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Diffstat (limited to 'gc/cord/private/cord_pos.h')
| -rw-r--r-- | gc/cord/private/cord_pos.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/gc/cord/private/cord_pos.h b/gc/cord/private/cord_pos.h new file mode 100644 index 0000000..d2b24bb --- /dev/null +++ b/gc/cord/private/cord_pos.h @@ -0,0 +1,118 @@ +/* + * Copyright (c) 1993-1994 by Xerox Corporation. All rights reserved. + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program + * for any purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is granted, + * provided the above notices are retained, and a notice that the code was + * modified is included with the above copyright notice. + */ +/* Boehm, May 19, 1994 2:23 pm PDT */ +# ifndef CORD_POSITION_H + +/* The representation of CORD_position. This is private to the */ +/* implementation, but the size is known to clients. Also */ +/* the implementation of some exported macros relies on it. */ +/* Don't use anything defined here and not in cord.h. */ + +# define MAX_DEPTH 48 + /* The maximum depth of a balanced cord + 1. */ + /* We don't let cords get deeper than MAX_DEPTH. */ + +struct CORD_pe { + CORD pe_cord; + size_t pe_start_pos; +}; + +/* A structure describing an entry on the path from the root */ +/* to current position. */ +typedef struct CORD_Pos { + size_t cur_pos; + int path_len; +# define CORD_POS_INVALID (0x55555555) + /* path_len == INVALID <==> position invalid */ + const char *cur_leaf; /* Current leaf, if it is a string. */ + /* If the current leaf is a function, */ + /* then this may point to function_buf */ + /* containing the next few characters. */ + /* Always points to a valid string */ + /* containing the current character */ + /* unless cur_end is 0. */ + size_t cur_start; /* Start position of cur_leaf */ + size_t cur_end; /* Ending position of cur_leaf */ + /* 0 if cur_leaf is invalid. */ + struct CORD_pe path[MAX_DEPTH + 1]; + /* path[path_len] is the leaf corresponding to cur_pos */ + /* path[0].pe_cord is the cord we point to. */ +# define FUNCTION_BUF_SZ 8 + char function_buf[FUNCTION_BUF_SZ]; /* Space for next few chars */ + /* from function node. */ +} CORD_pos[1]; + +/* Extract the cord from a position: */ +CORD CORD_pos_to_cord(CORD_pos p); + +/* Extract the current index from a position: */ +size_t CORD_pos_to_index(CORD_pos p); + +/* Fetch the character located at the given position: */ +char CORD_pos_fetch(CORD_pos p); + +/* Initialize the position to refer to the give cord and index. */ +/* Note that this is the most expensive function on positions: */ +void CORD_set_pos(CORD_pos p, CORD x, size_t i); + +/* Advance the position to the next character. */ +/* P must be initialized and valid. */ +/* Invalidates p if past end: */ +void CORD_next(CORD_pos p); + +/* Move the position to the preceding character. */ +/* P must be initialized and valid. */ +/* Invalidates p if past beginning: */ +void CORD_prev(CORD_pos p); + +/* Is the position valid, i.e. inside the cord? */ +int CORD_pos_valid(CORD_pos p); + +char CORD__pos_fetch(CORD_pos); +void CORD__next(CORD_pos); +void CORD__prev(CORD_pos); + +#define CORD_pos_fetch(p) \ + (((p)[0].cur_end != 0)? \ + (p)[0].cur_leaf[(p)[0].cur_pos - (p)[0].cur_start] \ + : CORD__pos_fetch(p)) + +#define CORD_next(p) \ + (((p)[0].cur_pos + 1 < (p)[0].cur_end)? \ + (p)[0].cur_pos++ \ + : (CORD__next(p), 0)) + +#define CORD_prev(p) \ + (((p)[0].cur_end != 0 && (p)[0].cur_pos > (p)[0].cur_start)? \ + (p)[0].cur_pos-- \ + : (CORD__prev(p), 0)) + +#define CORD_pos_to_index(p) ((p)[0].cur_pos) + +#define CORD_pos_to_cord(p) ((p)[0].path[0].pe_cord) + +#define CORD_pos_valid(p) ((p)[0].path_len != CORD_POS_INVALID) + +/* Some grubby stuff for performance-critical friends: */ +#define CORD_pos_chars_left(p) ((long)((p)[0].cur_end) - (long)((p)[0].cur_pos)) + /* Number of characters in cache. <= 0 ==> none */ + +#define CORD_pos_advance(p,n) ((p)[0].cur_pos += (n) - 1, CORD_next(p)) + /* Advance position by n characters */ + /* 0 < n < CORD_pos_chars_left(p) */ + +#define CORD_pos_cur_char_addr(p) \ + (p)[0].cur_leaf + ((p)[0].cur_pos - (p)[0].cur_start) + /* address of current character in cache. */ + +#endif |