forked from len0rd/rockbox
b8238f7b20
Added jpeg decoder jpegp.c using RAINBOW lib. Currently enabled only for pictures not supported by old decoder (as old decoder more optimized for low mem targets) Someone TODO: * Old decoder has optimized downscale logic which new decoder doesn't have (it gives big difference in required memory and time for decoding). This logic should be ported/adapted if possible. * Add smooth downscaling. * Grayscale support Change-Id: Ie96bc62848b51cc6a3942f8e069ec6ab02dc1c56
94 lines
1.8 KiB
C
94 lines
1.8 KiB
C
/* Simple buffered version of file reader.
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* JPEG decoding seems to work faster with it.
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* Not fully tested. In case of any issues try FILEGETC (see SOURCES)
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* */
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#include "rb_glue.h"
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static int fd;
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static unsigned char buff[256]; //TODO: Adjust it...
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static int length = 0;
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static int cur_buff_pos = 0;
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static int file_pos = 0;
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extern int GETC(void)
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{
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if (cur_buff_pos >= length)
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{
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length = rb->read(fd, buff, sizeof(buff));
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file_pos += length;
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cur_buff_pos = 0;
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}
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return buff[cur_buff_pos++];
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}
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// multibyte readers: host-endian independent - if evaluated in right order (ie. don't optimize)
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extern int GETWbi(void) // 16-bit big-endian
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{
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return ( GETC()<<8 ) | GETC();
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}
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extern int GETDbi(void) // 32-bit big-endian
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{
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return ( GETC()<<24 ) | ( GETC()<<16 ) | ( GETC()<<8 ) | GETC();
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}
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extern int GETWli(void) // 16-bit little-endian
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{
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return GETC() | ( GETC()<<8 );
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}
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extern int GETDli(void) // 32-bit little-endian
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{
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return GETC() | ( GETC()<<8 ) | ( GETC()<<16 ) | ( GETC()<<24 );
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}
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// seek
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extern void SEEK(int d)
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{
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int newPos = cur_buff_pos + d;
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if (newPos < length && newPos >= 0)
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{
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cur_buff_pos = newPos;
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return;
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}
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file_pos = rb->lseek(fd, (cur_buff_pos - length) + d, SEEK_CUR);
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cur_buff_pos = length = 0;
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}
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extern void POS(int d)
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{
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cur_buff_pos = length = 0;
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file_pos = d;
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rb->lseek(fd, d, SEEK_SET);
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}
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extern int TELL(void)
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{
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return file_pos + cur_buff_pos - length;
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}
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// OPEN/CLOSE file
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extern void *OPEN(char *f)
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{
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printf("Opening %s\n", f);
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cur_buff_pos = length = file_pos = 0;
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fd = rb->open(f,O_RDONLY);
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if ( fd < 0 )
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{
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printf("Error opening %s\n", f);
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return NULL;
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}
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return &fd;
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}
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extern int CLOSE(void)
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{
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cur_buff_pos = length = file_pos = 0;
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return rb->close(fd);
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}
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