/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <config.h>
#include "util.h"
+#include <assert.h>
#include <errno.h>
+#include <limits.h>
#include <stdarg.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <unistd.h>
+#include "byte-order.h"
#include "coverage.h"
+#include "openvswitch/types.h"
+#include "vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(util);
+
+COVERAGE_DEFINE(util_xalloc);
const char *program_name;
+static char *program_version;
void
-out_of_memory(void)
+out_of_memory(void)
{
- ovs_fatal(0, "virtual memory exhausted");
+ ovs_abort(0, "virtual memory exhausted");
}
void *
-xcalloc(size_t count, size_t size)
+xcalloc(size_t count, size_t size)
{
void *p = count && size ? calloc(count, size) : malloc(1);
COVERAGE_INC(util_xalloc);
}
void *
-xmalloc(size_t size)
+xzalloc(size_t size)
+{
+ return xcalloc(1, size);
+}
+
+void *
+xmalloc(size_t size)
{
void *p = malloc(size ? size : 1);
COVERAGE_INC(util_xalloc);
}
void *
-xrealloc(void *p, size_t size)
+xrealloc(void *p, size_t size)
{
p = realloc(p, size ? size : 1);
COVERAGE_INC(util_xalloc);
}
char *
-xstrdup(const char *s)
+xstrdup(const char *s)
{
return xmemdup0(s, strlen(s));
}
return s;
}
+/* Similar to strlcpy() from OpenBSD, but it never reads more than 'size - 1'
+ * bytes from 'src' and doesn't return anything. */
void
ovs_strlcpy(char *dst, const char *src, size_t size)
{
if (size > 0) {
- size_t n = strlen(src);
- size_t n_copy = MIN(n, size - 1);
- memcpy(dst, src, n_copy);
- dst[n_copy] = '\0';
+ size_t len = strnlen(src, size - 1);
+ memcpy(dst, src, len);
+ dst[len] = '\0';
}
}
+/* Copies 'src' to 'dst'. Reads no more than 'size - 1' bytes from 'src'.
+ * Always null-terminates 'dst' (if 'size' is nonzero), and writes a zero byte
+ * to every otherwise unused byte in 'dst'.
+ *
+ * Except for performance, the following call:
+ * ovs_strzcpy(dst, src, size);
+ * is equivalent to these two calls:
+ * memset(dst, '\0', size);
+ * ovs_strlcpy(dst, src, size);
+ *
+ * (Thus, ovs_strzcpy() is similar to strncpy() without some of the pitfalls.)
+ */
void
-ovs_fatal(int err_no, const char *format, ...)
+ovs_strzcpy(char *dst, const char *src, size_t size)
+{
+ if (size > 0) {
+ size_t len = strnlen(src, size - 1);
+ memcpy(dst, src, len);
+ memset(dst + len, '\0', size - len);
+ }
+}
+
+/* Prints 'format' on stderr, formatting it like printf() does. If 'err_no' is
+ * nonzero, then it is formatted with ovs_retval_to_string() and appended to
+ * the message inside parentheses. Then, terminates with abort().
+ *
+ * This function is preferred to ovs_fatal() in a situation where it would make
+ * sense for a monitoring process to restart the daemon.
+ *
+ * 'format' should not end with a new-line, because this function will add one
+ * itself. */
+void
+ovs_abort(int err_no, const char *format, ...)
{
va_list args;
- fprintf(stderr, "%s: ", program_name);
va_start(args, format);
- vfprintf(stderr, format, args);
+ ovs_error_valist(err_no, format, args);
va_end(args);
- if (err_no != 0)
- fprintf(stderr, " (%s)", strerror(err_no));
- putc('\n', stderr);
+ abort();
+}
+
+/* Prints 'format' on stderr, formatting it like printf() does. If 'err_no' is
+ * nonzero, then it is formatted with ovs_retval_to_string() and appended to
+ * the message inside parentheses. Then, terminates with EXIT_FAILURE.
+ *
+ * 'format' should not end with a new-line, because this function will add one
+ * itself. */
+void
+ovs_fatal(int err_no, const char *format, ...)
