| /* |
| * include/common/ist.h |
| * Very simple indirect string manipulation functions. |
| * |
| * Copyright (C) 2014-2017 Willy Tarreau - w@1wt.eu |
| * |
| * 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 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. |
| */ |
| |
| #ifndef _COMMON_IST_H |
| #define _COMMON_IST_H |
| |
| #include <string.h> |
| |
| #include <common/config.h> |
| |
| /* This string definition will most often be used to represent a read-only |
| * string returned from a function, based on the starting point and its length |
| * in bytes. No storage is provided, only a pointer and a length. The types |
| * here are important as we only want to have 2 native machine words there so |
| * that on modern architectures the compiler is capable of efficiently |
| * returning a register pair without having to allocate stack room from the |
| * caller. This is done with -freg-struct which is often enabled by default. |
| */ |
| struct ist { |
| char *ptr; |
| size_t len; |
| }; |
| |
| /* makes an ist from a regular zero terminated string. Null has length 0. |
| * Constants are detected and replaced with constant initializers. Other values |
| * are measured by hand without strlen() as it's much cheaper and inlinable on |
| * small strings. The construct is complex because we must never call |
| * __builtin_strlen() with an expression otherwise it involves a real |
| * measurement. |
| */ |
| #if __GNUC__ >= 4 |
| // gcc >= 4 detects constant propagation of str through __x and resolves the |
| // length of constant strings easily. |
| #define ist(str) ({ \ |
| char *__x = (void *)(str); \ |
| (struct ist){ \ |
| .ptr = __x, \ |
| .len = __builtin_constant_p(str) ? \ |
| ((void *)str == (void *)0) ? 0 : \ |
| __builtin_strlen(__x) : \ |
| ({ \ |
| size_t __l = 0; \ |
| if (__x) for (__l--; __x[++__l]; ) ; \ |
| __l; \ |
| }) \ |
| }; \ |
| }) |
| #else |
| // gcc < 4 can't do this, and the side effect is a warning each time a NULL is |
| // passed to ist() due to the check on __builtin_strlen(). It doesn't have the |
| // ability to know that this code is never called. |
| #define ist(str) ({ \ |
| char *__x = (void *)(str); \ |
| (struct ist){ \ |
| .ptr = __x, \ |
| .len = __builtin_constant_p(str) ? \ |
| ((void *)str == (void *)0) ? 0 : \ |
| __builtin_strlen(str) : \ |
| ({ \ |
| size_t __l = 0; \ |
| if (__x) for (__l--; __x[++__l]; ) ; \ |
| __l; \ |
| }) \ |
| }; \ |
| }) |
| #endif |
| |
| /* makes an ist struct from a string and a length */ |
| static inline struct ist ist2(const void *ptr, size_t len) |
| { |
| return (struct ist){ .ptr = (char *)ptr, .len = len }; |
| } |
| |
| /* returns the length of the string */ |
| static inline size_t istlen(const struct ist ist) |
| { |
| return ist.len; |
| } |
| |
| /* skips to next character in the string, always stops at the end */ |
| static inline struct ist istnext(const struct ist ist) |
| { |
| struct ist ret = ist; |
| |
| if (ret.len) { |
| ret.len--; |
| ret.ptr++; |
| } |
| return ret; |
| } |
| |
| /* copies the contents from string <ist> to buffer <buf> and adds a trailing |
| * zero. The caller must ensure <buf> is large enough. |
| */ |
| static inline struct ist istpad(void *buf, const struct ist ist) |
| { |
| struct ist ret = { .ptr = buf, .len = ist.len }; |
| |
| for (ret.len = 0; ret.len < ist.len; ret.len++) |
| ret.ptr[ret.len] = ist.ptr[ret.len]; |
| |
| ret.ptr[ret.len] = 0; |
| return ret; |
| } |
| |
| /* trims string <ist> to no more than <size> characters. The string is |
| * returned. |
| */ |
| static inline struct ist isttrim(const struct ist ist, size_t size) |
| { |
| struct ist ret = ist; |
| |
| if (ret.len > size) |
| ret.len = size; |
