[PATCH] Add av_file_map() and av_file_unmap() functions.
Stefano Sabatini
stefano.sabatini-lala
Fri Nov 26 01:27:58 CET 2010
---
configure | 2 +
libavutil/Makefile | 2 +
libavutil/file.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++
libavutil/file.h | 54 ++++++++++++++++++++++++++
libavutil/mem.h | 2 +
5 files changed, 166 insertions(+), 0 deletions(-)
create mode 100644 libavutil/file.c
create mode 100644 libavutil/file.h
diff --git a/configure b/configure
index 891e040..c192d12 100755
--- a/configure
+++ b/configure
@@ -1041,6 +1041,7 @@ HAVE_LIST="
malloc_h
memalign
mkstemp
+ mmap
pld
posix_memalign
round
@@ -2671,6 +2672,7 @@ check_func inet_aton $network_extralibs
check_func isatty
check_func ${malloc_prefix}memalign && enable memalign
check_func mkstemp
+check_func mmap
check_func ${malloc_prefix}posix_memalign && enable posix_memalign
check_func setrlimit
check_func strerror_r
diff --git a/libavutil/Makefile b/libavutil/Makefile
index e9ac965..fe0302c 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -15,6 +15,7 @@ HEADERS = adler32.h \
error.h \
eval.h \
fifo.h \
+ file.h \
intfloat_readwrite.h \
intreadwrite.h \
lfg.h \
@@ -42,6 +43,7 @@ OBJS = adler32.o \
error.o \
eval.o \
fifo.o \
+ file.o \
intfloat_readwrite.o \
inverse.o \
lfg.o \
diff --git a/libavutil/file.c b/libavutil/file.c
new file mode 100644
index 0000000..6c947ea
--- /dev/null
+++ b/libavutil/file.c
@@ -0,0 +1,106 @@
+/*
+ * 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 "file.h"
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#if HAVE_MMAP
+#include <sys/mman.h>
+#endif
+
+int av_file_map(const char *filename, uint8_t **bufptr, size_t *size, int protect,
+ void *log_ctx)
+{
+ int protect2, fd = open(filename, O_RDONLY);
+ struct stat st;
+ void *ptr;
+ off_t off_size;
+ size_t max_size = HAVE_MMAP ? SIZE_MAX : FF_INTERNAL_MEM_TYPE_MAX_VALUE;
+ *bufptr = NULL;
+ if (fd < 0) {
+ av_log(log_ctx, AV_LOG_ERROR,
+ "Cannot read file '%s': %s\n", filename, strerror(errno));
+ return AVERROR(errno);
+ }
+
+ if (lstat(filename, &st) < 0) {
+ close(fd);
+ return AVERROR(errno);
+ }
+
+ off_size = st.st_size;
+ if (off_size > max_size) {
+ av_log(log_ctx, AV_LOG_ERROR,
+ "File size for file '%s' is too big\n", filename);
+ close(fd);
+ return AVERROR(EINVAL);
+ }
+ *size = off_size;
+
+#if HAVE_MMAP
+ protect2 = protect & AV_FILE_PROT_READ ? PROT_READ : 0;
+ protect2 |= protect & AV_FILE_PROT_WRITE ? PROT_WRITE: 0;
+ protect2 |= protect & AV_FILE_PROT_EXEC ? PROT_EXEC : 0;
+ ptr = mmap(NULL, *size, protect2, MAP_PRIVATE, fd, 0);
+ if ((int)(ptr) == -1) {
+ av_log(log_ctx, AV_LOG_ERROR, "Error occurred in mmap(): %s\n", strerror(errno));
+ close(fd);
+ return AVERROR(errno);
+ }
+ *bufptr = ptr;
+#else
+ *bufptr = av_malloc(*size);
+ if (!*bufptr) {
+ close(fd);
+ return AVERROR(ENOMEM);
+ }
+ read(fd, *bufptr, *size);
+#endif
+
+ return fd;
+}
+
+void av_file_unmap(int fd, uint8_t *bufptr, size_t size)
+{
+#if HAVE_MMAP
+ munmap(bufptr, size);
+#else
+ av_free(bufptr);
+#endif
+ close(fd);
+}
+
+#ifdef TEST
+
+#undef printf
+
+int main(void)
+{
+ uint8_t *buf;
+ size_t size;
+ int fd = av_file_map("file.c", &buf, &size, AV_FILE_PROT_READ|AV_FILE_PROT_WRITE, NULL);
+ if (fd < 0)
+ return 1;
+
+ buf[0] = 's';
+ printf("%s", buf);
+ av_file_unmap(fd, buf, size);
+ return 0;
+}
+#endif
diff --git a/libavutil/file.h b/libavutil/file.h
new file mode 100644
index 0000000..ed212e3
--- /dev/null
+++ b/libavutil/file.h
@@ -0,0 +1,54 @@
+/*
+ * 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_FILE_H
+#define AVUTIL_FILE_H
+
+#include "avutil.h"
+
+/**
+ * @file misc file utilities
+ */
+
+#define AV_FILE_PROT_READ 1
+#define AV_FILE_PROT_WRITE 2
+#define AV_FILE_PROT_EXEC 4
+
+/**
+ * Read the file with name filename, and put its content in a newly
+ * allocated buffer or map it with mmap() when available.
+ * In case of success set *bufptr to the read or mmapped buffer, and
+ * set *size to the size in bytes of the buffer in *bufptr.
+ *
+ * @param protect flags that control what kind of access is permitted,
+ * it can be any combination of the AV_FILE_PROT* flags, it is ignored
+ * if mmap() is not available
+ * @param log_ctx context used for logging
+ * @return the file descriptor in case of success, a negative value
+ * corresponding to an AVERROR error code in case of failure
+ */
+int av_file_map(const char *filename, uint8_t **bufptr, size_t *size, int protect,
+ void *log_ctx);
+
+/**
+ * Unmap the file with filedescriptor fd, and free the allocated or
+ * mmapped buffer in *bufptr with size size.
+ */
+void av_file_unmap(int fd, uint8_t *bufptr, size_t size);
+
+#endif /* AVUTIL_FILE_H */
diff --git a/libavutil/mem.h b/libavutil/mem.h
index 458d3ac..ab73a32 100644
--- a/libavutil/mem.h
+++ b/libavutil/mem.h
@@ -64,8 +64,10 @@
#if LIBAVUTIL_VERSION_MAJOR < 51
# define FF_INTERNAL_MEM_TYPE unsigned int
+# define FF_INTERNAL_MEM_TYPE_MAX_VALUE UINT_MAX
#else
# define FF_INTERNAL_MEM_TYPE size_t
+# define FF_INTERNAL_MEM_TYPE_MAX_VALUE SIZE_MAX
#endif
/**
--
1.7.2.3
--Dxnq1zWXvFF0Q93v--
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