[geany/geany] e1ae97: Add ctags 'readtags' library to allow us parse ctags files - Commits

17 Oct 2023


      Branch:      refs/heads/master
Author:      Jiří Techet techet@gmail.com
Committer:   Jiří Techet techet@gmail.com
Date:        Thu, 12 Oct 2023 20:29:55 UTC
Commit:      e1ae976a7284d59f24b387825e967a2e6794a330
             https://github.com/geany/geany/commit/e1ae976a7284d59f24b387825e967a2e6794a3...
Log Message:
-----------
Add ctags 'readtags' library to allow us parse ctags files
Modified Paths:
--------------
    ctags/Makefile.am
    ctags/libreadtags/readtags.c
    ctags/libreadtags/readtags.h
    meson.build
Modified: ctags/Makefile.am
2 lines changed, 2 insertions(+), 0 deletions(-)
===================================================================
@@ -112,6 +112,8 @@ libctags_la_SOURCES = \
    dsl/optscript.h \
    dsl/es.c \
    dsl/es.h \
+	libreadtags/readtags.c \
+	libreadtags/readtags.h \
    main/args.c \
    main/args_p.h \
    main/colprint.c \
Modified: ctags/libreadtags/readtags.c
1310 lines changed, 1310 insertions(+), 0 deletions(-)
===================================================================
@@ -0,0 +1,1310 @@
+/*
+*   Copyright (c) 1996-2003, Darren Hiebert
+*
+*   This source code is released into the public domain.
+*
+*   This module contains functions for reading tag files.
+*/
+
+/*
+*   INCLUDE FILES
+*/
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/types.h>  /* to declare off_t */
+
+#include "readtags.h"
+
+/*
+*   MACROS
+*/
+#define TAB '\t'
+
+
+/*
+*   DATA DECLARATIONS
+*/
+typedef struct {
+	size_t size;
+	char *buffer;
+} vstring;
+
+/* Information about current tag file */
+struct sTagFile {
+		/* has the file been opened and this structure initialized? */
+	short initialized;
+		/* format of tag file */
+	short format;
+		/* how is the tag file sorted? */
+	tagSortType sortMethod;
+		/* pointer to file structure */
+	FILE* fp;
+		/* file position of first character of `line' */
+	off_t pos;
+		/* size of tag file in seekable positions */
+	off_t size;
+		/* last line read */
+	vstring line;
+		/* name of tag in last line read */
+	vstring name;
+		/* defines tag search state */
+	struct {
+				/* file position of last match for tag */
+			off_t pos;
+				/* name of tag last searched for */
+			char *name;
+				/* length of name for partial matches */
+			size_t nameLength;
+				/* performing partial match */
+			short partial;
+				/* ignoring case */
+			short ignorecase;
+	} search;
+		/* miscellaneous extension fields */
+	struct {
+				/* number of entries in `list' */
+			unsigned short max;
+				/* list of key value pairs */
+			tagExtensionField *list;
+	} fields;
+		/* buffers to be freed at close */
+	struct {
+			/* name of program author */
+		char *author;
+			/* name of program */
+		char *name;
+			/* URL of distribution */
+		char *url;
+			/* program version */
+		char *version;
+	} program;
+		/* 0 (initial state set by calloc), errno value,
+		 * or tagErrno typed value */
+	int err;
+};
+
+/*
+*   DATA DEFINITIONS
+*/
+static const char *const EmptyString = "";
+static const char *const PseudoTagPrefix = "!_";
+static const size_t PseudoTagPrefixLength = 2;
+
+/*
+*   FUNCTION DEFINITIONS
+*/
+
+/* Converts a hexadecimal digit to its value */
+static int xdigitValue (char digit)
+{
+	if (digit >= '0' && digit <= '9')
+		return digit - '0';
+	else if (digit >= 'a' && digit <= 'f')
+		return 10 + digit - 'a';
+	else if (digit >= 'A' && digit <= 'F')
+		return 10 + digit - 'A';
+	else
+		return 0;
+}
+
+/*
+ * Reads the first character from the string, possibly un-escaping it, and
+ * advances *s to the start of the next character.
+ */
+static int readTagCharacter (const char **s)
+{
+	int c = **(const unsigned char **)s;
+
+	(*s)++;
+
+	if (c == '\')
+	{
+		switch (**s)
+		{
+			case 't': c = '\t'; (*s)++; break;
+			case 'r': c = '\r'; (*s)++; break;
+			case 'n': c = '\n'; (*s)++; break;
+			case '\': c = '\'; (*s)++; break;
+			/* Universal-CTags extensions */
+			case 'a': c = '\a'; (*s)++; break;
+			case 'b': c = '\b'; (*s)++; break;
+			case 'v': c = '\v'; (*s)++; break;
+			case 'f': c = '\f'; (*s)++; break;
+			case 'x':
+				if (isxdigit ((*s)[1]) && isxdigit ((*s)[2]))
+				{
+					int val = (xdigitValue ((*s)[1]) << 4) | xdigitValue ((*s)[2]);
+					if (val < 0x80)
+					{
+						(*s) += 3;
+						c = val;
+					}
+				}
+				break;
+		}
+	}
+
+	return c;
+}
+
+/*
+ * Compare two strings, ignoring case.
+ * Return 0 for match, < 0 for smaller, > 0 for bigger
+ * Make sure case is folded to uppercase in comparison (like for 'sort -f')
+ * This makes a difference when one of the chars lies between upper and lower
+ * ie. one of the chars [ \ ] ^ _ ` for ascii. (The '_' in particular !)
