src/pulsecore/strbuf.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2006 Lennart Poettering
   5
   6   PulseAudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2.1 of the License,
   9   or (at your option) any later version.
  10
  11   PulseAudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with PulseAudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <sys/types.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <stdarg.h>
  30 #include <stdio.h>
  31
  32 #include <pulse/xmalloc.h>
  33 #include <pulsecore/macro.h>
  34
  35 #include "strbuf.h"
  36
  37 /* A chunk of the linked list that makes up the string */
  38 struct chunk {
  39     struct chunk *next;
  40     size_t length;
  41 };
  42
  43 #define CHUNK_TO_TEXT(c) ((char*) (c) + PA_ALIGN(sizeof(struct chunk)))
  44
  45 struct pa_strbuf {
  46     size_t length;
  47     struct chunk *head, *tail;
  48 };
  49
  50 pa_strbuf *pa_strbuf_new(void) {
  51     pa_strbuf *sb;
  52
  53     sb = pa_xnew(pa_strbuf, 1);
  54     sb->length = 0;
  55     sb->head = sb->tail = NULL;
  56
  57     return sb;
  58 }
  59
  60 void pa_strbuf_free(pa_strbuf *sb) {
  61     pa_assert(sb);
  62
  63     while (sb->head) {
  64         struct chunk *c = sb->head;
  65         sb->head = sb->head->next;
  66         pa_xfree(c);
  67     }
  68
  69     pa_xfree(sb);
  70 }
  71
  72 /* Make a C string from the string buffer. The caller has to free
  73  * string with pa_xfree(). */
  74 char *pa_strbuf_tostring(pa_strbuf *sb) {
  75     char *t, *e;
  76     struct chunk *c;
  77
  78     pa_assert(sb);
  79
  80     e = t = pa_xmalloc(sb->length+1);
  81
  82     for (c = sb->head; c; c = c->next) {
  83         pa_assert((size_t) (e-t) <= sb->length);
  84         memcpy(e, CHUNK_TO_TEXT(c), c->length);
  85         e += c->length;
  86     }
  87
  88     /* Trailing NUL */
  89     *e = 0;
  90
  91     pa_assert(e == t+sb->length);
  92
  93     return t;
  94 }
  95
  96 /* Combination of pa_strbuf_free() and pa_strbuf_tostring() */
  97 char *pa_strbuf_tostring_free(pa_strbuf *sb) {
  98     char *t;
  99
 100     pa_assert(sb);
 101     t = pa_strbuf_tostring(sb);
 102     pa_strbuf_free(sb);
 103
 104     return t;
 105 }
 106
 107 /* Append a string to the string buffer */
 108 void pa_strbuf_puts(pa_strbuf *sb, const char *t) {
 109
 110     pa_assert(sb);
 111     pa_assert(t);
 112
 113     pa_strbuf_putsn(sb, t, strlen(t));
 114 }
 115
 116 /* Append a character to the string buffer */
 117 void pa_strbuf_putc(pa_strbuf *sb, char c) {
 118     pa_assert(sb);
 119
 120     pa_strbuf_putsn(sb, &c, 1);
 121 }
 122
 123 /* Append a new chunk to the linked list */
 124 static void append(pa_strbuf *sb, struct chunk *c) {
 125     pa_assert(sb);
 126     pa_assert(c);
 127
 128     if (sb->tail) {
 129         pa_assert(sb->head);
 130         sb->tail->next = c;
 131     } else {
 132         pa_assert(!sb->head);
 133         sb->head = c;
 134     }
 135
 136     sb->tail = c;
 137     sb->length += c->length;
 138     c->next = NULL;
 139 }
 140
 141 /* Append up to l bytes of a string to the string buffer */
 142 void pa_strbuf_putsn(pa_strbuf *sb, const char *t, size_t l) {
 143     struct chunk *c;
 144
 145     pa_assert(sb);
 146     pa_assert(t);
 147
 148     if (!l)
 149         return;
 150
 151     c = pa_xmalloc(PA_ALIGN(sizeof(struct chunk)) + l);
 152     c->length = l;
 153     memcpy(CHUNK_TO_TEXT(c), t, l);
 154
 155     append(sb, c);
 156 }
 157
 158 /* Append a printf() style formatted string to the string buffer. */
 159 /* The following is based on an example from the GNU libc documentation */
 160 size_t pa_strbuf_printf(pa_strbuf *sb, const char *format, ...) {
 161     size_t size = 100;
 162     struct chunk *c = NULL;
 163
 164     pa_assert(sb);
 165     pa_assert(format);
 166
 167     for(;;) {
 168         va_list ap;
 169         int r;
 170
 171         c = pa_xrealloc(c, PA_ALIGN(sizeof(struct chunk)) + size);
 172
 173         va_start(ap, format);
 174         r = vsnprintf(CHUNK_TO_TEXT(c), size, format, ap);
 175         CHUNK_TO_TEXT(c)[size-1] = 0;
 176         va_end(ap);
 177
 178         if (r > -1 && (size_t) r < size) {
 179             c->length = (size_t) r;
 180             append(sb, c);
 181             return (size_t) r;
 182         }
 183
 184         if (r > -1)    /* glibc 2.1 */
 185             size = (size_t) r+1;
 186         else           /* glibc 2.0 */
 187             size *= 2;
 188     }
 189 }
 190
 191 pa_bool_t pa_strbuf_isempty(pa_strbuf *sb) {
 192     pa_assert(sb);
 193
 194     return sb->length <= 0;
 195 }