| return ret; |
| } |
| |
| /* trims string <ist> to no more than <size>-1 characters and ensures that a |
| * zero is placed after <ist.len> (possibly reduced by one) and before <size>, |
| * unless <size> is already zero. The string is returned. This is mostly aimed |
| * at building printable strings that need to be zero-terminated. |
| */ |
| static inline struct ist istzero(const struct ist ist, size_t size) |
| { |
| struct ist ret = ist; |
| |
| if (!size) |
| ret.len = 0; |
| else { |
| if (ret.len > size - 1) |
| ret.len = size - 1; |
| ret.ptr[ret.len] = 0; |
| } |
| return ret; |
| } |
| |
| /* returns the ordinal difference between two strings : |
| * < 0 if ist1 < ist2 |
| * = 0 if ist1 == ist2 |
| * > 0 if ist1 > ist2 |
| */ |
| static inline int istdiff(const struct ist ist1, const struct ist ist2) |
| { |
| struct ist l = ist1; |
| struct ist r = ist2; |
| |
| do { |
| if (!l.len--) |
| return -r.len; |
| if (!r.len--) |
| return 1; |
| } while (*l.ptr++ == *r.ptr++); |
| |
| return *(unsigned char *)(l.ptr - 1) - *(unsigned char *)(r.ptr - 1); |
| } |
| |
| /* returns non-zero if <ist1> starts like <ist2> (empty strings do match) */ |
| static inline int istmatch(const struct ist ist1, const struct ist ist2) |
| { |
| struct ist l = ist1; |
| struct ist r = ist2; |
| |
| if (l.len < r.len) |
| return 0; |
| |
| while (r.len--) { |
| if (*l.ptr++ != *r.ptr++) |
| return 0; |
| } |
| return 1; |
| } |
| |
| /* returns non-zero if <ist1> starts like <ist2> on the first <count> |
| * characters (empty strings do match). |
| */ |
| static inline int istnmatch(const struct ist ist1, const struct ist ist2, size_t count) |
| { |
| struct ist l = ist1; |
| struct ist r = ist2; |
| |
| if (l.len > count) |
| l.len = count; |
| if (r.len > count) |
| r.len = count; |
| return istmatch(l, r); |
| } |
| |
| /* returns non-zero if <ist1> equals <ist2> (empty strings are equal) */ |
| static inline int isteq(const struct ist ist1, const struct ist ist2) |
| { |
| struct ist l = ist1; |
| struct ist r = ist2; |
| |
| if (l.len != r.len) |
| return 0; |
| |
| while (l.len--) { |
| if (*l.ptr++ != *r.ptr++) |
| return 0; |
| } |
| return 1; |
| } |
| |
| /* returns non-zero if <ist1> equals <ist2> on the first <count> characters |
| * (empty strings are equal). |
| */ |
| static inline int istneq(const struct ist ist1, const struct ist ist2, size_t count) |
| { |
| struct ist l = ist1; |
| struct ist r = ist2; |
| |
| if (l.len > count) |
| l.len = count; |
| if (r.len > count) |
| r.len = count; |
| return isteq(l, r); |
| } |
| |
| /* copies <src> over <dst> for a maximum of <count> bytes. Returns the number |
| * of characters copied (src.len), or -1 if it does not fit. In all cases, the |
| * contents are copied prior to reporting an error, so that the destination |
| * at least contains a valid but truncated string. |
| */ |
| static inline ssize_t istcpy(struct ist *dst, const struct ist src, size_t count) |
| { |
| dst->len = 0; |
| |
| if (count > src.len) |
| count = src.len; |
| |
| while (dst->len < count) { |
| dst->ptr[dst->len] = src.ptr[dst->len]; |
| dst->len++; |
| } |
| |
| if (dst->len == src.len) |
| return src.len; |
| |
| return -1; |
| } |
| |
| /* copies <src> over <dst> for a maximum of <count> bytes. Returns the number |
| * of characters copied, or -1 if it does not fit. A (possibly truncated) valid |
| * copy of <src> is always left into <dst>, and a trailing \0 is appended as |
| * long as <count> is not null, even if that results in reducing the string by |
| * one character. |
| */ |
| static inline ssize_t istscpy(struct ist *dst, const struct ist src, size_t count) |
| { |
| dst->len = 0; |
| |
| if (!count) |
| goto fail; |
| |
