src/buf_text.c - third_party/libgit2 - Git at Google

 /*
  * Copyright (C) the libgit2 contributors. All rights reserved.
  *
  * 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, alloclen;

 	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;
 	}

 	GITERR_CHECK_ALLOC_ADD(&alloclen, total, 1);
 	if (git_buf_grow_by(buf, alloclen) < 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_crlf_to_lf(git_buf *tgt, const git_buf *src)
 {
 	const char *scan = src->ptr;
 	const char *scan_end = src->ptr + src->size;
 	const char *next = memchr(scan, '\r', src->size);
 	size_t new_size;
 	char *out;

 	assert(tgt != src);

 	if (!next)
 		return git_buf_set(tgt, src->ptr, src->size);

 	/* reduce reallocs while in the loop */
 	GITERR_CHECK_ALLOC_ADD(&new_size, src->size, 1);
 	if (git_buf_grow(tgt, new_size) < 0)
 		return -1;

 	out = tgt->ptr;
 	tgt->size = 0;

 	/* Find the next \r and copy whole chunk up to there to tgt */
 	for (; next; scan = next + 1, next = memchr(scan, '\r', scan_end - scan)) {
 		if (next > scan) {
 			size_t copylen = (size_t)(next - scan);
 			memcpy(out, scan, copylen);
 			out += copylen;
 		}

 		/* Do not drop \r unless it is followed by \n */
 		if (next + 1 == scan_end || next[1] != '\n')
 			*out++ = '\r';
 	}

 	/* Copy remaining input into dest */
 	if (scan < scan_end) {
 		size_t remaining = (size_t)(scan_end - scan);
 		memcpy(out, scan, remaining);
 		out += remaining;
 	}

 	tgt->size = (size_t)(out - tgt->ptr);
 	tgt->ptr[tgt->size] = '\0';

 	return 0;
 }

 int git_buf_text_lf_to_crlf(git_buf *tgt, const git_buf *src)
 {
 	const char *start = src->ptr;
 	const char *end = start + src->size;
 	const char *scan = start;
 	const char *next = memchr(scan, '\n', src->size);
 	size_t alloclen;

 	assert(tgt != src);

 	if (!next)
 		return git_buf_set(tgt, src->ptr, src->size);

 	/* attempt to reduce reallocs while in the loop */
 	GITERR_CHECK_ALLOC_ADD(&alloclen, src->size, src->size >> 4);
 	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, 1);
 	if (git_buf_grow(tgt, alloclen) < 0)
 		return -1;
 	tgt->size = 0;

 	for (; next; scan = next + 1, next = memchr(scan, '\n', end - scan)) {
 		size_t copylen = next - scan;

 		/* if we find mixed line endings, carry on */
 		if (copylen && next[-1] == '\r')
 			copylen--;

 		GITERR_CHECK_ALLOC_ADD(&alloclen, copylen, 3);
 		if (git_buf_grow_by(tgt, alloclen) < 0)
 			return -1;

 		if (copylen) {
 			memcpy(tgt->ptr + tgt->size, scan, copylen);
 			tgt->size += copylen;
 		}

 		tgt->ptr[tgt->size++] = '\r';
 		tgt->ptr[tgt->size++] = '\n';
 	}

 	tgt->ptr[tgt->size] = '\0';
 	return git_buf_put(tgt, scan, end - scan);
 }

 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;
 	git_bom_t bom;
 	int printable = 0, nonprintable = 0;

 	scan += git_buf_text_detect_bom(&bom, buf, 0);

 	if (bom > GIT_BOM_UTF8)
 		return 1;

 	while (scan < end) {
 		unsigned char c = *scan++;

 		/* Printable characters are those above SPACE (0x1F) excluding DEL,
 		 * and including BS, ESC and FF.
 		 */
 		if ((c > 0x1F && c != 127) || c == '\b' || c == '\033' || c == '\014')
 			printable++;
 		else if (c == '\0')
 			return true;
 		else if (!git__isspace(c))
 			nonprintable++;
 	}

 	return ((printable >> 7) < nonprintable);
 }

 bool git_buf_text_contains_nul(const git_buf *buf)
 {
 	return (memchr(buf->ptr, '\0', buf->size) != NULL);
 }

 int git_buf_text_detect_bom(git_bom_t *bom, const git_buf *buf, size_t offset)
 {
 	const char *ptr;
 	size_t len;