+ */
+static int taguppercmp (const char *s1, const char *s2)
+{
+	int result;
+	int c1, c2;
+	do
+	{
+		c1 = (unsigned char)*s1++;
+		c2 = readTagCharacter (&s2);
+
+		result = toupper (c1) - toupper (c2);
+	} while (result == 0  &&  c1 != '\0'  &&  c2 != '\0');
+	return result;
+}
+
+static int tagnuppercmp (const char *s1, const char *s2, size_t n)
+{
+	int result;
+	int c1, c2;
+	do
+	{
+		c1 = (unsigned char)*s1++;
+		c2 = readTagCharacter (&s2);
+
+		result = toupper (c1) - toupper (c2);
+	} while (result == 0  &&  --n > 0  &&  c1 != '\0'  &&  c2 != '\0');
+	return result;
+}
+
+static int tagcmp (const char *s1, const char *s2)
+{
+	int result;
+	int c1, c2;
+	do
+	{
+		c1 = (unsigned char)*s1++;
+		c2 = readTagCharacter (&s2);
+
+		result = c1 - c2;
+	} while (result == 0  &&  c1 != '\0'  &&  c2 != '\0');
+	return result;
+}
+
+static int tagncmp (const char *s1, const char *s2, size_t n)
+{
+	int result;
+	int c1, c2;
+	do
+	{
+		c1 = *s1++;
+		c2 = readTagCharacter (&s2);
+
+		result = c1 - c2;
+	} while (result == 0  &&  --n > 0  &&  c1 != '\0'  &&  c2 != '\0');
+	return result;
+}
+
+static tagResult growString (vstring *s)
+{
+	tagResult result = TagFailure;
+	size_t newLength;
+	char *newLine;
+	if (s->size == 0)
+	{
+		newLength = 128;
+		newLine = (char*) malloc (newLength);
+		if (newLine)
+			*newLine = '\0';
+	}
+	else
+	{
+		newLength = 2 * s->size;
+		newLine = (char*) realloc (s->buffer, newLength);
+	}
+	if (newLine == NULL)
+		perror ("string too large");
+	else
+	{
+		s->buffer = newLine;
+		s->size = newLength;
+		result = TagSuccess;
+	}
+	return result;
+}
+
+/* Copy name of tag out of tag line */
+static tagResult copyName (tagFile *const file)
+{
+	size_t length;
+	const char *end = strchr (file->line.buffer, '\t');
+	if (end == NULL)
+	{
+		end = strchr (file->line.buffer, '\n');
+		if (end == NULL)
+			end = strchr (file->line.buffer, '\r');
+	}
+	if (end != NULL)
+		length = end - file->line.buffer;
+	else
+		length = strlen (file->line.buffer);
+	while (length >= file->name.size)
+	{
+		if (growString (&file->name) != TagSuccess)
+			return TagFailure;
+	}
+	strncpy (file->name.buffer, file->line.buffer, length);
+	file->name.buffer [length] = '\0';
+	return TagSuccess;
+}
+
+/* Return 1 on success.
+ * Return 0 on failure or EOF.
+ * errno is set to *err unless EOF.
+ */
+static int readTagLineRaw (tagFile *const file, int *err)
+{
+	int result = 1;
+	int reReadLine;
+
+	/*  If reading the line places any character other than a null or a
+	 *  newline at the last character position in the buffer (one less than
+	 *  the buffer size), then we must resize the buffer and reattempt to read
+	 *  the line.
+	 */
+	do
+	{
+		char *const pLastChar = file->line.buffer + file->line.size - 2;
+		char *line;
+
+		file->pos = ftell (file->fp);
+		if (file->pos < 0)
+		{
+			*err = errno;
+			result = 0;
+			break;
+		}
+		reReadLine = 0;
+		*pLastChar = '\0';
+		line = fgets (file->line.buffer, (int) file->line.size, file->fp);
+		if (line == NULL)
+		{
+			/* read error */
+			*err = 0;
+			if (! feof (file->fp))
+				*err = errno;
+			result = 0;
+		}
+		else if (*pLastChar != '\0'  &&
+					*pLastChar != '\n'  &&  *pLastChar != '\r')
+		{
+			/*  buffer overflow */
+			if (growString (&file->line) != TagSuccess)
+			{
+				*err = ENOMEM;
+				result = 0;
+			}
+			if (fseek (file->fp, file->pos, SEEK_SET) < 0)
+			{
+				*err = errno;
+				result = 0;
+			}
+			reReadLine = 1;
+		}
+		else
+		{
+			size_t i = strlen (file->line.buffer);
+			while (i > 0  &&
+				   (file->line.buffer [i - 1] == '\n' || file->line.buffer [i - 1] == '\r'))
+			{
+				file->line.buffer [i - 1] = '\0';
+				--i;
+			}
+		}
+	} while (reReadLine  &&  result);
+	if (result)
+	{
+		if (copyName (file) != TagSuccess)
+		{
+			*err = ENOMEM;
+			result = 0;
+		}
+	}
+	return result;
+}
+
+/* Return 1 on success.
+ * Return 0 on failure or EOF.
+ * errno is set to *err unless EOF.
