lighttpd1.4/src/buffer.c

#include "first.h"

#include "buffer.h"

#include <stdlib.h>
#include <string.h>
#include <time.h>       /* strftime() */

static const char hex_chars_lc[] = "0123456789abcdef";
static const char hex_chars_uc[] = "0123456789ABCDEF";

/**
 * init the buffer
 *
 */

buffer* buffer_init(void) {
	buffer *b;

	b = malloc(sizeof(*b));
	force_assert(b);

	b->ptr = NULL;
	b->size = 0;
	b->used = 0;

	return b;
}

buffer *buffer_init_buffer(const buffer *src) {
	buffer *b = buffer_init();
	buffer_copy_buffer(b, src);
	return b;
}

buffer *buffer_init_string(const char *str) {
	buffer *b = buffer_init();
	buffer_copy_string(b, str);
	return b;
}

void buffer_free(buffer *b) {
	if (NULL == b) return;

	free(b->ptr);
	free(b);
}

void buffer_free_ptr(buffer *b) {
	free(b->ptr);
	b->ptr = NULL;
	b->used = 0;
	b->size = 0;
}

void buffer_move(buffer * restrict b, buffer * restrict src) {
	buffer tmp;
	force_assert(NULL != b);
	force_assert(NULL != src);

	buffer_clear(b);
	tmp = *src; *src = *b; *b = tmp;
}

/* make sure buffer is at least "size" big + 1 for '\0'. keep old data */
__attribute_cold__
__attribute_noinline__
__attribute_returns_nonnull__
static char* buffer_realloc(buffer * const restrict b, const size_t len) {
    #define BUFFER_PIECE_SIZE 64uL  /*(must be power-of-2)*/
    const size_t sz = (len + 1 + BUFFER_PIECE_SIZE-1) & ~(BUFFER_PIECE_SIZE-1);
    force_assert(sz > len);

    b->size = sz;
    b->ptr = realloc(b->ptr, sz);

    force_assert(NULL != b->ptr);
    return b->ptr;
}

__attribute_cold__
__attribute_noinline__
__attribute_returns_nonnull__
static char* buffer_alloc_replace(buffer * const restrict b, const size_t size) {
    /*(discard old data so realloc() does not copy)*/
    if (NULL != b->ptr) {
        free(b->ptr);
        b->ptr = NULL;
    }
    /*(note: if size larger than one lshift, use size instead of power-2)*/
    return buffer_realloc(b, (b->size << 1) > size ? (b->size << 1)-1 : size);
}

char* buffer_string_prepare_copy(buffer * const b, const size_t size) {
    b->used = 0;
    return (size < b->size)
      ? b->ptr
      : buffer_alloc_replace(b, size);
}

__attribute_cold__
__attribute_noinline__
__attribute_returns_nonnull__
static char* buffer_string_prepare_append_resize(buffer * const restrict b, const size_t size) {
    if (b->used < 2)  /* buffer_string_is_empty(b) */
        return buffer_string_prepare_copy(b, size);

    /* not empty, b->used already includes a terminating 0 */
    /*(note: if size larger than one lshift, use size instead of power-2)*/
    const size_t req_size = ((b->size << 1) - b->used > size)
      ? (b->size << 1)-1
      : b->used + size;

    /* check for overflow: unsigned overflow is defined to wrap around */
    force_assert(req_size >= b->used);

    return buffer_realloc(b, req_size) + b->used - 1;
}

char* buffer_string_prepare_append(buffer * const b, const size_t size) {
    const uint32_t len = b->used ? b->used-1 : 0;
    return (b->size - len >= size + 1)
      ? b->ptr + len
      : buffer_string_prepare_append_resize(b, size);
}

