1 files changed, 308 insertions, 0 deletions
diff --git a/string_buf.c b/string_buf.c
new file mode 100644
index 0000000..332d023
--- /dev/null
+++ b/string_buf.c
@@ -0,0 +1,308 @@
+/**
+ * C string buffers for easy construction of complex strings
+ *
+ * Copyright (C) 2021 Wojtek Kosior
+ * Redistribution terms are gathered in the `copyright' file.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <unistd.h>
+
+#define STRING_BUF_C
+#include "string_buf.h"
+
+#define MINIMUM_EXTEND_BYTES 63
+
+void stringbuf_init(struct stringbuf *sb)
+{
+	sb->buf = NULL;
+	sb->buf_len = 0;
+	sb->buf_filled = 0;
+}
+
+void stringbuf_destroy(struct stringbuf *sb)
+{
+	free(sb->buf);
+}
+
+void stringbuf_truncate(struct stringbuf *sb, size_t len)
+{
+	if (sb->buf_len <= len)
+		return;
+
+	sb->buf_filled = len;
+	sb->buf[len] = '\0';
+}
+
+#define _UNPACKED_ARGS &sb->buf, &sb->buf_len, &sb->buf_filled
+
+int extend_buf(struct stringbuf *sb, size_t extend_len)
+{
+	return extend_buf_raw(_UNPACKED_ARGS, extend_len);
+}
+
+int extend_buf_raw(_RAW_BUF_ARGS, size_t extend_len)
+{
+	ssize_t space_left = *buf_len - *buf_filled - 1;
+	size_t new_size, size_required, size_more_space;
+	char *new_buf;
+
+	if (space_left >= 0 && space_left >= extend_len)
+		return 0;
+
+	size_required = *buf_filled + extend_len + 1;
+	size_more_space = size_required + MINIMUM_EXTEND_BYTES;
+	new_size = *buf_len * 2;
+	if (new_size < size_more_space)
+		new_size = size_more_space;
+
+	new_buf = realloc(*buf, new_size);
+	if (!new_buf) {
+		new_size = size_required;
+		new_buf = realloc(*buf, new_size);
+	}
+	if (!new_buf)
+		return -1;
+
+	*buf = new_buf;
+	*buf_len = new_size;
+	return 0;
+}
+
+_SB_HEAD(bytes, const void *bytes, size_t bytes_len)
+{
+	return sb_raw_bytes(_UNPACKED_ARGS, bytes, bytes_len);
+}
+
+_SB_RAW_HEAD(bytes, const void *bytes, size_t bytes_len)
+{
+	if (extend_buf_raw(buf, buf_len, buf_filled, bytes_len))
+		return -1;
+
+	memcpy(*buf + *buf_filled, bytes, bytes_len);
+	(*buf)[*buf_filled + bytes_len] = '\0';
+	*buf_filled += bytes_len;
+
+	return 0;
+}
+
+_SB_HEAD(string, const char *string)
+{
+	return sb_raw_string(_UNPACKED_ARGS, string);
+}
+
+_SB_RAW_HEAD(string, const char *string)
+{
+	size_t string_len = strlen(string);
+
+	return sb_raw_bytes(buf, buf_len, buf_filled, string, string_len);
+}
+
+_SB_HEAD(char, char c)
+{
+	return sb_raw_char(_UNPACKED_ARGS, c);
+}
+
+_SB_RAW_HEAD(char, char c)
+{
+	return sb_raw_bytes(buf, buf_len, buf_filled, &c, 1);
+}
+
+_SB_HEAD(long, long num)
+{
+	return sb_raw_long(_UNPACKED_ARGS, num);
+}
+
+_SB_RAW_HEAD(long, long num)
+{
+	unsigned char repr[3 * sizeof(long) + 1];
+	int i;
+	bool neg = num < 0;
+
+	for (i = sizeof(repr); num; num /= 10)
+		repr[--i] = '0' + num % 10;
+
+	if (i == sizeof(repr))
+		repr[--i] = '0';
+	else if (neg)
+		repr[--i] = '-';
+
+	sb_raw_bytes(buf, buf_len, buf_filled,
+		     repr + i, sizeof(repr) - i);
+
+	return 0;
+}
+
+_SB_HEAD(file, FILE *file)
+{
