1 | /* |
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2 | * COPYRIGHT (c) 2012 Chris Johns <chrisj@rtems.org> |
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3 | * |
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4 | * The license and distribution terms for this file may be |
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5 | * found in the file LICENSE in this distribution or at |
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6 | * http://www.rtems.org/license/LICENSE. |
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7 | */ |
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8 | /** |
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9 | * @file |
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10 | * |
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11 | * @ingroup rtems_rtl |
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12 | * |
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13 | * @brief RTEMS Run-Time Linker Object File Compression manages a |
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14 | * compressed stream of data. |
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15 | * |
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16 | * This is a simple interface to the object file cache to stream data from |
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17 | * from a compressed object file. There is no ability to seek with the |
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18 | * data from a compressed file. The module exists to allocate the output |
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19 | * buffer when the loader starts and use the cache buffers will have been |
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20 | * allocated. |
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21 | */ |
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22 | |
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23 | #if !defined (_RTEMS_RTL_OBJ_COMP_H_) |
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24 | #define _RTEMS_RTL_OBJ_COMP_H_ |
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25 | |
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26 | #include <rtems/rtl/rtl-obj-cache.h> |
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27 | |
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28 | #ifdef __cplusplus |
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29 | extern "C" { |
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30 | #endif /* __cplusplus */ |
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31 | |
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32 | /** |
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33 | * The amount of input data read at a time from the file. |
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34 | */ |
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35 | #define RTEMS_RTL_DECOMP_INPUT_SIZE (256) |
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36 | |
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37 | /** |
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38 | * The types of supported compression. |
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39 | */ |
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40 | #define RTEMS_RTL_COMP_NONE (0) |
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41 | #define RTEMS_RTL_COMP_LZ77 (1) |
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42 | |
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43 | /** |
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44 | * The compressed file. |
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45 | */ |
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46 | typedef struct rtems_rtl_obj_cpmp_s |
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47 | { |
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48 | rtems_rtl_obj_cache_t* cache; /**< The cache provides the input |
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49 | * buffer. */ |
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50 | int fd; /**< The file descriptor. */ |
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51 | int compression; /**< The type of compression. */ |
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52 | off_t offset; /**< The base offset of the buffer. */ |
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53 | size_t size; /**< The size of the output buffer. */ |
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54 | size_t level; /**< The amount of data in the buffer. */ |
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55 | uint8_t* buffer; /**< The buffer */ |
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56 | uint32_t read; /**< The amount of data read. */ |
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57 | } rtems_rtl_obj_comp_t; |
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58 | |
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59 | /** |
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60 | * Return the input level. |
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61 | */ |
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62 | static inline uint32_t rtems_rtl_obj_comp_input (rtems_rtl_obj_comp_t* comp) |
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63 | { |
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64 | return comp->read; |
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65 | } |
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66 | |
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67 | /** |
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68 | * Open a compressor allocating the output buffer. |
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69 | * |
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70 | * @param comp The compressor to initialise. |
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71 | * @param size The size of the compressor's output buffer. |
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72 | * @retval true The compressor is open. |
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73 | * @retval false The compressor is not open. The RTL error is set. |
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74 | */ |
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75 | bool rtems_rtl_obj_comp_open (rtems_rtl_obj_comp_t* comp, |
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76 | size_t size); |
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77 | |
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78 | /** |
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79 | * Close a compressor. |
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80 | * |
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81 | * @param comp The compressor to close. |
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82 | */ |
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83 | void rtems_rtl_obj_comp_close (rtems_rtl_obj_comp_t* comp); |
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84 | |
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85 | /** |
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86 | * Set the cache and offset in the file the compressed stream starts. |
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87 | * |
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88 | * @param comp The compressor to set the offset in. |
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89 | * @param cache The cache to read the file in by. |
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90 | * @param fd The file descriptor. Must be an open file. |
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91 | * @param compression The type of compression being streamed. |
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92 | * @param offset The offset in the file the compressed stream starts. |
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93 | */ |
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94 | void rtems_rtl_obj_comp_set (rtems_rtl_obj_comp_t* comp, |
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95 | rtems_rtl_obj_cache_t* cache, |
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96 | int fd, |
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97 | int compression, |
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98 | off_t offset); |
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99 | |
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100 | /** |
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101 | * Read decompressed data. The length contains the amount of data that should |
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102 | * be available in the cache and referenced by the buffer handle. It must be |
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103 | * less than or equal to the size of the cache. This call will return the |
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104 | * amount of data that is available. It can be less than you ask if the offset |
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105 | * and size is past the end of the file. |
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106 | * |
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107 | * @param comp The compressor to read data from. |
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108 | * @param buffer The buffer the output is written too. |
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109 | * @param length The length of data to read. Can be modified to a |
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110 | * lesser value and true is still returned so check it. |
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111 | * @retval true The data referenced is in the cache. |
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112 | * @retval false The read failed and the RTL error has been set. |
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113 | */ |
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114 | bool rtems_rtl_obj_comp_read (rtems_rtl_obj_comp_t* comp, |
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115 | void* buffer, |
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116 | size_t length); |
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117 | |
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118 | #ifdef __cplusplus |
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119 | } |
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120 | #endif /* __cplusplus */ |
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121 | |
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122 | #endif |
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