+ */
+static int readTagLine (tagFile *const file, int *err)
+{
+	int result;
+	do
+	{
+		result = readTagLineRaw (file, err);
+	} while (result && *file->name.buffer == '\0');
+	return result;
+}
+
+static tagResult growFields (tagFile *const file)
+{
+	tagResult result = TagFailure;
+	unsigned short newCount = (unsigned short) 2 * file->fields.max;
+	tagExtensionField *newFields = (tagExtensionField*)
+			realloc (file->fields.list, newCount * sizeof (tagExtensionField));
+	if (newFields == NULL)
+		perror ("too many extension fields");
+	else
+	{
+		file->fields.list = newFields;
+		file->fields.max = newCount;
+		result = TagSuccess;
+	}
+	return result;
+}
+
+static tagResult parseExtensionFields (tagFile *const file, tagEntry *const entry,
+									   char *const string, int *err)
+{
+	char *p = string;
+	char *tail = string + (string? strlen(string):0);
+	size_t q_len;
+
+	while (p != NULL  &&  *p != '\0')
+	{
+		while (*p == TAB)
+			*p++ = '\0';
+		if (*p != '\0')
+		{
+			char *colon;
+			char *field = p;
+			p = strchr (p, TAB);
+			if (p != NULL)
+				*p++ = '\0';
+			colon = strchr (field, ':');
+			if (colon == NULL)
+				entry->kind = field;
+			else
+			{
+				const char *key = field;
+				char *q = colon + 1;
+				const char *value = q;
+				const int key_len = colon - key;
+				*colon = '\0';
+
+				q_len = tail - q;
+
+				/* Unescaping */
+				while (*q != '\0')
+				{
+					const char *next = q;
+					int ch = readTagCharacter (&next);
+					size_t skip = next - q;
+
+					*q = (char) ch;
+					q++;
+					q_len -= skip;
+					if (skip > 1)
+					{
+						/* + 1 is for moving the area including the last '\0'. */
+						memmove (q, next, q_len + 1);
+						if (p)
+							p -= skip - 1;
+						if (tail != string)
+							tail -= skip - 1;
+					}
+				}
+
+				if (key_len == 4)
+				{
+					if (memcmp (key, "kind", 4) == 0)
+						entry->kind = value;
+					else if (memcmp (key, "file", 4) == 0)
+						entry->fileScope = 1;
+					else if (memcmp (key, "line", 4) == 0)
+					{
+						char *endptr = NULL;
+						long m = strtol (value, &endptr, 10);
+						if (*endptr != '\0' || m < 0)
+						{
+							*err = TagErrnoUnexpectedLineno;
+							return TagFailure;
+						}
+						entry->address.lineNumber = m;
+					}
+					else
+						goto normalField;
+				}
+				else
+				{
+				normalField:
+					if (entry->fields.count == file->fields.max)
+					{
+						if (growFields (file) != TagSuccess)
+						{
+							*err = ENOMEM;
+							return TagFailure;
+						}
+					}
+					file->fields.list [entry->fields.count].key = key;
+					file->fields.list [entry->fields.count].value = value;
+					++entry->fields.count;
+				}
+			}
+		}
+	}
+	return TagSuccess;
+}
+
+static int isOdd (unsigned int i)
+{
+	return  (i % 2);
+}
+
+static unsigned int countContinuousBackslashesBackward(const char *from,
+						     const char *till)
+{
+	unsigned int counter = 0;
+
+	for (; from > till; from--)
+	{
+		if (*from == '\')
+			counter++;
+		else
+			break;
+	}
+	return counter;
+}
+
+static tagResult parseTagLine (tagFile *file, tagEntry *const entry, int *err)
+{
+	int i;
+	char *p = file->line.buffer;
+	size_t p_len = strlen (p);
+	char *tab = strchr (p, TAB);
+
+	memset(entry, 0, sizeof(*entry));
+
+	entry->name = p;
+	if (tab != NULL)
+	{
+		*tab = '\0';
+	}
+
+	/* When unescaping, the input string becomes shorter.
+	 * e.g. \t occupies two bytes on the tag file.
+	 * It is converted to 0x9 and occupies one byte.
+	 * memmove called here for shortening the line
+	 * buffer. */
+	while (*p != '\0')
+	{
+		const char *next = p;
+		int ch = readTagCharacter (&next);
+		size_t skip = next - p;
+
+		*p = (char) ch;
+		p++;
+		p_len -= skip;
+		if (skip > 1)
+		{
+			/* + 1 is for moving the area including the last '\0'. */
+			memmove (p, next, p_len + 1);
+			if (tab)
+				tab -= skip - 1;
+		}
+	}
+
+	if (tab != NULL)
+	{
+		p = tab + 1;
+		entry->file = p;
+		tab = strchr (p, TAB);
+		if (tab != NULL)
+		{
+			int fieldsPresent;
+			int combinedPattern;
+			*tab = '\0';
+			p = tab + 1;
+			if (*p == '/'  ||  *p == '?')
+			{
+				/* parse pattern */
+				int delimiter = *(unsigned char*) p;
+				entry->address.lineNumber = 0;
+				entry->address.pattern = p;
+				do
+				{
+					p = strchr (p + 1, delimiter);
+				} while (p != NULL
+					 &&  isOdd (countContinuousBackslashesBackward (p - 1,
+											entry->address.pattern)));
+
+				if (p == NULL)
+				{
+					/* TODO: invalid pattern */
+				}
+				else
+					++p;
+			}
+			else if (isdigit ((int) *(unsigned char*) p))
+			{
+				/* parse line number */
+				entry->address.pattern = p;
+				entry->address.lineNumber = atol (p);
+				while (isdigit ((int) *(unsigned char*) p))
+					++p;
+				if (p)
+				{
+					combinedPattern = (strncmp (p, ";/", 2) == 0) ||
+											(strncmp (p, ";?", 2) == 0);
+					if (combinedPattern)
+					{
+						++p;
+						/* parse pattern */
+						int delimiter = *(unsigned char*) p;
+						do
+						{
+							p = strchr (p + 1, delimiter);
+						} while (p != NULL
+							 &&  isOdd (countContinuousBackslashesBackward (p - 1,
+													entry->address.pattern)));
+
+						if (p == NULL)
+						{
+							/* TODO: invalid pattern */
+						}
+						else
+							++p;
+					}
+				}
