damus

cursor.h (16444B)

---

 
 #ifndef JB55_CURSOR_H
 #define JB55_CURSOR_H
 
 #include "typedefs.h"
 #include "varint.h"
 
 #include <stdio.h>
 #include <ctype.h>
 #include <assert.h>
 #include <string.h>
 
 #define unlikely(x) __builtin_expect((x),0)
 #define likely(x)   __builtin_expect((x),1)
 
 struct cursor {
 	unsigned char *start;
 	unsigned char *p;
 	unsigned char *end;
 };
 
 struct array {
 	struct cursor cur;
 	unsigned int elem_size;
 };
 
 static inline void reset_cursor(struct cursor *cursor)
 {
 	cursor->p = cursor->start;
 }
 
 static inline void wipe_cursor(struct cursor *cursor)
 {
 	reset_cursor(cursor);
 	memset(cursor->start, 0, cursor->end - cursor->start);
 }
 
 static inline void make_cursor(u8 *start, u8 *end, struct cursor *cursor)
 {
 	cursor->start = start;
 	cursor->p = start;
 	cursor->end = end;
 }
 
 static inline void make_array(struct array *a, u8* start, u8 *end, unsigned int elem_size)
 {
 	make_cursor(start, end, &a->cur);
 	a->elem_size = elem_size;
 }
 
 static inline int cursor_eof(struct cursor *c)
 {
 	return c->p == c->end;
 }
 
 static inline void *cursor_malloc(struct cursor *mem, unsigned long size)
 {
 	void *ret;
 
 	if (mem->p + size > mem->end) {
 		return NULL;
 	}
 
 	ret = mem->p;
 	mem->p += size;
 
 	return ret;
 }
 
 static inline void *cursor_alloc(struct cursor *mem, unsigned long size)
 {
 	void *ret;
 	if (!(ret = cursor_malloc(mem, size))) {
 		return 0;
 	}
 
 	memset(ret, 0, size);
 	return ret;
 }
 
 static inline int cursor_slice(struct cursor *mem, struct cursor *slice, size_t size)
 {
 	u8 *p;
 	if (!(p = cursor_alloc(mem, size))) {
 		return 0;
 	}
 	make_cursor(p, mem->p, slice);
 	return 1;
 }
 
 
 static inline void copy_cursor(struct cursor *src, struct cursor *dest)
 {
 	dest->start = src->start;
 	dest->p = src->p;
 	dest->end = src->end;
 }
 
 static inline int cursor_skip(struct cursor *cursor, int n)
 {
     if (cursor->p + n >= cursor->end)
         return 0;
 
     cursor->p += n;
 
     return 1;
 }
 
 static inline int pull_byte(struct cursor *cursor, u8 *c)
 {
 	if (unlikely(cursor->p >= cursor->end))
 		return 0;
 
 	*c = *cursor->p;
 	cursor->p++;
 
 	return 1;
 }
 
 static inline int parse_byte(struct cursor *cursor, u8 *c)
 {
     if (unlikely(cursor->p >= cursor->end))
         return 0;
 
     *c = *cursor->p;
     //cursor->p++;
 
     return 1;
 }
 
 static inline int parse_char(struct cursor *cur, char c) {
     if (cur->p >= cur->end)
         return 0;
         
     if (*cur->p == c) {
         cur->p++;
         return 1;
     }
     
     return 0;
 }
 
 static inline int peek_char(struct cursor *cur, int ind) {
     if ((cur->p + ind < cur->start) || (cur->p + ind >= cur->end))
         return -1;
     
     return *(cur->p + ind);
 }
 
 static inline int cursor_pull_c_str(struct cursor *cursor, const char **str)
 {
 	*str = (const char*)cursor->p;
 
 	for (; cursor->p < cursor->end; cursor->p++) {
 		if (*cursor->p == 0) {
 			cursor->p++;
 			return 1;
 		}
 	}
 
 	return 0;
 }
 
 
 static inline int cursor_push_byte(struct cursor *cursor, u8 c)
 {
 	if (unlikely(cursor->p + 1 > cursor->end)) {
 		return 0;
 	}
 
