devspec.en_US/project/recutils/src/rec-buf.c

   1 /* -*- mode: C -*-
   2  *
   3  *       File:         rec-buf.c
   4  *       Date:         Fri Dec 17 18:40:53 2010
   5  *
   6  *       GNU recutils - Flexible buffers.
   7  *
   8  */
   9
  10 /* Copyright (C) 2010-2019 Jose E. Marchesi */
  11
  12 /* This program is free software: you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation, either version 3 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24  */
  25
  26 #include <config.h>
  27
  28 #include <stdlib.h>
  29
  30 #include <rec.h>
  31
  32 #define REC_BUF_STEP 512
  33
  34 struct rec_buf_s
  35 {
  36   char *data;
  37   size_t size;
  38   size_t used;
  39
  40   /* Pointers to user-provided variables that will be updated at
  41      rec_buf_destroy time.  */
  42   char **data_pointer;
  43   size_t *size_pointer;
  44 };
  45
  46 /*
  47  * Public functions.
  48  */
  49
  50 rec_buf_t
  51 rec_buf_new (char **data, size_t *size)
  52 {
  53   rec_buf_t new;
  54
  55   new = malloc (sizeof (struct rec_buf_s));
  56   if (new)
  57     {
  58       new->data_pointer = data;
  59       new->size_pointer = size;
  60
  61       new->data = malloc (REC_BUF_STEP);
  62       new->size = REC_BUF_STEP;
  63       new->used = 0;
  64
  65       if (!new->data)
  66         {
  67           free (new);
  68           new = NULL;
  69         }
  70     }
  71
  72   return new;
  73 }
  74
  75 void
  76 rec_buf_close (rec_buf_t buf)
  77 {
  78   /* Adjust the buffer.  */
  79   if (buf->used > 0)
  80       buf->data = realloc (buf->data, buf->used + 1);
  81   buf->data[buf->used] = '\0';
  82
  83   /* Update the user-provided buffer and size.  */
  84   *(buf->data_pointer) = buf->data;
  85   *(buf->size_pointer) = buf->used;
  86
  87   /* Don't deallocate buf->data */
  88   free (buf);
  89 }
  90
  91 void
  92 rec_buf_rewind (rec_buf_t buf, int n)
  93 {
  94   if ((buf->used - n) >= 0)
  95     buf->used = buf->used - n;
  96 }
  97
  98 int
  99 rec_buf_putc (int c, rec_buf_t buf)
 100 {
 101   unsigned int ret;
 102
 103   if (c == EOF)
 104     return EOF;
 105
 106   ret = (unsigned int) c;
 107   if ((buf->used + 1) > buf->size)
 108     {
 109       /* Allocate a new block */
 110       buf->size = buf->size + REC_BUF_STEP;
 111       buf->data = realloc (buf->data, buf->size);
 112
 113       if (!buf->data)
 114         /* Not enough memory.
 115            REC_BUF_STEP should not be 0. */
 116         ret = EOF;
 117     }
 118
 119   if (ret != EOF)
 120     /* Add the character */
 121     buf->data[buf->used++] = (char) c;
 122
 123   return ret;
 124 }
 125
 126 int
 127 rec_buf_puts (const char *str, rec_buf_t buf)
 128 {
 129   int ret;
 130   const char *p;
 131
 132   ret = 0;
 133   p = str;
 134   while (*p != '\0')
 135     {
 136       if (rec_buf_putc (*p, buf) == EOF)
 137         {
 138           /* Error.  */
 139           ret = -1;
 140           break;
 141         }
 142
 143       ret++;
 144       p++;
 145     }
 146
 147   return ret;
 148 }
 149
 150 /* End of rec-buf.c */