GstJpegFrameHdr structure to fill in
*
* Parses the @frame_hdr JPEG frame header structure members from @segment.
*
* The caller must make sure there is enough data for the whole segment
* available.
*
* Returns: TRUE if the frame header was correctly parsed.
*
* Since: 1.6
*/
gboolean
gst_jpeg_segment_parse_frame_header (const GstJpegSegment * segment,
GstJpegFrameHdr * frame_hdr)
{
GstByteReader br;
guint8 val;
guint i;
g_return_val_if_fail (segment != NULL, FALSE);
g_return_val_if_fail (frame_hdr != NULL, FALSE);
if (segment->size < 8)
return FALSE;
gst_byte_reader_init (&br, segment->data + segment->offset, segment->size);
gst_byte_reader_skip_unchecked (&br, 2);
U_READ_UINT8 (&br, frame_hdr->sample_precision);
U_READ_UINT16 (&br, frame_hdr->height);
U_READ_UINT16 (&br, frame_hdr->width);
U_READ_UINT8 (&br, frame_hdr->num_components);
if (frame_hdr->num_components > GST_JPEG_MAX_SCAN_COMPONENTS)
return FALSE;
if (gst_byte_reader_get_remaining (&br) < 3 * frame_hdr->num_components)
return FALSE;
for (i = 0; i < frame_hdr->num_components; i++) {
U_READ_UINT8 (&br, frame_hdr->components[i].identifier);
U_READ_UINT8 (&br, val);
frame_hdr->components[i].horizontal_factor = (val >> 4) & 0x0F;
frame_hdr->components[i].vertical_factor = (val & 0x0F);
U_READ_UINT8 (&br, frame_hdr->components[i].quant_table_selector);
if (frame_hdr->components[i].horizontal_factor > 4
|| frame_hdr->components[i].vertical_factor > 4
|| frame_hdr->components[i].quant_table_selector >= 4)
return FALSE;
}
if (gst_byte_reader_get_remaining (&br) > 0)
GST_DEBUG ("data left at end of frame header segment");
return TRUE;
}
/**
* gst_jpeg_segment_parse_scan_header:
* @segment: the JPEG segment
* @scan_hdr: (out): The #GstJpegScanHdr structure to fill in
*
* Parses the @scan_hdr JPEG scan header structure members from @segment.
*
* The caller must make sure there is enough data for the whole segment
* available.
*
* Returns: TRUE if the scan header was correctly parsed
*
* Since: 1.6
*/
gboolean
gst_jpeg_segment_parse_scan_header (const GstJpegSegment * segment,
GstJpegScanHdr * scan_hdr)
{
GstByteReader br;
guint8 val;
guint i;
g_return_val_if_fail (segment != NULL, FALSE);
g_return_val_if_fail (scan_hdr != NULL, FALSE);
gst_byte_reader_init (&br, segment->data + segment->offset, segment->size);
if (segment->size < 3)
return FALSE;
gst_byte_reader_skip_unchecked (&br, 2);
U_READ_UINT8 (&br, scan_hdr->num_components);
if (scan_hdr->num_components > GST_JPEG_MAX_SCAN_COMPONENTS)
return FALSE;
if (gst_byte_reader_get_remaining (&br) < 2 * scan_hdr->num_components)
return FALSE;
for (i = 0; i < scan_hdr->num_components; i++) {
U_READ_UINT8 (&br, scan_hdr->components[i].component_selector);
U_READ_UINT8 (&br, val);
scan_hdr->components[i].dc_selector = (val >> 4) & 0x0F;
scan_hdr->components[i].ac_selector = val & 0x0F;
if (scan_hdr->components[i].dc_selector >= 4
|| scan_hdr->components[i].ac_selector >= 4)
return FALSE;
}
if (gst_byte_reader_get_remaining (&br) < 3)
return FALSE;
/* FIXME: Ss, Se, Ah, Al */
gst_byte_reader_skip_unchecked (&br, 3);
if (gst_byte_reader_get_remaining (&br) > 0)
GST_DEBUG ("data left at end of scan header segment");
return TRUE;
}
/**
* gst_jpeg_segment_parse_huffman_table:
* @segment: the JPEG segment
* @huff_tables: (out): The #GstJpegHuffmanTables structure to fill in
*
* Parses the JPEG Huffman table structure members from @segment.