 	*cursor->p = c;
 	cursor->p++;
 
 	return 1;
 }
 
 static inline int cursor_pull(struct cursor *cursor, u8 *data, int len)
 {
 	if (unlikely(cursor->p + len > cursor->end)) {
 		return 0;
 	}
 
 	memcpy(data, cursor->p, len);
 	cursor->p += len;
 
 	return 1;
 }
 
 static inline int pull_data_into_cursor(struct cursor *cursor,
 			  struct cursor *dest,
 			  unsigned char **data,
 			  int len)
 {
 	int ok;
 
 	if (unlikely(dest->p + len > dest->end)) {
 		printf("not enough room in dest buffer\n");
 		return 0;
 	}
 
 	ok = cursor_pull(cursor, dest->p, len);
 	if (!ok) return 0;
 
 	*data = dest->p;
 	dest->p += len;
 
 	return 1;
 }
 
 static inline int cursor_dropn(struct cursor *cur, int size, int n)
 {
 	if (n == 0)
 		return 1;
 
 	if (unlikely(cur->p - size*n < cur->start)) {
 		return 0;
 	}
 
 	cur->p -= size*n;
 	return 1;
 }
 
 static inline int cursor_drop(struct cursor *cur, int size)
 {
 	return cursor_dropn(cur, size, 1);
 }
 
 static inline unsigned char *cursor_topn(struct cursor *cur, int len, int n)
 {
 	n += 1;
 	if (unlikely(cur->p - len*n < cur->start)) {
 		return NULL;
 	}
 	return cur->p - len*n;
 }
 
 static inline unsigned char *cursor_top(struct cursor *cur, int len)
 {
 	if (unlikely(cur->p - len < cur->start)) {
 		return NULL;
 	}
 	return cur->p - len;
 }
 
 static inline int cursor_top_int(struct cursor *cur, int *i)
 {
 	u8 *p;
 	if (unlikely(!(p = cursor_top(cur, sizeof(*i))))) {
 		return 0;
 	}
 	*i = *((int*)p);
 	return 1;
 }
 
 static inline int cursor_pop(struct cursor *cur, u8 *data, int len)
 {
 	if (unlikely(cur->p - len < cur->start)) {
 		return 0;
 	}
 
 	cur->p -= len;
 	memcpy(data, cur->p, len);
 
 	return 1;
 }
 
 static inline int cursor_push(struct cursor *cursor, u8 *data, int len)
 {
 	if (unlikely(cursor->p + len >= cursor->end)) {
 		return 0;
 	}
 
 	if (cursor->p != data)
 		memcpy(cursor->p, data, len);
 
 	cursor->p += len;
 
 	return 1;
 }
 
 static inline int cursor_push_int(struct cursor *cursor, int i)
 {
 	return cursor_push(cursor, (u8*)&i, sizeof(i));
 }
 
 static inline size_t cursor_count(struct cursor *cursor, size_t elem_size)
 {
 	return (cursor->p - cursor->start)/elem_size;
 }
 
 /* TODO: push_varint */
 static inline int push_varint(struct cursor *cursor, int n)
 {
 	int ok, len;
 	unsigned char b;
 	len = 0;
 
 	while (1) {
 		b = (n & 0xFF) | 0x80;
 		n >>= 7;
 		if (n == 0) {
 			b &= 0x7F;
 			ok = cursor_push_byte(cursor, b);
 			len++;
 			if (!ok) return 0;
 			break;
 		}
 
 		ok = cursor_push_byte(cursor, b);
 		len++;
 		if (!ok) return 0;
 	}
 
 	return len;
 }
 
 /* TODO: pull_varint */
 static inline int pull_varint(struct cursor *cursor, int *n)
 {
 	int ok, i;
 	unsigned char b;
 	*n = 0;
 
 	for (i = 0;; i++) {
 		ok = pull_byte(cursor, &b);
 		if (!ok) return 0;
 
 		*n |= ((int)b & 0x7F) << (i * 7);
 
