mirror of
https://git.ffmpeg.org/ffmpeg.git
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248 lines
6.5 KiB
C
248 lines
6.5 KiB
C
/*
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* Copyright (c) 2012 Nicolas George
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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#include "bprint.h"
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#include "common.h"
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#include "error.h"
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#include "mem.h"
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#if defined(_WIN32)
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static int vsnprintf_fixed(char *s, size_t n, const char *format, va_list va)
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{
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va_list va2;
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int r;
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va_copy(va2, va);
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r = vsnprintf(s, n, format, va2);
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va_end(va2);
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if (r == -1)
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r = _vscprintf(format, va);
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return r;
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}
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#define vsnprintf vsnprintf_fixed
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#endif
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#define av_bprint_room(buf) ((buf)->size - FFMIN((buf)->len, (buf)->size))
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#define av_bprint_is_allocated(buf) ((buf)->str != (buf)->reserved_internal_buffer)
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static int av_bprint_alloc(AVBPrint *buf, unsigned room)
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{
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char *old_str, *new_str;
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unsigned min_size, new_size;
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if (buf->size == buf->size_max)
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return AVERROR(EIO);
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if (!av_bprint_is_complete(buf))
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return AVERROR_INVALIDDATA; /* it is already truncated anyway */
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min_size = buf->len + 1 + FFMIN(UINT_MAX - buf->len - 1, room);
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new_size = buf->size > buf->size_max / 2 ? buf->size_max : buf->size * 2;
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if (new_size < min_size)
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new_size = FFMIN(buf->size_max, min_size);
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old_str = av_bprint_is_allocated(buf) ? buf->str : NULL;
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new_str = av_realloc(old_str, new_size);
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if (!new_str)
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return AVERROR(ENOMEM);
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if (!old_str)
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memcpy(new_str, buf->str, buf->len + 1);
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buf->str = new_str;
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buf->size = new_size;
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return 0;
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}
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static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
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{
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/* arbitrary margin to avoid small overflows */
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extra_len = FFMIN(extra_len, UINT_MAX - 5 - buf->len);
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buf->len += extra_len;
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if (buf->size)
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buf->str[FFMIN(buf->len, buf->size - 1)] = 0;
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}
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void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
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{
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unsigned size_auto = (char *)buf + sizeof(*buf) -
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buf->reserved_internal_buffer;
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if (size_max == 1)
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size_max = size_auto;
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buf->str = buf->reserved_internal_buffer;
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buf->len = 0;
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buf->size = FFMIN(size_auto, size_max);
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buf->size_max = size_max;
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*buf->str = 0;
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if (size_init > buf->size)
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av_bprint_alloc(buf, size_init - 1);
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}
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void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
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{
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buf->str = buffer;
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buf->len = 0;
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buf->size = size;
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buf->size_max = size;
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*buf->str = 0;
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}
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void av_bprintf(AVBPrint *buf, const char *fmt, ...)
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{
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unsigned room;
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char *dst;
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va_list vl;
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int extra_len;
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while (1) {
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room = av_bprint_room(buf);
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dst = room ? buf->str + buf->len : NULL;
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va_start(vl, fmt);
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extra_len = vsnprintf(dst, room, fmt, vl);
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va_end(vl);
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if (extra_len <= 0)
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return;
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if (extra_len < room)
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break;
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if (av_bprint_alloc(buf, extra_len))
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break;
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}
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av_bprint_grow(buf, extra_len);
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}
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void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
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{
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unsigned room, real_n;
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while (1) {
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room = av_bprint_room(buf);
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if (n < room)
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break;
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if (av_bprint_alloc(buf, n))
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break;
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}
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if (room) {
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real_n = FFMIN(n, room - 1);
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memset(buf->str + buf->len, c, real_n);
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}
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av_bprint_grow(buf, n);
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}
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void av_bprint_clear(AVBPrint *buf)
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{
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if (buf->len) {
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*buf->str = 0;
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buf->len = 0;
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}
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}
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int av_bprint_finalize(AVBPrint *buf, char **ret_str)
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{
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unsigned real_size = FFMIN(buf->len + 1, buf->size);
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char *str;
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int ret = 0;
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if (ret_str) {
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if (av_bprint_is_allocated(buf)) {
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str = av_realloc(buf->str, real_size);
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if (!str)
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str = buf->str;
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buf->str = NULL;
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} else {
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str = av_malloc(real_size);
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if (str)
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memcpy(str, buf->str, real_size);
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else
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ret = AVERROR(ENOMEM);
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}
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*ret_str = str;
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} else {
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if (av_bprint_is_allocated(buf))
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av_freep(&buf->str);
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}
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buf->size = real_size;
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return ret;
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}
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#ifdef TEST
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#undef printf
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static void bprint_pascal(AVBPrint *b, unsigned size)
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{
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unsigned p[size + 1], i, j;
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p[0] = 1;
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av_bprintf(b, "%8d\n", 1);
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for (i = 1; i <= size; i++) {
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p[i] = 1;
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for (j = i - 1; j > 0; j--)
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p[j] = p[j] + p[j - 1];
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for (j = 0; j <= i; j++)
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av_bprintf(b, "%8d", p[j]);
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av_bprintf(b, "\n");
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}
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}
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int main(void)
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{
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AVBPrint b;
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char buf[256];
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av_bprint_init(&b, 0, -1);
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bprint_pascal(&b, 5);
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printf("Short text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
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printf("%s\n", b.str);
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av_bprint_finalize(&b, NULL);
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av_bprint_init(&b, 0, -1);
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bprint_pascal(&b, 25);
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printf("Long text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
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av_bprint_finalize(&b, NULL);
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av_bprint_init(&b, 0, 2048);
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bprint_pascal(&b, 25);
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printf("Long text in limited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
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av_bprint_finalize(&b, NULL);
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av_bprint_init(&b, 0, 1);
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bprint_pascal(&b, 5);
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printf("Short text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
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av_bprint_init(&b, 0, 1);
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bprint_pascal(&b, 25);
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printf("Long text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str)/8*8, b.len);
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/* Note that the size of the automatic buffer is arch-dependant. */
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av_bprint_init(&b, 0, 0);
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bprint_pascal(&b, 25);
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printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
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av_bprint_init_for_buffer(&b, buf, sizeof(buf));
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bprint_pascal(&b, 25);
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printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(buf), b.len);
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return 0;
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}
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#endif
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