kc3-lang/libxkbcommon/src/scanner-utils.c

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• Hash : e120807b
  Author :
  Date : 2025-01-29T15:35:22
  

  Update license notices to SDPX short identifiers + update LICENSE
  
  Fix #628.
  
  Signed-off-by: Ran Benita <ran@unusedvar.com>
  

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• src/scanner-utils.c

• /*
   * Copyright © 2025 Ran Benita <ran@unusedvar.com>
   * SPDX-License-Identifier: MIT
   */
  
  #include "scanner-utils.h"
  
  struct scanner_loc
  scanner_token_location(struct scanner *s)
  {
      /*
       * The following article and accompying code compares some algorithms:
       * https://lemire.me/blog/2017/02/14/how-fast-can-you-count-lines/
       * https://github.com/lemire/Code-used-on-Daniel-Lemire-s-blog/blob/master/2017/02/14/newlines.c
       * This is the fastest portable one for me, and it's simple.
       *
       * To avoid rescanning on each call, cache the previously found position
       * and start from that on the next call. This is effective as long as the
       * tokens go forward.
       */
      size_t line, column;
      size_t line_pos = 0;
      if (s->cached_pos > s->token_pos) {
          s->cached_pos = 0;
          s->cached_loc.line = s->cached_loc.column = 1;
      }
      line = s->cached_loc.line;
      const char *ptr = s->s + s->cached_pos;
      const char *last = s->s + s->token_pos;
      while ((ptr = memchr(ptr, '\n', last - ptr))) {
          line++;
          ptr++;
          line_pos = ptr - s->s;
      }
      if (line == s->cached_loc.line) {
          column = s->cached_loc.column + (s->token_pos - s->cached_pos);
      } else {
          column = s->token_pos - line_pos + 1;
      }
      struct scanner_loc loc = {.line = line, .column = column};
      s->cached_pos = s->token_pos;
      s->cached_loc = loc;
      return loc;
  }
  

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