utils: add {un,}map_file to read an entire file

This wraps the current mmap call and adds a fallback implementation for
systems which do not have mmap (e.g. mingw).

Signed-off-by: Ran Benita <ran234@gmail.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..a00b04e
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright © 2013 Ran Benita <ran234@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "utils.h"
+
+#ifdef HAVE_MMAP
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+bool
+map_file(FILE *file, const char **string_out, size_t *size_out)
+{
+    struct stat stat_buf;
+    const int fd = fileno(file);
+    char *string;
+
+    /* Make sure to keep the errno on failure! */
+
+    if (fstat(fd, &stat_buf) != 0)
+        return false;
+
+    string = mmap(NULL, stat_buf.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    if (string == MAP_FAILED)
+        return false;
+
+    *string_out = string;
+    *size_out = stat_buf.st_size;
+    return true;
+}
+
+void
+unmap_file(const char *str, size_t size)
+{
+    munmap(UNCONSTIFY(str), size);
+}
+
+#else
+
+bool
+map_file(FILE *file, const char **string_out, size_t *size_out)
+{
+    long ret;
+    size_t ret_s;
+    char *string;
+    size_t size;
+
+    /* Make sure to keep the errno on failure! */
+
+    ret = fseek(file, 0, SEEK_END);
+    if (ret != 0)
+        return false;
+
+    ret = ftell(file);
+    if (ret < 0)
+        return false;
+    size = (size_t) ret;
+
+    ret = fseek(file, 0, SEEK_SET);
+    if (ret < 0)
+        return false;
+
+    string = malloc(size);
+    if (!string)
+        return false;
+
+    ret_s = fread(string, 1, size, file);
+    if (ret_s < size) {
+        free(string);
+        return false;
+    }
+
+    *string_out = string;
+    *size_out = size;
+    return true;
+}
+
+void
+unmap_file(const char *str, size_t size)
+{
+    free(UNCONSTIFY(str));
+}
+
+#endif