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

Signed-off-by: Martin Storsjö <martin@martin.st>

compat/msvcrt/snprintf.c

+/*
+ * C99-compatible snprintf() and vsnprintf() implementations
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <limits.h>
+#include <string.h>
+
+#include "libavutil/error.h"
+
+int avpriv_snprintf(char *s, size_t n, const char *fmt, ...)
+{
+    va_list ap;
+    int ret;
+
+    va_start(ap, fmt);
+    ret = avpriv_vsnprintf(s, n, fmt, ap);
+    va_end(ap);
+
+    return ret;
+}
+
+int avpriv_vsnprintf(char *s, size_t n, const char *fmt,
+                     va_list ap)
+{
+    int ret;
+
+    if (n == 0)
+        return 0;
+    else if (n > INT_MAX)
+        return AVERROR(EOVERFLOW);
+
+    /* 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/strtod.c

+/*
+ * C99-compatible strtod() implementation
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; 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 <stdlib.h>
+
+#include "libavutil/avstring.h"
+#include "libavutil/mathematics.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 strtod(const char *, char **);
+
+double avpriv_strtod(const char *nptr, char **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;
+}

configure

@@ -1183,6 +1183,7 @@ HAVE_LIST="
     mkstemp
     mm_empty
     mmap
+    msvcrt
     nanosleep
     poll_h
     posix_memalign
@@ -2808,6 +2809,12 @@ elif check_header _mingw.h; then
         die "ERROR: MinGW runtime version must be >= 3.15."
 elif check_cpp_condition newlib.h "defined _NEWLIB_VERSION"; then
     libc_type=newlib
+elif check_func_headers stdlib.h _get_doserrno; then
+    libc_type=msvcrt
+    add_cflags -Dstrtod=avpriv_strtod
+    add_cflags -Dsnprintf=avpriv_snprintf   \
+               -D_snprintf=avpriv_snprintf  \
+               -Dvsnprintf=avpriv_vsnprintf
 elif check_cpp_condition stddef.h "defined __KLIBC__"; then
     libc_type=klibc
 fi

libavutil/Makefile

@@ -87,6 +87,9 @@ OBJS = adler32.o                                                        \
        utils.o                                                          \
        xtea.o                                                           \
 
+OBJS-$(HAVE_MSVCRT) += ../compat/msvcrt/snprintf.o                      \
+                       ../compat/strtod.o
+
 TESTPROGS = adler32                                                     \
             aes                                                         \
             avstring                                                    \