+{
+ va_list args;
+
+ va_start(args, format);
+ ovs_fatal_valist(err_no, format, args);
+}
+
+/* Same as ovs_fatal() except that the arguments are supplied as a va_list. */
+void
+ovs_fatal_valist(int err_no, const char *format, va_list args)
+{
+ ovs_error_valist(err_no, format, args);
exit(EXIT_FAILURE);
}
+/* Prints 'format' on stderr, formatting it like printf() does. If 'err_no' is
+ * nonzero, then it is formatted with ovs_retval_to_string() and appended to
+ * the message inside parentheses.
+ *
+ * 'format' should not end with a new-line, because this function will add one
+ * itself. */
void
ovs_error(int err_no, const char *format, ...)
{
- int save_errno = errno;
va_list args;
- fprintf(stderr, "%s: ", program_name);
va_start(args, format);
- vfprintf(stderr, format, args);
+ ovs_error_valist(err_no, format, args);
va_end(args);
- if (err_no != 0)
- fprintf(stderr, " (%s)", strerror(err_no));
+}
+
+/* Same as ovs_error() except that the arguments are supplied as a va_list. */
+void
+ovs_error_valist(int err_no, const char *format, va_list args)
+{
+ int save_errno = errno;
+
+ fprintf(stderr, "%s: ", program_name);
+ vfprintf(stderr, format, args);
+ if (err_no != 0) {
+ fprintf(stderr, " (%s)", ovs_retval_to_string(err_no));
+ }
putc('\n', stderr);
errno = save_errno;
}
-/* Sets program_name based on 'argv0'. Should be called at the beginning of
- * main(), as "set_program_name(argv[0]);". */
-void set_program_name(const char *argv0)
+/* Many OVS functions return an int which is one of:
+ * - 0: no error yet
+ * - >0: errno value
+ * - EOF: end of file (not necessarily an error; depends on the function called)
+ *
+ * Returns the appropriate human-readable string. The caller must copy the
+ * string if it wants to hold onto it, as the storage may be overwritten on
+ * subsequent function calls.
+ */
+const char *
+ovs_retval_to_string(int retval)
+{
+ static char unknown[48];
+
+ if (!retval) {
+ return "";
+ }
+ if (retval > 0) {
+ return strerror(retval);
+ }
+ if (retval == EOF) {
+ return "End of file";
+ }
+ snprintf(unknown, sizeof unknown, "***unknown return value: %d***", retval);
+ return unknown;
+}
+
+/* Sets global "program_name" and "program_version" variables. Should
+ * be called at the beginning of main() with "argv[0]" as the argument
+ * to 'argv0'.
+ *
+ * 'version' should contain the version of the caller's program. If 'version'
+ * is the same as the VERSION #define, the caller is assumed to be part of Open
+ * vSwitch. Otherwise, it is assumed to be an external program linking against
+ * the Open vSwitch libraries.
+ *
+ * The 'date' and 'time' arguments should likely be called with
+ * "__DATE__" and "__TIME__" to use the time the binary was built.
+ * Alternatively, the "set_program_name" macro may be called to do this
+ * automatically.
+ */
+void
+set_program_name__(const char *argv0, const char *version, const char *date,
+ const char *time)
{
const char *slash = strrchr(argv0, '/');
program_name = slash ? slash + 1 : argv0;
+
+ free(program_version);
+
+ if (!strcmp(version, VERSION)) {
+ program_version = xasprintf("%s (Open vSwitch) "VERSION"\n"
+ "Compiled %s %s\n",
+ program_name, date, time);
+ } else {
+ program_version = xasprintf("%s %s\n"
+ "Open vSwitch Library "VERSION"\n"
+ "Compiled %s %s\n",
+ program_name, version, date, time);
+ }
+}
+
+/* Returns a pointer to a string describing the program version. The
+ * caller must not modify or free the returned string.
+ */
+const char *
+get_program_version(void)
+{
+ return program_version;
}
/* Print the version information for the program. */
void
-ovs_print_version(char *date, char *time,
- uint8_t min_ofp, uint8_t max_ofp)
+ovs_print_version(uint8_t min_ofp, uint8_t max_ofp)
{
- printf("%s (Open vSwitch) "VERSION BUILDNR"\n", program_name);
- printf("Compiled %s %s\n", date, time);
+ printf("%s", program_version);
if (min_ofp || max_ofp) {
printf("OpenFlow versions %#x:%#x\n", min_ofp, max_ofp);
}
{
return str_to_llong(s, base, (long long *) ull);
}
+
+/* Converts floating-point string 's' into a double. If successful, stores
+ * the double in '*d' and returns true; on failure, stores 0 in '*d' and
+ * returns false.
