haproxy/include/common/ist.h
Jerome Magnin 9dde0b2d31 MINOR: ist: add an iststop() function
Add a function that finds a character in an ist and returns an
updated ist with the length of the portion of the original string
that doesn't contain the char.

Might be backported to 2.1
2020-02-21 11:47:25 +01:00

724 lines
23 KiB
C

/*
* 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 <ctype.h>
#include <string.h>
#include <unistd.h>
#include <common/config.h>
/* ASCII to lower case conversion table */
#define _IST_LC ((const unsigned char[256]){ \
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, \
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, \
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, \
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, \
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, \
0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, \
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, \
0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, \
0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, \
0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, \
0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, \
0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, \
0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, \
0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, \
0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, \
0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, \
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, \
0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, \
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, \
0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, \
0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, \
0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, \
0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, \
0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, \
0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, \
0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, \
0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, \
0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, \
0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, \
0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, \
0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, \
0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, \
})
/* ASCII to upper case conversion table */
#define _IST_UC ((const unsigned char[256]){ \
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, \
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, \
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, \
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, \
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, \
0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, \
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, \
0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, \
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, \
0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, \
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, \
0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, \
0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, \
0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, \
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, \
0x58, 0x59, 0x5a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, \
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, \
0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, \
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, \
0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, \
0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, \
0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, \
0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, \
0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, \
0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, \
0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, \
0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, \
0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, \
0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, \
0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, \
0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, \
0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, \
})
#ifdef USE_OBSOLETE_LINKER
/* some old linkers and some non-ELF platforms have issues with the weak
* attribute so we turn these arrays to literals there.
*/
#define ist_lc _IST_LC
#define ist_uc _IST_UC
#else
const unsigned char ist_lc[256] __attribute__((weak)) = _IST_LC;
const unsigned char ist_uc[256] __attribute__((weak)) = _IST_UC;
#endif
/* 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 a constant ist from a constant string, for use in array declarations */
#define IST(str) { .ptr = str "", .len = (sizeof str "") - 1 }
/* 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 };
}
/* This function MODIFIES the string to add a zero AFTER the end, and returns
* the start pointer. The purpose is to use it on strings extracted by parsers
* from larger strings cut with delimiters that are not important and can be
* destroyed. It allows any such string to be used with regular string
* functions. It's also convenient to use with printf() to show data extracted
* from writable areas. The caller is obviously responsible for ensuring that
* the string is valid and that the first byte past the end is writable. If
* these conditions cannot be satisfied, use istpad() below instead.
*/
static inline char *ist0(struct ist ist)
{
ist.ptr[ist.len] = 0;
return ist.ptr;
}
/* 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>, ignoring the case (empty strings are equal) */
static inline int isteqi(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 &&
ist_lc[(unsigned char)*l.ptr] != ist_lc[(unsigned char)*r.ptr])
return 0;
l.ptr++;
r.ptr++;
}
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;
}
/* copies the entire <src> over <dst>, which must be allocated large enough to
* hold the whole contents. No trailing zero is appended, this is mainly used