+			}
+			else
+			{
+				/* TODO: invalid pattern */
+			}
+
+			if (p)
+			{
+				fieldsPresent = (strncmp (p, ";"", 2) == 0);
+				*p = '\0';
+				if (fieldsPresent)
+				{
+					if (parseExtensionFields (file, entry, p + 2, err) != TagSuccess)
+						return TagFailure;
+				}
+			}
+		}
+	}
+	if (entry->fields.count > 0)
+		entry->fields.list = file->fields.list;
+	for (i = entry->fields.count  ;  i < file->fields.max  ;  ++i)
+	{
+		file->fields.list [i].key = NULL;
+		file->fields.list [i].value = NULL;
+	}
+	return TagSuccess;
+}
+
+static char *duplicate (const char *str)
+{
+	char *result = NULL;
+	if (str != NULL)
+	{
+		result = strdup (str);
+		if (result == NULL)
+			perror (NULL);
+	}
+	return result;
+}
+
+static int isPseudoTagLine (const char *buffer)
+{
+	return (strncmp (buffer, PseudoTagPrefix, PseudoTagPrefixLength) == 0);
+}
+
+static tagResult readPseudoTags (tagFile *const file, tagFileInfo *const info)
+{
+	fpos_t startOfLine;
+	int err = 0;
+	tagResult result = TagSuccess;
+	const size_t prefixLength = strlen (PseudoTagPrefix);
+
+	info->file.format     = 1;
+	info->file.sort       = TAG_UNSORTED;
+	info->program.author  = NULL;
+	info->program.name    = NULL;
+	info->program.url     = NULL;
+	info->program.version = NULL;
+
+	while (1)
+	{
+		if (fgetpos (file->fp, &startOfLine) < 0)
+		{
+			err = errno;
+			break;
+		}
+		if (! readTagLine (file, &err))
+			break;
+		if (!isPseudoTagLine (file->line.buffer))
+			break;
+		else
+		{
+			tagEntry entry;
+			const char *key, *value;
+			if (parseTagLine (file, &entry, &err) != TagSuccess)
+				break;
+			key = entry.name + prefixLength;
+			value = entry.file;
+			if (strcmp (key, "TAG_FILE_SORTED") == 0)
+			{
+				char *endptr = NULL;
+				long m = strtol (value, &endptr, 10);
+				if (*endptr != '\0' || m < 0 || m > 2)
+				{
+					err = TagErrnoUnexpectedSortedMethod;
+					break;
+				}
+				file->sortMethod = (tagSortType) m;
+			}
+			else if (strcmp (key, "TAG_FILE_FORMAT") == 0)
+			{
+				char *endptr = NULL;
+				long m = strtol (value, &endptr, 10);
+				if (*endptr != '\0' || m < 1 || m > 2)
+				{
+					err = TagErrnoUnexpectedFormat;
+					break;
+				}
+				file->format = (short) m;
+			}
+			else if (strcmp (key, "TAG_PROGRAM_AUTHOR") == 0)
+			{
+				file->program.author = duplicate (value);
+				if (value && file->program.author == NULL)
+				{
+					err = ENOMEM;
+					break;
+				}
+			}
+			else if (strcmp (key, "TAG_PROGRAM_NAME") == 0)
+			{
+				file->program.name = duplicate (value);
+				if (value && file->program.name == NULL)
+				{
+					err = ENOMEM;
+					break;
+				}
+			}
+			else if (strcmp (key, "TAG_PROGRAM_URL") == 0)
+			{
+				file->program.url = duplicate (value);
+				if (value && file->program.url == NULL)
+				{
+					err = ENOMEM;
+					break;
+				}
+			}
+			else if (strcmp (key, "TAG_PROGRAM_VERSION") == 0)
+			{
+				file->program.version = duplicate (value);
+				if (value && file->program.version == NULL)
+				{
+					err = ENOMEM;
+					break;
+				}
+			}
+
+			info->file.format     = file->format;
+			info->file.sort       = file->sortMethod;
+			info->program.author  = file->program.author;
+			info->program.name    = file->program.name;
+			info->program.url     = file->program.url;
+			info->program.version = file->program.version;
+		}
+	}
+	if (fsetpos (file->fp, &startOfLine) < 0)
+		err = errno;
+
+	info->status.error_number = err;
+	if (err)
+		result = TagFailure;
+	return result;
+}
+
+static int doesFilePointPseudoTag (tagFile *const file, void *unused)
+{
+	return isPseudoTagLine (file->name.buffer);
+}
+
+static tagResult gotoFirstLogicalTag (tagFile *const file)
+{
+	fpos_t startOfLine;
+
+	if (fseek(file->fp, 0L, SEEK_SET) == -1)
+	{
+		file->err = errno;
+		return TagFailure;
+	}
+
+	while (1)
+	{
+		if (fgetpos (file->fp, &startOfLine) < 0)
+		{
+			file->err = errno;
+			return TagFailure;
+		}
+		if (! readTagLine (file, &file->err))
+		{
+			if (file->err)
+				return TagFailure;
+			break;
+		}
+		if (!isPseudoTagLine (file->line.buffer))
+			break;
+	}
+	if (fsetpos (file->fp, &startOfLine) < 0)
+	{
+		file->err = errno;
+		return TagFailure;
+	}
+	return TagSuccess;
+}
+
+static tagFile *initialize (const char *const filePath, tagFileInfo *const info)
+{
+	tagFile *result = (tagFile*) calloc ((size_t) 1, sizeof (tagFile));
+
+	if (result == NULL)
+	{
+		info->status.opened = 0;
+		info->status.error_number = ENOMEM;
+		return NULL;
+	}
+
+	if (growString (&result->line) != TagSuccess)
+		goto mem_error;
+	if (growString (&result->name) != TagSuccess)
+		goto mem_error;
+	result->fields.max = 20;
+	result->fields.list = (tagExtensionField*) calloc (
+		result->fields.max, sizeof (tagExtensionField));
+	if (result->fields.list == NULL)
+		goto mem_error;
+	result->fp = fopen (filePath, "rb");
+	if (result->fp == NULL)
+	{
+		info->status.error_number = errno;
+		goto file_error;
+	}
+	else
+	{
+		if (fseek (result->fp, 0, SEEK_END) == -1)
+		{
+			info->status.error_number = errno;
+			goto file_error;
+		}
+		result->size = ftell (result->fp);
+		if (result->size == -1)
+		{
+			info->status.error_number = errno;
+			goto file_error;
+		}
+		if (fseek(result->fp, 0L, SEEK_SET) == -1)
+		{
+			info->status.error_number = errno;
