/* * 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 <time.h> #include "avassert.h" #include "avstring.h" #include "bprint.h" #include "common.h" #include "compat/va_copy.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_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg) { unsigned room; char *dst; int extra_len; va_list vl; while (1) { room = av_bprint_room(buf); dst = room ? buf->str + buf->len : NULL; va_copy(vl, vl_arg); 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_append_data(AVBPrint *buf, const char *data, unsigned size) { unsigned room, real_n; while (1) { room = av_bprint_room(buf); if (size < room) break; if (av_bprint_alloc(buf, size)) break; } if (room) { real_n = FFMIN(size, room - 1); memcpy(buf->str + buf->len, data, real_n); } av_bprint_grow(buf, size); } void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm) { unsigned room; size_t l; if (!*fmt) return; while (1) { room = av_bprint_room(buf); if (room && (l = strftime(buf->str + buf->len, room, fmt, tm))) break; /* strftime does not tell us how much room it would need: let us retry with twice as much until the buffer is large enough */ room = !room ? strlen(fmt) + 1 : room <= INT_MAX / 2 ? room * 2 : INT_MAX; if (av_bprint_alloc(buf, room)) { /* impossible to grow, try to manage something useful anyway */ room = av_bprint_room(buf); if (room < 1024) { /* if strftime fails because the buffer has (almost) reached its maximum size, let us try in a local buffer; 1k should be enough to format any real date+time string */ char buf2[1024]; if ((l = strftime(buf2, sizeof(buf2), fmt, tm))) { av_bprintf(buf, "%s", buf2); return; } } if (room) { /* if anything else failed and the buffer is not already truncated, let us add a stock string and force truncation */ static const char txt[] = "[truncated strftime output]"; memset(buf->str + buf->len, '!', room); memcpy(buf->str + buf->len, txt, FFMIN(sizeof(txt) - 1, room)); av_bprint_grow(buf, room); /* force truncation */ } return; } } av_bprint_grow(buf, l); } void av_bprint_get_buffer(AVBPrint *buf, unsigned size, unsigned char **mem, unsigned *actual_size) { if (size > av_bprint_room(buf)) av_bprint_alloc(buf, size); *actual_size = av_bprint_room(buf); *mem = *actual_size ? buf->str + buf->len : NULL; } 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; } #define WHITESPACES " \n\t" void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars, enum AVEscapeMode mode, int flags) { const char *src0 = src; if (mode == AV_ESCAPE_MODE_AUTO) mode = AV_ESCAPE_MODE_BACKSLASH; /* TODO: implement a heuristic */ switch (mode) { case AV_ESCAPE_MODE_QUOTE: /* enclose the string between '' */ av_bprint_chars(dstbuf, '\'', 1); for (; *src; src++) { if (*src == '\'') av_bprintf(dstbuf, "'\\''"); else av_bprint_chars(dstbuf, *src, 1); } av_bprint_chars(dstbuf, '\'', 1); break; /* case AV_ESCAPE_MODE_BACKSLASH or unknown mode */ default: /* \-escape characters */ for (; *src; src++) { int is_first_last = src == src0 || !*(src+1); int is_ws = !!strchr(WHITESPACES, *src); int is_strictly_special = special_chars && strchr(special_chars, *src); int is_special = is_strictly_special || strchr("'\\", *src) || (is_ws && (flags & AV_ESCAPE_FLAG_WHITESPACE)); if (is_strictly_special || (!(flags & AV_ESCAPE_FLAG_STRICT) && (is_special || (is_ws && is_first_last)))) av_bprint_chars(dstbuf, '\\', 1); av_bprint_chars(dstbuf, *src, 1); } break; } } #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]; struct tm testtime = { .tm_year = 100, .tm_mon = 11, .tm_mday = 20 }; 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-dependent. */ 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); av_bprint_init(&b, 0, -1); av_bprint_strftime(&b, "%Y-%m-%d", &testtime); printf("strftime full: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str); av_bprint_finalize(&b, NULL); av_bprint_init(&b, 0, 8); av_bprint_strftime(&b, "%Y-%m-%d", &testtime); printf("strftime truncated: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str); return 0; } #endif