/* * 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