+			goto file_error;
+		}
+
+		if (readPseudoTags (result, info) == TagFailure)
+			goto file_error;
+
+		info->status.opened = 1;
+		result->initialized = 1;
+	}
+	return result;
+ mem_error:
+	info->status.error_number = ENOMEM;
+ file_error:
+	free (result->line.buffer);
+	free (result->name.buffer);
+	free (result->fields.list);
+	if (result->fp)
+		fclose (result->fp);
+	free (result);
+	info->status.opened = 0;
+	return NULL;
+}
+
+static void terminate (tagFile *const file)
+{
+	fclose (file->fp);
+
+	free (file->line.buffer);
+	free (file->name.buffer);
+	free (file->fields.list);
+
+	if (file->program.author != NULL)
+		free (file->program.author);
+	if (file->program.name != NULL)
+		free (file->program.name);
+	if (file->program.url != NULL)
+		free (file->program.url);
+	if (file->program.version != NULL)
+		free (file->program.version);
+	if (file->search.name != NULL)
+		free (file->search.name);
+
+	memset (file, 0, sizeof (tagFile));
+
+	free (file);
+}
+
+static tagResult readNext (tagFile *const file, tagEntry *const entry)
+{
+	tagResult result;
+
+	if (file == NULL)
+		return TagFailure;
+
+	if (! file->initialized)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	if (! readTagLine (file, &file->err))
+		return TagFailure;
+
+	result = (entry != NULL)
+		? parseTagLine (file, entry, &file->err)
+		: TagSuccess;
+
+	return result;
+}
+
+static const char *readFieldValue (
+	const tagEntry *const entry, const char *const key)
+{
+	const char *result = NULL;
+	int i;
+	if (strcmp (key, "kind") == 0)
+		result = entry->kind;
+	else if (strcmp (key, "file") == 0)
+		result = EmptyString;
+	else for (i = 0  ;  i < entry->fields.count  &&  result == NULL  ;  ++i)
+		if (strcmp (entry->fields.list [i].key, key) == 0)
+			result = entry->fields.list [i].value;
+	return result;
+}
+
+static int readTagLineSeek (tagFile *const file, const off_t pos)
+{
+	if (fseek (file->fp, pos, SEEK_SET) < 0)
+	{
+		file->err = errno;
+		return 0;
+	}
+
+	/* read probable partial line */
+	if (!readTagLine (file, &file->err))
+		return 0;
+
+	/* read complete line */
+	if (pos > 0)
+		return readTagLine (file, &file->err);
+
+	return 1;
+}
+
+static int nameComparison (tagFile *const file)
+{
+	int result;
+	if (file->search.ignorecase)
+	{
+		if (file->search.partial)
+			result = tagnuppercmp (file->search.name, file->name.buffer,
+					file->search.nameLength);
+		else
+			result = taguppercmp (file->search.name, file->name.buffer);
+	}
+	else
+	{
+		if (file->search.partial)
+			result = tagncmp (file->search.name, file->name.buffer,
+					file->search.nameLength);
+		else
+			result = tagcmp (file->search.name, file->name.buffer);
+	}
+	return result;
+}
+
+static tagResult findFirstNonMatchBefore (tagFile *const file)
+{
+#define JUMP_BACK 512
+	int more_lines;
+	int comp;
+	off_t start = file->pos;
+	off_t pos = start;
+	do
+	{
+		if (pos < (off_t) JUMP_BACK)
+			pos = 0;
+		else
+			pos = pos - JUMP_BACK;
+		more_lines = readTagLineSeek (file, pos);
+		if (more_lines == 0 && file->err)
+			return TagFailure;
+		comp = nameComparison (file);
+	} while (more_lines  &&  comp == 0  &&  pos > 0  &&  pos < start);
+	return TagSuccess;
+}
+
+static tagResult findFirstMatchBefore (tagFile *const file)
+{
+	tagResult result = TagFailure;
+	int more_lines;
+	off_t start = file->pos;
+	if (findFirstNonMatchBefore (file) != TagSuccess)
+		return TagFailure;
+	do
+	{
+		more_lines = readTagLine (file, &file->err);
+		if (more_lines == 0 && file->err)
+			return TagFailure;
+		if (nameComparison (file) == 0)
+			result = TagSuccess;
+	} while (more_lines  &&  result != TagSuccess  &&  file->pos < start);
+	return result;
+}
+
+static tagResult findBinary (tagFile *const file)
+{
+	tagResult result = TagFailure;
+	off_t lower_limit = 0;
+	off_t upper_limit = file->size;
+	off_t last_pos = 0;
+	off_t pos = upper_limit / 2;
+	while (result != TagSuccess)
+	{
+		if (! readTagLineSeek (file, pos))
+		{
+			if (file->err)
+				break;
+			/* in case we fell off end of file */
+			result = findFirstMatchBefore (file);
+			break;
+		}
+		else if (pos == last_pos)
+		{
+			/* prevent infinite loop if we backed up to beginning of file */
+			break;
+		}
+		else
+		{
+			const int comp = nameComparison (file);
+			last_pos = pos;
+			if (comp < 0)
+			{
+				upper_limit = pos;
+				pos = lower_limit + ((upper_limit - lower_limit) / 2);
+			}
+			else if (comp > 0)
+			{
+				lower_limit = pos;
+				pos = lower_limit + ((upper_limit - lower_limit) / 2);
+			}
+			else if (pos == 0)
+				result = TagSuccess;
+			else
+			{
+				result = findFirstMatchBefore (file);
+				if (result != TagSuccess && file->err)
+					break;
+			}
+		}
+	}
+	return result;
+}
+
+static tagResult findSequentialFull (tagFile *const file,
+									 int (* isAcceptable) (tagFile *const, void *),
+									 void *data)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	tagResult result = TagFailure;
+	while (result == TagFailure)
+	{
+		if (! readTagLine (file, &file->err))
+			break;
+		if (isAcceptable (file, data))
+			result = TagSuccess;
+	}
+	return result;
+}
+
+static int nameAcceptable (tagFile *const file, void *unused)
+{
+	return (nameComparison (file) == 0);
+}
+
+static tagResult findSequential (tagFile *const file)
