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os/ossrv/genericopenlibs/liboil/tsrc/examples/jpeg/src/jpeg_bits.c
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib. 
     1 /*

     2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 #include <stdio.h>

    19 

    20 #include "jpeg_bits.h"

    21 

    22 /* FIXME */

    23 #define TRUE 1

    24 #define FALSE 0

    25 

    26 int jpeg_bits_error (JpegBits *bits)

    27 {

    28   return bits->error;

    29 }

    30 

    31 int jpeg_bits_get_u8 (JpegBits *bits)

    32 {

    33   if (bits->ptr < bits->end) {

    34     return *bits->ptr++;

    35   } 

    36   bits->error = TRUE;

    37   return 0;

    38 }

    39 

    40 void jpeg_bits_skip (JpegBits *bits, int n)

    41 {

    42   bits->ptr += n;

    43   if (bits->ptr > bits->end) {

    44     bits->error = TRUE;

    45     bits->ptr = bits->end;

    46   }

    47 }

    48 

    49 int jpeg_bits_get_u16_be (JpegBits *bits)

    50 {

    51   int x;

    52 

    53   x = jpeg_bits_get_u8 (bits) << 8;

    54   x |= jpeg_bits_get_u8 (bits);

    55 

    56   return x;

    57 }

    58 

    59 int jpeg_bits_available (JpegBits *bits)

    60 {

    61   return bits->end - bits->ptr;

    62 }

    63 

    64 int bits_needbits(JpegBits *b, int n_bytes)

    65 {

    66   if(b->ptr==NULL)return 1;

    67   if(b->ptr + n_bytes > b->end)return 1;

    68 

    69   return 0;

    70 }

    71 

    72 int getbit(JpegBits *b)

    73 {

    74 	int r;

    75 

    76 	r = ((*b->ptr)>>(7-b->idx))&1;

    77 

    78 	b->idx++;

    79 	if(b->idx>=8){

    80 		b->ptr++;

    81 		b->idx = 0;

    82 	}

    83 

    84 	return r;

    85 }

    86 

    87 unsigned int getbits(JpegBits *b, int n)

    88 {

    89 	unsigned long r = 0;

    90 	int i;

    91 

    92 	for(i=0;i<n;i++){

    93 		r <<=1;

    94 		r |= getbit(b);

    95 	}

    96 

    97 	return r;

    98 }

    99 

   100 unsigned int peekbits(JpegBits *b, int n)

   101 {

   102 	JpegBits tmp = *b;

   103 

   104 	return getbits(&tmp, n);

   105 }

   106 

   107 int getsbits(JpegBits *b, int n)

   108 {

   109 	unsigned long r = 0;

   110 	int i;

   111 

   112 	if(n==0)return 0;

   113 	r = -getbit(b);

   114 	for(i=1;i<n;i++){

   115 		r <<=1;

   116 		r |= getbit(b);

   117 	}

   118 

   119 	return r;

   120 }

   121 

   122 unsigned int peek_u8(JpegBits *b)

   123 {

   124 	return *b->ptr;

   125 }

   126 

   127 unsigned int get_u8(JpegBits *b)

   128 {

   129 	return *b->ptr++;

   130 }

   131 

   132 unsigned int get_u16(JpegBits *b)

   133 {

   134 	unsigned int r;

   135 

   136 	r = b->ptr[0] | (b->ptr[1]<<8);

   137 	b->ptr+=2;

   138 

   139 	return r;

   140 }

   141 

   142 unsigned int get_be_u16(JpegBits *b)

   143 {

   144 	unsigned int r;

   145 

   146 	r = (b->ptr[0]<<8) | b->ptr[1];

   147 	b->ptr+=2;

   148 

   149 	return r;

   150 }

   151 

   152 unsigned int get_u32(JpegBits *b)

   153 {

   154 	unsigned int r;

   155 

   156 	r = b->ptr[0] | (b->ptr[1]<<8) | (b->ptr[2]<<16) | (b->ptr[3]<<24);

   157 	b->ptr+=4;

   158 

   159 	return r;

   160 }

   161 

   162 void syncbits(JpegBits *b)

   163 {

   164 	if(b->idx){

   165 		b->ptr++;

   166 		b->idx=0;

   167 	}

   168 

   169 }

   170
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