Add ability to read Format 1 metadata files

1 files changed, 125 insertions, 0 deletions

diff --git a/src/utils.c b/src/utils.c
index 5cdef6b..2247151 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -80,6 +80,18 @@ xmalloc(size_t size)
         return result;
 }
 
+/* Ditto for realloc */
+void *
+xrealloc(void *ptr, size_t size)
+{
+        void *result = realloc(ptr, size);
+        if (!result) {
+                msg(MSG_CRITICAL, "Failed to realloc %zu bytes\n", size);
+                exit(EXIT_FAILURE);
+        }
+        return result;
+}
+
 /* Ditto for strdup */
 char *
 xstrdup(const char *s)
@@ -143,6 +155,19 @@ write_string(const char *string, FILE *to)
 	xfwrite(string, strlen(string) + 1, to);
 }
 
+/* Get the value of a hex digit */
+static int
+xdigitval(int c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'A' && c <= 'F')
+		return 10 + c - 'A';
+	if (c >= 'a' && c <= 'f')
+		return 10 + c - 'a';
+	return -1;
+}
+
 /* Check if a character being put into a URL must be encoded */
 static int
 char_url_mustencode(int c)
@@ -192,6 +217,15 @@ write_string_url(const char *string, FILE *to)
 		write_char_url(c, to);
 }
 
+/* Reads a single char from a file */
+int
+read_char(const char **from, const char *max)
+{
+	if (*from >= max)
+		return EOF;
+	return *((*from)++);
+}
+
 /* Reads an int from a file, using len bytes, in little-endian order */
 uint64_t
 read_int(const char **from, size_t len, const char *max)
@@ -211,6 +245,27 @@ read_int(const char **from, size_t len, const char *max)
 	return result;
 }
 
+/* Reads an int from a file, stored as an ASCII string, to the first non-digit */
+long
+read_int_string(const char **from, const char *max, int base)
+{
+	long result = 0;
+	int sign = 1, i;
+
+	if (*from < max && **from == '-') {
+		sign = -1;
+		*from += 1;
+	}
+
+	while (*from < max && (i = xdigitval(**from)) >= 0 && i < base) {
+		result *= base;
+		result += i;
+		*from += 1;
+	}
+
+	return result * sign;
+}
+
 /* Reads a binary string from a file */
 char *
 read_binary_string(const char **from, size_t len, const char *max)
@@ -229,6 +284,69 @@ read_binary_string(const char **from, size_t len, const char *max)
 	return result;
 }
 
+/* Reads binary data from a file, which was stored URL-encoded */
+char *
+read_binary_url(const char **pfrom, const char *max, ssize_t *plen)
+{
+	const char *from;
+	size_t bufsize, len;
+	char * buf;
+	int hi, lo;
+
+	from = *pfrom;
+	bufsize = 32;
+	buf = xmalloc(bufsize);
+	len = 0;
+
+	while (from < max) {
+		if (len == bufsize) {
+			bufsize *= 2;
+			buf = xrealloc(buf, bufsize);
+		}
+
+		if (*from == '%' && (max - from) >= 3) {
+			/* URL-encoded char - decode */
+			from++;
+			hi = xdigitval(*from++);
+			lo = xdigitval(*from++);
+			if (hi < 0 || lo < 0) {
+				/* Invalid encoding */
+				free(buf);
+				*pfrom = from;
+				return NULL;
+			}
+			if (hi == 0 && lo == 0 && !plen) {
+				/* NUL in C string? Stop here */
+				break;
+			}
+			buf[len++] = (hi << 4) + lo;
+		}
+		else if (char_url_mustencode(*from)) {
+			/* Un-encoded char. Stop here */
+			break;
+		}
+		else {
+			buf[len++] = *from++;
+		}
+	}
+
+	if (plen) {
+		/* plen is non-NULL means read binary data - return length */
+		*plen = len;
+	}
+	else {
+		/* plen is NULL actually means read C string - NUL terminate */
+		if (len == bufsize) {
+			bufsize *= 2;
+			buf = xrealloc(buf, bufsize);
+		}
+		buf[len++] = '\0';
+	}
+
+	*pfrom = from;
+	return buf;
+}
+
 /* Reads a normal C string from a file */
 char *
 read_string(const char **from, const char *max)
@@ -236,6 +354,13 @@ read_string(const char **from, const char *max)
 	return read_binary_string(from, strlen(*from) + 1, max);
 }
 
+/* Reads a normal C string from a file, which was stored URL-encoded */
+char *
+read_string_url(const char **from, const char *max)
+{
+	return read_binary_url(from, max, NULL);
+}
+
 /* For group caching */
 static struct group *gtable = NULL;