+ *
+ * Underflow (e.g. "1e-9999") is not considered an error, but overflow
+ * (e.g. "1e9999)" is. */
+bool
+str_to_double(const char *s, double *d)
+{
+ int save_errno = errno;
+ char *tail;
+ errno = 0;
+ *d = strtod(s, &tail);
+ if (errno == EINVAL || (errno == ERANGE && *d != 0)
+ || tail == s || *tail != '\0') {
+ errno = save_errno;
+ *d = 0;
+ return false;
+ } else {
+ errno = save_errno;
+ return true;
+ }
+}
+
+/* Returns the value of 'c' as a hexadecimal digit. */
+int
+hexit_value(int c)
+{
+ switch (c) {
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+ return c - '0';
+
+ case 'a': case 'A':
+ return 0xa;
+
+ case 'b': case 'B':
+ return 0xb;
+
+ case 'c': case 'C':
+ return 0xc;
+
+ case 'd': case 'D':
+ return 0xd;
+
+ case 'e': case 'E':
+ return 0xe;
+
+ case 'f': case 'F':
+ return 0xf;
+
+ default:
+ return -1;
+ }
+}
+
+/* Returns the integer value of the 'n' hexadecimal digits starting at 's', or
+ * UINT_MAX if one of those "digits" is not really a hex digit. If 'ok' is
+ * nonnull, '*ok' is set to true if the conversion succeeds or to false if a
+ * non-hex digit is detected. */
+unsigned int
+hexits_value(const char *s, size_t n, bool *ok)
+{
+ unsigned int value;
+ size_t i;
+
+ value = 0;
+ for (i = 0; i < n; i++) {
+ int hexit = hexit_value(s[i]);
+ if (hexit < 0) {
+ if (ok) {
+ *ok = false;
+ }
+ return UINT_MAX;
+ }
+ value = (value << 4) + hexit;
+ }
+ if (ok) {
+ *ok = true;
+ }
+ return value;
+}
+
+/* Returns the current working directory as a malloc()'d string, or a null
+ * pointer if the current working directory cannot be determined. */
+char *
+get_cwd(void)
+{
+ long int path_max;
+ size_t size;
+
+ /* Get maximum path length or at least a reasonable estimate. */
+ path_max = pathconf(".", _PC_PATH_MAX);
+ size = (path_max < 0 ? 1024
+ : path_max > 10240 ? 10240
+ : path_max);
+
+ /* Get current working directory. */
+ for (;;) {
+ char *buf = xmalloc(size);
+ if (getcwd(buf, size)) {
+ return xrealloc(buf, strlen(buf) + 1);
+ } else {
+ int error = errno;
+ free(buf);
+ if (error != ERANGE) {
+ VLOG_WARN("getcwd failed (%s)", strerror(error));
+ return NULL;
+ }
+ size *= 2;
+ }
+ }
+}
+
+static char *
+all_slashes_name(const char *s)
+{
+ return xstrdup(s[0] == '/' && s[1] == '/' && s[2] != '/' ? "//"
+ : s[0] == '/' ? "/"
+ : ".");
+}
+
+/* Returns the directory name portion of 'file_name' as a malloc()'d string,
+ * similar to the POSIX dirname() function but thread-safe. */
+char *
+dir_name(const char *file_name)
+{
+ size_t len = strlen(file_name);
+ while (len > 0 && file_name[len - 1] == '/') {
+ len--;
+ }
+ while (len > 0 && file_name[len - 1] != '/') {
+ len--;
+ }
+ while (len > 0 && file_name[len - 1] == '/') {
+ len--;
+ }
+ return len ? xmemdup0(file_name, len) : all_slashes_name(file_name);
+}
+
+/* Returns the file name portion of 'file_name' as a malloc()'d string,
+ * similar to the POSIX basename() function but thread-safe. */
+char *
+base_name(const char *file_name)
+{
+ size_t end, start;
+
+ end = strlen(file_name);
+ while (end > 0 && file_name[end - 1] == '/') {
+ end--;
+ }
+
+ if (!end) {
+ return all_slashes_name(file_name);
+ }
+
+ start = end;
+ while (start > 0 && file_name[start - 1] != '/') {
+ start--;
+ }
+
+ return xmemdup0(file_name + start, end - start);
+}
+
+/* If 'file_name' starts with '/', returns a copy of 'file_name'. Otherwise,
+ * returns an absolute path to 'file_name' considering it relative to 'dir',
+ * which itself must be absolute. 'dir' may be null or the empty string, in
+ * which case the current working directory is used.
