yading@11: /*
yading@11:  * Copyright (c) 2012 Nicolas George
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include <stdarg.h>
yading@11: #include <stdio.h>
yading@11: #include <string.h>
yading@11: #include <time.h>
yading@11: #include "avassert.h"
yading@11: #include "avstring.h"
yading@11: #include "bprint.h"
yading@11: #include "common.h"
yading@11: #include "error.h"
yading@11: #include "mem.h"
yading@11: 
yading@11: #define av_bprint_room(buf) ((buf)->size - FFMIN((buf)->len, (buf)->size))
yading@11: #define av_bprint_is_allocated(buf) ((buf)->str != (buf)->reserved_internal_buffer)
yading@11: 
yading@11: static int av_bprint_alloc(AVBPrint *buf, unsigned room)
yading@11: {
yading@11:     char *old_str, *new_str;
yading@11:     unsigned min_size, new_size;
yading@11: 
yading@11:     if (buf->size == buf->size_max)
yading@11:         return AVERROR(EIO);
yading@11:     if (!av_bprint_is_complete(buf))
yading@11:         return AVERROR_INVALIDDATA; /* it is already truncated anyway */
yading@11:     min_size = buf->len + 1 + FFMIN(UINT_MAX - buf->len - 1, room);
yading@11:     new_size = buf->size > buf->size_max / 2 ? buf->size_max : buf->size * 2;
yading@11:     if (new_size < min_size)
yading@11:         new_size = FFMIN(buf->size_max, min_size);
yading@11:     old_str = av_bprint_is_allocated(buf) ? buf->str : NULL;
yading@11:     new_str = av_realloc(old_str, new_size);
yading@11:     if (!new_str)
yading@11:         return AVERROR(ENOMEM);
yading@11:     if (!old_str)
yading@11:         memcpy(new_str, buf->str, buf->len + 1);
yading@11:     buf->str  = new_str;
yading@11:     buf->size = new_size;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
yading@11: {
yading@11:     /* arbitrary margin to avoid small overflows */
yading@11:     extra_len = FFMIN(extra_len, UINT_MAX - 5 - buf->len);
yading@11:     buf->len += extra_len;
yading@11:     if (buf->size)
yading@11:         buf->str[FFMIN(buf->len, buf->size - 1)] = 0;
yading@11: }
yading@11: 
yading@11: void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
yading@11: {
yading@11:     unsigned size_auto = (char *)buf + sizeof(*buf) -
yading@11:                          buf->reserved_internal_buffer;
yading@11: 
yading@11:     if (size_max == 1)
yading@11:         size_max = size_auto;
yading@11:     buf->str      = buf->reserved_internal_buffer;
yading@11:     buf->len      = 0;
yading@11:     buf->size     = FFMIN(size_auto, size_max);
yading@11:     buf->size_max = size_max;
yading@11:     *buf->str = 0;
yading@11:     if (size_init > buf->size)
yading@11:         av_bprint_alloc(buf, size_init - 1);
yading@11: }
yading@11: 
yading@11: void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
yading@11: {
yading@11:     buf->str      = buffer;
yading@11:     buf->len      = 0;
yading@11:     buf->size     = size;
yading@11:     buf->size_max = size;
yading@11:     *buf->str = 0;
yading@11: }
yading@11: 
yading@11: void av_bprintf(AVBPrint *buf, const char *fmt, ...)