/*(prefer smaller code than inlining buffer_extend in many places in buffer.c)*/
__attribute_noinline__
char*
buffer_extend (buffer * const b, const size_t x)
{
    /* extend buffer to append x (reallocate by power-2 (or larger), if needed)
     * (combine buffer_string_prepare_append() and buffer_commit())
     * (future: might make buffer.h static inline func for HTTP/1.1 performance)
     * pre-sets '\0' byte and b->used (unlike buffer_string_prepare_append())*/
    const uint32_t len = b->used ? b->used-1 : 0;
    char * const s = (b->size - len >= x + 1)
      ? b->ptr + len
      : buffer_string_prepare_append_resize(b, x);
    b->used = len+x+1;
    s[x] = '\0';
    return s;
}

void buffer_string_set_length(buffer *b, uint32_t len) {
    /*(intended for string truncate; prefer buffer_extend() to extend string)*/
    /*(unlike others routines, this routine potentially extends string
     * extra len + (up to) BUFFER_PIECE_SIZE without power-2 reallocation,
     * but does not optimize realloc of empty string)*/
    b->used = len + 1; /*(not resizing for power-2)*/
    (len < b->size ? b->ptr : buffer_realloc(b, len))[len] = '\0';
}

void buffer_commit(buffer *b, size_t size)
{
	force_assert(NULL != b);
	force_assert(b->size > 0);

	if (0 == b->used) b->used = 1;

	if (size > 0) {
		/* check for overflow: unsigned overflow is defined to wrap around */
		size_t sz = b->used + size;
		force_assert(sz > b->used);
		force_assert(sz <= b->size);
		b->used = sz;
	}

	b->ptr[b->used - 1] = '\0';
}

void buffer_copy_string(buffer * restrict b, const char * restrict s) {
	buffer_copy_string_len(b, s, NULL != s ? strlen(s) : 0);
}

void buffer_copy_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
    b->used = len + 1;
    char * const restrict d = (len < b->size)
      ? b->ptr
      : buffer_alloc_replace(b, len);
    d[len] = '\0';
    memcpy(d, s, len);
}

void buffer_append_string(buffer * restrict b, const char * restrict s) {
	buffer_append_string_len(b, s, NULL != s ? strlen(s) : 0);
}

/**
 * append a string to the end of the buffer
 *
 * the resulting buffer is terminated with a '\0'
 * s is treated as a un-terminated string (a \0 is handled a normal character)
 *
 * @param b a buffer
 * @param s the string
 * @param s_len size of the string (without the terminating \0)
 */

void buffer_append_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
    memcpy(buffer_extend(b, len), s, len);
}

void buffer_append_str2(buffer * const restrict b, const char * const s1, const size_t len1, const char * const s2, const size_t len2) {
    char * const restrict s = buffer_extend(b, len1+len2);
  #ifdef HAVE_MEMPCPY
    mempcpy(mempcpy(s, s1, len1), s2, len2);
  #else
    memcpy(s,      s1, len1);
    memcpy(s+len1, s2, len2);
  #endif
}

void buffer_append_str3(buffer * const restrict b, const char * const s1, const size_t len1, const char * const s2, const size_t len2, const char * const s3, const size_t len3) {
    char * restrict s = buffer_extend(b, len1+len2+len3);
  #ifdef HAVE_MEMPCPY
    mempcpy(mempcpy(mempcpy(s, s1, len1), s2, len2), s3, len3);
  #else
    memcpy(s,         s1, len1);
    memcpy((s+=len1), s2, len2);
    memcpy((s+=len2), s3, len3);
  #endif
}

void buffer_append_iovec(buffer * const restrict b, const struct const_iovec * const iov, const size_t n) {
    size_t len = 0;
    for (size_t i = 0; i < n; ++i)
        len += iov[i].iov_len;
    char *s = buffer_extend(b, len);
    for (size_t i = 0; i < n; ++i) {
        if (0 == iov[i].iov_len) continue;
      #ifdef HAVE_MEMPCPY
        s = mempcpy(s, iov[i].iov_base, iov[i].iov_len);
      #else
        memcpy(s, iov[i].iov_base, iov[i].iov_len);
        s += iov[i].iov_len;
      #endif
    }
}

void buffer_append_path_len(buffer * restrict b, const char * restrict a, size_t alen) {
    char * restrict s = buffer_string_prepare_append(b, alen+1);
    const int aslash = (alen && a[0] == '/');
    if (b->used > 1 && s[-1] == '/') {
        if (aslash) {
            ++a;
            --alen;
        }
    }
    else {
        if (0 == b->used) b->used = 1;
        if (!aslash) {
            *s++ = '/';
            ++b->used;
        }
    }
    b->used += alen;
    s[alen] = '\0';
    memcpy(s, a, alen);
}

void buffer_append_uint_hex_lc(buffer *b, uintmax_t value) {
	char *buf;
	unsigned int shift = 0;