+ *
+ * Returns a null pointer if 'dir' is null and getcwd() fails. */
+char *
+abs_file_name(const char *dir, const char *file_name)
+{
+ if (file_name[0] == '/') {
+ return xstrdup(file_name);
+ } else if (dir && dir[0]) {
+ char *separator = dir[strlen(dir) - 1] == '/' ? "" : "/";
+ return xasprintf("%s%s%s", dir, separator, file_name);
+ } else {
+ char *cwd = get_cwd();
+ if (cwd) {
+ char *abs_name = xasprintf("%s/%s", cwd, file_name);
+ free(cwd);
+ return abs_name;
+ } else {
+ return NULL;
+ }
+ }
+}
+
+
+/* Pass a value to this function if it is marked with
+ * __attribute__((warn_unused_result)) and you genuinely want to ignore
+ * its return value. (Note that every scalar type can be implicitly
+ * converted to bool.) */
+void ignore(bool x OVS_UNUSED) { }
+
+/* Returns an appropriate delimiter for inserting just before the 0-based item
+ * 'index' in a list that has 'total' items in it. */
+const char *
+english_list_delimiter(size_t index, size_t total)
+{
+ return (index == 0 ? ""
+ : index < total - 1 ? ", "
+ : total > 2 ? ", and "
+ : " and ");
+}
+
+/* Given a 32 bit word 'n', calculates floor(log_2('n')). This is equivalent
+ * to finding the bit position of the most significant one bit in 'n'. It is
+ * an error to call this function with 'n' == 0. */
+int
+log_2_floor(uint32_t n)
+{
+ assert(n);
+
+#if !defined(UINT_MAX) || !defined(UINT32_MAX)
+#error "Someone screwed up the #includes."
+#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+ return 31 - __builtin_clz(n);
+#else
+ {
+ int log = 0;
+
+#define BIN_SEARCH_STEP(BITS) \
+ if (n >= (1 << BITS)) { \
+ log += BITS; \
+ n >>= BITS; \
+ }
+ BIN_SEARCH_STEP(16);
+ BIN_SEARCH_STEP(8);
+ BIN_SEARCH_STEP(4);
+ BIN_SEARCH_STEP(2);
+ BIN_SEARCH_STEP(1);
+#undef BIN_SEARCH_STEP
+ return log;
+ }
+#endif
+}
+
+/* Given a 32 bit word 'n', calculates ceil(log_2('n')). It is an error to
+ * call this function with 'n' == 0. */
+int
+log_2_ceil(uint32_t n)
+{
+ return log_2_floor(n) + !IS_POW2(n);
+}
+
+/* Returns the number of trailing 0-bits in 'n', or 32 if 'n' is 0. */
+int
+ctz(uint32_t n)
+{
+ if (!n) {
+ return 32;
+ } else {
+#if !defined(UINT_MAX) || !defined(UINT32_MAX)
+#error "Someone screwed up the #includes."
+#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+ return __builtin_ctz(n);
+#else
+ unsigned int k;
+ int count = 31;
+
+#define CTZ_STEP(X) \
+ k = n << (X); \
+ if (k) { \
+ count -= X; \
+ n = k; \
+ }
+ CTZ_STEP(16);
+ CTZ_STEP(8);
+ CTZ_STEP(4);
+ CTZ_STEP(2);
+ CTZ_STEP(1);
+#undef CTZ_STEP
+
+ return count;
+#endif
+ }
+}
+
+/* Returns true if the 'n' bytes starting at 'p' are zeros. */
+bool
+is_all_zeros(const uint8_t *p, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++) {
+ if (p[i] != 0x00) {
+ return false;
+ }
+ }
+ return true;
+}
+
+/* Returns true if the 'n' bytes starting at 'p' are 0xff. */
+bool
+is_all_ones(const uint8_t *p, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++) {
+ if (p[i] != 0xff) {
+ return false;
+ }
+ }
+ return true;
+}
+
+/* Copies 'n_bits' bits starting from bit 'src_ofs' in 'src' to the 'n_bits'
+ * starting from bit 'dst_ofs' in 'dst'. 'src' is 'src_len' bytes long and
+ * 'dst' is 'dst_len' bytes long.