*
* The caller must make sure there is enough data for the whole segment
* available.
*
* Note: @huf_tables represents the complete set of possible Huffman
* tables. However, the parser will only write to the Huffman table
* specified by the table destination identifier (Th). While doing so,
* the @valid flag of the specified Huffman table will also be set to
* %TRUE;
*
* Returns: TRUE if the Huffman table was correctly parsed.
*
* Since: 1.6
*/
gboolean
gst_jpeg_segment_parse_huffman_table (const GstJpegSegment * segment,
GstJpegHuffmanTables * huff_tables)
{
GstByteReader br;
GstJpegHuffmanTable *huf_table;
guint8 val, table_class, table_index;
guint32 value_count;
guint i;
g_return_val_if_fail (segment != NULL, FALSE);
g_return_val_if_fail (huff_tables != NULL, FALSE);
if (segment->size < 2)
return FALSE;
gst_byte_reader_init (&br, segment->data + segment->offset, segment->size);
gst_byte_reader_skip_unchecked (&br, 2);
while (gst_byte_reader_get_remaining (&br) > 0) {
U_READ_UINT8 (&br, val);
table_class = ((val >> 4) & 0x0F);
table_index = (val & 0x0F);
if (table_index >= GST_JPEG_MAX_SCAN_COMPONENTS)
return FALSE;
if (table_class == 0) {
huf_table = &huff_tables->dc_tables[table_index];
} else {
huf_table = &huff_tables->ac_tables[table_index];
}
READ_BYTES (&br, huf_table->huf_bits, 16);
value_count = 0;
for (i = 0; i < 16; i++)
value_count += huf_table->huf_bits[i];
READ_BYTES (&br, huf_table->huf_values, value_count);
huf_table->valid = TRUE;
}
return TRUE;
failed:
return FALSE;
}
/**
* gst_jpeg_segment_parse_quantization_table:
* @segment: the JPEG segment
* @quant_tables: (out): The #GstJpegQuantTables structure to fill in
*
* Parses the JPEG quantization table structure members from @segment.
*
* The caller must make sure there is enough data for the whole segment
* available.
*
* Note: @quant_tables represents the complete set of possible
* quantization tables. However, the parser will only write to the
* quantization table specified by the table destination identifier
* (Tq). While doing so, the @valid flag of the specified quantization
* table will also be set to %TRUE.
*
* Returns: TRUE if the quantization table was correctly parsed.
*
* Since: 1.6
*/
gboolean
gst_jpeg_segment_parse_quantization_table (const GstJpegSegment * segment,
GstJpegQuantTables * quant_tables)
{
GstByteReader br;
GstJpegQuantTable *quant_table;
guint8 val, table_index;
guint i;
g_return_val_if_fail (segment != NULL, FALSE);
g_return_val_if_fail (quant_tables != NULL, FALSE);
if (segment->size < 2)
return FALSE;
gst_byte_reader_init (&br, segment->data + segment->offset, segment->size);
gst_byte_reader_skip_unchecked (&br, 2);
while (gst_byte_reader_get_remaining (&br) > 0) {
guint8 element_size;
U_READ_UINT8 (&br, val);
table_index = (val & 0x0f);
if (table_index >= GST_JPEG_MAX_SCAN_COMPONENTS)
return FALSE;
quant_table = &quant_tables->quant_tables[table_index];
quant_table->quant_precision = ((val >> 4) & 0x0f);
element_size = (quant_table->quant_precision == 0) ? 1 : 2;
if (gst_byte_reader_get_remaining (&br) <
GST_JPEG_MAX_QUANT_ELEMENTS * element_size)
return FALSE;
for (i = 0; i < GST_JPEG_MAX_QUANT_ELEMENTS; i++) {
if (!quant_table->quant_precision) { /* 8-bit values */
U_READ_UINT8 (&br, val);
quant_table->quant_table[i] = val;
} else { /* 16-bit values */
U_READ_UINT16 (&br, quant_table->quant_table[i]);
}
}
quant_table->valid = TRUE;
}
return TRUE;
}
/**
* gst_jpeg_segment_parse_restart_interval:
* @segment: the JPEG segment
* @interval: (out): The parsed restart interval value
*
* The caller must make sure there is enough data for the whole segment
* available.