 		/* is_last */
 		if ((b & 0x80) == 0) {
 			return i+1;
 		}
 
 		if (i == 4) return 0;
 	}
 
 	return 0;
 }
 
 static inline int cursor_pull_int(struct cursor *cursor, int *i)
 {
 	return cursor_pull(cursor, (u8*)i, sizeof(*i));
 }
 
 static inline int cursor_push_u32(struct cursor *cursor, uint32_t i) {
     return cursor_push(cursor, (unsigned char*)&i, sizeof(i));
 }
 
 static inline int cursor_push_u16(struct cursor *cursor, u16 i)
 {
 	return cursor_push(cursor, (u8*)&i, sizeof(i));
 }
 
 static inline void *index_cursor(struct cursor *cursor, unsigned int index, int elem_size)
 {
 	u8 *p;
 	p = &cursor->start[elem_size * index];
 
 	if (unlikely(p >= cursor->end))
 		return NULL;
 
 	return (void*)p;
 }
 
 
 static inline int push_sized_str(struct cursor *cursor, const char *str, int len)
 {
 	return cursor_push(cursor, (u8*)str, len);
 }
 
 static inline int cursor_push_lowercase(struct cursor *cur, const char *str, int len)
 {
 	int i;
 
 	if (unlikely(cur->p + len >= cur->end))
 		return 0;
 
 	for (i = 0; i < len; i++)
 		cur->p[i] = tolower(str[i]);
 
 	cur->p += len;
 	return 1;
 }
 
 static inline int cursor_push_str(struct cursor *cursor, const char *str)
 {
 	return cursor_push(cursor, (u8*)str, (int)strlen(str));
 }
 
 static inline int cursor_push_c_str(struct cursor *cursor, const char *str)
 {
 	return cursor_push_str(cursor, str) && cursor_push_byte(cursor, 0);
 }
 
 /* TODO: push varint size */
 static inline int push_prefixed_str(struct cursor *cursor, const char *str)
 {
 	int ok, len;
 	len = (int)strlen(str);
 	ok = push_varint(cursor, len);
 	if (!ok) return 0;
 	return push_sized_str(cursor, str, len);
 }
 
 static inline int pull_prefixed_str(struct cursor *cursor, struct cursor *dest_buf, const char **str)
 {
 	int len, ok;
 
 	ok = pull_varint(cursor, &len);
 	if (!ok) return 0;
 
 	if (unlikely(dest_buf->p + len > dest_buf->end)) {
 		return 0;
 	}
 
 	ok = pull_data_into_cursor(cursor, dest_buf, (unsigned char**)str, len);
 	if (!ok) return 0;
 
 	ok = cursor_push_byte(dest_buf, 0);
 
 	return 1;
 }
 
 static inline int cursor_remaining_capacity(struct cursor *cursor)
 {
 	return (int)(cursor->end - cursor->p);
 }
 
 
 #define max(a,b) ((a) > (b) ? (a) : (b))
 static inline void cursor_print_around(struct cursor *cur, int range)
 {
 	unsigned char *c;
 
 	printf("[%ld/%ld]\n", cur->p - cur->start, cur->end - cur->start);
 
 	c = max(cur->p - range, cur->start);
 	for (; c < cur->end && c < (cur->p + range); c++) {
 		printf("%02x", *c);
 	}
 	printf("\n");
 
 	c = max(cur->p - range, cur->start);
 	for (; c < cur->end && c < (cur->p + range); c++) {
 		if (c == cur->p) {
 			printf("^");
 			continue;
 		}
 		printf("  ");
 	}
 	printf("\n");
 }
 #undef max
 
 static inline int pull_bytes(struct cursor *cur, int count, const u8 **bytes) {
     if (cur->p + count > cur->end)
         return 0;
     
