code.delx.au - pulseaudio/blob - src/pulsecore/strbuf.c

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