runtime/bc_read_stream.h

   1 /*********************************************************************
   2
   3   Gazelle: a system for building fast, reusable parsers
   4
   5   bc_read_stream.h
   6
   7   This file presents a public stream-based interface for reading files
   8   in Bitcode format.  It allows skipping blocks and rewinding to the
   9   beginning of a block.
  10
  11   Copyright (c) 2007 Joshua Haberman.  See LICENSE for details.
  12
  13 *********************************************************************/
  14
  15 #ifndef BITCODE_READ_STREAM
  16 #define BITCODE_READ_STREAM
  17
  18 #include <stdint.h>
  19
  20 struct bc_read_stream;
  21
  22 /**********************************************************
  23
  24   Open/Close Stream
  25
  26 ***********************************************************/
  27
  28 struct bc_read_stream *bc_rs_open_file(const char *filename);
  29 struct bc_read_stream *bc_rs_open_mem(const char *data);
  30 void bc_rs_close_stream(struct bc_read_stream *stream);
  31
  32 /**********************************************************
  33
  34   Moving around the stream
  35
  36 ***********************************************************/
  37
  38 enum RecordType {
  39   DataRecord,    /* This is a normal data record that contains a series of integers */
  40   StartBlock,    /* This is the start of a block: you can descend into it or skip over it */
  41   EndBlock,      /* This indicates the end of a block. */
  42   DefineAbbrev,  /* This record defines an abbreviation. */
  43   Eof,           /* This indicates end-of-file. */
  44   Err            /* This indicates an error. */
  45 };
  46
  47 struct record_info {
  48     enum RecordType record_type;
  49     uint32_t id;  /* record id for data records, block id for StartBlock */
  50 };
  51
  52 /* Advance to the next record in the file, returning a tag indicating what
  53  * kind of record it is.
  54  *
  55  * Note that not every literal record in the stream will be passed to you,
  56  * the client.  Some, like records that define abbreviations, are handled
  57  * internally because they do not contain stream-level data. */
  58 struct record_info bc_rs_next_data_record(struct bc_read_stream *stream);
  59
  60 /* Get the total number of integers in this data record, or the remaining number
  61  * of integers in this data record, respectively. */
  62 int bc_rs_get_record_size(struct bc_read_stream *stream);
  63 int bc_rs_get_remaining_record_size(struct bc_read_stream *stream);
  64
  65 /* Skip a block by calling this function before reading the first record
  66  * of a block.  Calling it in other circumstances is an error and the
  67  * results are undefined. */
  68 void bc_rs_skip_block(struct bc_read_stream *stream);
  69
  70 void bc_rs_rewind_block(struct bc_read_stream *stream);
  71
  72 /**********************************************************
  73
  74   Reading Data
  75
  76 ***********************************************************/
  77
  78 /* Get the next integer from the current data record and advance the stream.
  79  * If there an error of any kind occurs, the corresponding error bits
  80  * are set on the stream (check them with bc_rs_get_error()), and these
  81  * functions themselves return an undefined value. */
  82 uint8_t   bc_rs_read_next_8(struct bc_read_stream *stream);
  83 uint16_t  bc_rs_read_next_16(struct bc_read_stream *stream);
  84 uint32_t  bc_rs_read_next_32(struct bc_read_stream *stream);
  85 uint64_t  bc_rs_read_next_64(struct bc_read_stream *stream);
  86
  87 uint8_t   bc_rs_read_8(struct bc_read_stream *stream, int i);
  88 uint16_t  bc_rs_read_16(struct bc_read_stream *stream, int i);
  89 uint32_t  bc_rs_read_32(struct bc_read_stream *stream, int i);
  90 uint64_t  bc_rs_read_64(struct bc_read_stream *stream, int i);
  91
  92 /**********************************************************
  93
  94   Error Reporting
  95
  96 ***********************************************************/
  97
  98 /* These are the error flags for the data stream, and a means for reading them. */
  99
 100 /* The value in the stream was too large for the bc_rs_get_* function you called.
 101  * For example, the stream's value was 257 but you called bc_rs_get_8(). */
 102 #define BITCODE_ERR_VALUE_TOO_LARGE 0x1
 103
 104 /* There were no more values in a record when you called bc_rs_get_*. */
 105 #define BITCODE_ERR_NO_SUCH_VALUE   0x2
 106
 107 /* I/O error reading the input file */
 108 #define BITCODE_ERR_IO              0x4
 109
 110 /* Bitcode data is corrupt */
 111 #define BITCODE_ERR_CORRUPT_INPUT   0x8
 112
 113 #define BITCODE_ERR_INTERNAL        0x10
 114
 115 int bc_rs_get_error(struct bc_read_stream *stream);
 116
 117 #endif
 118
 119 /*
 120  * Local Variables:
 121  * c-file-style: "bsd"
 122  * c-basic-offset: 4
 123  * indent-tabs-mode: nil
 124  * End:
 125  * vim:et:sts=4:sw=4
 126  */