     *bytes = cur->p;
     cur->p += count;
     return 1;
 }
 
 static inline int parse_str(struct cursor *cur, const char *str) {
     int i;
     char c, cs;
     unsigned long len;
     
     len = strlen(str);
     
     if (cur->p + len >= cur->end)
         return 0;
     
     for (i = 0; i < len; i++) {
         c = tolower(cur->p[i]);
         cs = tolower(str[i]);
         
         if (c != cs)
             return 0;
     }
     
     cur->p += len;
     
     return 1;
 }
 
 static inline int is_whitespace(int c) {
     return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r';
 }
 
 
 static inline int next_char_is_whitespace(unsigned char *curChar, unsigned char *endChar) {
     unsigned char * next = curChar + 1;
     if(next > endChar) return 0;
     else if(next == endChar) return 1;
     return is_whitespace(*next);
 }
 
 static int char_disallowed_at_end_url(char c){
     return c == '.' || c == ',';
 }
 
 static inline int is_final_url_char(unsigned char *curChar, unsigned char *endChar){
     if(is_whitespace(*curChar)){
         return 1;
     }
     else if(next_char_is_whitespace(curChar, endChar)) {
         // next char is whitespace so this char could be the final char in the url
         return char_disallowed_at_end_url(*curChar);
     }
     else{
         // next char isn't whitespace so it can't be a final char
         return 0;
     }
 }
 
 static inline int is_underscore(int c) {
     return c == '_';
 }
 
 static inline int is_utf8_byte(u8 c) {
     return c & 0x80;
 }
 
 static inline int parse_utf8_char(struct cursor *cursor, unsigned int *code_point, unsigned int *utf8_length)
 {
     u8 first_byte;
     if (!parse_byte(cursor, &first_byte))
         return 0; // Not enough data
 
     // Determine the number of bytes in this UTF-8 character
     int remaining_bytes = 0;
     if (first_byte < 0x80) {
         *code_point = first_byte;
         return 1;
     } else if ((first_byte & 0xE0) == 0xC0) {
         remaining_bytes = 1;
         *utf8_length = remaining_bytes + 1;
         *code_point = first_byte & 0x1F;
     } else if ((first_byte & 0xF0) == 0xE0) {
         remaining_bytes = 2;
         *utf8_length = remaining_bytes + 1;
         *code_point = first_byte & 0x0F;
     } else if ((first_byte & 0xF8) == 0xF0) {
         remaining_bytes = 3;
         *utf8_length = remaining_bytes + 1;
         *code_point = first_byte & 0x07;
     } else {
         remaining_bytes = 0;
         *utf8_length = 1; // Assume 1 byte length for unrecognized UTF-8 characters
         // TODO: We need to gracefully handle unrecognized UTF-8 characters
         printf("Invalid UTF-8 byte: %x\n", *code_point);
         *code_point = ((first_byte & 0xF0) << 6); // Prevent testing as punctuation
         return 0; // Invalid first byte
     }
 
     // Peek at remaining bytes
     for (int i = 0; i < remaining_bytes; ++i) {
         signed char next_byte;
         if ((next_byte = peek_char(cursor, i+1)) == -1) {
             *utf8_length = 1;
             return 0; // Not enough data
         }
         
         // Debugging lines
         //printf("Cursor: %s\n", cursor->p);
         //printf("Codepoint: %x\n", *code_point);
         //printf("Codepoint <<6: %x\n", ((*code_point << 6) | (next_byte & 0x3F)));
         //printf("Remaining bytes: %x\n", remaining_bytes);
         //printf("First byte: %x\n", first_byte);
         //printf("Next byte: %x\n", next_byte);
         //printf("Bitwise AND result: %x\n", (next_byte & 0xC0));
         
         if ((next_byte & 0xC0) != 0x80) {
             *utf8_length = 1;
             return 0; // Invalid byte in sequence
         }
 
         *code_point = (*code_point << 6) | (next_byte & 0x3F);
     }
 
     return 1;
 }
 
 /**
   * Checks if a given Unicode code point is a punctuation character
   *
   * @param codepoint The Unicode code point to check. @return true if the
   * code point is a punctuation character, false otherwise.
   */
 static inline int is_punctuation(unsigned int codepoint) {
 
     // Check for underscore (underscore is not treated as punctuation)
     if (is_underscore(codepoint))
         return 0;
     
     // Check for ASCII punctuation
     if (ispunct(codepoint))
         return 1;
 
     // Check for Unicode punctuation exceptions (punctuation allowed in hashtags)
     if (codepoint == 0x301C || codepoint == 0xFF5E) // Japanese Wave Dash / Tilde
         return 0;
     
