1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
// Text buffers - These store the contents of a file.
// To make inserting characters faster, the file contents are split up into
// blocks of a few thousand bytes. Block boundaries are not necessarily
// on character boundaries, so one block might have part of a UTF-8 character
// with the next block having the rest.
#include "unicode.h"
#include "util.c"
#include "text.h"
#define TEXT_BLOCK_MAX_SIZE 400
// Once two adjacent blocks are at most this big, combine them into
// one bigger text block.
#define TEXT_BLOCK_COMBINE_SIZE (3*(TEXT_BLOCK_MAX_SIZE / 4))
// A good size for text blocks to be. When a file is loaded, there
// shouldn't be just full blocks, because they will all immediately split.
// Instead, we use blocks of this size.
#define TEXT_BLOCK_DEFAULT_SIZE (3*(TEXT_BLOCK_MAX_SIZE / 4))
typedef struct {
u16 len;
char *contents;
} TextBlock;
typedef struct {
u32 nblocks; // number of text blocks
double scroll_x, scroll_y; // number of characters scrolled in the x/y direction
TextBlock *blocks;
} TextBuffer;
// Returns a new block added at index `where`,
// or NULL if there's not enough memory.
static TextBlock *text_buffer_add_block(TextBuffer *buffer, u32 where) {
// make sure we can actually allocate enough memory for the contents of the block
// before doing anything
char *block_contents = calloc(1, TEXT_BLOCK_MAX_SIZE);
if (!block_contents) {
return NULL;
}
u32 nblocks_before = buffer->nblocks;
u32 nblocks_after = buffer->nblocks + 1;
if (util_is_power_of_2(nblocks_after)) {
// whenever the number of blocks is a power of 2, we need to grow the blocks array.
buffer->blocks = realloc(buffer->blocks, 2 * nblocks_after * sizeof *buffer->blocks);
if (!buffer->blocks) {
// out of memory
free(block_contents);
return NULL;
}
}
if (where != nblocks_before) { // if we aren't just inserting the block at the end,
// make space for the new block
memmove(buffer->blocks + (where + 1), buffer->blocks + where, nblocks_before - where);
}
TextBlock *block = buffer->blocks + where;
util_zero_memory(block, sizeof *buffer->blocks); // zero everything
block->contents = block_contents;
buffer->nblocks = nblocks_after;
return block;
}
Status text_buffer_load_file(TextBuffer *buffer, FILE *fp) {
char block_contents[TEXT_BLOCK_DEFAULT_SIZE];
size_t bytes_read;
util_zero_memory(buffer, sizeof *buffer);
// read file one block at a time
do {
bytes_read = fread(block_contents, 1, sizeof block_contents, fp);
if (bytes_read > 0) {
TextBlock *block = text_buffer_add_block(buffer, buffer->nblocks);
if (!block) {
return false;
}
memcpy(block->contents, block_contents, bytes_read);
block->len = (u16)bytes_read;
}
} while (bytes_read == sizeof block_contents);
if (ferror(fp))
return false;
return true;
}
static void text_buffer_print_internal(TextBuffer *buffer, bool debug) {
printf("\033[2J\033[;H");
TextBlock *blocks = buffer->blocks;
u32 nblocks = buffer->nblocks;
for (u32 i = 0; i < nblocks; ++i) {
TextBlock *block = &blocks[i];
fwrite(block->contents, 1, block->len, stdout);
if (debug)
printf("\n\n------\n\n"); // NOTE: could be bad with UTF-8
}
fflush(stdout);
}
// print the contents of a buffer to stdout
void text_buffer_print(TextBuffer *buffer) {
text_buffer_print_internal(buffer, false);
}
// print the contents of a buffer to stdout, along with debugging information
void text_buffer_print_debug(TextBuffer *buffer) {
text_buffer_print_internal(buffer, true);
}
// Does not free the pointer `buffer` (buffer might not have even been allocated with malloc)
void text_buffer_free(TextBuffer *buffer) {
TextBlock *blocks = buffer->blocks;
u32 nblocks = buffer->nblocks;
for (u32 i = 0; i < nblocks; ++i) {
free(blocks[i].contents);
}
free(blocks);
}
void text_buffer_scroll(TextBuffer *buffer, double dx, double dy) {
buffer->scroll_x += dx;
buffer->scroll_y += dy;
}
// Render the text buffer in the given rectangle
void text_buffer_render(TextBuffer *buffer, Font *font, float x1, float y1, float x2, float y2) {
mbstate_t mbstate = {0};
uint nblocks = buffer->nblocks;
TextBlock *blocks = buffer->blocks;
float char_height = text_font_char_height(font);
glColor3f(0.5f,0.5f,0.5f);
glBegin(GL_LINE_STRIP);
glVertex2f(x1,y1);
glVertex2f(x1,y2);
glVertex2f(x2,y2);
glVertex2f(x2,y1);
glVertex2f(x1-1,y1);
glEnd();
glColor3f(1,1,1);
text_chars_begin(font);
TextRenderState text_state = {
.x = x1, .y = y1 + text_font_char_height(font),
.min_x = x1, .min_y = y1,
.max_x = x2, .max_y = y2
};
// @TODO: make this better (we should figure out where to start rendering, etc.)
text_state.x -= (float)buffer->scroll_x * char_height;
text_state.y -= (float)buffer->scroll_y * char_height;
for (uint block_idx = 0; block_idx < nblocks; ++block_idx) {
TextBlock *block = &blocks[block_idx];
char *p = block->contents, *end = p + block->len;
while (p != end) {
char32_t c;
size_t n = mbrtoc32(&c, p, (size_t)(end - p), &mbstate);
if (n == 0) {
// null character
c = UNICODE_BOX_CHARACTER;
++p;
} else if (n == (size_t)(-3)) {
// no bytes consumed, but a character was produced
} else if (n == (size_t)(-2)) {
// incomplete character at end of block.
c = 0;
p = end;
} else if (n == (size_t)(-1)) {
// invalid UTF-8
c = UNICODE_BOX_CHARACTER;
++p;
} else {
p += n;
}
switch (c) {
case L'\n':
text_state.x = x1;
text_state.y += text_font_char_height(font);
break;
case L'\r': break; // for CRLF line endings
case L'\t':
for (int i = 0; i < 4; ++i)
text_render_char(font, L' ', &text_state);
break;
default:
text_render_char(font, c, &text_state);
break;
}
}
}
text_chars_end(font);
}
|
