Merge pull request #1088 from arrbee/consolidate-text-functions

Consolidate text buffer functions

1 files changed, 208 insertions, 0 deletions

diff --git a/src/buf_text.c b/src/buf_text.c
new file mode 100644
index 000000000..3c5024e6c
--- /dev/null
+++ b/src/buf_text.c
@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#include "buf_text.h"
+
+int git_buf_text_puts_escaped(
+	git_buf *buf,
+	const char *string,
+	const char *esc_chars,
+	const char *esc_with)
+{
+	const char *scan;
+	size_t total = 0, esc_len = strlen(esc_with), count;
+
+	if (!string)
+		return 0;
+
+	for (scan = string; *scan; ) {
+		/* count run of non-escaped characters */
+		count = strcspn(scan, esc_chars);
+		total += count;
+		scan += count;
+		/* count run of escaped characters */
+		count = strspn(scan, esc_chars);
+		total += count * (esc_len + 1);
+		scan += count;
+	}
+
+	if (git_buf_grow(buf, buf->size + total + 1) < 0)
+		return -1;
+
+	for (scan = string; *scan; ) {
+		count = strcspn(scan, esc_chars);
+
+		memmove(buf->ptr + buf->size, scan, count);
+		scan += count;
+		buf->size += count;
+
+		for (count = strspn(scan, esc_chars); count > 0; --count) {
+			/* copy escape sequence */
+			memmove(buf->ptr + buf->size, esc_with, esc_len);
+			buf->size += esc_len;
+			/* copy character to be escaped */
+			buf->ptr[buf->size] = *scan;
+			buf->size++;
+			scan++;
+		}
+	}
+
+	buf->ptr[buf->size] = '\0';
+
+	return 0;
+}
+
+void git_buf_text_unescape(git_buf *buf)
+{
+	buf->size = git__unescape(buf->ptr);
+}
+
+int git_buf_text_common_prefix(git_buf *buf, const git_strarray *strings)
+{
+	size_t i;
+	const char *str, *pfx;
+
+	git_buf_clear(buf);
+
+	if (!strings || !strings->count)
+		return 0;
+
+	/* initialize common prefix to first string */
+	if (git_buf_sets(buf, strings->strings[0]) < 0)
+		return -1;
+
+	/* go through the rest of the strings, truncating to shared prefix */
+	for (i = 1; i < strings->count; ++i) {
+
+		for (str = strings->strings[i], pfx = buf->ptr;
+			 *str && *str == *pfx; str++, pfx++)
+			/* scanning */;
+
+		git_buf_truncate(buf, pfx - buf->ptr);
+
+		if (!buf->size)
+			break;
+	}
+
+	return 0;
+}
+
+bool git_buf_text_is_binary(const git_buf *buf)
+{
+	const char *scan = buf->ptr, *end = buf->ptr + buf->size;
+	int printable = 0, nonprintable = 0;
+
+	while (scan < end) {
+		unsigned char c = *scan++;
+
+		if (c > 0x1F && c < 0x7F)
+			printable++;
+		else if (c == '\0')
+			return true;
+		else if (!git__isspace(c))
+			nonprintable++;
+	}
+
+	return ((printable >> 7) < nonprintable);
+}
+
+int git_buf_text_detect_bom(git_bom_t *bom, const git_buf *buf, size_t offset)
+{
+	const char *ptr;
+	size_t len;
+
+	/* need at least 2 bytes after offset to look for any BOM */
+	if (buf->size < offset + 2)
+		return 0;
+
+	ptr = buf->ptr + offset;
+	len = buf->size - offset;
+
+	switch (*ptr++) {
+	case 0:
+		if (len >= 4 && ptr[0] == 0 && ptr[1] == '\xFE' && ptr[2] == '\xFF') {
+			*bom = GIT_BOM_UTF32_BE;
+			return 4;
+		}
+		break;
+	case '\xEF':
+		if (len >= 3 && ptr[0] == '\xBB' && ptr[1] == '\xBF') {
+			*bom = GIT_BOM_UTF8;
+			return 3;
+		}
+		break;
+	case '\xFE':
+		if (*ptr == '\xFF') {
+			*bom = GIT_BOM_UTF16_BE;
+			return 2;
+		}
+		break;
+	case '\xFF':
+		if (*ptr != '\xFE')
+			break;
+		if (len >= 4 && ptr[1] == 0 && ptr[2] == 0) {
+			*bom = GIT_BOM_UTF32_LE;
+			return 4;
+		} else {
+			*bom = GIT_BOM_UTF16_LE;
+			return 2;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+bool git_buf_text_gather_stats(
+	git_buf_text_stats *stats, const git_buf *buf, bool skip_bom)
+{
+	const char *scan = buf->ptr, *end = buf->ptr + buf->size;
+	int skip;
+
+	memset(stats, 0, sizeof(*stats));
+
+	/* BOM detection */
+	skip = git_buf_text_detect_bom(&stats->bom, buf, 0);
+	if (skip_bom)
+		scan += skip;
+
+	/* Ignore EOF character */
+	if (buf->size > 0 && end[-1] == '\032')
+		end--;
+
+	/* Counting loop */
+	while (scan < end) {
+		unsigned char c = *scan++;
+
+		if ((c > 0x1F && c < 0x7F) || c > 0x9f)
+			stats->printable++;
+		else switch (c) {
+			case '\0':
+				stats->nul++;
+				stats->nonprintable++;
+				break;
+			case '\n':
+				stats->lf++;
+				break;
+			case '\r':
+				stats->cr++;
+				if (scan < end && *scan == '\n')
+					stats->crlf++;
+				break;
+			case '\t': case '\f': case '\v': case '\b': case 0x1b: /*ESC*/
+				stats->printable++;
+				break;
+			default:
+				stats->nonprintable++;
+				break;
+			}
+	}
+
+	return (stats->nul > 0 ||
+		((stats->printable >> 7) < stats->nonprintable));
+}