+ *
+ * If you consider all of 'src' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in src[src_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in src[src_len -
+ * 2], and so on. Similarly for 'dst'.
+ *
+ * Required invariants:
+ * src_ofs + n_bits <= src_len * 8
+ * dst_ofs + n_bits <= dst_len * 8
+ * 'src' and 'dst' must not overlap.
+ */
+void
+bitwise_copy(const void *src_, unsigned int src_len, unsigned int src_ofs,
+ void *dst_, unsigned int dst_len, unsigned int dst_ofs,
+ unsigned int n_bits)
+{
+ const uint8_t *src = src_;
+ uint8_t *dst = dst_;
+
+ src += src_len - (src_ofs / 8 + 1);
+ src_ofs %= 8;
+
+ dst += dst_len - (dst_ofs / 8 + 1);
+ dst_ofs %= 8;
+
+ if (src_ofs == 0 && dst_ofs == 0) {
+ unsigned int n_bytes = n_bits / 8;
+ if (n_bytes) {
+ dst -= n_bytes - 1;
+ src -= n_bytes - 1;
+ memcpy(dst, src, n_bytes);
+
+ n_bits %= 8;
+ src--;
+ dst--;
+ }
+ if (n_bits) {
+ uint8_t mask = (1 << n_bits) - 1;
+ *dst = (*dst & ~mask) | (*src & mask);
+ }
+ } else {
+ while (n_bits > 0) {
+ unsigned int max_copy = 8 - MAX(src_ofs, dst_ofs);
+ unsigned int chunk = MIN(n_bits, max_copy);
+ uint8_t mask = ((1 << chunk) - 1) << dst_ofs;
+
+ *dst &= ~mask;
+ *dst |= ((*src >> src_ofs) << dst_ofs) & mask;
+
+ src_ofs += chunk;
+ if (src_ofs == 8) {
+ src--;
+ src_ofs = 0;
+ }
+ dst_ofs += chunk;
+ if (dst_ofs == 8) {
+ dst--;
+ dst_ofs = 0;
+ }
+ n_bits -= chunk;
+ }
+ }
+}
+
+/* Zeros the 'n_bits' bits starting from bit 'dst_ofs' in 'dst'. 'dst' is
+ * 'dst_len' bytes long.
+ *
+ * If you consider all of 'dst' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in dst[dst_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in dst[dst_len -
+ * 2], and so on.
+ *
+ * Required invariant:
+ * dst_ofs + n_bits <= dst_len * 8
+ */
+void
+bitwise_zero(void *dst_, unsigned int dst_len, unsigned dst_ofs,
+ unsigned int n_bits)
+{
+ uint8_t *dst = dst_;
+
+ if (!n_bits) {
+ return;
+ }
+
+ dst += dst_len - (dst_ofs / 8 + 1);
+ dst_ofs %= 8;
+
+ if (dst_ofs) {
+ unsigned int chunk = MIN(n_bits, 8 - dst_ofs);
+
+ *dst &= ~(((1 << chunk) - 1) << dst_ofs);
+
+ n_bits -= chunk;
+ if (!n_bits) {
+ return;
+ }
+
+ dst--;
+ }
+
+ while (n_bits >= 8) {
+ *dst-- = 0;
+ n_bits -= 8;
+ }
+
+ if (n_bits) {
+ *dst &= ~((1 << n_bits) - 1);
+ }
+}
+
+/* Sets to 1 all of the 'n_bits' bits starting from bit 'dst_ofs' in 'dst'.
+ * 'dst' is 'dst_len' bytes long.
+ *
+ * If you consider all of 'dst' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in dst[dst_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in dst[dst_len -
+ * 2], and so on.
