lavu: add snprintf(), vsnprint() and strtod() replacements for MS runtime.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

compat/snprintf.c

+/*
+ * C99-compatible snprintf() and vsnprintf() implementations
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * 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 <limits.h>
+#include <string.h>
+
+#include "libavutil/error.h"
+#include "snprintf.h"
+
+#undef snprintf
+int avpriv_snprintf(char *restrict s, size_t n, const char *restrict fmt, ...)
+{
+    va_list ap;
+    int ret;
+
+    va_start(ap, fmt);
+    ret = avpriv_vsnprintf(s, n, fmt, ap);
+    va_end(ap);
+
+    return ret;
+}
+
+#undef vsnprintf
+int avpriv_vsnprintf(char *restrict s, size_t n, const char *restrict fmt,
+                     va_list ap)
+{
+    int ret;
+
+    if (n == 0)
+        return 0;
+    else if (n > INT_MAX)
+        return AVERROR(EINVAL);
+
+    /* we use n - 1 here because if the buffer is not big enough, the MS
+     * runtime libraries don't add a terminating zero at the end. MSDN
+     * recommends to provide _snprintf/_vsnprintf() a buffer size that
+     * is one less than the actual buffer, and zero it before calling
+     * _snprintf/_vsnprintf() to workaround this problem.
+     * See http://msdn.microsoft.com/en-us/library/1kt27hek(v=vs.80).aspx */
+    memset(s, 0, n);
+    ret = vsnprintf(s, n - 1, fmt, ap);
+    if (ret == -1)
+        ret = n;
+
+    return ret;
+}

compat/snprintf.h

+/*
+ * C99-compatible snprintf() and vsnprintf() implementations
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * 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
+ */
+
+#ifndef AVCOMPAT_SNPRINTF_H
+#define AVCOMPAT_SNPRINTF_H
+
+#include <stdarg.h>
+#include <stdio.h>
+
+/*
+ * snprintf() on MSVCRT returns -1 (instead of required buffer length)
+ * if the input buffer isn't big enough. Also, if the required buffer
+ * length is exactly identical to the input buffer size, or if the
+ * return value is -1 because the input buffer isn't big enough, MSVCRT
+ * will fail to NULL-terminate the output buffer. vsnprintf() has the
+ * same issue.
+ *
+ * Thus, provide our own fallback wrappers with correct behaviour.
+ */
+#undef snprintf
+#define snprintf avpriv_snprintf
+int snprintf(char *restrict s, size_t n, const char *restrict format, ...);
+
+#undef vsnprintf
+#define vsnprintf avpriv_vsnprintf
+int vsnprintf(char *restrict s, size_t n, const char *restrict format, va_list ap);
+
+#endif /* AVCOMPAT_SNPRINTF_H */

compat/strtod.c

+/*
+ * C99-compatible strtod() implementation
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * 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 <ctype.h>
+#include <limits.h>
+
+#include "libavutil/avstring.h"
+#include "libavutil/mathematics.h"
+#include "strtod.h"
+
+static char *check_nan_suffix(char *s)
+{
+    char *start = s;
+
+    if (*s++ != '(')
+        return start;
+
+    while ((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
+           (*s >= '0' && *s <= '9') ||  *s == '_')
+        s++;
+
+    return *s == ')' ? s + 1 : start;
+}
+
+#undef strtod
+double avpriv_strtod(char *restrict nptr, char **restrict endptr)
+{
+    char *end;
+    double res;
+
+    /* Skip leading spaces */
+    while (isspace(*nptr))
+        nptr++;
+
+    if (!av_strncasecmp(nptr, "infinity", 8)) {
+        end = nptr + 8;
+        res = INFINITY;
+    } else if (!av_strncasecmp(nptr, "inf", 3)) {
+        end = nptr + 3;
+        res = INFINITY;
+    } else if (!av_strncasecmp(nptr, "+infinity", 9)) {
+        end = nptr + 9;
+        res = INFINITY;
+    } else if (!av_strncasecmp(nptr, "+inf", 4)) {
+        end = nptr + 4;
+        res = INFINITY;
+    } else if (!av_strncasecmp(nptr, "-infinity", 9)) {
+        end = nptr + 9;
+        res = -INFINITY;
+    } else if (!av_strncasecmp(nptr, "-inf", 4)) {
+        end = nptr + 4;
+        res = -INFINITY;
+    } else if (!av_strncasecmp(nptr, "nan", 3)) {
+        end = check_nan_suffix(nptr + 3);
+        res = NAN;
+    } else if (!av_strncasecmp(nptr, "+nan", 4) ||
+               !av_strncasecmp(nptr, "-nan", 4)) {
+        end = check_nan_suffix(nptr + 4);
+        res = NAN;
+    } else if (!av_strncasecmp(nptr, "0x", 2) ||
+               !av_strncasecmp(nptr, "-0x", 3) ||
+               !av_strncasecmp(nptr, "+0x", 3)) {
+        /* FIXME this doesn't handle exponents, non-integers (float/double)
+         * and numbers too large for long long */
+        res = strtoll(nptr, &end, 16);
+    } else {
+        res = strtod(nptr, &end);
+    }
+
+    if (endptr)
+        *endptr = end;
+
+    return res;
+}