yading@11: {
yading@11:     unsigned room;
yading@11:     char *dst;
yading@11:     va_list vl;
yading@11:     int extra_len;
yading@11: 
yading@11:     while (1) {
yading@11:         room = av_bprint_room(buf);
yading@11:         dst = room ? buf->str + buf->len : NULL;
yading@11:         va_start(vl, fmt);
yading@11:         extra_len = vsnprintf(dst, room, fmt, vl);
yading@11:         va_end(vl);
yading@11:         if (extra_len <= 0)
yading@11:             return;
yading@11:         if (extra_len < room)
yading@11:             break;
yading@11:         if (av_bprint_alloc(buf, extra_len))
yading@11:             break;
yading@11:     }
yading@11:     av_bprint_grow(buf, extra_len);
yading@11: }
yading@11: 
yading@11: void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
yading@11: {
yading@11:     unsigned room, real_n;
yading@11: 
yading@11:     while (1) {
yading@11:         room = av_bprint_room(buf);
yading@11:         if (n < room)
yading@11:             break;
yading@11:         if (av_bprint_alloc(buf, n))
yading@11:             break;
yading@11:     }
yading@11:     if (room) {
yading@11:         real_n = FFMIN(n, room - 1);
yading@11:         memset(buf->str + buf->len, c, real_n);
yading@11:     }
yading@11:     av_bprint_grow(buf, n);
yading@11: }
yading@11: 
yading@11: void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm)
yading@11: {
yading@11:     unsigned room;
yading@11:     size_t l;
yading@11: 
yading@11:     if (!*fmt)
yading@11:         return;
yading@11:     while (1) {
yading@11:         room = av_bprint_room(buf);
yading@11:         if (room && (l = strftime(buf->str + buf->len, room, fmt, tm)))
yading@11:             break;
yading@11:         /* strftime does not tell us how much room it would need: let us
yading@11:            retry with twice as much until the buffer is large enough */
yading@11:         room = !room ? strlen(fmt) + 1 :
yading@11:                room <= INT_MAX / 2 ? room * 2 : INT_MAX;
yading@11:         if (av_bprint_alloc(buf, room)) {
yading@11:             /* impossible to grow, try to manage something useful anyway */
yading@11:             room = av_bprint_room(buf);
yading@11:             if (room < 1024) {
yading@11:                 /* if strftime fails because the buffer has (almost) reached
yading@11:                    its maximum size, let us try in a local buffer; 1k should
yading@11:                    be enough to format any real date+time string */
yading@11:                 char buf2[1024];
yading@11:                 if ((l = strftime(buf2, sizeof(buf2), fmt, tm))) {
yading@11:                     av_bprintf(buf, "%s", buf2);
yading@11:                     return;
yading@11:                 }
yading@11:             }
yading@11:             if (room) {
yading@11:                 /* if anything else failed and the buffer is not already
yading@11:                    truncated, let us add a stock string and force truncation */
yading@11:                 static const char txt[] = "[truncated strftime output]";
yading@11:                 memset(buf->str + buf->len, '!', room);
yading@11:                 memcpy(buf->str + buf->len, txt, FFMIN(sizeof(txt) - 1, room));
yading@11:                 av_bprint_grow(buf, room); /* force truncation */
yading@11:             }
yading@11:             return;
yading@11:         }
yading@11:     }
yading@11:     av_bprint_grow(buf, l);
yading@11: }
yading@11: 
yading@11: void av_bprint_get_buffer(AVBPrint *buf, unsigned size,
yading@11:                           unsigned char **mem, unsigned *actual_size)
yading@11: {
yading@11:     if (size > av_bprint_room(buf))
yading@11:         av_bprint_alloc(buf, size);
yading@11:     *actual_size = av_bprint_room(buf);
yading@11:     *mem = *actual_size ? buf->str + buf->len : NULL;
yading@11: }
yading@11: 
yading@11: void av_bprint_clear(AVBPrint *buf)
yading@11: {
yading@11:     if (buf->len) {
yading@11:         *buf->str = 0;
yading@11:         buf->len  = 0;
yading@11:     }
yading@11: }
yading@11: 
yading@11: int av_bprint_finalize(AVBPrint *buf, char **ret_str)
yading@11: {
yading@11:     unsigned real_size = FFMIN(buf->len + 1, buf->size);
yading@11:     char *str;
yading@11:     int ret = 0;
yading@11: 
yading@11:     if (ret_str) {
yading@11:         if (av_bprint_is_allocated(buf)) {
yading@11:             str = av_realloc(buf->str, real_size);
yading@11:             if (!str)
yading@11:                 str = buf->str;
yading@11:             buf->str = NULL;
yading@11:         } else {
yading@11:             str = av_malloc(real_size);
yading@11:             if (str)
yading@11:                 memcpy(str, buf->str, real_size);
yading@11:             else
yading@11:                 ret = AVERROR(ENOMEM);
yading@11:         }
yading@11:         *ret_str = str;
yading@11:     } else {
yading@11:         if (av_bprint_is_allocated(buf))
yading@11:             av_freep(&buf->str);
yading@11:     }