*
* Returns: TRUE if the restart interval value was correctly parsed.
*
* Since: 1.6
*/
gboolean
gst_jpeg_segment_parse_restart_interval (const GstJpegSegment * segment,
guint * interval)
{
GstByteReader br;
guint16 val;
g_return_val_if_fail (segment != NULL, FALSE);
g_return_val_if_fail (interval != NULL, FALSE);
if (segment->size < 4)
return FALSE;
gst_byte_reader_init (&br, segment->data + segment->offset, segment->size);
gst_byte_reader_skip_unchecked (&br, 2);
U_READ_UINT16 (&br, val);
*interval = val;
return TRUE;
}
static int
compare_huffman_table_entry (const void *a, const void *b)
{
const GstJpegHuffmanTableEntry *const e1 = *(GstJpegHuffmanTableEntry **) a;
const GstJpegHuffmanTableEntry *const e2 = *(GstJpegHuffmanTableEntry **) b;
if (e1->length == e2->length)
return (gint) e1->value - (gint) e2->value;
return (gint) e1->length - (gint) e2->length;
}
static void
build_huffman_table (GstJpegHuffmanTable * huf_table,
const GstJpegHuffmanTableEntry * entries, guint num_entries)
{
const GstJpegHuffmanTableEntry *sorted_entries[256];
guint i, j, n;
g_assert (num_entries <= G_N_ELEMENTS (sorted_entries));
for (i = 0; i < num_entries; i++)
sorted_entries[i] = &entries[i];
qsort ((void *) sorted_entries, num_entries, sizeof (sorted_entries[0]),
compare_huffman_table_entry);
for (i = 0, j = 1, n = 0; i < num_entries; i++) {
const GstJpegHuffmanTableEntry *const e = sorted_entries[i];
if (e->length != j) {
huf_table->huf_bits[j++ - 1] = n;
for (; j < e->length; j++)
huf_table->huf_bits[j - 1] = 0;
n = 0;
}
huf_table->huf_values[i] = e->value;
n++;
}
huf_table->huf_bits[j - 1] = n;
for (; j < G_N_ELEMENTS (huf_table->huf_bits); j++)
huf_table->huf_bits[j] = 0;
for (; i < G_N_ELEMENTS (huf_table->huf_values); i++)
huf_table->huf_values[i] = 0;
huf_table->valid = TRUE;
}
/**
* gst_jpeg_get_default_huffman_tables:
* @huf_tables: (out): The default DC/AC Huffman tables to fill in
*
* Fills in @huf_tables with the default AC/DC Huffman tables, as
* specified by the JPEG standard.
*
* Since: 1.6
*/
void
gst_jpeg_get_default_huffman_tables (GstJpegHuffmanTables * huf_tables)
{
g_return_if_fail (huf_tables != NULL);
/* Build DC tables */
build_huffman_table (&huf_tables->dc_tables[0], default_luminance_dc_table,
G_N_ELEMENTS (default_luminance_dc_table));
build_huffman_table (&huf_tables->dc_tables[1], default_chrominance_dc_table,
G_N_ELEMENTS (default_chrominance_dc_table));
memcpy (&huf_tables->dc_tables[2], &huf_tables->dc_tables[1],
sizeof (huf_tables->dc_tables[2]));
/* Build AC tables */
build_huffman_table (&huf_tables->ac_tables[0], default_luminance_ac_table,
G_N_ELEMENTS (default_luminance_ac_table));
build_huffman_table (&huf_tables->ac_tables[1], default_chrominance_ac_table,
G_N_ELEMENTS (default_chrominance_ac_table));
memcpy (&huf_tables->ac_tables[2], &huf_tables->ac_tables[1],
sizeof (huf_tables->ac_tables[2]));
}
static void
build_quant_table (GstJpegQuantTable * quant_table, const guint8 values[64])
{
guint i;
for (i = 0; i < 64; i++)
quant_table->quant_table[i] = values[zigzag_index[i]];
quant_table->quant_precision = 0; /* Pq = 0 (8-bit precision) */
quant_table->valid = TRUE;
}
/**
* gst_jpeg_get_default_quantization_table:
* @quant_tables: (out): The default luma/chroma quant-tables in zigzag mode
*
* Fills in @quant_tables with the default quantization tables, as
* specified by the JPEG standard.