	{
		uintmax_t copy = value;
		do {
			copy >>= 8;
			shift += 8; /* counting bits */
		} while (0 != copy);
	}

	buf = buffer_extend(b, shift >> 2); /*nibbles (4 bits)*/

	while (shift > 0) {
		shift -= 4;
		*(buf++) = hex_chars_lc[(value >> shift) & 0x0F];
	}
}

__attribute_returns_nonnull__
static char* utostr(char * const buf_end, uintmax_t val) {
	char *cur = buf_end;
	do {
		int mod = val % 10;
		val /= 10;
		/* prepend digit mod */
		*(--cur) = (char) ('0' + mod);
	} while (0 != val);
	return cur;
}

__attribute_returns_nonnull__
static char* itostr(char * const buf_end, intmax_t val) {
	/* absolute value not defined for INTMAX_MIN, but can take absolute
	 * value of any negative number via twos complement cast to unsigned.
	 * negative sign is prepended after (now unsigned) value is converted
	 * to string */
	uintmax_t uval = val >= 0 ? (uintmax_t)val : ((uintmax_t)~val) + 1;
	char *cur = utostr(buf_end, uval);
	if (val < 0) *(--cur) = '-';

	return cur;
}

void buffer_append_int(buffer *b, intmax_t val) {
	char buf[LI_ITOSTRING_LENGTH];
	char* const buf_end = buf + sizeof(buf);
	char *str;

	force_assert(NULL != b);

	str = itostr(buf_end, val);
	force_assert(buf_end > str && str >= buf);

	buffer_append_string_len(b, str, buf_end - str);
}

void buffer_append_strftime(buffer * const restrict b, const char * const restrict format, const struct tm * const restrict tm) {
    force_assert(NULL != format);
    /*(localtime_r() or gmtime_r() producing tm should not have failed)*/
    if (__builtin_expect( (NULL == tm), 0)) return;

    /*(expecting typical format strings to result in < 64 bytes needed;
     * skipping buffer_string_space() calculation and providing fixed size)*/
    size_t rv = strftime(buffer_string_prepare_append(b, 63), 64, format, tm);

    /* 0 (in some apis) signals the string may have been too small;
     * but the format could also just have lead to an empty string */
    if (__builtin_expect( (0 == rv), 0) || __builtin_expect( (rv > 63), 0)) {
        /* unexpected; give it a second try with a larger string */
        rv = strftime(buffer_string_prepare_append(b, 4095), 4096, format, tm);
        if (__builtin_expect( (rv > 4095), 0))/*(input format was ridiculous)*/
            return;
    }

    /*buffer_commit(b, rv);*/
    b->used += (uint32_t)rv + (0 == b->used);
}


size_t li_itostrn(char *buf, size_t buf_len, intmax_t val) {
	char p_buf[LI_ITOSTRING_LENGTH];
	char* const str = itostr(p_buf+sizeof(p_buf), val);
	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
	force_assert(len <= buf_len);
	memcpy(buf, str, len);
	return len;
}

size_t li_utostrn(char *buf, size_t buf_len, uintmax_t val) {
	char p_buf[LI_ITOSTRING_LENGTH];
	char* const str = utostr(p_buf+sizeof(p_buf), val);
	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
	force_assert(len <= buf_len);
	memcpy(buf, str, len);
	return len;
}

#define li_ntox_lc(n) ((n) <= 9 ? (n) + '0' : (n) + 'a' - 10)

/* c (char) and n (nibble) MUST be unsigned integer types */
#define li_cton(c,n) \
  (((n) = (c) - '0') <= 9 || (((n) = ((c)&0xdf) - 'A') <= 5 ? ((n) += 10) : 0))