+	return sb_raw_file(_UNPACKED_ARGS, file);
+}
+
+_SB_RAW_HEAD(file, FILE *file)
+{
+	long file_size;
+
+	if (fseek(file, 0, SEEK_END))
+		return -1;
+
+	file_size = ftell(file);
+	if (file_size < 0)
+		return -1;
+
+	if (extend_buf_raw(buf, buf_len, buf_filled, file_size))
+		return -1;
+
+	rewind(file);
+
+	if (fread(*buf + *buf_filled, file_size, 1, file) != 1)
+		return -1;
+
+	(*buf)[*buf_filled + file_size] = '\0';
+	*buf_filled += file_size;
+
+	return 0;
+}
+
+_SB_HEAD(filepath, const char *path)
+{
+	return sb_raw_filepath(_UNPACKED_ARGS, path);
+}
+
+_SB_RAW_HEAD(filepath, const char *path)
+{
+	FILE *file;
+	int retval;
+
+	file = fopen(path, "r");
+	if (!file)
+		return -1;
+
+	retval = sb_raw_file(buf, buf_len, buf_filled, file);
+
+	fclose(file);
+	return retval;
+}
+
+_SB_HEAD(vsprintf, const char *fmt, va_list ap)
+{
+	return sb_raw_vsprintf(_UNPACKED_ARGS, fmt, ap);
+}
+
+_SB_RAW_HEAD(vsprintf, const char *fmt, va_list ap)
+{
+	const unsigned char *in_pos = (const unsigned char*) fmt;
+	char c;
+	size_t i = 0;
+	bool percent = false;
+
+	long num_arg;
+	int (*sb_cb)(char**, size_t*, size_t*, void*);
+
+	while (in_pos[i]) {
+		c = in_pos[i++];
+
+		if (!percent) {
+			if (c == '%') {
+				percent = true;
+				if (sb_raw_bytes(buf, buf_len, buf_filled,
+						 in_pos, i - 1))
+					return -1;
+			}
+
+			continue;
+		}
+
+		percent = false;
+		in_pos += i;
+		i = 0;
+
+		switch (c) {
+		case 'd':
+		case 'u':
+			num_arg = c == 'd' ?
+				va_arg(ap, int) : va_arg(ap, unsigned);
+
+			if (sb_raw_long(buf, buf_len, buf_filled, num_arg))
+				return -1;
+			break;
+		case 'f':
+			if (sb_raw_file(buf, buf_len, buf_filled,
+					va_arg(ap, FILE*)))
+				return -1;
+			break;
+		case 'p':
+			if (sb_raw_filepath(buf, buf_len, buf_filled,
+					    va_arg(ap, const char*)))
+				return -1;
+			break;
+		case 's':
+			if (sb_raw_string(buf, buf_len, buf_filled,
+					  va_arg(ap, const char*)))
+				return -1;
+			break;
+		case '_':
+			sb_cb = va_arg(ap, int (*)(char**, size_t*,
+						   size_t*, void*));
+			if (sb_cb(buf, buf_len, buf_filled,
+				  va_arg(ap, void*)))
+				return -1;
+			break;
+		case '%':
+			in_pos--;
+			i++;
+		}
+	}
+
+	if (!percent && sb_raw_bytes(buf, buf_len, buf_filled, in_pos, i))
+		return -1;
+
+	return 0;
+}
+
+_SB_HEAD(sprintf, const char *fmt, ...)
+{
+	va_list ap;
+	int res;
+
+	va_start(ap, fmt);
+	res = sb_raw_vsprintf(_UNPACKED_ARGS, fmt, ap);
+	va_end(ap);
+
+	return res;
+}
+
+_SB_RAW_HEAD(sprintf, const char *fmt, ...)
+{
+	va_list ap;
+	int res;
+
+	va_start(ap, fmt);
+	res = sb_raw_vsprintf(buf, buf_len, buf_filled, fmt, ap);
+	va_end(ap);
+
+	return res;
+}
+
+int crop_buf(struct stringbuf *sb)
+{
+	return crop_buf_raw(_UNPACKED_ARGS);
+}
+
+int crop_buf_raw(_RAW_BUF_ARGS)
+{
+	char *new_buf;
+
+	if (*buf_len <= *buf_filled + 1)
+		return 0;
+
+	new_buf = realloc(*buf, *buf_filled + 1);
+	if (!new_buf)
+		return -1;
+
+	*buf = new_buf;
+	*buf_len = *buf_filled + 1;
+	return 0;
+}