src/liblzma/api/lzma/index_hash.h

   1 /**
   2  * \file        lzma/index_hash.h
   3  * \brief       Validate Index by using a hash function
   4  * \note        Never include this file directly. Use <lzma.h> instead.
   5  *
   6  * Hashing makes it possible to use constant amount of memory to validate
   7  * Index of arbitrary size.
   8  */
   9
  10 /*
  11  * Author: Lasse Collin
  12  *
  13  * This file has been put into the public domain.
  14  * You can do whatever you want with this file.
  15  */
  16
  17 #ifndef LZMA_H_INTERNAL
  18 #       error Never include this file directly. Use <lzma.h> instead.
  19 #endif
  20
  21 /**
  22  * \brief       Opaque data type to hold the Index hash
  23  */
  24 typedef struct lzma_index_hash_s lzma_index_hash;
  25
  26
  27 /**
  28  * \brief       Allocate and initialize a new lzma_index_hash structure
  29  *
  30  * If index_hash is NULL, this function allocates and initializes a new
  31  * lzma_index_hash structure and returns a pointer to it. If allocation
  32  * fails, NULL is returned.
  33  *
  34  * If index_hash is non-NULL, this function reinitializes the lzma_index_hash
  35  * structure and returns the same pointer. In this case, return value cannot
  36  * be NULL or a different pointer than the index_hash that was given as
  37  * an argument.
  38  *
  39  * \param       index_hash  Pointer to a lzma_index_hash structure or NULL.
  40  * \param       allocator   lzma_allocator for custom allocator functions.
  41  *                          Set to NULL to use malloc() and free().
  42  *
  43  * \return      Initialized lzma_index_hash structure on success or
  44  *              NULL on failure.
  45  */
  46 extern LZMA_API(lzma_index_hash *) lzma_index_hash_init(
  47                 lzma_index_hash *index_hash, const lzma_allocator *allocator)
  48                 lzma_nothrow lzma_attr_warn_unused_result;
  49
  50
  51 /**
  52  * \brief       Deallocate lzma_index_hash structure
  53  *
  54  * \param       index_hash  Pointer to a lzma_index_hash structure to free.
  55  * \param       allocator   lzma_allocator for custom allocator functions.
  56  *                          Set to NULL to use malloc() and free().
  57  */
  58 extern LZMA_API(void) lzma_index_hash_end(
  59                 lzma_index_hash *index_hash, const lzma_allocator *allocator)
  60                 lzma_nothrow;
  61
  62
  63 /**
  64  * \brief       Add a new Record to an Index hash
  65  *
  66  * \param       index_hash        Pointer to a lzma_index_hash structure
  67  * \param       unpadded_size     Unpadded Size of a Block
  68  * \param       uncompressed_size Uncompressed Size of a Block
  69  *
  70  * \return      Possible lzma_ret values:
  71  *              - LZMA_OK
  72  *              - LZMA_DATA_ERROR: Compressed or uncompressed size of the
  73  *                Stream or size of the Index field would grow too big.
  74  *              - LZMA_PROG_ERROR: Invalid arguments or this function is being
  75  *                used when lzma_index_hash_decode() has already been used.
  76  */
  77 extern LZMA_API(lzma_ret) lzma_index_hash_append(lzma_index_hash *index_hash,
  78                 lzma_vli unpadded_size, lzma_vli uncompressed_size)
  79                 lzma_nothrow lzma_attr_warn_unused_result;
  80
  81
  82 /**
  83  * \brief       Decode and validate the Index field
  84  *
  85  * After telling the sizes of all Blocks with lzma_index_hash_append(),
  86  * the actual Index field is decoded with this function. Specifically,
  87  * once decoding of the Index field has been started, no more Records
  88  * can be added using lzma_index_hash_append().
  89  *
  90  * This function doesn't use lzma_stream structure to pass the input data.
  91  * Instead, the input buffer is specified using three arguments. This is
  92  * because it matches better the internal APIs of liblzma.
  93  *
  94  * \param       index_hash      Pointer to a lzma_index_hash structure
  95  * \param       in              Pointer to the beginning of the input buffer
  96  * \param[out]  in_pos          in[*in_pos] is the next byte to process
  97  * \param       in_size         in[in_size] is the first byte not to process
  98  *
  99  * \return      Possible lzma_ret values:
 100  *              - LZMA_OK: So far good, but more input is needed.
 101  *              - LZMA_STREAM_END: Index decoded successfully and it matches
 102  *                the Records given with lzma_index_hash_append().
 103  *              - LZMA_DATA_ERROR: Index is corrupt or doesn't match the
 104  *                information given with lzma_index_hash_append().
 105  *              - LZMA_BUF_ERROR: Cannot progress because *in_pos >= in_size.
 106  *              - LZMA_PROG_ERROR
 107  */
 108 extern LZMA_API(lzma_ret) lzma_index_hash_decode(lzma_index_hash *index_hash,
 109                 const uint8_t *in, size_t *in_pos, size_t in_size)
 110                 lzma_nothrow lzma_attr_warn_unused_result;
 111
 112
 113 /**
 114  * \brief       Get the size of the Index field as bytes
 115  *
 116  * This is needed to verify the Backward Size field in the Stream Footer.
 117  *
 118  * \param       index_hash      Pointer to a lzma_index_hash structure
 119  *
 120  * \return      Size of the Index field in bytes.
 121  */
 122 extern LZMA_API(lzma_vli) lzma_index_hash_size(
 123                 const lzma_index_hash *index_hash)
 124                 lzma_nothrow lzma_attr_pure;