58 lines
1.7 KiB
C
58 lines
1.7 KiB
C
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/* dbf.h — Deshab Bitmap Font format reader
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*
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* DBF File Layout:
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* [0..3] magic "DBF\x10" (version 16)
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* [4..7] u32 glyph_count
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* [8..9] u16 default_glyph_width
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* [10..11] u16 default_glyph_height
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* [12..13] u16 bits_per_pixel (8 = grayscale, 1 = BW)
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* [14..] index[] array of glyph_count entries:
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* [0..1] u16 codepoint (Unicode BMP)
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* [2..3] u16 actual_width (pixels)
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* [4..7] u32 data_offset (from file start)
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* [8..11] u32 data_size (bytes)
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* Each index entry is 12 bytes.
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* [14 + index*12 ..] glyph_bitmap[] raw 8bpp row-major data
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*
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* Usage:
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* const u8 *font_data = ...; // mmap or load entire .dbf
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* dbf_header *hdr = (dbf_header *)font_data;
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* dbf_index_entry *idx = (dbf_index_entry *)(font_data + 14);
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* // binary search for codepoint in idx[0..hdr->count-1]
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* // glyph data at font_data + idx[i].offset, size idx[i].size
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*/
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#ifndef DBF_H
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#define DBF_H
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#include <stdint.h>
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typedef struct {
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uint8_t magic[4]; /* "DBF\x10" */
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uint32_t count;
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uint16_t width;
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uint16_t height;
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uint16_t bpp;
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} __attribute__((packed)) dbf_header;
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typedef struct {
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uint16_t codepoint;
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uint16_t width;
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uint32_t offset;
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uint32_t size;
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} __attribute__((packed)) dbf_index_entry;
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/* Binary search for codepoint. Returns entry index or -1. */
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static inline int dbf_lookup(dbf_index_entry *idx, uint32_t count, uint16_t cp) {
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int lo = 0, hi = (int)count - 1;
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while (lo <= hi) {
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int mid = (lo + hi) / 2;
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if (idx[mid].codepoint == cp) return mid;
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if (idx[mid].codepoint < cp) lo = mid + 1;
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else hi = mid - 1;
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}
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return -1;
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}
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#endif
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