mdw@git.distorted.org.uk Git - mLib/blob - struct/dstr.c

   1 /* -*-c-*-
   2  *
   3  * Handle dynamically growing strings
   4  *
   5  * (c) 1998 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib 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 Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include "alloc.h"
  35 #include "dstr.h"
  36 #include "growbuf.h"
  37
  38 /*----- Tunable constants -------------------------------------------------*/
  39
  40 /*
  41  * If the buffer is empty, it is set to @DSTR_INITSZ@ bytes in size.
  42  * Otherwise, it's set to the next power of two that's large enough.  This is
  43  * memory-hungry, but efficient.
  44  */
  45
  46 #define DSTR_INITSZ 64                  /* Initial buffer size */
  47
  48 /*----- Main code ---------------------------------------------------------*/
  49
  50 /* --- @dstr_create@ --- *
  51  *
  52  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  53  *
  54  * Returns:     ---
  55  *
  56  * Use:         Initializes a dynamic string.
  57  */
  58
  59 void dstr_create(dstr *d) { DCREATE(d); }
  60
  61 /* --- @dstr_destroy@ --- *
  62  *
  63  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  64  *
  65  * Returns:     ---
  66  *
  67  * Use:         Reclaims the space used by a dynamic string.
  68  */
  69
  70 void dstr_destroy(dstr *d) { DDESTROY(d); }
  71
  72 /* --- @dstr_reset@ --- *
  73  *
  74  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  75  *
  76  * Returns:     ---
  77  *
  78  * Use:         Resets a string so that new data gets put at the beginning.
  79  */
  80
  81 void dstr_reset(dstr *d) { DRESET(d); }
  82
  83 /* --- @dstr_ensure@ --- *
  84  *
  85  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  86  *              @size_t sz@ = amount of free space to ensure
  87  *
  88  * Returns:     ---
  89  *
  90  * Use:         Ensures that at least @sz@ bytes are available in the
  91  *              given string.
  92  */
  93
  94 void dstr_ensure(dstr *d, size_t sz)
  95 {
  96   GROWBUF_EXTEND(size_t, d->a, d->buf, d->sz, d->len + sz,
  97                  DSTR_INITSZ, 1);
  98 }
  99
 100 /* --- @dstr_putc@ --- *
 101  *
 102  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 103  *              @int ch@ = character to append
 104  *
 105  * Returns:     ---
 106  *
 107  * Use:         Appends a character to a string.
 108  */
 109
 110 void dstr_putc(dstr *d, int ch) { DPUTC(d, ch); }
 111
 112 /* --- @dstr_putz@ --- *
 113  *
 114  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 115  *
 116  * Returns:     ---
 117  *
 118  * Use:         Appends a null byte to a string.  The null byte does not
 119  *              contribute to the string's length, and will be overwritten
 120  *              by subsequent `put' operations.
 121  */
 122
 123 void dstr_putz(dstr *d) { DPUTZ(d); }
 124
 125 /* --- @dstr_puts@ --- *
 126  *
 127  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 128  *              @const char *s@ = pointer to string to append
 129  *
 130  * Returns:     ---
 131  *
 132  * Use:         Appends a character string to a string.  A trailing null
 133  *              byte is added, as for @dstr_putz@.
 134  */
 135
 136 void dstr_puts(dstr *d, const char *s) { DPUTS(d, s); }
 137
 138 /* --- @dstr_putd@ --- *
 139  *
 140  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 141  *              @const dstr *s@ = pointer to a dynamic string to append
 142  *
 143  * Returns:     ---
 144  *
 145  * Use:         Appends a dynamic string to a string.  A trailing null
 146  *              byte is added, as for @dstr_putz@.
 147  */
 148
 149 void dstr_putd(dstr *d, const dstr *s) { DPUTD(d, s); }
 150
 151 /* --- @dstr_putm@ --- *
 152  *
 153  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 154  *              @const void *p@ = pointer to a block to append
 155  *              @size_t sz@ = size of the block
 156  *
 157  * Returns:     Appends an arbitrary data block to a string.  No trailing
 158  *              null is appended.
 159  */
 160
 161 void dstr_putm(dstr *d, const void *p, size_t sz) { DPUTM(d, p, sz); }
 162
 163 /* --- @dstr_tidy@ --- *
 164  *
 165  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 166  *
 167  * Returns:     ---
 168  *
 169  * Use:         Reduces the amount of memory used by a string.  A trailing
 170  *              null byte is added, as for @dstr_putz@.
 171  */
 172
 173 void dstr_tidy(dstr *d)
 174 {
 175   d->buf = x_realloc(d->a, d->buf, d->len + 1, d->sz);
 176   d->buf[d->len] = 0;
 177   d->sz = d->len + 1;
 178 }
 179
 180 /* --- @dstr_putline@ --- *
 181  *
 182  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 183  *              @FILE *fp@ = a stream to read from
 184  *
 185  * Returns:     The number of characters read into the buffer, or @EOF@ if
 186  *              end-of-file was reached before any characters were read.
 187  *
 188  * Use:         Appends the next line from the given input stream to the
 189  *              string.  A trailing newline is not added; a trailing null
 190  *              byte is appended, as for @dstr_putz@.
 191  */
 192
 193 int dstr_putline(dstr *d, FILE *fp)
 194 {
 195   size_t left = d->sz - d->len;
 196   size_t off = d->len;
 197   int rd = 0;
 198   int ch;
 199
 200   for (;;) {
 201
 202     /* --- Read the next byte --- */
 203
 204     ch = getc(fp);
 205
 206     /* --- End-of-file when no characters read is special --- */
 207
 208     if (ch == EOF && !rd)
 209       return (EOF);
 210
 211     /* --- Make sure there's some buffer space --- */
 212
 213     if (!left) {
 214       d->len = off;
 215       dstr_ensure(d, 1);
 216       left = d->sz - off;
 217     }
 218
 219     /* --- End-of-file or newline ends the loop --- */
 220
 221     if (ch == EOF || ch == '\n') {
 222       d->buf[off] = 0;
 223       d->len = off;
 224       return rd;
 225     }
 226
 227     /* --- Append the character and continue --- */
 228
 229     d->buf[off++] = ch;
 230     left--; rd++;
 231   }
 232 }
 233
 234 /* --- @dstr_write@ --- *
 235  *
 236  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 237  *              @FILE *fp@ = a stream to write on
 238  *
 239  * Returns:     The number of bytes written (as for @fwrite@).
 240  *
 241  * Use:         Writes a dynamic string to a file.
 242  */
 243
 244 size_t dstr_write(const dstr *d, FILE *fp) { return (DWRITE(d, fp)); }
 245
 246 /*----- That's all, folks -------------------------------------------------*/