| if (count > src.len) |
| count = src.len + 1; |
| |
| while (dst->len < count - 1) { |
| dst->ptr[dst->len] = src.ptr[dst->len]; |
| dst->len++; |
| } |
| |
| dst->ptr[dst->len] = 0; |
| if (dst->len == src.len) |
| return src.len; |
| fail: |
| return -1; |
| } |
| |
| /* appends <src> after <dst> for a maximum of <count> total bytes in <dst> after |
| * the copy. <dst> is assumed to be <count> or less before the call. The new |
| * string's length is returned, or -1 if a truncation happened. In all cases, |
| * the contents are copied prior to reporting an error, so that the destination |
| * at least contains a valid but truncated string. |
| */ |
| static inline ssize_t istcat(struct ist *dst, const struct ist src, size_t count) |
| { |
| const char *s = src.ptr; |
| |
| while (dst->len < count && s != src.ptr + src.len) |
| dst->ptr[dst->len++] = *s++; |
| |
| if (s == src.ptr + src.len) |
| return dst->len; |
| |
| return -1; |
| } |
| |
| /* appends <src> after <dst> for a maximum of <count> total bytes in <dst> after |
| * the copy. <dst> is assumed to be <count> or less before the call. The new |
| * string's length is returned, or -1 if a truncation happened. In all cases, |
| * the contents are copied prior to reporting an error, so that the destination |
| * at least contains a valid but truncated string. |
| */ |
| static inline ssize_t istscat(struct ist *dst, const struct ist src, size_t count) |
| { |
| const char *s = src.ptr; |
| |
| if (!count) |
| goto fail; |
| |
| while (dst->len < count - 1 && s != src.ptr + src.len) { |
| dst->ptr[dst->len++] = *s++; |
| } |
| |
| dst->ptr[dst->len] = 0; |
| if (s == src.ptr + src.len) |
| return dst->len; |
| fail: |
| return -1; |
| } |
| |
| /* looks for first occurrence of character <chr> in string <ist>. Returns the |
| * pointer if found, or NULL if not found. |
| */ |
| static inline char *istchr(const struct ist ist, char chr) |
| { |
| char *s = ist.ptr; |
| |
| do { |
| if (s >= ist.ptr + ist.len) |
| return NULL; |
| } while (*s++ != chr); |
| return s - 1; |
| } |
| |
| /* looks for first occurrence of character <chr> in string <ist> and returns |
| * the tail of the string starting with this character, or (ist.end,0) if not |
| * found. |
| */ |
| static inline struct ist istfind(const struct ist ist, char chr) |
| { |
| struct ist ret = ist; |
| |
| while (ret.len--) { |
| if (*ret.ptr++ == chr) |
| return ist2(ret.ptr - 1, ret.len + 1); |
| } |
| return ist2(ret.ptr, 0); |
| } |
| |
| /* looks for first occurrence of character different from <chr> in string <ist> |
| * and returns the tail of the string starting at this character, or (ist_end,0) |
| * if not found. |
| */ |
| static inline struct ist istskip(const struct ist ist, char chr) |
| { |
| struct ist ret = ist; |
| |
| while (ret.len--) { |
| if (*ret.ptr++ != chr) |
| return ist2(ret.ptr - 1, ret.len + 1); |
| } |
| return ist2(ret.ptr, 0); |
| } |
| |
| /* looks for first occurrence of string <pat> in string <ist> and returns the |
| * tail of the string starting at this position, or (NULL,0) if not found. The |
| * empty pattern is found everywhere. |
| */ |
| static inline struct ist istist(const struct ist ist, const struct ist pat) |
| { |
| struct ist ret = ist; |
| size_t pos; |
| |
| if (!pat.len) |
| return ret; |
| |
| while (1) { |
| loop: |
| ret = istfind(ret, *pat.ptr); |
| if (ret.len < pat.len) |
| break; |
| |
| /* ret.len >= 1, pat.len >= 1 and *ret.ptr == *pat.ptr */ |
| |
| ret = istnext(ret); |
| for (pos = 0; pos < pat.len - 1; ) { |
| ++pos; |
| if (ret.ptr[pos - 1] != pat.ptr[pos]) |
| goto loop; |
| } |
| return ist2(ret.ptr - 1, ret.len + 1); |
| } |
| return ist2(NULL, 0); |
| } |
| |
| #endif |