/* converts hex char (0-9, A-Z, a-z) to decimal.
 * returns 0xFF on invalid input.
 */
char hex2int(unsigned char hex) {
	unsigned char n;
	return li_cton(hex,n) ? (char)n : 0xFF;
}


int buffer_eq_icase_ssn(const char * const a, const char * const b, const size_t len) {
    for (size_t i = 0; i < len; ++i) {
        unsigned int ca = ((unsigned char *)a)[i];
        unsigned int cb = ((unsigned char *)b)[i];
        if (ca != cb) {
            ca |= 0x20;
            cb |= 0x20;
            if (ca != cb) return 0;
            if (!light_islower(ca)) return 0;
            if (!light_islower(cb)) return 0;
        }
    }
    return 1;
}

int buffer_eq_icase_ss(const char * const a, const size_t alen, const char * const b, const size_t blen) {
    /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
    return (alen == blen && buffer_eq_icase_ssn(a, b, blen));
}

int buffer_eq_icase_slen(const buffer * const b, const char * const s, const size_t slen) {
    /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
    /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
    return (b->used == slen + 1 && buffer_eq_icase_ssn(b->ptr, s, slen));
}

int buffer_eq_slen(const buffer * const b, const char * const s, const size_t slen) {
    /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
    /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
    return (b->used == slen + 1 && 0 == memcmp(b->ptr, s, slen));
}


/**
 * check if two buffer contain the same data
 */

int buffer_is_equal(const buffer *a, const buffer *b) {
	force_assert(NULL != a && NULL != b);

	/* 1 = equal; 0 = not equal */
	return (a->used == b->used && 0 == memcmp(a->ptr, b->ptr, a->used));
}

int buffer_is_equal_string(const buffer *a, const char *s, size_t b_len) {
	force_assert(NULL != a && NULL != s);
	force_assert(b_len + 1 > b_len);

	/* 1 = equal; 0 = not equal */
	return (a->used == b_len + 1 && 0 == memcmp(a->ptr, s, b_len));
}

int buffer_is_equal_right_len(const buffer *b1, const buffer *b2, size_t len) {
	/* no len -> equal */
	if (len == 0) return 1;

	/* len > 0, but empty buffers -> not equal */
	if (b1->used == 0 || b2->used == 0) return 0;

	/* buffers too small -> not equal */
	if (b1->used - 1 < len || b2->used - 1 < len) return 0;

	return 0 == memcmp(b1->ptr + b1->used - 1 - len, b2->ptr + b2->used - 1 - len, len);
}


void li_tohex_lc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
	force_assert(2 * s_len > s_len);
	force_assert(2 * s_len < buf_len);

	for (size_t i = 0; i < s_len; ++i) {
		buf[2*i]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
		buf[2*i+1] = hex_chars_lc[s[i] & 0x0F];
	}
	buf[2*s_len] = '\0';
}

void li_tohex_uc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
	force_assert(2 * s_len > s_len);
	force_assert(2 * s_len < buf_len);

	for (size_t i = 0; i < s_len; ++i) {
		buf[2*i]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
		buf[2*i+1] = hex_chars_uc[s[i] & 0x0F];
	}
	buf[2*s_len] = '\0';
}


void buffer_substr_replace (buffer * const restrict b, const size_t offset,
                            const size_t len, const buffer * const restrict replace)
{
    const size_t blen = buffer_string_length(b);
    const size_t rlen = buffer_string_length(replace);

    if (rlen > len) {
        buffer_string_set_length(b, blen-len+rlen);
        memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
    }

    memcpy(b->ptr+offset, replace->ptr, rlen);

    if (rlen < len) {
        memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
        buffer_string_set_length(b, blen-len+rlen);
    }
}


void buffer_append_string_encoded_hex_lc(buffer * const restrict b, const char * const restrict s, size_t len) {
    unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
    for (size_t i = 0; i < len; ++i) {
        p[(i<<1)]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
        p[(i<<1)+1] = hex_chars_lc[(s[i])      & 0x0F];
    }
}

void buffer_append_string_encoded_hex_uc(buffer * const restrict b, const char * const restrict s, size_t len) {
    unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
    for (size_t i = 0; i < len; ++i) {
        p[(i<<1)]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
        p[(i<<1)+1] = hex_chars_uc[(s[i])      & 0x0F];
    }
}


/* everything except: ! ( ) * - . 0-9 A-Z _ a-z */
static const char encoded_chars_rel_uri_part[] = {
	/*
	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
	*/
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1,  /*  20 -  2F space " # $ % & ' + , / */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
};

/* everything except: ! ( ) * - . / 0-9 A-Z _ a-z */
static const char encoded_chars_rel_uri[] = {
	/*
	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
	*/
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0,  /*  20 -  2F space " # $ % & ' + , */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
};

static const char encoded_chars_html[] = {
	/*
	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
	*/
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
	0, 0, 0, 0, 0, 0, 0,