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-rw-r--r--libavutil/bprint.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/libavutil/bprint.c b/libavutil/bprint.c
new file mode 100644
index 0000000..373a492
--- /dev/null
+++ b/libavutil/bprint.c
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2012 Nicolas George
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include "avassert.h"
+#include "bprint.h"
+#include "common.h"
+#include "error.h"
+#include "mem.h"
+
+#define av_bprint_room(buf) ((buf)->size - FFMIN((buf)->len, (buf)->size))
+#define av_bprint_is_allocated(buf) ((buf)->str != (buf)->reserved_internal_buffer)
+
+static int av_bprint_alloc(AVBPrint *buf, unsigned room)
+{
+ char *old_str, *new_str;
+ unsigned min_size, new_size;
+
+ if (buf->size == buf->size_max)
+ return AVERROR(EIO);
+ if (!av_bprint_is_complete(buf))
+ return AVERROR_INVALIDDATA; /* it is already truncated anyway */
+ min_size = buf->len + 1 + FFMIN(UINT_MAX - buf->len - 1, room);
+ new_size = buf->size > buf->size_max / 2 ? buf->size_max : buf->size * 2;
+ if (new_size < min_size)
+ new_size = FFMIN(buf->size_max, min_size);
+ old_str = av_bprint_is_allocated(buf) ? buf->str : NULL;
+ new_str = av_realloc(old_str, new_size);
+ if (!new_str)
+ return AVERROR(ENOMEM);
+ if (!old_str)
+ memcpy(new_str, buf->str, buf->len + 1);
+ buf->str = new_str;
+ buf->size = new_size;
+ return 0;
+}
+
+static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
+{
+ /* arbitrary margin to avoid small overflows */
+ extra_len = FFMIN(extra_len, UINT_MAX - 5 - buf->len);
+ buf->len += extra_len;
+ if (buf->size)
+ buf->str[FFMIN(buf->len, buf->size - 1)] = 0;
+}
+
+void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
+{
+ unsigned size_auto = (char *)buf + sizeof(*buf) -
+ buf->reserved_internal_buffer;
+
+ if (size_max == 1)
+ size_max = size_auto;
+ buf->str = buf->reserved_internal_buffer;
+ buf->len = 0;
+ buf->size = FFMIN(size_auto, size_max);
+ buf->size_max = size_max;
+ *buf->str = 0;
+ if (size_init > buf->size)
+ av_bprint_alloc(buf, size_init - 1);
+}
+
+void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
+{
+ buf->str = buffer;
+ buf->len = 0;
+ buf->size = size;
+ buf->size_max = size;
+ *buf->str = 0;
+}
+
+void av_bprintf(AVBPrint *buf, const char *fmt, ...)
+{
+ unsigned room;
+ char *dst;
+ va_list vl;
+ int extra_len;
+
+ while (1) {
+ room = av_bprint_room(buf);
+ dst = room ? buf->str + buf->len : NULL;
+ va_start(vl, fmt);
+ extra_len = vsnprintf(dst, room, fmt, vl);
+ va_end(vl);
+ if (extra_len <= 0)
+ return;
+ if (extra_len < room)
+ break;
+ if (av_bprint_alloc(buf, extra_len))
+ break;
+ }
+ av_bprint_grow(buf, extra_len);
+}
+
+void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
+{
+ unsigned room, real_n;
+
+ while (1) {
+ room = av_bprint_room(buf);
+ if (n < room)
+ break;
+ if (av_bprint_alloc(buf, n))
+ break;
+ }
+ if (room) {
+ real_n = FFMIN(n, room - 1);
+ memset(buf->str + buf->len, c, real_n);
+ }
+ av_bprint_grow(buf, n);
+}
+
+void av_bprint_clear(AVBPrint *buf)
+{
+ if (buf->len) {
+ *buf->str = 0;
+ buf->len = 0;
+ }
+}
+
+int av_bprint_finalize(AVBPrint *buf, char **ret_str)
+{
+ unsigned real_size = FFMIN(buf->len + 1, buf->size);
+ char *str;
+ int ret = 0;
+
+ if (ret_str) {
+ if (av_bprint_is_allocated(buf)) {
+ str = av_realloc(buf->str, real_size);
+ if (!str)
+ str = buf->str;
+ buf->str = NULL;
+ } else {
+ str = av_malloc(real_size);
+ if (str)
+ memcpy(str, buf->str, real_size);
+ else
+ ret = AVERROR(ENOMEM);
+ }
+ *ret_str = str;
+ } else {
+ if (av_bprint_is_allocated(buf))
+ av_freep(&buf->str);
+ }
+ buf->size = real_size;
+ return ret;
+}
+
+#ifdef TEST
+
+#undef printf
+
+static void bprint_pascal(AVBPrint *b, unsigned size)
+{
+ unsigned i, j;
+ unsigned p[42];
+
+ av_assert0(size < FF_ARRAY_ELEMS(p));
+
+ p[0] = 1;
+ av_bprintf(b, "%8d\n", 1);
+ for (i = 1; i <= size; i++) {
+ p[i] = 1;
+ for (j = i - 1; j > 0; j--)
+ p[j] = p[j] + p[j - 1];
+ for (j = 0; j <= i; j++)
+ av_bprintf(b, "%8d", p[j]);
+ av_bprintf(b, "\n");
+ }
+}
+
+int main(void)
+{
+ AVBPrint b;
+ char buf[256];
+
+ av_bprint_init(&b, 0, -1);
+ bprint_pascal(&b, 5);
+ printf("Short text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
+ printf("%s\n", b.str);
+ av_bprint_finalize(&b, NULL);
+
+ av_bprint_init(&b, 0, -1);
+ bprint_pascal(&b, 25);
+ printf("Long text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
+ av_bprint_finalize(&b, NULL);
+
+ av_bprint_init(&b, 0, 2048);
+ bprint_pascal(&b, 25);
+ printf("Long text in limited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
+ av_bprint_finalize(&b, NULL);
+
+ av_bprint_init(&b, 0, 1);
+ bprint_pascal(&b, 5);
+ printf("Short text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
+
+ av_bprint_init(&b, 0, 1);
+ bprint_pascal(&b, 25);
+ printf("Long text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str)/8*8, b.len);
+ /* Note that the size of the automatic buffer is arch-dependant. */
+
+ av_bprint_init(&b, 0, 0);
+ bprint_pascal(&b, 25);
+ printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
+
+ av_bprint_init_for_buffer(&b, buf, sizeof(buf));
+ bprint_pascal(&b, 25);
+ printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(buf), b.len);
+
+ return 0;
+}
+
+#endif
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