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author | 2015-11-08 12:56:12 +0100 | |
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committer | 2015-11-08 12:56:12 +0100 | |
commit | 7c19aac60e12d6f5ea301bdb34d7826a01e0b06f (patch) | |
tree | f310d86aa2c6bfc19d115307dedde4eb0cd52dad /src/lib/formats/imageutl.cpp | |
parent | a57b46ae933badd7441ce1644711dbb851e2b504 (diff) |
Rename *.c -> *.cpp in our source (nw)
Diffstat (limited to 'src/lib/formats/imageutl.cpp')
-rw-r--r-- | src/lib/formats/imageutl.cpp | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/lib/formats/imageutl.cpp b/src/lib/formats/imageutl.cpp new file mode 100644 index 00000000000..e6386da44c8 --- /dev/null +++ b/src/lib/formats/imageutl.cpp @@ -0,0 +1,193 @@ +// license:BSD-3-Clause +// copyright-holders:Aaron Giles +/*************************************************************************** + + imageutl.h + + Image related utilities + +***************************************************************************/ + +#include <ctype.h> +#include "imageutl.h" + +int compute_log2(int val) +{ + int count = 0; + + while(val > 1) + { + if (val & 1) + return -1; + val /= 2; + count++; + } + return (val == 0) ? -1 : count; +} + +/* + Compute CCITT CRC-16 using the correct bit order for floppy disks. + CRC code courtesy of Tim Mann. +*/ + +/* Accelerator table to compute the CRC eight bits at a time */ +static const unsigned short ccitt_crc16_table[256] = +{ + 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, + 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, + 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, + 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, + 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, + 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, + 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, + 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, + 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, + 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, + 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, + 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, + 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, + 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, + 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, + 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, + 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, + 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, + 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, + 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, + 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, + 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, + 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, + 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, + 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, + 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, + 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, + 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, + 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, + 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, + 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, + 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 +}; + +unsigned short ccitt_crc16(unsigned short crc, const unsigned char *buffer, size_t buffer_len) +{ + size_t i; + for (i = 0; i < buffer_len; i++) + crc = (crc << 8) ^ ccitt_crc16_table[(crc >> 8) ^ buffer[i]]; + return crc; +} + +unsigned short ccitt_crc16_one( unsigned short crc, const unsigned char data ) +{ + return (crc << 8) ^ ccitt_crc16_table[(crc >> 8) ^ data]; +} + + +/*------------------------------------------------- + is_delim - returns whether c is a comma or \0 +-------------------------------------------------*/ + +static int is_delim(char c) +{ + return (c == '\0') || (c == ','); +} + + + +/*------------------------------------------------- + image_internal_find_extension - find an extension in + an extension list +-------------------------------------------------*/ + +static int image_internal_find_extension(const char *extension_list, const char *target_extension) +{ + /* this version allows target_extension to be delimited with a comma */ + int pos = 0; + int i; + + while(extension_list[pos] != '\0') + { + /* compare a file extension */ + i = 0; + while(!is_delim(extension_list[pos + i]) + && !is_delim(target_extension[i]) + && (tolower(extension_list[pos + i]) == tolower(target_extension[i]))) + { + i++; + } + + /* check to see if it was found */ + if (is_delim(extension_list[pos + i]) && is_delim(target_extension[i])) + return TRUE; + + /* move to next position in the buffer */ + pos += i; + while(!is_delim(extension_list[pos])) + pos++; + while(extension_list[pos] == ',') + pos++; + } + + /* not found */ + return FALSE; +} + + + +/*------------------------------------------------- + image_find_extension - find an extension in an extension + list +-------------------------------------------------*/ + +int image_find_extension(const char *extension_list, const char *target_extension) +{ + /* the internal function allows something that we do not */ + if (strchr(target_extension, ',')) + return FALSE; + + /* special case to allow ext to be in the form '.EXT' */ + if (*target_extension == '.') + target_extension++; + + /* do the actual work */ + return image_internal_find_extension(extension_list, target_extension); +} + + + +/*------------------------------------------------- + image_specify_extension - merge a comma-delimited + list of file extensions onto an existing list +-------------------------------------------------*/ + +void image_specify_extension(char *buffer, size_t buffer_len, const char *extension) +{ + int extension_pos = 0; + int len; + int found; + + /* determine the length of the buffer */ + len = strlen(buffer); + + /* be aware that extension can be NULL */ + if (extension != NULL) + { + while(extension[extension_pos] != '\0') + { + /* try to find the file extension */ + found = image_internal_find_extension(buffer, &extension[extension_pos]); + + /* append a delimiter if we have to */ + if (!found && (len > 0)) + len += snprintf(&buffer[len], buffer_len - len, ","); + + /* move to the next extension, appending the extension if not found */ + while(!is_delim(extension[extension_pos])) + { + if (!found) + len += snprintf(&buffer[len], buffer_len - len, "%c", extension[extension_pos]); + extension_pos++; + } + while(extension[extension_pos] == ',') + extension_pos++; + } + } +} |