*
* Since: 1.6
*/
void
gst_jpeg_get_default_quantization_tables (GstJpegQuantTables * quant_tables)
{
g_return_if_fail (quant_tables != NULL);
build_quant_table (&quant_tables->quant_tables[0],
default_luminance_quant_table);
build_quant_table (&quant_tables->quant_tables[1],
default_chrominance_quant_table);
build_quant_table (&quant_tables->quant_tables[2],
default_chrominance_quant_table);
}
/**
* gst_jpeg_parse:
* @segment: (out): pointer to a #GstJpegSegment structure to fill in
* @data: The data to parse
* @size: The size of @data
* @offset: The offset from which to start parsing
*
* Parses the JPEG bitstream contained in @data, and returns the
* detected segment as a #GstJpegSegment.
*
* Note that a valid segment may be returned with a length that exceeds
* the available data. It is up to the caller to make sure there's enough
* data available when parsing the segment.
*
* Returns: TRUE if a packet start code was found.
*
* Since: 1.6
*/
gboolean
gst_jpeg_parse (GstJpegSegment * segment,
const guint8 * data, gsize size, guint offset)
{
GstJpegSegment *seg = segment;
GstByteReader br;
guint16 length;
g_return_val_if_fail (seg != NULL, FALSE);
g_return_val_if_fail (data != NULL, FALSE);
if (size <= offset) {
GST_DEBUG ("failed to parse from offset %u, buffer is too small", offset);
return FALSE;
}
size -= offset;
gst_byte_reader_init (&br, &data[offset], size);
if (!jpeg_parse_to_next_marker (&br, &seg->marker)) {
GST_DEBUG ("failed to find marker code");
return FALSE;
}
gst_byte_reader_skip_unchecked (&br, 2);
seg->offset = offset + gst_byte_reader_get_pos (&br);
seg->size = -1;
/* Try to find end of segment */
switch (seg->marker) {
case GST_JPEG_MARKER_SOI:
case GST_JPEG_MARKER_EOI:
fixed_size_segment:
seg->size = 0;
break;
case (GST_JPEG_MARKER_SOF_MIN + 0): /* Lf */
case (GST_JPEG_MARKER_SOF_MIN + 1): /* Lf */
case (GST_JPEG_MARKER_SOF_MIN + 2): /* Lf */
case (GST_JPEG_MARKER_SOF_MIN + 3): /* Lf */
case (GST_JPEG_MARKER_SOF_MIN + 9): /* Lf */
case (GST_JPEG_MARKER_SOF_MIN + 10): /* Lf */
case (GST_JPEG_MARKER_SOF_MIN + 11): /* Lf */
case GST_JPEG_MARKER_SOS: /* Ls */
case GST_JPEG_MARKER_DQT: /* Lq */
case GST_JPEG_MARKER_DHT: /* Lh */
case GST_JPEG_MARKER_DAC: /* La */
case GST_JPEG_MARKER_DRI: /* Lr */
case GST_JPEG_MARKER_COM: /* Lc */
case GST_JPEG_MARKER_DNL: /* Ld */
variable_size_segment:
READ_UINT16 (&br, length);
seg->size = length;
break;
default:
/* Application data segment length (Lp) */
if (seg->marker >= GST_JPEG_MARKER_APP_MIN &&
seg->marker <= GST_JPEG_MARKER_APP_MAX)
goto variable_size_segment;
/* Restart markers (fixed size, two bytes only) */
if (seg->marker >= GST_JPEG_MARKER_RST_MIN &&
seg->marker <= GST_JPEG_MARKER_RST_MAX)
goto fixed_size_segment;
/* Fallback: scan for next marker */
if (!jpeg_parse_to_next_marker (&br, NULL))
goto failed;
seg->size = gst_byte_reader_get_pos (&br) - seg->offset;
break;
}
seg->data = data;
return TRUE;
failed:
return FALSE;
}
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