+{
+	return findSequentialFull (file, nameAcceptable, NULL);
+}
+
+static tagResult find (tagFile *const file, tagEntry *const entry,
+					   const char *const name, const int options)
+{
+	tagResult result;
+	if (file->search.name != NULL)
+		free (file->search.name);
+	file->search.name = duplicate (name);
+	if (file->search.name == NULL)
+	{
+		file->err = ENOMEM;
+		return TagFailure;
+	}
+	file->search.nameLength = strlen (name);
+	file->search.partial = (options & TAG_PARTIALMATCH) != 0;
+	file->search.ignorecase = (options & TAG_IGNORECASE) != 0;
+	if (fseek (file->fp, 0, SEEK_END) < 0)
+	{
+		file->err = errno;
+		return TagFailure;
+	}
+	file->size = ftell (file->fp);
+	if (file->size == -1)
+	{
+		file->err = errno;
+		return TagFailure;
+	}
+	if (fseek(file->fp, 0L, SEEK_SET) == -1)
+	{
+		file->err = errno;
+		return TagFailure;
+	}
+	if ((file->sortMethod == TAG_SORTED      && !file->search.ignorecase) ||
+		(file->sortMethod == TAG_FOLDSORTED  &&  file->search.ignorecase))
+	{
+		result = findBinary (file);
+		if (result == TagFailure && file->err)
+			return TagFailure;
+	}
+	else
+	{
+		result = findSequential (file);
+		if (result == TagFailure && file->err)
+			return TagFailure;
+	}
+
+	if (result != TagSuccess)
+		file->search.pos = file->size;
+	else
+	{
+		file->search.pos = file->pos;
+		result = (entry != NULL)
+			? parseTagLine (file, entry, &file->err)
+			: TagSuccess;
+	}
+	return result;
+}
+
+static tagResult findNextFull (tagFile *const file, tagEntry *const entry,
+							   int sorted,
+							   int (* isAcceptable) (tagFile *const, void *),
+							   void *data)
+{
+	tagResult result;
+	if (sorted)
+	{
+		result = tagsNext (file, entry);
+		if (result == TagSuccess  && !isAcceptable (file, data))
+			result = TagFailure;
+	}
+	else
+	{
+		result = findSequentialFull (file, isAcceptable, data);
+		if (result == TagSuccess  &&  entry != NULL)
+			result = parseTagLine (file, entry, &file->err);
+	}
+	return result;
+}
+
+static tagResult findNext (tagFile *const file, tagEntry *const entry)
+{
+	return findNextFull (file, entry,
+						 (file->sortMethod == TAG_SORTED      && !file->search.ignorecase) ||
+						 (file->sortMethod == TAG_FOLDSORTED  &&  file->search.ignorecase),
+						 nameAcceptable, NULL);
+}
+
+static tagResult findPseudoTag (tagFile *const file, int rewindBeforeFinding, tagEntry *const entry)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	if (rewindBeforeFinding)
+	{
+		if (fseek(file->fp, 0L, SEEK_SET) == -1)
+		{
+			file->err = errno;
+			return TagFailure;
+		}
+	}
+	return findNextFull (file, entry,
+						 (file->sortMethod == TAG_SORTED || file->sortMethod == TAG_FOLDSORTED),
+						 doesFilePointPseudoTag,
+						 NULL);
+}
+
+
+/*
+*  EXTERNAL INTERFACE
+*/
+
+extern tagFile *tagsOpen (const char *const filePath, tagFileInfo *const info)
+{
+	tagFileInfo infoDummy;
+	return initialize (filePath, info? info: &infoDummy);
+}
+
+extern tagResult tagsSetSortType (tagFile *const file, const tagSortType type)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	switch (type)
+	{
+	case TAG_UNSORTED:
+	case TAG_SORTED:
+	case TAG_FOLDSORTED:
+		file->sortMethod = type;
+		return TagSuccess;
+	default:
+		file->err = TagErrnoUnexpectedSortedMethod;
+		return TagFailure;
+	}
+}
+
+extern tagResult tagsFirst (tagFile *const file, tagEntry *const entry)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	if (gotoFirstLogicalTag (file) != TagSuccess)
+		return TagFailure;
+	return readNext (file, entry);
+}
+
+extern tagResult tagsNext (tagFile *const file, tagEntry *const entry)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	return readNext (file, entry);
+}
+
+extern const char *tagsField (const tagEntry *const entry, const char *const key)
+{
+	const char *result = NULL;
+	if (entry != NULL)
+		result = readFieldValue (entry, key);
+	return result;
+}
+
+extern tagResult tagsFind (tagFile *const file, tagEntry *const entry,
+						   const char *const name, const int options)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	return find (file, entry, name, options);
+}
+
+extern tagResult tagsFindNext (tagFile *const file, tagEntry *const entry)
+{
+	if (file == NULL)
+		return TagFailure;
+
+	if (!file->initialized || file->err)
+	{
+		file->err = TagErrnoInvalidArgument;
+		return TagFailure;
+	}
+
+	return findNext (file, entry);
+}
+
+extern tagResult tagsFirstPseudoTag (tagFile *const file, tagEntry *const entry)
+{
+	return findPseudoTag (file, 1, entry);
+}
+
+extern tagResult tagsNextPseudoTag (tagFile *const file, tagEntry *const entry)
+{
+	return findPseudoTag (file, 0, entry);
+}
+
+extern tagResult tagsClose (tagFile *const file)
+{
+	tagResult result = TagFailure;
+	if (file != NULL  &&  file->initialized)
+	{
+		terminate (file);
+		result = TagSuccess;
+	}
+	return result;
+}
+
+extern int tagsGetErrno (tagFile *const file)
+{
+	if (file == NULL)
+		return TagErrnoInvalidArgument;
+	return file->err;
+}
Modified: ctags/libreadtags/readtags.h
295 lines changed, 295 insertions(+), 0 deletions(-)
===================================================================
@@ -0,0 +1,295 @@
+/*
+*   Copyright (c) 1996-2003, Darren Hiebert
+*
+*   This source code is released for the public domain.