* for protocol processing where the frame length has already been checked. An
* ist made of the output and its length are returned. The destination is not
* touched if src.len is null.
*/
static inline struct ist ist2bin(char *dst, const struct ist src)
{
size_t ofs = 0;
/* discourage the compiler from trying to optimize for large strings,
* but tell it that most of our strings are not empty.
*/
if (__builtin_expect(ofs < src.len, 1)) {
do {
dst[ofs] = src.ptr[ofs];
ofs++;
} while (__builtin_expect(ofs < src.len, 0));
}
return ist2(dst, ofs);
}
/* copies the entire <src> over <dst>, which must be allocated large enough to
* hold the whole contents as well as a trailing zero which is always appended.
* This is mainly used for protocol conversions where the frame length has
* already been checked. An ist made of the output and its length (not counting
* the trailing zero) are returned.
*/
static inline struct ist ist2str(char *dst, const struct ist src, size_t count)
{
size_t ofs = 0;
/* discourage the compiler from trying to optimize for large strings,
* but tell it that most of our strings are not empty.
*/
if (__builtin_expect(ofs < src.len, 1)) {
do {
dst[ofs] = src.ptr[ofs];
ofs++;
} while (__builtin_expect(ofs < src.len, 0));
}
dst[ofs] = 0;
return ist2(dst, ofs);
}
/* makes a lower case copy of the entire <src> into <dst>, which must have been
* allocated large enough to hold the whole contents. No trailing zero is
* appended, this is mainly used for protocol processing where the frame length
* has already been checked. An ist made of the output and its length are
* returned. The destination is not touched if src.len is null.
*/
static inline struct ist ist2bin_lc(char *dst, const struct ist src)
{
size_t ofs = 0;
/* discourage the compiler from trying to optimize for large strings,
* but tell it that most of our strings are not empty.
*/
if (__builtin_expect(ofs < src.len, 1)) {
do {
dst[ofs] = ist_lc[(unsigned char)src.ptr[ofs]];
ofs++;
} while (__builtin_expect(ofs < src.len, 0));
}
return ist2(dst, ofs);
}
/* makes a lower case copy of the entire <src> into <dst>, which must have been
* allocated large enough to hold the whole contents as well as a trailing zero
* which is always appended. This is mainly used for protocol conversions where
* the frame length has already been checked. An ist made of the output and its
* length (not counting the trailing zero) are returned.
*/
static inline struct ist ist2str_lc(char *dst, const struct ist src, size_t count)
{
size_t ofs = 0;
/* discourage the compiler from trying to optimize for large strings,
* but tell it that most of our strings are not empty.
*/
if (__builtin_expect(ofs < src.len, 1)) {
do {
dst[ofs] = ist_lc[(unsigned char)src.ptr[ofs]];
ofs++;
} while (__builtin_expect(ofs < src.len, 0));
}
dst[ofs] = 0;
return ist2(dst, ofs);
}
/* makes an upper case copy of the entire <src> into <dst>, which must have
* been allocated large enough to hold the whole contents. No trailing zero is
* appended, this is mainly used for protocol processing where the frame length
* has already been checked. An ist made of the output and its length are
* returned. The destination is not touched if src.len is null.
*/
static inline struct ist ist2bin_uc(char *dst, const struct ist src)
{
size_t ofs = 0;
/* discourage the compiler from trying to optimize for large strings,
* but tell it that most of our strings are not empty.
*/
if (__builtin_expect(ofs < src.len, 1)) {
do {
dst[ofs] = ist_uc[(unsigned char)src.ptr[ofs]];
ofs++;
} while (__builtin_expect(ofs < src.len, 0));
}
return ist2(dst, ofs);
}
/* makes an upper case copy of the entire <src> into <dst>, which must have been
* allocated large enough to hold the whole contents as well as a trailing zero
* which is always appended. This is mainly used for protocol conversions where
* the frame length has already been checked. An ist made of the output and its
* length (not counting the trailing zero) are returned.
*/
static inline struct ist ist2str_uc(char *dst, const struct ist src, size_t count)
{
size_t ofs = 0;
/* discourage the compiler from trying to optimize for large strings,
* but tell it that most of our strings are not empty.
*/
if (__builtin_expect(ofs < src.len, 1)) {
do {
dst[ofs] = ist_uc[(unsigned char)src.ptr[ofs]];
ofs++;
} while (__builtin_expect(ofs < src.len, 0));
}
dst[ofs] = 0;
return ist2(dst, ofs);
}
/* 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;
}
/* Returns a pointer to the first control character found in <ist>, or NULL if
* none is present. A control character is defined as a byte whose value is
* between 0x00 and 0x1F included. The function is optimized for strings having
* no CTL chars by processing up to sizeof(long) bytes at once on architectures
* supporting efficient unaligned accesses. Despite this it is not very fast
* (~0.43 byte/cycle) and should mostly be used on low match probability when
* it can save a call to a much slower function.
*/
static inline const char *ist_find_ctl(const struct ist ist)
{
const union { unsigned long v; } __attribute__((packed)) *u;
const char *curr = (void *)ist.ptr - sizeof(long);
const char *last = curr + ist.len;
unsigned long l1, l2;
do {
curr += sizeof(long);
if (curr > last)
break;
u = (void *)curr;
/* subtract 0x202020...20 to the value to generate a carry in
* the lower byte if the byte contains a lower value. If we
* generate a bit 7 that was not there, it means the byte was
* within 0x00..0x1F.
*/
l2 = u->v;
l1 = ~l2 & ((~0UL / 255) * 0x80); /* 0x808080...80 */
l2 -= (~0UL / 255) * 0x20; /* 0x202020...20 */
} while ((l1 & l2) == 0);
last += sizeof(long);
if (__builtin_expect(curr < last, 0)) {
do {
if ((uint8_t)*curr < 0x20)
return curr;
curr++;
} while (curr < last);
}
return NULL;
}
/* 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);
}
/*
* looks for the first occurence of <chr> in string <ist> and returns a shorter
* ist if char is found.
*/
static inline struct ist iststop(const struct ist ist, char chr)
{
size_t len = 0;
while (len++ < ist.len && ist.ptr[len - 1] != chr)
;
return ist2(ist.ptr, len - 1);
}
#endif