+ *
+ * Required invariant:
+ * dst_ofs + n_bits <= dst_len * 8
+ */
+void
+bitwise_one(void *dst_, unsigned int dst_len, unsigned dst_ofs,
+ unsigned int n_bits)
+{
+ uint8_t *dst = dst_;
+
+ if (!n_bits) {
+ return;
+ }
+
+ dst += dst_len - (dst_ofs / 8 + 1);
+ dst_ofs %= 8;
+
+ if (dst_ofs) {
+ unsigned int chunk = MIN(n_bits, 8 - dst_ofs);
+
+ *dst |= ((1 << chunk) - 1) << dst_ofs;
+
+ n_bits -= chunk;
+ if (!n_bits) {
+ return;
+ }
+
+ dst--;
+ }
+
+ while (n_bits >= 8) {
+ *dst-- = 0xff;
+ n_bits -= 8;
+ }
+
+ if (n_bits) {
+ *dst |= (1 << n_bits) - 1;
+ }
+}
+
+/* Scans the 'n_bits' bits starting from bit 'dst_ofs' in 'dst' for 1-bits.
+ * Returns false if any 1-bits are found, otherwise true. 'dst' is 'dst_len'
+ * bytes long.
+ *
+ * If you consider all of 'dst' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in dst[dst_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in dst[dst_len -
+ * 2], and so on.
+ *
+ * Required invariant:
+ * dst_ofs + n_bits <= dst_len * 8
+ */
+bool
+bitwise_is_all_zeros(const void *p_, unsigned int len, unsigned int ofs,
+ unsigned int n_bits)
+{
+ const uint8_t *p = p_;
+
+ if (!n_bits) {
+ return true;
+ }
+
+ p += len - (ofs / 8 + 1);
+ ofs %= 8;
+
+ if (ofs) {
+ unsigned int chunk = MIN(n_bits, 8 - ofs);
+
+ if (*p & (((1 << chunk) - 1) << ofs)) {
+ return false;
+ }
+
+ n_bits -= chunk;
+ if (!n_bits) {
+ return true;
+ }
+
+ p--;
+ }
+
+ while (n_bits >= 8) {
+ if (*p) {
+ return false;
+ }
+ n_bits -= 8;
+ p--;
+ }
+
+ if (n_bits && *p & ((1 << n_bits) - 1)) {
+ return false;
+ }
+
+ return true;
+}
+
+/* Copies the 'n_bits' low-order bits of 'value' into the 'n_bits' bits
+ * starting at bit 'dst_ofs' in 'dst', which is 'dst_len' bytes long.
+ *
+ * If you consider all of 'dst' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in dst[dst_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in dst[dst_len -
+ * 2], and so on.
+ *
+ * Required invariants:
+ * dst_ofs + n_bits <= dst_len * 8
+ * n_bits <= 64
+ */
+void
+bitwise_put(uint64_t value,
+ void *dst, unsigned int dst_len, unsigned int dst_ofs,
+ unsigned int n_bits)
+{
+ ovs_be64 n_value = htonll(value);
+ bitwise_copy(&n_value, sizeof n_value, 0,
+ dst, dst_len, dst_ofs,
+ n_bits);
+}
+
+/* Returns the value of the 'n_bits' bits starting at bit 'src_ofs' in 'src',
+ * which is 'src_len' bytes long.
+ *
+ * If you consider all of 'src' to be a single unsigned integer in network byte
+ * order, then bit N is the bit with value 2**N. That is, bit 0 is the bit
+ * with value 1 in src[src_len - 1], bit 1 is the bit with value 2, bit 2 is
+ * the bit with value 4, ..., bit 8 is the bit with value 1 in src[src_len -
+ * 2], and so on.
+ *
+ * Required invariants:
+ * src_ofs + n_bits <= src_len * 8
+ * n_bits <= 64
+ */
+uint64_t
+bitwise_get(const void *src, unsigned int src_len,
+ unsigned int src_ofs, unsigned int n_bits)
+{
+ ovs_be64 value = htonll(0);
+
+ bitwise_copy(src, src_len, src_ofs,
+ &value, sizeof value, 0,
+ n_bits);
+ return ntohll(value);
+}
git://git.onelab.eu / sliver-openvswitch.git / blobdiff