+*
+*   This file defines the public interface for looking up tag entries in tag
+*   files.
+*
+*   The functions defined in this interface are intended to provide tag file
+*   support to a software tool. The tag lookups provided are sufficiently fast
+*   enough to permit opening a sorted tag file, searching for a matching tag,
+*   then closing the tag file each time a tag is looked up (search times are
+*   on the order of hundredths of a second, even for huge tag files). This is
+*   the recommended use of this library for most tool applications. Adhering
+*   to this approach permits a user to regenerate a tag file at will without
+*   the tool needing to detect and resynchronize with changes to the tag file.
+*   Even for an unsorted 24MB tag file, tag searches take about one second.
+*/
+#ifndef READTAGS_H
+#define READTAGS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+*  MACROS
+*/
+
+/* Options for tagsSetSortType() */
+typedef enum {
+	TAG_UNSORTED, TAG_SORTED, TAG_FOLDSORTED
+} tagSortType ;
+
+/* For source code level compatibility, sortType is defined here.
+*  Define TAG_NO_COMPAT_SORT_TYPE if you want to avoid namespace pollution.
+*/
+#ifndef TAG_NO_COMPAT_SORT_TYPE
+#define sortType tagSortType
+#endif
+
+/* Options for tagsFind() */
+#define TAG_FULLMATCH     0x0
+#define TAG_PARTIALMATCH  0x1
+
+#define TAG_OBSERVECASE   0x0
+#define TAG_IGNORECASE    0x2
+
+/*
+*  DATA DECLARATIONS
+*/
+
+typedef enum { TagFailure = 0, TagSuccess = 1 } tagResult;
+
+typedef enum {
+	TagErrnoUnexpectedSortedMethod = -1, /* Unexpected sorted method */
+	TagErrnoUnexpectedFormat       = -2, /* Unexpected format number */
+	TagErrnoUnexpectedLineno       = -3, /* Unexpected value for line: field
+										  * (Zero or a positive integer is expected.) */
+	TagErrnoInvalidArgument        = -4, /* Unexpected argument passed to the API
+										  * function */
+} tagErrno;
+
+struct sTagFile;
+
+typedef struct sTagFile tagFile;
+
+/* This structure contains information about the tag file. */
+typedef struct {
+
+	struct {
+			/* was the tag file successfully opened? */
+		int opened;
+
+			/* errno value or tagErrno typed value
+			   when 'opened' is false */
+		int error_number;
+	} status;
+
+		/* information about the structure of the tag file */
+	struct {
+				/* format of tag file (1 = original, 2 = extended) */
+			short format;
+
+				/* how is the tag file sorted? */
+			tagSortType sort;
+	} file;
+
+
+		/* information about the program which created this tag file */
+	struct {
+			/* name of author of generating program (may be null) */
+		const char *author;
+
+			/* name of program (may be null) */
+		const char *name;
+
+			/* URL of distribution (may be null) */
+		const char *url;
+
+			/* program version (may be null) */
+		const char *version;
+	} program;
+
+} tagFileInfo;
+
+/* This structure contains information about an extension field for a tag.
+ * These exist at the end of the tag in the form "key:value").
+ */
+typedef struct {
+
+		/* the key of the extension field */
+	const char *key;
+
+		/* the value of the extension field (may be an empty string) */
+	const char *value;
+
+} tagExtensionField;
+
+/* This structure contains information about a specific tag. */
+typedef struct {
+
+		/* name of tag */
+	const char *name;
+
+		/* path of source file containing definition of tag.
+		   For a broken tags file, this can be NULL. */
+	const char *file;
+
+		/* address for locating tag in source file */
+	struct {
+			/* pattern for locating source line
+			 * (may be NULL if not present) */
+		const char *pattern;
+
+			/* line number in source file of tag definition
+			 * (may be zero if not known) */
+		unsigned long lineNumber;
+	} address;
+
+		/* kind of tag (may by name, character, or NULL if not known) */
+	const char *kind;
+
+		/* is tag of file-limited scope? */
+	short fileScope;
+
+		/* miscellaneous extension fields */
+	struct {
+			/* number of entries in `list' */
+		unsigned short count;
+
+			/* list of key value pairs */
+		tagExtensionField *list;
+	} fields;
+
+} tagEntry;
+
+
+/*
+*  FUNCTION PROTOTYPES
+*/
+
+/*
+*  This function must be called before calling other functions in this
+*  library. It is passed the path to the tag file to read and a (possibly
+*  null) pointer to a structure which, if not null, will be populated with
+*  information about the tag file. If successful, the function will return a
+*  handle which must be supplied to other calls to read information from the
+*  tag file, and info.status.opened will be set to true.
+*  If unsuccessful, the function will return NULL, and
+*  info.status.opened will be set to false and
+*  info.status.error_number will be set to either the errno value
+*  representing the system error preventing the tag file from being
+*  successfully opened, or the tagErrno typed value representing the
+*  library level error. The error_number will be ENOMEM if the memory
+*  allocation for the handle is failed.