yading@11:     buf->size = real_size;
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: #define WHITESPACES " \n\t"
yading@11: 
yading@11: void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
yading@11:                       enum AVEscapeMode mode, int flags)
yading@11: {
yading@11:     const char *src0 = src;
yading@11: 
yading@11:     if (mode == AV_ESCAPE_MODE_AUTO)
yading@11:         mode = AV_ESCAPE_MODE_BACKSLASH; /* TODO: implement a heuristic */
yading@11: 
yading@11:     switch (mode) {
yading@11:     case AV_ESCAPE_MODE_QUOTE:
yading@11:         /* enclose the string between '' */
yading@11:         av_bprint_chars(dstbuf, '\'', 1);
yading@11:         for (; *src; src++) {
yading@11:             if (*src == '\'')
yading@11:                 av_bprintf(dstbuf, "'\\''");
yading@11:             else
yading@11:                 av_bprint_chars(dstbuf, *src, 1);
yading@11:         }
yading@11:         av_bprint_chars(dstbuf, '\'', 1);
yading@11:         break;
yading@11: 
yading@11:     /* case AV_ESCAPE_MODE_BACKSLASH or unknown mode */
yading@11:     default:
yading@11:         /* \-escape characters */
yading@11:         for (; *src; src++) {
yading@11:             int is_first_last       = src == src0 || !*(src+1);
yading@11:             int is_ws               = !!strchr(WHITESPACES, *src);
yading@11:             int is_strictly_special = special_chars && strchr(special_chars, *src);
yading@11:             int is_special          =
yading@11:                 is_strictly_special || strchr("'\\", *src) ||
yading@11:                 (is_ws && (flags & AV_ESCAPE_FLAG_WHITESPACE));
yading@11: 
yading@11:             if (is_strictly_special ||
yading@11:                 (!(flags & AV_ESCAPE_FLAG_STRICT) &&
yading@11:                  (is_special || (is_ws && is_first_last))))
yading@11:                 av_bprint_chars(dstbuf, '\\', 1);
yading@11:             av_bprint_chars(dstbuf, *src, 1);
yading@11:         }
yading@11:         break;
yading@11:     }
yading@11: }
yading@11: 
yading@11: #ifdef TEST
yading@11: 
yading@11: #undef printf
yading@11: 
yading@11: static void bprint_pascal(AVBPrint *b, unsigned size)
yading@11: {
yading@11:     unsigned i, j;
yading@11:     unsigned p[42];
yading@11: 
yading@11:     av_assert0(size < FF_ARRAY_ELEMS(p));
yading@11: 
yading@11:     p[0] = 1;
yading@11:     av_bprintf(b, "%8d\n", 1);
yading@11:     for (i = 1; i <= size; i++) {
yading@11:         p[i] = 1;
yading@11:         for (j = i - 1; j > 0; j--)
yading@11:             p[j] = p[j] + p[j - 1];
yading@11:         for (j = 0; j <= i; j++)
yading@11:             av_bprintf(b, "%8d", p[j]);
yading@11:         av_bprintf(b, "\n");
yading@11:     }
yading@11: }
yading@11: 
yading@11: int main(void)
yading@11: {
yading@11:     AVBPrint b;
yading@11:     char buf[256];
yading@11:     struct tm testtime = { .tm_year = 100, .tm_mon = 11, .tm_mday = 20 };
yading@11: 
yading@11:     av_bprint_init(&b, 0, -1);
yading@11:     bprint_pascal(&b, 5);
yading@11:     printf("Short text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
yading@11:     printf("%s\n", b.str);
yading@11:     av_bprint_finalize(&b, NULL);
yading@11: 
yading@11:     av_bprint_init(&b, 0, -1);
yading@11:     bprint_pascal(&b, 25);
yading@11:     printf("Long text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
yading@11:     av_bprint_finalize(&b, NULL);
yading@11: 
yading@11:     av_bprint_init(&b, 0, 2048);
yading@11:     bprint_pascal(&b, 25);
yading@11:     printf("Long text in limited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
yading@11:     av_bprint_finalize(&b, NULL);
yading@11: 
yading@11:     av_bprint_init(&b, 0, 1);
yading@11:     bprint_pascal(&b, 5);
yading@11:     printf("Short text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
yading@11: 
yading@11:     av_bprint_init(&b, 0, 1);
yading@11:     bprint_pascal(&b, 25);
yading@11:     printf("Long text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str)/8*8, b.len);
yading@11:     /* Note that the size of the automatic buffer is arch-dependant. */
yading@11: 
yading@11:     av_bprint_init(&b, 0, 0);
yading@11:     bprint_pascal(&b, 25);
yading@11:     printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
yading@11: 
yading@11:     av_bprint_init_for_buffer(&b, buf, sizeof(buf));
yading@11:     bprint_pascal(&b, 25);
yading@11:     printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(buf), b.len);
yading@11: 
yading@11:     av_bprint_init(&b, 0, -1);
yading@11:     av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
yading@11:     printf("strftime full: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
yading@11:     av_bprint_finalize(&b, NULL);
yading@11: 
yading@11:     av_bprint_init(&b, 0, 8);
yading@11:     av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
yading@11:     printf("strftime truncated: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: #endif