diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/Fl_Text_Buffer.cxx | 58 |
1 files changed, 39 insertions, 19 deletions
diff --git a/src/Fl_Text_Buffer.cxx b/src/Fl_Text_Buffer.cxx index 933073e21..887983137 100644 --- a/src/Fl_Text_Buffer.cxx +++ b/src/Fl_Text_Buffer.cxx @@ -1586,43 +1586,63 @@ static int general_input_filter(char *buffer, int buflen, /* filter that produces, from an input stream fed by reading from fp, a UTF-8-encoded output stream written in buffer. + Returns #bytes read into 'buffer'. + Input can be UTF-8. If it is not, it is decoded with CP1252. Output is UTF-8. - *input_was_changed is set to true if the input was not strict UTF-8 so output + + *input_was_changed returns true if input was not strict UTF-8, so output differs from input. */ -static int utf8_input_filter(char *buffer, int buflen, char *line, int sline, char* &endline, - FILE *fp, int *input_was_changed) +static int utf8_input_filter(char *buffer, // result buffer we fill with utf8 encoded text + int buflen, // max size of buffer from caller + char *line, // file line buffer caller wants us to use + int sline, // max size of line buffer + char* &endline, // keeps track of leftovers in line[] buffer between calls + FILE *fp, // open file we're reading data from + int *input_was_changed) // returned flag: 'true' if buffer[] different from file due to utf8 encoding { + // p - work pointer to line[] + // q - work pointer to buffer[] + // l - length of utf8 sequence being worked on + // lp - fl_utf8decode() length of utf8 sequence being worked on + // lq - fl_utf8encode() length of utf8 sequence being worked on + // r - bytes read from last fread() + // u - utf8 decoded sequence as a single multibyte unsigned integer char *p, *q, multibyte[5]; int l, lp, lq, r; unsigned u; p = line; q = buffer; while (q < buffer + buflen) { - if (p >= endline) { - r = fread(line, 1, sline, fp); + if (p >= endline) { // walked off end of input file's line buffer? + r = fread(line, 1, sline, fp); // read another block of sline bytes from file endline = line + r; - if (r == 0) return q - buffer; + if (r == 0) return q - buffer; // EOF? return bytes read into buffer[] p = line; } - l = fl_utf8len1(*p); - if (p + l > endline) { - memmove(line, p, endline - p); + // Predict length of utf8 sequence + // See if utf8 seq we're working on would extend off end of line buffer, + // and if so, adjust + load more data so that it doesn't. + // + l = fl_utf8len1(*p); // anticipate length of utf8 sequence + if (p + l > endline) { // would walk off end of line buffer? + memmove(line, p, endline - p); // re-jigger line buffer to get some room endline -= (p - line); - r = fread(endline, 1, sline - (endline - line), fp); + r = fread(endline, 1, sline - (endline - line), fp); // re-fill line buffer endline += r; p = line; - if (endline - line < l) break; + if (endline - line < l) break; // sequence *still* extends past end? stop loop } while ( l > 0) { - u = fl_utf8decode(p, p+l, &lp); - lq = fl_utf8encode(u, multibyte); + u = fl_utf8decode(p, p+l, &lp); // get single utf8 encoded char as a Unicode value + lq = fl_utf8encode(u, multibyte); // re-encode Unicode value to utf8 in multibyte[] if (lp != l || lq != l) *input_was_changed = true; - if (q + lq > buffer + buflen) { - memmove(line, p, endline - p); - endline -= (p - line); - return q - buffer; + + if (q + lq > buffer + buflen) { // encoding would walk off end of buffer[]? + memmove(line, p, endline - p); // re-jigger line[] buffer for next call + endline -= (p - line); // adjust end of line[] buffer for next call + return q - buffer; // return what's decoded so far, caller will enlarge buffer } memcpy(q, multibyte, lq); q += lq; @@ -1672,13 +1692,13 @@ const char *Fl_Text_Buffer::file_encoding_warning_message = buffer[l] = 0; insert(pos, buffer); pos += l; - } + } int e = ferror(fp) ? 2 : 0; fclose(fp); delete[]buffer; if ( (!e) && input_file_was_transcoded && transcoding_warning_action) { transcoding_warning_action(this); - } + } return e; } |