add some string functions

Originally committed as revision 9400 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/Makefile

@@ -15,10 +15,11 @@ OBJS= mathematics.o \
       random.o \
       aes.o \
       base64.o \
+      string.o \
 
 HEADERS = avutil.h common.h mathematics.h integer.h rational.h \
           intfloat_readwrite.h md5.h adler32.h log.h fifo.h lzo.h \
-          random.h mem.h base64.h
+          random.h mem.h base64.h avstring.h
 
 NAME=avutil
 LIBVERSION=$(LAVUVERSION)

libavutil/avstring.h

+/*
+ * Copyright (c) 2007 Mans Rullgard
+ *
+ * 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 AVUTIL_STRING_H
+#define AVUTIL_STRING_H
+
+#include <stddef.h>
+
+/**
+ * Return non-zero if pfx is a prefix of str. If it is, *ptr is set to
+ * the address of the first character in str after the prefix.
+ *
+ * @param str input string
+ * @param pfx prefix to test
+ * @param ptr updated after the prefix in str in there is a match
+ * @return non-zero if the prefix matches, zero otherwise
+ */
+int av_strstart(const char *str, const char *pfx, const char **ptr);
+
+/**
+ * Return non-zero if pfx is a prefix of str independent of case. If
+ * it is, *ptr is set to the address of the first character in str
+ * after the prefix.
+ *
+ * @param str input string
+ * @param pfx prefix to test
+ * @param ptr updated after the prefix in str in there is a match
+ * @return non-zero if the prefix matches, zero otherwise
+ */
+int av_stristart(const char *str, const char *pfx, const char **ptr);
+
+/**
+ * Copy the string src to dst, but no more than size - 1 bytes, and
+ * null terminate dst.
+ *
+ * This function is the same as BSD strlcpy().
+ *
+ * @param dst destination buffer
+ * @param src source string
+ * @param size size of destination buffer
+ * @return the length of src
+ */
+size_t av_strlcpy(char *dst, const char *src, size_t size);
+
+/**
+ * Append the string src to the string dst, but to a total length of
+ * no more than size - 1 bytes, and null terminate dst.
+ *
+ * This function is similar to BSD strlcat(), but differs when
+ * size <= strlen(dst).
+ *
+ * @param dst destination buffer
+ * @param src source string
+ * @param size size of destination buffer
+ * @return the total length of src and dst
+ */
+size_t av_strlcat(char *dst, const char *src, size_t size);
+
+#endif /* AVUTIL_STRING_H */

libavutil/string.c

+/*
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
+ * Copyright (c) 2007 Mans Rullgard
+ *
+ * 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 <string.h>
+#include <ctype.h>
+#include "avstring.h"
+
+int av_strstart(const char *str, const char *pfx, const char **ptr)
+{
+    while (*pfx && *pfx++ == *str++);
+    if (!*pfx && ptr)
+        *ptr = str;
+    return !*pfx;
+}
+
+int av_stristart(const char *str, const char *pfx, const char **ptr)
+{
+    while (*pfx && toupper((unsigned)*pfx++) == toupper((unsigned)*str++));
+    if (!*pfx && ptr)
+        *ptr = str;
+    return !*pfx;
+}
+
+size_t av_strlcpy(char *dst, const char *src, size_t size)
+{
+    size_t len = 0;
+    while (++len < size && *src)
+        *dst++ = *src++;
+    if (len <= size)
+        *dst = 0;
+    return len + strlen(src) - 1;
+}
+
+size_t av_strlcat(char *dst, const char *src, size_t size)
+{
+    size_t len = strlen(dst);
+    if (size <= len + 1)
+        return len + strlen(src);
+    return len + av_strlcpy(dst + len, src, size - len);
+}