 	*bom = GIT_BOM_NONE;
 	/* 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)
 			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));
 }
	/*
	* Copyright (C) the libgit2 contributors. All rights reserved.
	*
	* 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, alloclen;

	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;
	}

	GITERR_CHECK_ALLOC_ADD(&alloclen, total, 1);
	if (git_buf_grow_by(buf, alloclen) < 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_crlf_to_lf(git_buf tgt, const git_buf src)
	{
	const char *scan = src->ptr;
	const char *scan_end = src->ptr + src->size;
	const char *next = memchr(scan, '\r', src->size);
	size_t new_size;
	char *out;

	assert(tgt != src);

	if (!next)
	return git_buf_set(tgt, src->ptr, src->size);

	/* reduce reallocs while in the loop */
	GITERR_CHECK_ALLOC_ADD(&new_size, src->size, 1);
	if (git_buf_grow(tgt, new_size) < 0)
	return -1;

	out = tgt->ptr;
	tgt->size = 0;

	/* Find the next \r and copy whole chunk up to there to tgt */
	for (; next; scan = next + 1, next = memchr(scan, '\r', scan_end - scan)) {
	if (next > scan) {
	size_t copylen = (size_t)(next - scan);
	memcpy(out, scan, copylen);
	out += copylen;
	}

	/* Do not drop \r unless it is followed by \n */
	if (next + 1 == scan_end \|\| next[1] != '\n')
	*out++ = '\r';
	}

	/* Copy remaining input into dest */
	if (scan < scan_end) {
	size_t remaining = (size_t)(scan_end - scan);
	memcpy(out, scan, remaining);
	out += remaining;
	}

	tgt->size = (size_t)(out - tgt->ptr);
	tgt->ptr[tgt->size] = '\0';

	return 0;
	}

	int git_buf_text_lf_to_crlf(git_buf tgt, const git_buf src)
	{
	const char *start = src->ptr;
	const char *end = start + src->size;
	const char *scan = start;
	const char *next = memchr(scan, '\n', src->size);
	size_t alloclen;

	assert(tgt != src);

	if (!next)
	return git_buf_set(tgt, src->ptr, src->size);

	/* attempt to reduce reallocs while in the loop */
	GITERR_CHECK_ALLOC_ADD(&alloclen, src->size, src->size >> 4);
	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, 1);
	if (git_buf_grow(tgt, alloclen) < 0)
	return -1;
	tgt->size = 0;

	for (; next; scan = next + 1, next = memchr(scan, '\n', end - scan)) {
	size_t copylen = next - scan;

	/* if we find mixed line endings, carry on */
	if (copylen && next[-1] == '\r')
	copylen--;

	GITERR_CHECK_ALLOC_ADD(&alloclen, copylen, 3);
	if (git_buf_grow_by(tgt, alloclen) < 0)
	return -1;

	if (copylen) {
	memcpy(tgt->ptr + tgt->size, scan, copylen);
	tgt->size += copylen;
	}

	tgt->ptr[tgt->size++] = '\r';
	tgt->ptr[tgt->size++] = '\n';
	}

	tgt->ptr[tgt->size] = '\0';
	return git_buf_put(tgt, scan, end - scan);
	}

	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;
	git_bom_t bom;
	int printable = 0, nonprintable = 0;

	scan += git_buf_text_detect_bom(&bom, buf, 0);

	if (bom > GIT_BOM_UTF8)
	return 1;

	while (scan < end) {
	unsigned char c = *scan++;

	/* Printable characters are those above SPACE (0x1F) excluding DEL,
	* and including BS, ESC and FF.
	*/
	if ((c > 0x1F && c != 127) \|\| c == '\b' \|\| c == '\033' \|\| c == '\014')
	printable++;
	else if (c == '\0')
	return true;
	else if (!git__isspace(c))
	nonprintable++;
	}

	return ((printable >> 7) < nonprintable);
	}

	bool git_buf_text_contains_nul(const git_buf *buf)
	{
	return (memchr(buf->ptr, '\0', buf->size) != NULL);
	}

	int git_buf_text_detect_bom(git_bom_t bom, const git_buf buf, size_t offset)
	{
	const char *ptr;
	size_t len;

	*bom = GIT_BOM_NONE;
	/* 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)
	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));
	}