+*/
+extern tagFile *tagsOpen (const char *const filePath, tagFileInfo *const info);
+
+/*
+*  This function allows the client to override the normal automatic detection
+*  of how a tag file is sorted. Permissible values for `type' are
+*  TAG_UNSORTED, TAG_SORTED, TAG_FOLDSORTED. Tag files in the new extended
+*  format contain a key indicating whether or not they are sorted. However,
+*  tag files in the original format do not contain such a key even when
+*  sorted, preventing this library from taking advantage of fast binary
+*  lookups. If the client knows that such an unmarked tag file is indeed
+*  sorted (or not), it can override the automatic detection. Note that
+*  incorrect lookup results will result if a tag file is marked as sorted when
+*  it actually is not. The function will return TagSuccess if called on an
+*  open tag file or TagFailure if not.
+*/
+extern tagResult tagsSetSortType (tagFile *const file, const tagSortType type);
+
+/*
+*  Reads the first tag in the file, if any. It is passed the handle to an
+*  opened tag file and a (possibly null) pointer to a structure which, if not
+*  null, will be populated with information about the first tag file entry.
+*  The function will return TagSuccess another tag entry is found, or
+*  TagFailure if not (i.e. it reached end of file).
+*/
+extern tagResult tagsFirst (tagFile *const file, tagEntry *const entry);
+
+/*
+*  Step to the next tag in the file, if any. It is passed the handle to an
+*  opened tag file and a (possibly null) pointer to a structure which, if not
+*  null, will be populated with information about the next tag file entry. The
+*  function will return TagSuccess another tag entry is found, or TagFailure
+*  if not (i.e. it reached end of file). It will always read the first tag in
+*  the file immediately after calling tagsOpen().
+*/
+extern tagResult tagsNext (tagFile *const file, tagEntry *const entry);
+
+/*
+*  Retrieve the value associated with the extension field for a specified key.
+*  It is passed a pointer to a structure already populated with values by a
+*  previous call to tagsNext(), tagsFind(), or tagsFindNext(), and a string
+*  containing the key of the desired extension field. If no such field of the
+*  specified key exists, the function will return null.
+*/
+extern const char *tagsField (const tagEntry *const entry, const char *const key);
+
+/*
+*  Find the first tag matching `name'. The structure pointed to by `entry'
+*  will be populated with information about the tag file entry. If a tag file
+*  is sorted using the C locale, a binary search algorithm is used to search
+*  the tag file, resulting in very fast tag lookups, even in huge tag files.
+*  Various options controlling the matches can be combined by bit-wise or-ing
+*  certain values together. The available values are:
+*
+*    TAG_PARTIALMATCH
+*        Tags whose leading characters match `name' will qualify.
+*
+*    TAG_FULLMATCH
+*        Only tags whose full lengths match `name' will qualify.
+*
+*    TAG_IGNORECASE
+*        Matching will be performed in a case-insensitive manner. Note that
+*        this disables binary searches of the tag file.
+*
+*    TAG_OBSERVECASE
+*        Matching will be performed in a case-sensitive manner. Note that
+*        this enables binary searches of the tag file.
+*
+*  The function will return TagSuccess if a tag matching the name is found, or
+*  TagFailure if not.
+*/
+extern tagResult tagsFind (tagFile *const file, tagEntry *const entry, const char *const name, const int options);
+
+/*
+*  Find the next tag matching the name and options supplied to the most recent
+*  call to tagsFind() for the same tag file. The structure pointed to by
+*  `entry' will be populated with information about the tag file entry. The
+*  function will return TagSuccess if another tag matching the name is found,
+*  or TagFailure if not.
+*/
+extern tagResult tagsFindNext (tagFile *const file, tagEntry *const entry);
+
+/*
+*  Does the same as tagsFirst(), but is specialized to pseudo tags.
+*  If tagFileInfo doesn't contain pseudo tags you are interested, read
+*  them sequentially with this function and tagsNextPseudoTag().
+*/
+extern tagResult tagsFirstPseudoTag (tagFile *const file, tagEntry *const entry);
+
+/*
+*  Does the same as tagsNext(), but is specialized to pseudo tags. Use with
+*  tagsFirstPseudoTag().
+*/
+extern tagResult tagsNextPseudoTag (tagFile *const file, tagEntry *const entry);
+
+/*
+*  Call tagsClose() at completion of reading the tag file, which will
+*  close the file and free any internal memory allocated. The function will
+*  return TagFailure if no file is currently open, TagSuccess otherwise.
+*/
+extern tagResult tagsClose (tagFile *const file);
+
+/*
+*  Get the error status set in the last API call.
+*  Much of the API functions return TagFailure because (1) no tag is
+*  found, or (2) an error occurs. tagsGetErrno() is for distinguishing
+*  (1) or (2). This function will return 0 for (1). The errno value
+*  representing the system error or tagErrno value for (2).
+*
+*  This function does not deal with the results of tagsOpen(),
+*  tagsClose(), and tagsField().
+*/
+extern int tagsGetErrno (tagFile *const file);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif
Modified: meson.build
4 lines changed, 3 insertions(+), 1 deletions(-)
===================================================================
@@ -232,7 +232,7 @@ sci_cflags += [ '-std=c++17', '-Wno-non-virtual-dtor', '-DNDEBUG', '-DSCI_LEXER'
iregex = include_directories('ctags/gnu_regex')
 ifnmatch = include_directories('ctags/fnmatch')
-ictags = include_directories('ctags/main', 'ctags/parsers', 'ctags/dsl')
+ictags = include_directories('ctags/main', 'ctags/parsers', 'ctags/dsl', 'ctags/libreadtags')
 itagmanager = include_directories('src/tagmanager')
 iscintilla = include_directories('scintilla/include', 'scintilla/lexilla/include')
 igeany = include_directories('src')
@@ -472,6 +472,8 @@ ctags = static_library('ctags',
    'ctags/dsl/es.h',
    'ctags/dsl/optscript.c',
    'ctags/dsl/optscript.h',
+	'ctags/libreadtags/readtags.c',
+	'ctags/libreadtags/readtags.h',
    'ctags/main/args.c',
    'ctags/main/args_p.h',
    'ctags/main/colprint.c',
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