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Add core JPEG reader, adapted from the JPEG plugin's decoder, with some changes to prevent include conflicts between the two decoders.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20836 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Andrew Mahone 2009-05-01 23:24:23 +00:00
parent b22516f995
commit 60d4209383
9 changed files with 2262 additions and 68 deletions
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68
apps/plugins/jpeg/jpeg_decoder.h
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@ -27,62 +27,7 @@
#ifndef _JPEG_JPEG_DECODER_H
#define _JPEG_JPEG_DECODER_H
#define HUFF_LOOKAHEAD 8 /* # of bits of lookahead */
struct derived_tbl
{
/* Basic tables: (element [0] of each array is unused) */
long mincode[17]; /* smallest code of length k */
long maxcode[18]; /* largest code of length k (-1 if none) */
/* (maxcode[17] is a sentinel to ensure huff_DECODE terminates) */
int valptr[17]; /* huffval[] index of 1st symbol of length k */
/* Back link to public Huffman table (needed only in slow_DECODE) */
int* pub;
/* Lookahead tables: indexed by the next HUFF_LOOKAHEAD bits of
the input data stream. If the next Huffman code is no more
than HUFF_LOOKAHEAD bits long, we can obtain its length and
the corresponding symbol directly from these tables. */
int look_nbits[1<<HUFF_LOOKAHEAD]; /* # bits, or 0 if too long */
unsigned char look_sym[1<<HUFF_LOOKAHEAD]; /* symbol, or unused */
};
#define QUANT_TABLE_LENGTH 64
/* for type of Huffman table */
#define DC_LEN 28
#define AC_LEN 178
struct huffman_table
{ /* length and code according to JFIF format */
int huffmancodes_dc[DC_LEN];
int huffmancodes_ac[AC_LEN];
};
struct frame_component
{
int ID;
int horizontal_sampling;
int vertical_sampling;
int quanttable_select;
};
struct scan_component
{
int ID;
int DC_select;
int AC_select;
};
struct bitstream
{
unsigned long get_buffer; /* current bit-extraction buffer */
int bits_left; /* # of unused bits in it */
unsigned char* next_input_byte;
unsigned char* input_end; /* upper limit +1 */
};
#include "jpeg_common.h"
struct jpeg
{
@ -113,17 +58,6 @@ struct jpeg
int subsample_y[3];
};
/* possible return flags for process_markers() */
#define HUFFTAB 0x0001 /* with huffman table */
#define QUANTTAB 0x0002 /* with quantization table */
#define APP0_JFIF 0x0004 /* with APP0 segment following JFIF standard */
#define FILL_FF 0x0008 /* with 0xFF padding bytes at begin/end */
#define SOF0 0x0010 /* with SOF0-Segment */
#define DHT 0x0020 /* with Definition of huffman tables */
#define SOS 0x0040 /* with Start-of-Scan segment */
#define DQT 0x0080 /* with definition of quantization table */
/* various helper functions */
void default_huff_tbl(struct jpeg* p_jpeg);
void build_lut(struct jpeg* p_jpeg);