compat/strtod.h

+/*
+ * C99-compatible strtod() implementation
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * 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
+ */
+
+#ifndef AVCOMPAT_STRTOD_H
+#define AVCOMPAT_STRTOD_H
+
+#include <stdlib.h>
+
+/*
+ * strtod() on MSVCRT doesn't handle strings like 'inf' or 'nan'. Also,
+ * it doesn't handle "0x" prefixes for hexadecimal input.
+ *
+ * Thus, provide our own fallback wrapper with correct behaviour.
+ */
+#undef strtod
+#define strtod avpriv_strtod
+double strtod(char *restrict nptr, char **restrict endptr);
+
+#endif /* AVCOMPAT_STRTOD_H */

configure

@@ -1043,6 +1043,11 @@ cp_if_changed(){
     cp -f "$1" "$2"
 }
 
+force_include(){
+    flag=$(eval printf '%s%s\\n' '$FORCE_INC' $1)
+    append CFLAGS "$flag"
+}
+
 # CONFIG_LIST contains configurable options, while HAVE_LIST is for
 # system-dependent things.
 
@@ -1240,6 +1245,7 @@ HAVE_LIST="
     asm_types_h
     attribute_may_alias
     attribute_packed
+    broken_strtod
     cbrtf
     clock_gettime
     closesocket
@@ -1326,6 +1332,7 @@ HAVE_LIST="
     setrlimit
     Sleep
     sndio_h
+    snprintf
     socklen_t
     soundcard_h
     strerror_r
@@ -2038,6 +2045,7 @@ CC_O='-o $@'
 CXX_C='-c'
 CXX_O='-o $@'
 LD_O='-o $@'
+FORCE_INC="-include"
 HOSTCC_C='-c'
 HOSTCC_O='-o $@'
 
@@ -3358,6 +3366,7 @@ check_func  mmap
 check_func  ${malloc_prefix}posix_memalign      && enable posix_memalign
 check_func_headers malloc.h _aligned_malloc     && enable aligned_malloc
 check_func  setrlimit
+check_func  snprintf
 check_func  strerror_r
 check_func  strptime
 check_func  sched_getaffinity
@@ -3378,6 +3387,15 @@ check_func_headers windows.h Sleep
 check_func_headers windows.h VirtualAlloc
 check_func_headers glob.h glob
 
+# Check for MSVCRT; it has a broken strtod() that can't parse some input.
+# Use old dos symbol to detect it. If we are on mingw, it already provides
+# its own replacement and we don't need to redo that.
+if check_func _get_doserrno; then
+    if test $target_os != mingw32; then
+        enable broken_strtod
+    fi
+fi
+
 check_header dlfcn.h
 check_header dxva.h
 check_header dxva2api.h -D_WIN32_WINNT=0x0600
@@ -3749,6 +3767,14 @@ elif enabled pathscale; then
     add_cflags -fstrict-overflow -OPT:wrap_around_unsafe_opt=OFF
 fi
 
+# If a missing snprintf/broken strtod is detected, force-include headers
+# that override prototypes and define it to a prefixed one implemented in
+# libavutil. We do this at the end since -I flags aren't set in configure,
+# and any additional check_cflags() beyond here will thus fail (because
+# it can't find these files, because the -I$(srcdir) wasn't set).
+enabled snprintf || force_include compat/snprintf.h
+enabled broken_strtod && force_include compat/strtod.h
+
 enabled_any $THREADS_LIST      && enable threads
 
 check_deps $CONFIG_LIST       \

libavutil/Makefile

@@ -94,6 +94,9 @@ OBJS = adler32.o                                                        \
        utils.o                                                          \
        xtea.o                                                           \
 
+OBJS-$(!HAVE_SNPRINTF) += ../compat/snprintf.o
+OBJS-$(HAVE_BROKEN_STRTOD) += ../compat/strtod.o
+
 TESTPROGS = adler32                                                     \
             aes                                                         \
             avstring                                                    \