     // Check for Unicode punctuation
     // NOTE: We may need to adjust the codepoint ranges in the future,
     // to include/exclude certain types of Unicode characters in hashtags.
     // Unicode Blocks Reference: https://www.compart.com/en/unicode/block
     return (
         // Latin-1 Supplement No-Break Space (NBSP): U+00A0
         (codepoint == 0x00A0) ||
         
         // Latin-1 Supplement Punctuation: U+00A1 to U+00BF
         (codepoint >= 0x00A1 && codepoint <= 0x00BF) ||
 
         // General Punctuation: U+2000 to U+206F
         (codepoint >= 0x2000 && codepoint <= 0x206F) ||
 
         // Currency Symbols: U+20A0 to U+20CF
         (codepoint >= 0x20A0 && codepoint <= 0x20CF) ||
 
         // Supplemental Punctuation: U+2E00 to U+2E7F
         (codepoint >= 0x2E00 && codepoint <= 0x2E7F) ||
 
         // CJK Symbols and Punctuation: U+3000 to U+303F
         (codepoint >= 0x3000 && codepoint <= 0x303F) ||
 
         // Ideographic Description Characters: U+2FF0 to U+2FFF
         (codepoint >= 0x2FF0 && codepoint <= 0x2FFF)
     );
 }
 
 static inline int is_right_boundary(int c) {
     return is_whitespace(c) || is_punctuation(c);
 }
 
 static inline int is_left_boundary(char c) {
     return is_right_boundary(c) || is_utf8_byte(c);
 }
 
 static inline int is_alphanumeric(char c) {
     return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9');
 }
 
 static inline int consume_until_boundary(struct cursor *cur) {
     unsigned int c;
     unsigned int char_length = 1;
     unsigned int *utf8_char_length = &char_length;
     
     while (cur->p < cur->end) {
         c = *cur->p;
         
         *utf8_char_length = 1;
         
         if (is_whitespace(c))
             return 1;
         
         // Need to check for UTF-8 characters, which can be multiple bytes long
         if (is_utf8_byte(c)) {
             if (!parse_utf8_char(cur, &c, utf8_char_length)) {
                 if (!is_right_boundary(c)){
                     // TODO: We should work towards handling all UTF-8 characters.
                     printf("Invalid UTF-8 code point: %x\n", c);
                 }
             }
         }
         
         if (is_right_boundary(c))
             return 1;
         
         // Need to use a variable character byte length for UTF-8 (2-4 bytes)
         if (cur->p + *utf8_char_length <= cur->end)
             cur->p += *utf8_char_length;
         else
             cur->p++;
     }
     
     return 1;
 }
 
 static inline int consume_until_whitespace(struct cursor *cur, int or_end) {
     char c;
     int consumedAtLeastOne = 0;
     
     while (cur->p < cur->end) {
         c = *cur->p;
         
         if (is_whitespace(c))
             return consumedAtLeastOne;
         
         cur->p++;
         consumedAtLeastOne = 1;
     }
     
     return or_end;
 }
 
 static inline int consume_until_end_url(struct cursor *cur, int or_end) {
     char c;
     int consumedAtLeastOne = 0;
     
     while (cur->p < cur->end) {
         c = *cur->p;
         
         if (is_final_url_char(cur->p, cur->end))
             return consumedAtLeastOne;
         
         cur->p++;
         consumedAtLeastOne = 1;
     }
     
     return or_end;
 }
 
 static inline int consume_until_non_alphanumeric(struct cursor *cur, int or_end) {
     char c;
     int consumedAtLeastOne = 0;
 
     while (cur->p < cur->end) {
         c = *cur->p;
 
         if (!is_alphanumeric(c))
             return consumedAtLeastOne;
 
         cur->p++;
         consumedAtLeastOne = 1;
     }
 
     return or_end;
 }
 
 
 static inline int cursor_memset(struct cursor *cursor, unsigned char c, int n)
 {
     if (cursor->p + n >= cursor->end)
         return 0;
 
     memset(cursor->p, c, n);
     cursor->p += n;
 
     return 1;
 }
 
 
 #endif