kc3-lang/pkgconf/libpkgconf/buffer.c

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• Hash : 88258bd9
  Author :
  Date : 2025-02-04T16:31:01
  

  libpkgconf: buffer: round up buffer allocations to 4KB granules
  
  Signed-off-by: Ariadne Conill <ariadne@ariadne.space>
  

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• libpkgconf/buffer.c

• /*
   * buffer.c
   * dynamically-managed buffers
   *
   * Copyright (c) 2024 pkgconf authors (see AUTHORS).
   *
   * Permission to use, copy, modify, and/or distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * This software is provided 'as is' and without any warranty, express or
   * implied.  In no event shall the authors be liable for any damages arising
   * from the use of this software.
   */
  
  #include <libpkgconf/stdinc.h>
  #include <libpkgconf/libpkgconf.h>
  
  /*
   * !doc
   *
   * libpkgconf `buffer` module
   * ==========================
   *
   * The libpkgconf `buffer` module contains the functions related to managing
   * dynamically-allocated buffers.
   */
  
  static inline size_t
  target_allocation_size(size_t target_size)
  {
  	return 4096 + (4096 * (target_size / 4096));
  }
  
  void
  pkgconf_buffer_append(pkgconf_buffer_t *buffer, const char *text)
  {
  	size_t needed = strlen(text) + 1;
  	size_t newsize = pkgconf_buffer_len(buffer) + needed;
  
  	char *newbase = realloc(buffer->base, target_allocation_size(newsize));
  
  	/* XXX: silently failing here is antisocial */
  	if (newbase == NULL)
  		return;
  
  	char *newend = newbase + pkgconf_buffer_len(buffer);
  	pkgconf_strlcpy(newend, text, needed);
  
  	buffer->base = newbase;
  	buffer->end = newend + needed;
  }
  
  void
  pkgconf_buffer_push_byte(pkgconf_buffer_t *buffer, char byte)
  {
  	size_t newsize = pkgconf_buffer_len(buffer) + 1;
  	char *newbase = realloc(buffer->base, target_allocation_size(newsize));
  
  	/* XXX: silently failing here remains antisocial */
  	if (newbase == NULL)
  		return;
  
  	char *newend = newbase + newsize;
  	*(newend - 1) = byte;
  	*newend = '\0';
  
  	buffer->base = newbase;
  	buffer->end = newend;
  }
  
  void
  pkgconf_buffer_trim_byte(pkgconf_buffer_t *buffer)
  {
  	size_t newsize = pkgconf_buffer_len(buffer) - 1;
  	char *newbase = realloc(buffer->base, target_allocation_size(newsize));
  
  	buffer->base = newbase;
  	buffer->end = newbase + newsize;
  	*(buffer->end) = '\0';
  }
  
  void
  pkgconf_buffer_finalize(pkgconf_buffer_t *buffer)
  {
  	free(buffer->base);
  }
  

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